Adding debian version 1:9.6p1-4.debian/1%9.6p1-4

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
author: Daniel Baumann <daniel.baumann@progress-linux.org> 2024-04-10 19:49:47 +0000
committer: Daniel Baumann <daniel.baumann@progress-linux.org> 2024-04-10 19:49:47 +0000
commit: 9c5dd847393c7c0f37ef557d7a0d402deedd8d2a (patch)
tree: dcb9b4740181f58a5d235e8ca52f9855494f486e /debian/patches
parent: Adding upstream version 1:9.6p1. (diff)
download: openssh-9c5dd847393c7c0f37ef557d7a0d402deedd8d2a.tar.xz
openssh-9c5dd847393c7c0f37ef557d7a0d402deedd8d2a.zip
29 files changed, 6938 insertions, 0 deletions
diff --git a/debian/patches/authorized-keys-man-symlink.patch b/debian/patches/authorized-keys-man-symlink.patch
new file mode 100644
index 0000000..beeafd6
--- /dev/null
+++ b/debian/patches/authorized-keys-man-symlink.patch
@@ -0,0 +1,26 @@
+From 9413092a071a763ffceb02b3df527032cdf74d71 Mon Sep 17 00:00:00 2001
+From: Tomas Pospisek <tpo_deb@sourcepole.ch>
+Date: Sun, 9 Feb 2014 16:10:07 +0000
+Subject: Install authorized_keys(5) as a symlink to sshd(8)
+
+Bug: https://bugzilla.mindrot.org/show_bug.cgi?id=1720
+Bug-Debian: http://bugs.debian.org/441817
+Last-Update: 2013-09-14
+
+Patch-Name: authorized-keys-man-symlink.patch
+---
+ Makefile.in | 1 +
+ 1 file changed, 1 insertion(+)
+
+diff --git a/Makefile.in b/Makefile.in
+index f9488099a..e0e45c9b9 100644
+--- a/Makefile.in
++++ b/Makefile.in
+@@ -415,6 +415,7 @@ install-files:
+ 	$(INSTALL) -m 644 sshd_config.5.out $(DESTDIR)$(mandir)/$(mansubdir)5/sshd_config.5
+ 	$(INSTALL) -m 644 ssh_config.5.out $(DESTDIR)$(mandir)/$(mansubdir)5/ssh_config.5
+ 	$(INSTALL) -m 644 sshd.8.out $(DESTDIR)$(mandir)/$(mansubdir)8/sshd.8
++	ln -s ../$(mansubdir)8/sshd.8 $(DESTDIR)$(mandir)/$(mansubdir)5/authorized_keys.5
+ 	$(INSTALL) -m 644 sftp.1.out $(DESTDIR)$(mandir)/$(mansubdir)1/sftp.1
+ 	$(INSTALL) -m 644 sftp-server.8.out $(DESTDIR)$(mandir)/$(mansubdir)8/sftp-server.8
+ 	$(INSTALL) -m 644 ssh-keysign.8.out $(DESTDIR)$(mandir)/$(mansubdir)8/ssh-keysign.8
diff --git a/debian/patches/broken-zero-call-used-regs.patch b/debian/patches/broken-zero-call-used-regs.patch
new file mode 100644
index 0000000..96449e1
--- /dev/null
+++ b/debian/patches/broken-zero-call-used-regs.patch
@@ -0,0 +1,46 @@
+From 66eb7a60b33a813422df2f9109aa328bd5027018 Mon Sep 17 00:00:00 2001
+From: Colin Watson <cjwatson@debian.org>
+Date: Thu, 21 Dec 2023 15:18:52 +0000
+Subject: Improve detection of broken -fzero-call-used-regs=used
+
+Origin: other, https://bugzilla.mindrot.org/attachment.cgi?id=3776&action=diff
+Bug: https://bugzilla.mindrot.org/show_bug.cgi?id=3645
+Last-Update: 2023-12-21
+
+Patch-Name: broken-zero-call-used-regs.patch
+---
+ m4/openssh.m4 | 12 +++++++++---
+ 1 file changed, 9 insertions(+), 3 deletions(-)
+
+diff --git a/m4/openssh.m4 b/m4/openssh.m4
+index 5d4c56280..033df501c 100644
+--- a/m4/openssh.m4
++++ b/m4/openssh.m4
+@@ -20,18 +20,24 @@ char *f2(char *s, ...) {
+ 	va_end(args);
+ 	return strdup(ret);
+ }
++const char *f3(int s) {
++	return s ? "good" : "gooder";
++}
+ int main(int argc, char **argv) {
+-	(void)argv;
+ 	char b[256], *cp;
++	const char *s;
+ 	/* Some math to catch -ftrapv problems in the toolchain */
+ 	int i = 123 * argc, j = 456 + argc, k = 789 - argc;
+ 	float l = i * 2.1;
+ 	double m = l / 0.5;
+ 	long long int n = argc * 12345LL, o = 12345LL * (long long int)argc;
++	(void)argv;
+ 	f(1);
+-	snprintf(b, sizeof b, "%d %d %d %f %f %lld %lld\n", i,j,k,l,m,n,o);
++	s = f3(f(2));
++	snprintf(b, sizeof b, "%d %d %d %f %f %lld %lld %s\n", i,j,k,l,m,n,o,s);
+ 	if (write(1, b, 0) == -1) exit(0);
+-	cp = f2("%d %d %d %f %f %lld %lld\n", i,j,k,l,m,n,o);
++	cp = f2("%d %d %d %f %f %lld %lld %s\n", i,j,k,l,m,n,o,s);
++	if (write(1, cp, 0) == -1) exit(0);
+ 	free(cp);
+ 	/*
+ 	 * Test fallthrough behaviour.  clang 10's -Wimplicit-fallthrough does
diff --git a/debian/patches/conch-ssh-rsa.patch b/debian/patches/conch-ssh-rsa.patch
new file mode 100644
index 0000000..4d913a0
--- /dev/null
+++ b/debian/patches/conch-ssh-rsa.patch
@@ -0,0 +1,42 @@
+From df5489f19fc05621a5902490692de3245528d424 Mon Sep 17 00:00:00 2001
+From: Colin Watson <cjwatson@debian.org>
+Date: Tue, 15 Feb 2022 18:25:35 +0000
+Subject: Work around RSA SHA-2 signature issues in conch
+
+This was supposed to be fixed in Twisted upstream
+(https://twistedmatrix.com/trac/ticket/9765), and that fix is in Debian
+now.  However, regression tests still seem to fail in GitLab CI but not
+locally (see e.g.
+https://salsa.debian.org/ssh-team/openssh/-/jobs/3513178).  Leave this
+in place for now until we figure out what's wrong.
+
+Forwarded: not-needed
+Last-Update: 2022-11-14
+
+Patch-Name: conch-ssh-rsa.patch
+---
+ regress/test-exec.sh | 11 +++++++++++
+ 1 file changed, 11 insertions(+)
+
+diff --git a/regress/test-exec.sh b/regress/test-exec.sh
+index 603848683..09d91e3b8 100644
+--- a/regress/test-exec.sh
++++ b/regress/test-exec.sh
+@@ -749,6 +749,17 @@ REGRESS_INTEROP_CONCH=no
+ if test -x "$CONCH" ; then
+ 	REGRESS_INTEROP_CONCH=yes
+ fi
++case "$SCRIPT" in
++*conch*)	;;
++*)		REGRESS_INTEROP_CONCH=no
++esac
++
++if test "$REGRESS_INTEROP_CONCH" = "yes" ; then
++	# Work around missing support for RSA SHA-2 signatures:
++	# https://twistedmatrix.com/trac/ticket/9765
++	echo HostKeyAlgorithms +ssh-rsa >> $OBJ/sshd_config
++	echo PubkeyAcceptedAlgorithms +ssh-rsa >> $OBJ/sshd_config
++fi
+ 
+ # If PuTTY is present, new enough and we are running a PuTTY test, prepare
+ # keys and configuration.
diff --git a/debian/patches/debian-banner.patch b/debian/patches/debian-banner.patch
new file mode 100644
index 0000000..94bee33
--- /dev/null
+++ b/debian/patches/debian-banner.patch
@@ -0,0 +1,170 @@
+From a3b95c8a438d7d8eff92c62e2b8ea18af5a56466 Mon Sep 17 00:00:00 2001
+From: Kees Cook <kees@debian.org>
+Date: Sun, 9 Feb 2014 16:10:06 +0000
+Subject: Add DebianBanner server configuration option
+
+Setting this to "no" causes sshd to omit the Debian revision from its
+initial protocol handshake, for those scared by package-versioning.patch.
+
+Bug-Debian: http://bugs.debian.org/562048
+Forwarded: not-needed
+Last-Update: 2023-12-18
+
+Patch-Name: debian-banner.patch
+---
+ kex.c         |  5 +++--
+ kex.h         |  2 +-
+ servconf.c    | 10 ++++++++++
+ servconf.h    |  2 ++
+ sshconnect.c  |  2 +-
+ sshd.c        |  2 +-
+ sshd_config.5 |  5 +++++
+ 7 files changed, 23 insertions(+), 5 deletions(-)
+
+diff --git a/kex.c b/kex.c
+index a532d8cb0..db6717e9f 100644
+--- a/kex.c
++++ b/kex.c
+@@ -1522,7 +1522,7 @@ send_error(struct ssh *ssh, char *msg)
+  */
+ int
+ kex_exchange_identification(struct ssh *ssh, int timeout_ms,
+-    const char *version_addendum)
++    int debian_banner, const char *version_addendum)
+ {
+ 	int remote_major, remote_minor, mismatch, oerrno = 0;
+ 	size_t len, n;
+@@ -1540,7 +1540,8 @@ kex_exchange_identification(struct ssh *ssh, int timeout_ms,
+ 	if (version_addendum != NULL && *version_addendum == '\0')
+ 		version_addendum = NULL;
+ 	if ((r = sshbuf_putf(our_version, "SSH-%d.%d-%s%s%s\r\n",
+-	    PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2, SSH_RELEASE,
++	    PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2,
++	    debian_banner ? SSH_RELEASE : SSH_RELEASE_MINIMUM,
+ 	    version_addendum == NULL ? "" : " ",
+ 	    version_addendum == NULL ? "" : version_addendum)) != 0) {
+ 		oerrno = errno;
+diff --git a/kex.h b/kex.h
+index faee60f16..4aff3b756 100644
+--- a/kex.h
++++ b/kex.h
+@@ -208,7 +208,7 @@ void	 kex_proposal_populate_entries(struct ssh *, char *prop[PROPOSAL_MAX],
+ void	 kex_proposal_free_entries(char *prop[PROPOSAL_MAX]);
+ int	 kex_gss_names_valid(const char *);
+ 
+-int	 kex_exchange_identification(struct ssh *, int, const char *);
++int	 kex_exchange_identification(struct ssh *, int, int, const char *);
+ 
+ struct kex *kex_new(void);
+ int	 kex_ready(struct ssh *, char *[PROPOSAL_MAX]);
+diff --git a/servconf.c b/servconf.c
+index b61295758..cecbef9a1 100644
+--- a/servconf.c
++++ b/servconf.c
+@@ -201,6 +201,7 @@ initialize_server_options(ServerOptions *options)
+ 	options->channel_timeouts = NULL;
+ 	options->num_channel_timeouts = 0;
+ 	options->unused_connection_timeout = -1;
++	options->debian_banner = -1;
+ }
+ 
+ /* Returns 1 if a string option is unset or set to "none" or 0 otherwise. */
+@@ -459,6 +460,8 @@ fill_default_server_options(ServerOptions *options)
+ 		options->required_rsa_size = SSH_RSA_MINIMUM_MODULUS_SIZE;
+ 	if (options->unused_connection_timeout == -1)
+ 		options->unused_connection_timeout = 0;
++	if (options->debian_banner == -1)
++		options->debian_banner = 1;
+ 
+ 	assemble_algorithms(options);
+ 
+@@ -544,6 +547,7 @@ typedef enum {
+ 	sAllowStreamLocalForwarding, sFingerprintHash, sDisableForwarding,
+ 	sExposeAuthInfo, sRDomain, sPubkeyAuthOptions, sSecurityKeyProvider,
+ 	sRequiredRSASize, sChannelTimeout, sUnusedConnectionTimeout,
++	sDebianBanner,
+ 	sDeprecated, sIgnore, sUnsupported
+ } ServerOpCodes;
+ 
+@@ -717,6 +721,7 @@ static struct {
+ 	{ "requiredrsasize", sRequiredRSASize, SSHCFG_ALL },
+ 	{ "channeltimeout", sChannelTimeout, SSHCFG_ALL },
+ 	{ "unusedconnectiontimeout", sUnusedConnectionTimeout, SSHCFG_ALL },
++	{ "debianbanner", sDebianBanner, SSHCFG_GLOBAL },
+ 	{ NULL, sBadOption, 0 }
+ };
+ 
+@@ -2584,6 +2589,10 @@ process_server_config_line_depth(ServerOptions *options, char *line,
+ 		}
+ 		goto parse_time;
+ 
++	case sDebianBanner:
++		intptr = &options->debian_banner;
++		goto parse_flag;
++
+ 	case sDeprecated:
+ 	case sIgnore:
+ 	case sUnsupported:
+@@ -3131,6 +3140,7 @@ dump_config(ServerOptions *o)
+ 	dump_cfg_fmtint(sStreamLocalBindUnlink, o->fwd_opts.streamlocal_bind_unlink);
+ 	dump_cfg_fmtint(sFingerprintHash, o->fingerprint_hash);
+ 	dump_cfg_fmtint(sExposeAuthInfo, o->expose_userauth_info);
++	dump_cfg_fmtint(sDebianBanner, o->debian_banner);
+ 
+ 	/* string arguments */
+ 	dump_cfg_string(sPidFile, o->pid_file);
+diff --git a/servconf.h b/servconf.h
+index 2ce4ae0ad..e0c0af903 100644
+--- a/servconf.h
++++ b/servconf.h
+@@ -236,6 +236,8 @@ typedef struct {
+ 	u_int	num_channel_timeouts;
+ 
+ 	int	unused_connection_timeout;
++
++	int	debian_banner;
+ }       ServerOptions;
+ 
+ /* Information about the incoming connection as used by Match */
+diff --git a/sshconnect.c b/sshconnect.c
+index f3096cad9..ccccb4a52 100644
+--- a/sshconnect.c
++++ b/sshconnect.c
+@@ -1581,7 +1581,7 @@ ssh_login(struct ssh *ssh, Sensitive *sensitive, const char *orighost,
+ 	lowercase(host);
+ 
+ 	/* Exchange protocol version identification strings with the server. */
+-	if ((r = kex_exchange_identification(ssh, timeout_ms, NULL)) != 0)
++	if ((r = kex_exchange_identification(ssh, timeout_ms, 1, NULL)) != 0)
+ 		sshpkt_fatal(ssh, r, "banner exchange");
+ 
+ 	/* Put the connection into non-blocking mode. */
+diff --git a/sshd.c b/sshd.c
+index 1895a9972..d56ba490b 100644
+--- a/sshd.c
++++ b/sshd.c
+@@ -2249,7 +2249,7 @@ main(int ac, char **av)
+ 	if (!debug_flag)
+ 		alarm(options.login_grace_time);
+ 
+-	if ((r = kex_exchange_identification(ssh, -1,
++	if ((r = kex_exchange_identification(ssh, -1, options.debian_banner,
+ 	    options.version_addendum)) != 0)
+ 		sshpkt_fatal(ssh, r, "banner exchange");
+ 
+diff --git a/sshd_config.5 b/sshd_config.5
+index 5de2fd8cf..630c18736 100644
+--- a/sshd_config.5
++++ b/sshd_config.5
+@@ -621,6 +621,11 @@ or
+ .Cm no .
+ The default is
+ .Cm yes .
++.It Cm DebianBanner
++Specifies whether the distribution-specified extra version suffix is
++included during initial protocol handshake.
++The default is
++.Cm yes .
+ .It Cm DenyGroups
+ This keyword can be followed by a list of group name patterns, separated
+ by spaces.
diff --git a/debian/patches/debian-config.patch b/debian/patches/debian-config.patch
new file mode 100644
index 0000000..eb1f35b
--- /dev/null
+++ b/debian/patches/debian-config.patch
@@ -0,0 +1,285 @@
+From c9eb9a51710efba1a6a6d344557c6a6b9c4e7866 Mon Sep 17 00:00:00 2001
+From: Colin Watson <cjwatson@debian.org>
+Date: Sun, 9 Feb 2014 16:10:18 +0000
+Subject: Various Debian-specific configuration changes
+
+ssh: Enable ForwardX11Trusted, returning to earlier semantics which cause
+fewer problems with existing setups (http://bugs.debian.org/237021).
+
+ssh: Set 'SendEnv LANG LC_*' by default (http://bugs.debian.org/264024).
+
+ssh: Enable HashKnownHosts by default to try to limit the spread of ssh
+worms.
+
+ssh: Enable GSSAPIAuthentication by default.
+
+ssh: Include /etc/ssh/ssh_config.d/*.conf.
+
+sshd: Enable PAM, disable KbdInteractiveAuthentication, and disable
+PrintMotd.
+
+sshd: Enable X11Forwarding.
+
+sshd: Set 'AcceptEnv LANG LC_*' by default.
+
+sshd: Change sftp subsystem path to /usr/lib/openssh/sftp-server.
+
+sshd: Include /etc/ssh/sshd_config.d/*.conf.
+
+regress: Run tests with 'UsePAM yes', to match sshd_config.
+
+Document all of this.
+
+Author: Russ Allbery <rra@debian.org>
+Forwarded: not-needed
+Last-Update: 2023-01-03
+
+Patch-Name: debian-config.patch
+---
+ readconf.c           |  2 +-
+ regress/test-exec.sh |  1 +
+ ssh.1                | 24 ++++++++++++++++++++++++
+ ssh_config           |  8 +++++++-
+ ssh_config.5         | 26 +++++++++++++++++++++++++-
+ sshd_config          | 18 ++++++++++++------
+ sshd_config.5        | 29 +++++++++++++++++++++++++++++
+ 7 files changed, 99 insertions(+), 9 deletions(-)
+
+diff --git a/readconf.c b/readconf.c
+index 6cf3612e7..2e6d3e726 100644
+--- a/readconf.c
++++ b/readconf.c
+@@ -2702,7 +2702,7 @@ fill_default_options(Options * options)
+ 	if (options->forward_x11 == -1)
+ 		options->forward_x11 = 0;
+ 	if (options->forward_x11_trusted == -1)
+-		options->forward_x11_trusted = 0;
++		options->forward_x11_trusted = 1;
+ 	if (options->forward_x11_timeout == -1)
+ 		options->forward_x11_timeout = 1200;
+ 	/*
+diff --git a/regress/test-exec.sh b/regress/test-exec.sh
+index 089ef73c4..603848683 100644
+--- a/regress/test-exec.sh
++++ b/regress/test-exec.sh
+@@ -606,6 +606,7 @@ cat << EOF > $OBJ/sshd_config
+ 	AcceptEnv		_XXX_TEST_*
+ 	AcceptEnv		_XXX_TEST
+ 	Subsystem	sftp	$SFTPSERVER
++	UsePAM			yes
+ EOF
+ 
+ # This may be necessary if /usr/src and/or /usr/obj are group-writable,
+diff --git a/ssh.1 b/ssh.1
+index 0d56f3dc1..ddfe75b95 100644
+--- a/ssh.1
++++ b/ssh.1
+@@ -861,6 +861,16 @@ directive in
+ .Xr ssh_config 5
+ for more information.
+ .Pp
++(Debian-specific: X11 forwarding is not subjected to X11 SECURITY extension
++restrictions by default, because too many programs currently crash in this
++mode.
++Set the
++.Cm ForwardX11Trusted
++option to
++.Dq no
++to restore the upstream behaviour.
++This may change in future depending on client-side improvements.)
++.Pp
+ .It Fl x
+ Disables X11 forwarding.
+ .Pp
+@@ -869,6 +879,20 @@ Enables trusted X11 forwarding.
+ Trusted X11 forwardings are not subjected to the X11 SECURITY extension
+ controls.
+ .Pp
++(Debian-specific: In the default configuration, this option is equivalent to
++.Fl X ,
++since
++.Cm ForwardX11Trusted
++defaults to
++.Dq yes
++as described above.
++Set the
++.Cm ForwardX11Trusted
++option to
++.Dq no
++to restore the upstream behaviour.
++This may change in future depending on client-side improvements.)
++.Pp
+ .It Fl y
+ Send log information using the
+ .Xr syslog 3
+diff --git a/ssh_config b/ssh_config
+index 16197d15d..92d06ef38 100644
+--- a/ssh_config
++++ b/ssh_config
+@@ -17,9 +17,12 @@
+ # list of available options, their meanings and defaults, please see the
+ # ssh_config(5) man page.
+ 
+-# Host *
++Include /etc/ssh/ssh_config.d/*.conf
++
++Host *
+ #   ForwardAgent no
+ #   ForwardX11 no
++#   ForwardX11Trusted yes
+ #   PasswordAuthentication yes
+ #   HostbasedAuthentication no
+ #   GSSAPIAuthentication no
+@@ -46,3 +49,6 @@
+ #   ProxyCommand ssh -q -W %h:%p gateway.example.com
+ #   RekeyLimit 1G 1h
+ #   UserKnownHostsFile ~/.ssh/known_hosts.d/%k
++    SendEnv LANG LC_*
++    HashKnownHosts yes
++    GSSAPIAuthentication yes
+diff --git a/ssh_config.5 b/ssh_config.5
+index 943260617..4ec34d1a3 100644
+--- a/ssh_config.5
++++ b/ssh_config.5
+@@ -71,6 +71,29 @@ Since the first obtained value for each parameter is used, more
+ host-specific declarations should be given near the beginning of the
+ file, and general defaults at the end.
+ .Pp
++Note that the Debian
++.Ic openssh-client
++package sets several options as standard in
++.Pa /etc/ssh/ssh_config
++which are not the default in
++.Xr ssh 1 :
++.Pp
++.Bl -bullet -offset indent -compact
++.It
++.Cm Include /etc/ssh/ssh_config.d/*.conf
++.It
++.Cm SendEnv No LANG LC_*
++.It
++.Cm HashKnownHosts No yes
++.It
++.Cm GSSAPIAuthentication No yes
++.El
++.Pp
++.Pa /etc/ssh/ssh_config.d/*.conf
++files are included at the start of the system-wide configuration file, so
++options set there will override those in
++.Pa /etc/ssh/ssh_config.
++.Pp
+ The file contains keyword-argument pairs, one per line.
+ Lines starting with
+ .Ql #
+@@ -891,11 +914,12 @@ elapsed.
+ .It Cm ForwardX11Trusted
+ If this option is set to
+ .Cm yes ,
++(the Debian-specific default),
+ remote X11 clients will have full access to the original X11 display.
+ .Pp
+ If this option is set to
+ .Cm no
+-(the default),
++(the upstream default),
+ remote X11 clients will be considered untrusted and prevented
+ from stealing or tampering with data belonging to trusted X11
+ clients.
+diff --git a/sshd_config b/sshd_config
+index ecfe8d026..677f97d5d 100644
+--- a/sshd_config
++++ b/sshd_config
+@@ -10,6 +10,8 @@
+ # possible, but leave them commented.  Uncommented options override the
+ # default value.
+ 
++Include /etc/ssh/sshd_config.d/*.conf
++
+ #Port 22
+ #AddressFamily any
+ #ListenAddress 0.0.0.0
+@@ -57,8 +59,9 @@ AuthorizedKeysFile	.ssh/authorized_keys
+ #PasswordAuthentication yes
+ #PermitEmptyPasswords no
+ 
+-# Change to no to disable s/key passwords
+-#KbdInteractiveAuthentication yes
++# Change to yes to enable challenge-response passwords (beware issues with
++# some PAM modules and threads)
++KbdInteractiveAuthentication no
+ 
+ # Kerberos options
+ #KerberosAuthentication no
+@@ -81,16 +84,16 @@ AuthorizedKeysFile	.ssh/authorized_keys
+ # If you just want the PAM account and session checks to run without
+ # PAM authentication, then enable this but set PasswordAuthentication
+ # and KbdInteractiveAuthentication to 'no'.
+-#UsePAM no
++UsePAM yes
+ 
+ #AllowAgentForwarding yes
+ #AllowTcpForwarding yes
+ #GatewayPorts no
+-#X11Forwarding no
++X11Forwarding yes
+ #X11DisplayOffset 10
+ #X11UseLocalhost yes
+ #PermitTTY yes
+-#PrintMotd yes
++PrintMotd no
+ #PrintLastLog yes
+ #TCPKeepAlive yes
+ #PermitUserEnvironment no
+@@ -107,8 +110,11 @@ AuthorizedKeysFile	.ssh/authorized_keys
+ # no default banner path
+ #Banner none
+ 
++# Allow client to pass locale environment variables
++AcceptEnv LANG LC_*
++
+ # override default of no subsystems
+-Subsystem	sftp	/usr/libexec/sftp-server
++Subsystem	sftp	/usr/lib/openssh/sftp-server
+ 
+ # Example of overriding settings on a per-user basis
+ #Match User anoncvs
+diff --git a/sshd_config.5 b/sshd_config.5
+index 98bd201b0..d0bf6d641 100644
+--- a/sshd_config.5
++++ b/sshd_config.5
+@@ -56,6 +56,35 @@ Arguments may optionally be enclosed in double quotes
+ .Pq \&"
+ in order to represent arguments containing spaces.
+ .Pp
++Note that the Debian
++.Ic openssh-server
++package sets several options as standard in
++.Pa /etc/ssh/sshd_config
++which are not the default in
++.Xr sshd 8 :
++.Pp
++.Bl -bullet -offset indent -compact
++.It
++.Cm Include /etc/ssh/sshd_config.d/*.conf
++.It
++.Cm KbdInteractiveAuthentication No no
++.It
++.Cm X11Forwarding No yes
++.It
++.Cm PrintMotd No no
++.It
++.Cm AcceptEnv No LANG LC_*
++.It
++.Cm Subsystem No sftp /usr/lib/openssh/sftp-server
++.It
++.Cm UsePAM No yes
++.El
++.Pp
++.Pa /etc/ssh/sshd_config.d/*.conf
++files are included at the start of the configuration file, so options set
++there will override those in
++.Pa /etc/ssh/sshd_config.
++.Pp
+ The possible
+ keywords and their meanings are as follows (note that
+ keywords are case-insensitive and arguments are case-sensitive):
diff --git a/debian/patches/dnssec-sshfp.patch b/debian/patches/dnssec-sshfp.patch
new file mode 100644
index 0000000..90bf812
--- /dev/null
+++ b/debian/patches/dnssec-sshfp.patch
@@ -0,0 +1,94 @@
+From bdf9d563e4ecfcf17de88d67df844af469c3d77e Mon Sep 17 00:00:00 2001
+From: Colin Watson <cjwatson@debian.org>
+Date: Sun, 9 Feb 2014 16:10:01 +0000
+Subject: Force use of DNSSEC even if "options edns0" isn't in resolv.conf
+
+This allows SSHFP DNS records to be verified if glibc 2.11 is installed.
+
+Origin: vendor, https://cvs.fedoraproject.org/viewvc/F-12/openssh/openssh-5.2p1-edns.patch?revision=1.1&view=markup
+Bug: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=572049
+Bug-Debian: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=572049
+Last-Update: 2023-06-19
+
+Patch-Name: dnssec-sshfp.patch
+---
+ dns.c                           | 14 +++++++++++++-
+ openbsd-compat/getrrsetbyname.c | 10 +++++-----
+ openbsd-compat/getrrsetbyname.h |  3 +++
+ 3 files changed, 21 insertions(+), 6 deletions(-)
+
+diff --git a/dns.c b/dns.c
+index 939241440..bf47a079f 100644
+--- a/dns.c
++++ b/dns.c
+@@ -198,6 +198,7 @@ verify_host_key_dns(const char *hostname, struct sockaddr *address,
+ {
+ 	u_int counter;
+ 	int result;
++	unsigned int rrset_flags = 0;
+ 	struct rrsetinfo *fingerprints = NULL;
+ 
+ 	u_int8_t hostkey_algorithm;
+@@ -220,8 +221,19 @@ verify_host_key_dns(const char *hostname, struct sockaddr *address,
+ 		return -1;
+ 	}
+ 
++	/*
++	 * Original getrrsetbyname function, found on OpenBSD for example,
++	 * doesn't accept any flag and prerequisite for obtaining AD bit in
++	 * DNS response is set by "options edns0" in resolv.conf.
++	 *
++	 * Our version is more clever and use RRSET_FORCE_EDNS0 flag.
++	 */
++#ifndef HAVE_GETRRSETBYNAME
++	rrset_flags |= RRSET_FORCE_EDNS0;
++#endif
+ 	result = getrrsetbyname(hostname, DNS_RDATACLASS_IN,
+-	    DNS_RDATATYPE_SSHFP, 0, &fingerprints);
++	    DNS_RDATATYPE_SSHFP, rrset_flags, &fingerprints);
++
+ 	if (result) {
+ 		verbose("DNS lookup error: %s", dns_result_totext(result));
+ 		return -1;
+diff --git a/openbsd-compat/getrrsetbyname.c b/openbsd-compat/getrrsetbyname.c
+index 8f5939840..6091a2591 100644
+--- a/openbsd-compat/getrrsetbyname.c
++++ b/openbsd-compat/getrrsetbyname.c
+@@ -214,8 +214,8 @@ getrrsetbyname(const char *hostname, unsigned int rdclass,
+ 		goto fail;
+ 	}
+ 
+-	/* don't allow flags yet, unimplemented */
+-	if (flags) {
++	/* Allow RRSET_FORCE_EDNS0 flag only. */
++	if ((flags & ~RRSET_FORCE_EDNS0) != 0) {
+ 		result = ERRSET_INVAL;
+ 		goto fail;
+ 	}
+@@ -231,9 +231,9 @@ getrrsetbyname(const char *hostname, unsigned int rdclass,
+ #endif /* DEBUG */
+ 
+ #ifdef RES_USE_DNSSEC
+-	/* turn on DNSSEC if EDNS0 is configured */
+-	if (_resp->options & RES_USE_EDNS0)
+-		_resp->options |= RES_USE_DNSSEC;
++	/* turn on DNSSEC if required  */
++	if (flags & RRSET_FORCE_EDNS0)
++		_resp->options |= (RES_USE_EDNS0|RES_USE_DNSSEC);
+ #endif /* RES_USE_DNSEC */
+ 
+ 	/* make query */
+diff --git a/openbsd-compat/getrrsetbyname.h b/openbsd-compat/getrrsetbyname.h
+index 1283f5506..dbbc85a2a 100644
+--- a/openbsd-compat/getrrsetbyname.h
++++ b/openbsd-compat/getrrsetbyname.h
+@@ -72,6 +72,9 @@
+ #ifndef RRSET_VALIDATED
+ # define RRSET_VALIDATED	1
+ #endif
++#ifndef RRSET_FORCE_EDNS0
++# define RRSET_FORCE_EDNS0	0x0001
++#endif
+ 
+ /*
+  * Return codes for getrrsetbyname()
diff --git a/debian/patches/doc-hash-tab-completion.patch b/debian/patches/doc-hash-tab-completion.patch
new file mode 100644
index 0000000..ba7559f
--- /dev/null
+++ b/debian/patches/doc-hash-tab-completion.patch
@@ -0,0 +1,28 @@
+From 395ff5777853680af3372975add24fde69399ba3 Mon Sep 17 00:00:00 2001
+From: Colin Watson <cjwatson@debian.org>
+Date: Sun, 9 Feb 2014 16:10:11 +0000
+Subject: Document that HashKnownHosts may break tab-completion
+
+Bug: https://bugzilla.mindrot.org/show_bug.cgi?id=1727
+Bug-Debian: http://bugs.debian.org/430154
+Last-Update: 2021-11-05
+
+Patch-Name: doc-hash-tab-completion.patch
+---
+ ssh_config.5 | 3 +++
+ 1 file changed, 3 insertions(+)
+
+diff --git a/ssh_config.5 b/ssh_config.5
+index bebfe1cee..943260617 100644
+--- a/ssh_config.5
++++ b/ssh_config.5
+@@ -1010,6 +1010,9 @@ Note that existing names and addresses in known hosts files
+ will not be converted automatically,
+ but may be manually hashed using
+ .Xr ssh-keygen 1 .
++Use of this option may break facilities such as tab-completion that rely
++on being able to read unhashed host names from
++.Pa ~/.ssh/known_hosts .
+ .It Cm HostbasedAcceptedAlgorithms
+ Specifies the signature algorithms that will be used for hostbased
+ authentication as a comma-separated list of patterns.
diff --git a/debian/patches/gnome-ssh-askpass2-icon.patch b/debian/patches/gnome-ssh-askpass2-icon.patch
new file mode 100644
index 0000000..21a5115
--- /dev/null
+++ b/debian/patches/gnome-ssh-askpass2-icon.patch
@@ -0,0 +1,26 @@
+From 872a2374d3af341b9cf1c76b3d009f715f6220fb Mon Sep 17 00:00:00 2001
+From: Vincent Untz <vuntz@ubuntu.com>
+Date: Sun, 9 Feb 2014 16:10:16 +0000
+Subject: Give the ssh-askpass-gnome window a default icon
+
+Bug-Ubuntu: https://bugs.launchpad.net/bugs/27152
+Last-Update: 2010-02-28
+
+Patch-Name: gnome-ssh-askpass2-icon.patch
+---
+ contrib/gnome-ssh-askpass2.c | 2 ++
+ 1 file changed, 2 insertions(+)
+
+diff --git a/contrib/gnome-ssh-askpass2.c b/contrib/gnome-ssh-askpass2.c
+index a62f98152..304569802 100644
+--- a/contrib/gnome-ssh-askpass2.c
++++ b/contrib/gnome-ssh-askpass2.c
+@@ -320,6 +320,8 @@ main(int argc, char **argv)
+ 
+ 	gtk_init(&argc, &argv);
+ 
++	gtk_window_set_default_icon_from_file ("/usr/share/pixmaps/ssh-askpass-gnome.png", NULL);
++
+ 	if (argc > 1) {
+ 		message = g_strjoinv(" ", argv + 1);
+ 	} else {
diff --git a/debian/patches/gssapi.patch b/debian/patches/gssapi.patch
new file mode 100644
index 0000000..0590558
--- /dev/null
+++ b/debian/patches/gssapi.patch
@@ -0,0 +1,4168 @@
+From cabc0eedcbd5c1aa3e09c56968ecdc8b47317c37 Mon Sep 17 00:00:00 2001
+From: Simon Wilkinson <simon@sxw.org.uk>
+Date: Sun, 9 Feb 2014 16:09:48 +0000
+Subject: GSSAPI key exchange support
+
+This patch has been rejected upstream: "None of the OpenSSH developers are
+in favour of adding this, and this situation has not changed for several
+years.  This is not a slight on Simon's patch, which is of fine quality, but
+just that a) we don't trust GSSAPI implementations that much and b) we don't
+like adding new KEX since they are pre-auth attack surface.  This one is
+particularly scary, since it requires hooks out to typically root-owned
+system resources."
+
+However, quite a lot of people rely on this in Debian, and it's better to
+have it merged into the main openssh package rather than having separate
+-krb5 packages (as we used to have).  It seems to have a generally good
+security history.
+
+Author: Simon Wilkinson <simon@sxw.org.uk>
+Author: Colin Watson <cjwatson@debian.org>
+Author: Jakub Jelen <jjelen@redhat.com>
+Origin: other, https://github.com/openssh-gsskex/openssh-gsskex/pull/23
+Bug: https://bugzilla.mindrot.org/show_bug.cgi?id=1242
+Last-Updated: 2023-12-18
+
+Patch-Name: gssapi.patch
+---
+ Makefile.in     |   5 +-
+ README.md       |  36 +++
+ auth.c          |  94 +-------
+ auth2-gss.c     |  56 ++++-
+ auth2.c         |   2 +
+ canohost.c      |  91 ++++++++
+ canohost.h      |   3 +
+ clientloop.c    |  13 ++
+ configure.ac    |  24 ++
+ gss-genr.c      | 297 +++++++++++++++++++++++-
+ gss-serv-krb5.c |  87 ++++++-
+ gss-serv.c      | 205 +++++++++++++++--
+ kex.c           |  66 +++++-
+ kex.h           |  29 +++
+ kexdh.c         |  10 +
+ kexgen.c        |   2 +-
+ kexgssc.c       | 602 ++++++++++++++++++++++++++++++++++++++++++++++++
+ kexgsss.c       | 478 ++++++++++++++++++++++++++++++++++++++
+ monitor.c       | 139 ++++++++++-
+ monitor.h       |   2 +
+ monitor_wrap.c  |  57 ++++-
+ monitor_wrap.h  |   4 +-
+ readconf.c      |  74 ++++++
+ readconf.h      |   6 +
+ servconf.c      |  47 ++++
+ servconf.h      |   3 +
+ session.c       |  10 +-
+ ssh-gss.h       |  54 ++++-
+ ssh-null.c      | 108 +++++++++
+ ssh.1           |   8 +
+ ssh.c           |   6 +-
+ ssh_config      |   2 +
+ ssh_config.5    |  57 +++++
+ sshconnect2.c   | 156 ++++++++++++-
+ sshd.c          |  62 ++++-
+ sshd_config     |   2 +
+ sshd_config.5   |  30 +++
+ sshkey.c        |   8 +-
+ sshkey.h        |   1 +
+ 39 files changed, 2772 insertions(+), 164 deletions(-)
+ create mode 100644 kexgssc.c
+ create mode 100644 kexgsss.c
+ create mode 100644 ssh-null.c
+
+diff --git a/Makefile.in b/Makefile.in
+index 1efe11f6f..f9488099a 100644
+--- a/Makefile.in
++++ b/Makefile.in
+@@ -101,7 +101,7 @@ LIBSSH_OBJS=${LIBOPENSSH_OBJS} \
+ 	readpass.o ttymodes.o xmalloc.o addr.o addrmatch.o \
+ 	atomicio.o dispatch.o mac.o misc.o utf8.o \
+ 	monitor_fdpass.o rijndael.o ssh-dss.o ssh-ecdsa.o ssh-ecdsa-sk.o \
+-	ssh-ed25519-sk.o ssh-rsa.o dh.o \
++	ssh-ed25519-sk.o ssh-rsa.o ssh-null.o dh.o \
+ 	msg.o progressmeter.o dns.o entropy.o gss-genr.o umac.o umac128.o \
+ 	ssh-pkcs11.o smult_curve25519_ref.o \
+ 	poly1305.o chacha.o cipher-chachapoly.o cipher-chachapoly-libcrypto.o \
+@@ -110,6 +110,7 @@ LIBSSH_OBJS=${LIBOPENSSH_OBJS} \
+ 	kex.o kexdh.o kexgex.o kexecdh.o kexc25519.o \
+ 	kexgexc.o kexgexs.o \
+ 	kexsntrup761x25519.o sntrup761.o kexgen.o \
++	kexgssc.o \
+ 	sftp-realpath.o platform-pledge.o platform-tracing.o platform-misc.o \
+ 	sshbuf-io.o
+ 
+@@ -126,7 +127,7 @@ SSHDOBJS=sshd.o auth-rhosts.o auth-passwd.o \
+ 	auth-bsdauth.o auth2-hostbased.o auth2-kbdint.o \
+ 	auth2-none.o auth2-passwd.o auth2-pubkey.o auth2-pubkeyfile.o \
+ 	monitor.o monitor_wrap.o auth-krb5.o \
+-	auth2-gss.o gss-serv.o gss-serv-krb5.o \
++	auth2-gss.o gss-serv.o gss-serv-krb5.o kexgsss.o \
+ 	loginrec.o auth-pam.o auth-shadow.o auth-sia.o \
+ 	srclimit.o sftp-server.o sftp-common.o \
+ 	sandbox-null.o sandbox-rlimit.o sandbox-systrace.o sandbox-darwin.o \
+diff --git a/README.md b/README.md
+index 9431b0ffd..e5051828c 100644
+--- a/README.md
++++ b/README.md
+@@ -1,3 +1,39 @@
++Portable OpenSSH with GSSAPI Key Exchange patches
++=================================================
++
++[![Language grade: C/C++](https://img.shields.io/lgtm/grade/cpp/g/openssh-gsskex/openssh-gsskex.svg?logo=lgtm&logoWidth=18)](https://lgtm.com/projects/g/openssh-gsskex/openssh-gsskex/context:cpp)
++
++Currently, there are two branches with gssapi key exchange related
++patches:
++
++ * fedora/master: Changes that are shipped in Fedora [![Build Status](https://travis-ci.org/openssh-gsskex/openssh-gsskex.svg?branch=fedora%2Fmaster)](https://travis-ci.org/openssh-gsskex/openssh-gsskex)
++ * debian/master: Changes that are shipped in Debian [![Build Status](https://travis-ci.org/openssh-gsskex/openssh-gsskex.svg?branch=debian%2Fmaster)](https://travis-ci.org/openssh-gsskex/openssh-gsskex)
++
++The target is to converge to a shared repository with single master
++branch from where we could build releases for both OSes.
++
++
++What is in:
++
++ * The original patch implementing missing parts of RFC4462 by Simon Wilkinson
++   adapted to the current OpenSSH versions and with several fixes
++ * New methods for GSSAPI Kex from IETF draft [1] from Jakub Jelen
++
++
++Missing kerberos-related parts:
++
++ * .k5login and .kusers support available in Fedora [2] [3].
++ * Improved handling of kerberos ccache location [4]
++
++
++
++[1] https://tools.ietf.org/html/draft-ietf-curdle-gss-keyex-sha2-08
++[2] https://src.fedoraproject.org/rpms/openssh/blob/master/f/openssh-6.6p1-kuserok.patch
++[3] https://src.fedoraproject.org/rpms/openssh/blob/master/f/openssh-6.6p1-GSSAPIEnablek5users.patch
++[4] https://bugzilla.mindrot.org/show_bug.cgi?id=2775
++
++-------------------------------------------------------------------------------
++
+ # Portable OpenSSH
+ 
+ [![C/C++ CI](https://github.com/openssh/openssh-portable/actions/workflows/c-cpp.yml/badge.svg)](https://github.com/openssh/openssh-portable/actions/workflows/c-cpp.yml)
+diff --git a/auth.c b/auth.c
+index 3b380d9bb..8ccf06370 100644
+--- a/auth.c
++++ b/auth.c
+@@ -357,7 +357,8 @@ auth_root_allowed(struct ssh *ssh, const char *method)
+ 	case PERMIT_NO_PASSWD:
+ 		if (strcmp(method, "publickey") == 0 ||
+ 		    strcmp(method, "hostbased") == 0 ||
+-		    strcmp(method, "gssapi-with-mic") == 0)
++		    strcmp(method, "gssapi-with-mic") == 0 ||
++		    strcmp(method, "gssapi-keyex") == 0)
+ 			return 1;
+ 		break;
+ 	case PERMIT_FORCED_ONLY:
+@@ -637,97 +638,6 @@ fakepw(void)
+ 	return (&fake);
+ }
+ 
+-/*
+- * Returns the remote DNS hostname as a string. The returned string must not
+- * be freed. NB. this will usually trigger a DNS query the first time it is
+- * called.
+- * This function does additional checks on the hostname to mitigate some
+- * attacks on based on conflation of hostnames and IP addresses.
+- */
+-
+-static char *
+-remote_hostname(struct ssh *ssh)
+-{
+-	struct sockaddr_storage from;
+-	socklen_t fromlen;
+-	struct addrinfo hints, *ai, *aitop;
+-	char name[NI_MAXHOST], ntop2[NI_MAXHOST];
+-	const char *ntop = ssh_remote_ipaddr(ssh);
+-
+-	/* Get IP address of client. */
+-	fromlen = sizeof(from);
+-	memset(&from, 0, sizeof(from));
+-	if (getpeername(ssh_packet_get_connection_in(ssh),
+-	    (struct sockaddr *)&from, &fromlen) == -1) {
+-		debug("getpeername failed: %.100s", strerror(errno));
+-		return xstrdup(ntop);
+-	}
+-
+-	ipv64_normalise_mapped(&from, &fromlen);
+-	if (from.ss_family == AF_INET6)
+-		fromlen = sizeof(struct sockaddr_in6);
+-
+-	debug3("Trying to reverse map address %.100s.", ntop);
+-	/* Map the IP address to a host name. */
+-	if (getnameinfo((struct sockaddr *)&from, fromlen, name, sizeof(name),
+-	    NULL, 0, NI_NAMEREQD) != 0) {
+-		/* Host name not found.  Use ip address. */
+-		return xstrdup(ntop);
+-	}
+-
+-	/*
+-	 * if reverse lookup result looks like a numeric hostname,
+-	 * someone is trying to trick us by PTR record like following:
+-	 *	1.1.1.10.in-addr.arpa.	IN PTR	2.3.4.5
+-	 */
+-	memset(&hints, 0, sizeof(hints));
+-	hints.ai_socktype = SOCK_DGRAM;	/*dummy*/
+-	hints.ai_flags = AI_NUMERICHOST;
+-	if (getaddrinfo(name, NULL, &hints, &ai) == 0) {
+-		logit("Nasty PTR record \"%s\" is set up for %s, ignoring",
+-		    name, ntop);
+-		freeaddrinfo(ai);
+-		return xstrdup(ntop);
+-	}
+-
+-	/* Names are stored in lowercase. */
+-	lowercase(name);
+-
+-	/*
+-	 * Map it back to an IP address and check that the given
+-	 * address actually is an address of this host.  This is
+-	 * necessary because anyone with access to a name server can
+-	 * define arbitrary names for an IP address. Mapping from
+-	 * name to IP address can be trusted better (but can still be
+-	 * fooled if the intruder has access to the name server of
+-	 * the domain).
+-	 */
+-	memset(&hints, 0, sizeof(hints));
+-	hints.ai_family = from.ss_family;
+-	hints.ai_socktype = SOCK_STREAM;
+-	if (getaddrinfo(name, NULL, &hints, &aitop) != 0) {
+-		logit("reverse mapping checking getaddrinfo for %.700s "
+-		    "[%s] failed.", name, ntop);
+-		return xstrdup(ntop);
+-	}
+-	/* Look for the address from the list of addresses. */
+-	for (ai = aitop; ai; ai = ai->ai_next) {
+-		if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop2,
+-		    sizeof(ntop2), NULL, 0, NI_NUMERICHOST) == 0 &&
+-		    (strcmp(ntop, ntop2) == 0))
+-				break;
+-	}
+-	freeaddrinfo(aitop);
+-	/* If we reached the end of the list, the address was not there. */
+-	if (ai == NULL) {
+-		/* Address not found for the host name. */
+-		logit("Address %.100s maps to %.600s, but this does not "
+-		    "map back to the address.", ntop, name);
+-		return xstrdup(ntop);
+-	}
+-	return xstrdup(name);
+-}
+-
+ /*
+  * Return the canonical name of the host in the other side of the current
+  * connection.  The host name is cached, so it is efficient to call this
+diff --git a/auth2-gss.c b/auth2-gss.c
+index f72a38998..da3bf99c1 100644
+--- a/auth2-gss.c
++++ b/auth2-gss.c
+@@ -1,7 +1,7 @@
+ /* $OpenBSD: auth2-gss.c,v 1.34 2023/03/31 04:22:27 djm Exp $ */
+ 
+ /*
+- * Copyright (c) 2001-2003 Simon Wilkinson. All rights reserved.
++ * Copyright (c) 2001-2007 Simon Wilkinson. All rights reserved.
+  *
+  * Redistribution and use in source and binary forms, with or without
+  * modification, are permitted provided that the following conditions
+@@ -57,6 +57,48 @@ static int input_gssapi_mic(int type, u_int32_t plen, struct ssh *ssh);
+ static int input_gssapi_exchange_complete(int type, u_int32_t plen, struct ssh *ssh);
+ static int input_gssapi_errtok(int, u_int32_t, struct ssh *);
+ 
++/*
++ * The 'gssapi_keyex' userauth mechanism.
++ */
++static int
++userauth_gsskeyex(struct ssh *ssh)
++{
++	Authctxt *authctxt = ssh->authctxt;
++	int r, authenticated = 0;
++	struct sshbuf *b = NULL;
++	gss_buffer_desc mic, gssbuf;
++	u_char *p;
++	size_t len;
++
++	if ((r = sshpkt_get_string(ssh, &p, &len)) != 0 ||
++	    (r = sshpkt_get_end(ssh)) != 0)
++		fatal_fr(r, "parsing");
++
++	if ((b = sshbuf_new()) == NULL)
++		fatal_f("sshbuf_new failed");
++
++	mic.value = p;
++	mic.length = len;
++
++	ssh_gssapi_buildmic(b, authctxt->user, authctxt->service,
++	    "gssapi-keyex", ssh->kex->session_id);
++
++	if ((gssbuf.value = sshbuf_mutable_ptr(b)) == NULL)
++		fatal_f("sshbuf_mutable_ptr failed");
++	gssbuf.length = sshbuf_len(b);
++
++	/* gss_kex_context is NULL with privsep, so we can't check it here */
++	if (!GSS_ERROR(PRIVSEP(ssh_gssapi_checkmic(gss_kex_context,
++	    &gssbuf, &mic))))
++		authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user,
++		    authctxt->pw, 1));
++
++	sshbuf_free(b);
++	free(mic.value);
++
++	return (authenticated);
++}
++
+ /*
+  * We only support those mechanisms that we know about (ie ones that we know
+  * how to check local user kuserok and the like)
+@@ -267,7 +309,8 @@ input_gssapi_exchange_complete(int type, u_int32_t plen, struct ssh *ssh)
+ 	if ((r = sshpkt_get_end(ssh)) != 0)
+ 		fatal_fr(r, "parse packet");
+ 
+-	authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));
++	authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user,
++	    authctxt->pw, 1));
+ 
+ 	if ((!use_privsep || mm_is_monitor()) &&
+ 	    (displayname = ssh_gssapi_displayname()) != NULL)
+@@ -313,7 +356,8 @@ input_gssapi_mic(int type, u_int32_t plen, struct ssh *ssh)
+ 	gssbuf.length = sshbuf_len(b);
+ 
+ 	if (!GSS_ERROR(PRIVSEP(ssh_gssapi_checkmic(gssctxt, &gssbuf, &mic))))
+-		authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));
++		authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user,
++		    authctxt->pw, 0));
+ 	else
+ 		logit("GSSAPI MIC check failed");
+ 
+@@ -333,6 +377,12 @@ input_gssapi_mic(int type, u_int32_t plen, struct ssh *ssh)
+ 	return 0;
+ }
+ 
++Authmethod method_gsskeyex = {
++	"gssapi-keyex",
++	userauth_gsskeyex,
++	&options.gss_authentication
++};
++
+ Authmethod method_gssapi = {
+ 	"gssapi-with-mic",
+ 	NULL,
+diff --git a/auth2.c b/auth2.c
+index 271789a77..514a697ca 100644
+--- a/auth2.c
++++ b/auth2.c
+@@ -71,6 +71,7 @@ extern Authmethod method_passwd;
+ extern Authmethod method_kbdint;
+ extern Authmethod method_hostbased;
+ #ifdef GSSAPI
++extern Authmethod method_gsskeyex;
+ extern Authmethod method_gssapi;
+ #endif
+ 
+@@ -78,6 +79,7 @@ Authmethod *authmethods[] = {
+ 	&method_none,
+ 	&method_pubkey,
+ #ifdef GSSAPI
++	&method_gsskeyex,
+ 	&method_gssapi,
+ #endif
+ 	&method_passwd,
+diff --git a/canohost.c b/canohost.c
+index 28f086e5a..33213ab05 100644
+--- a/canohost.c
++++ b/canohost.c
+@@ -35,6 +35,97 @@
+ #include "canohost.h"
+ #include "misc.h"
+ 
++/*
++ * Returns the remote DNS hostname as a string. The returned string must not
++ * be freed. NB. this will usually trigger a DNS query the first time it is
++ * called.
++ * This function does additional checks on the hostname to mitigate some
++ * attacks on legacy rhosts-style authentication.
++ */
++
++char *
++remote_hostname(struct ssh *ssh)
++{
++	struct sockaddr_storage from;
++	socklen_t fromlen;
++	struct addrinfo hints, *ai, *aitop;
++	char name[NI_MAXHOST], ntop2[NI_MAXHOST];
++	const char *ntop = ssh_remote_ipaddr(ssh);
++
++	/* Get IP address of client. */
++	fromlen = sizeof(from);
++	memset(&from, 0, sizeof(from));
++	if (getpeername(ssh_packet_get_connection_in(ssh),
++	    (struct sockaddr *)&from, &fromlen) == -1) {
++		debug("getpeername failed: %.100s", strerror(errno));
++		return xstrdup(ntop);
++	}
++
++	ipv64_normalise_mapped(&from, &fromlen);
++	if (from.ss_family == AF_INET6)
++		fromlen = sizeof(struct sockaddr_in6);
++
++	debug3("Trying to reverse map address %.100s.", ntop);
++	/* Map the IP address to a host name. */
++	if (getnameinfo((struct sockaddr *)&from, fromlen, name, sizeof(name),
++	    NULL, 0, NI_NAMEREQD) != 0) {
++		/* Host name not found.  Use ip address. */
++		return xstrdup(ntop);
++	}
++
++	/*
++	 * if reverse lookup result looks like a numeric hostname,
++	 * someone is trying to trick us by PTR record like following:
++	 *	1.1.1.10.in-addr.arpa.	IN PTR	2.3.4.5
++	 */
++	memset(&hints, 0, sizeof(hints));
++	hints.ai_socktype = SOCK_DGRAM;	/*dummy*/
++	hints.ai_flags = AI_NUMERICHOST;
++	if (getaddrinfo(name, NULL, &hints, &ai) == 0) {
++		logit("Nasty PTR record \"%s\" is set up for %s, ignoring",
++		    name, ntop);
++		freeaddrinfo(ai);
++		return xstrdup(ntop);
++	}
++
++	/* Names are stored in lowercase. */
++	lowercase(name);
++
++	/*
++	 * Map it back to an IP address and check that the given
++	 * address actually is an address of this host.  This is
++	 * necessary because anyone with access to a name server can
++	 * define arbitrary names for an IP address. Mapping from
++	 * name to IP address can be trusted better (but can still be
++	 * fooled if the intruder has access to the name server of
++	 * the domain).
++	 */
++	memset(&hints, 0, sizeof(hints));
++	hints.ai_family = from.ss_family;
++	hints.ai_socktype = SOCK_STREAM;
++	if (getaddrinfo(name, NULL, &hints, &aitop) != 0) {
++		logit("reverse mapping checking getaddrinfo for %.700s "
++		    "[%s] failed.", name, ntop);
++		return xstrdup(ntop);
++	}
++	/* Look for the address from the list of addresses. */
++	for (ai = aitop; ai; ai = ai->ai_next) {
++		if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop2,
++		    sizeof(ntop2), NULL, 0, NI_NUMERICHOST) == 0 &&
++		    (strcmp(ntop, ntop2) == 0))
++				break;
++	}
++	freeaddrinfo(aitop);
++	/* If we reached the end of the list, the address was not there. */
++	if (ai == NULL) {
++		/* Address not found for the host name. */
++		logit("Address %.100s maps to %.600s, but this does not "
++		    "map back to the address.", ntop, name);
++		return xstrdup(ntop);
++	}
++	return xstrdup(name);
++}
++
+ void
+ ipv64_normalise_mapped(struct sockaddr_storage *addr, socklen_t *len)
+ {
+diff --git a/canohost.h b/canohost.h
+index 26d62855a..0cadc9f18 100644
+--- a/canohost.h
++++ b/canohost.h
+@@ -15,6 +15,9 @@
+ #ifndef _CANOHOST_H
+ #define _CANOHOST_H
+ 
++struct ssh;
++
++char		*remote_hostname(struct ssh *);
+ char		*get_peer_ipaddr(int);
+ int		 get_peer_port(int);
+ char		*get_local_ipaddr(int);
+diff --git a/clientloop.c b/clientloop.c
+index eb4902905..1ffe685a3 100644
+--- a/clientloop.c
++++ b/clientloop.c
+@@ -115,6 +115,10 @@
+ #include "ssherr.h"
+ #include "hostfile.h"
+ 
++#ifdef GSSAPI
++#include "ssh-gss.h"
++#endif
++
+ /* Permitted RSA signature algorithms for UpdateHostkeys proofs */
+ #define HOSTKEY_PROOF_RSA_ALGS	"rsa-sha2-512,rsa-sha2-256"
+ 
+@@ -1594,6 +1598,15 @@ client_loop(struct ssh *ssh, int have_pty, int escape_char_arg,
+ 		/* Do channel operations. */
+ 		channel_after_poll(ssh, pfd, npfd_active);
+ 
++#ifdef GSSAPI
++		if (!ssh_packet_is_rekeying(ssh) &&
++		    options.gss_renewal_rekey &&
++		    ssh_gssapi_credentials_updated(NULL)) {
++			debug("credentials updated - forcing rekey");
++			need_rekeying = 1;
++		}
++#endif
++
+ 		/* Buffer input from the connection.  */
+ 		if (conn_in_ready)
+ 			client_process_net_input(ssh);
+diff --git a/configure.ac b/configure.ac
+index 379cd746b..2aeab040c 100644
+--- a/configure.ac
++++ b/configure.ac
+@@ -766,6 +766,30 @@ int main(void) { if (NSVersionOfRunTimeLibrary("System") >= (60 << 16))
+ 	    [Use tunnel device compatibility to OpenBSD])
+ 	AC_DEFINE([SSH_TUN_PREPEND_AF], [1],
+ 	    [Prepend the address family to IP tunnel traffic])
++	AC_MSG_CHECKING([if we have the Security Authorization Session API])
++	AC_TRY_COMPILE([#include <Security/AuthSession.h>],
++		[SessionCreate(0, 0);],
++		[ac_cv_use_security_session_api="yes"
++		 AC_DEFINE([USE_SECURITY_SESSION_API], [1],
++			[platform has the Security Authorization Session API])
++		 LIBS="$LIBS -framework Security"
++		 AC_MSG_RESULT([yes])],
++		[ac_cv_use_security_session_api="no"
++		 AC_MSG_RESULT([no])])
++	AC_MSG_CHECKING([if we have an in-memory credentials cache])
++	AC_TRY_COMPILE(
++		[#include <Kerberos/Kerberos.h>],
++		[cc_context_t c;
++		 (void) cc_initialize (&c, 0, NULL, NULL);],
++		[AC_DEFINE([USE_CCAPI], [1],
++			[platform uses an in-memory credentials cache])
++		 LIBS="$LIBS -framework Security"
++		 AC_MSG_RESULT([yes])
++		 if test "x$ac_cv_use_security_session_api" = "xno"; then
++			AC_MSG_ERROR([*** Need a security framework to use the credentials cache API ***])
++		fi],
++		[AC_MSG_RESULT([no])]
++	)
+ 	m4_pattern_allow([AU_IPv])
+ 	AC_CHECK_DECL([AU_IPv4], [],
+ 	    AC_DEFINE([AU_IPv4], [0], [System only supports IPv4 audit records])
+diff --git a/gss-genr.c b/gss-genr.c
+index 2cd695e54..9f9745b7f 100644
+--- a/gss-genr.c
++++ b/gss-genr.c
+@@ -1,7 +1,7 @@
+ /* $OpenBSD: gss-genr.c,v 1.28 2021/01/27 10:05:28 djm Exp $ */
+ 
+ /*
+- * Copyright (c) 2001-2007 Simon Wilkinson. All rights reserved.
++ * Copyright (c) 2001-2009 Simon Wilkinson. All rights reserved.
+  *
+  * Redistribution and use in source and binary forms, with or without
+  * modification, are permitted provided that the following conditions
+@@ -42,9 +42,33 @@
+ #include "sshbuf.h"
+ #include "log.h"
+ #include "ssh2.h"
++#include "cipher.h"
++#include "sshkey.h"
++#include "kex.h"
++#include "digest.h"
++#include "packet.h"
+ 
+ #include "ssh-gss.h"
+ 
++typedef struct {
++	char *encoded;
++	gss_OID oid;
++} ssh_gss_kex_mapping;
++
++/*
++ * XXX - It would be nice to find a more elegant way of handling the
++ * XXX   passing of the key exchange context to the userauth routines
++ */
++
++Gssctxt *gss_kex_context = NULL;
++
++static ssh_gss_kex_mapping *gss_enc2oid = NULL;
++
++int
++ssh_gssapi_oid_table_ok(void) {
++	return (gss_enc2oid != NULL);
++}
++
+ /* sshbuf_get for gss_buffer_desc */
+ int
+ ssh_gssapi_get_buffer_desc(struct sshbuf *b, gss_buffer_desc *g)
+@@ -60,6 +84,159 @@ ssh_gssapi_get_buffer_desc(struct sshbuf *b, gss_buffer_desc *g)
+ 	return 0;
+ }
+ 
++/* sshpkt_get of gss_buffer_desc */
++int
++ssh_gssapi_sshpkt_get_buffer_desc(struct ssh *ssh, gss_buffer_desc *g)
++{
++	int r;
++	u_char *p;
++	size_t len;
++
++	if ((r = sshpkt_get_string(ssh, &p, &len)) != 0)
++		return r;
++	g->value = p;
++	g->length = len;
++	return 0;
++}
++
++/*
++ * Return a list of the gss-group1-sha1 mechanisms supported by this program
++ *
++ * We test mechanisms to ensure that we can use them, to avoid starting
++ * a key exchange with a bad mechanism
++ */
++
++char *
++ssh_gssapi_client_mechanisms(const char *host, const char *client,
++    const char *kex) {
++	gss_OID_set gss_supported = NULL;
++	OM_uint32 min_status;
++
++	if (GSS_ERROR(gss_indicate_mechs(&min_status, &gss_supported)))
++		return NULL;
++
++	return ssh_gssapi_kex_mechs(gss_supported, ssh_gssapi_check_mechanism,
++	    host, client, kex);
++}
++
++char *
++ssh_gssapi_kex_mechs(gss_OID_set gss_supported, ssh_gssapi_check_fn *check,
++    const char *host, const char *client, const char *kex) {
++	struct sshbuf *buf = NULL;
++	size_t i;
++	int r = SSH_ERR_ALLOC_FAIL;
++	int oidpos, enclen;
++	char *mechs, *encoded;
++	u_char digest[SSH_DIGEST_MAX_LENGTH];
++	char deroid[2];
++	struct ssh_digest_ctx *md = NULL;
++	char *s, *cp, *p;
++
++	if (gss_enc2oid != NULL) {
++		for (i = 0; gss_enc2oid[i].encoded != NULL; i++)
++			free(gss_enc2oid[i].encoded);
++		free(gss_enc2oid);
++	}
++
++	gss_enc2oid = xmalloc(sizeof(ssh_gss_kex_mapping) *
++	    (gss_supported->count + 1));
++
++	if ((buf = sshbuf_new()) == NULL)
++		fatal_f("sshbuf_new failed");
++
++	oidpos = 0;
++	s = cp = xstrdup(kex);
++	for (i = 0; i < gss_supported->count; i++) {
++		if (gss_supported->elements[i].length < 128 &&
++		    (*check)(NULL, &(gss_supported->elements[i]), host, client)) {
++
++			deroid[0] = SSH_GSS_OIDTYPE;
++			deroid[1] = gss_supported->elements[i].length;
++
++			if ((md = ssh_digest_start(SSH_DIGEST_MD5)) == NULL ||
++			    (r = ssh_digest_update(md, deroid, 2)) != 0 ||
++			    (r = ssh_digest_update(md,
++			        gss_supported->elements[i].elements,
++			        gss_supported->elements[i].length)) != 0 ||
++			    (r = ssh_digest_final(md, digest, sizeof(digest))) != 0)
++				fatal_fr(r, "digest failed");
++			ssh_digest_free(md);
++			md = NULL;
++
++			encoded = xmalloc(ssh_digest_bytes(SSH_DIGEST_MD5)
++			    * 2);
++			enclen = __b64_ntop(digest,
++			    ssh_digest_bytes(SSH_DIGEST_MD5), encoded,
++			    ssh_digest_bytes(SSH_DIGEST_MD5) * 2);
++
++			cp = strncpy(s, kex, strlen(kex));
++			for ((p = strsep(&cp, ",")); p && *p != '\0';
++				(p = strsep(&cp, ","))) {
++				if (sshbuf_len(buf) != 0 &&
++				    (r = sshbuf_put_u8(buf, ',')) != 0)
++					fatal_fr(r, "sshbuf_put_u8 error");
++				if ((r = sshbuf_put(buf, p, strlen(p))) != 0 ||
++				    (r = sshbuf_put(buf, encoded, enclen)) != 0)
++					fatal_fr(r, "sshbuf_put error");
++			}
++
++			gss_enc2oid[oidpos].oid = &(gss_supported->elements[i]);
++			gss_enc2oid[oidpos].encoded = encoded;
++			oidpos++;
++		}
++	}
++	free(s);
++	gss_enc2oid[oidpos].oid = NULL;
++	gss_enc2oid[oidpos].encoded = NULL;
++
++	if ((mechs = sshbuf_dup_string(buf)) == NULL)
++		fatal_f("sshbuf_dup_string failed");
++
++	sshbuf_free(buf);
++
++	if (strlen(mechs) == 0) {
++		free(mechs);
++		mechs = NULL;
++	}
++
++	return (mechs);
++}
++
++gss_OID
++ssh_gssapi_id_kex(Gssctxt *ctx, char *name, int kex_type) {
++	int i = 0;
++
++#define SKIP_KEX_NAME(type) \
++	case type: \
++		if (strlen(name) < sizeof(type##_ID)) \
++			return GSS_C_NO_OID; \
++		name += sizeof(type##_ID) - 1; \
++		break;
++
++	switch (kex_type) {
++	SKIP_KEX_NAME(KEX_GSS_GRP1_SHA1)
++	SKIP_KEX_NAME(KEX_GSS_GRP14_SHA1)
++	SKIP_KEX_NAME(KEX_GSS_GRP14_SHA256)
++	SKIP_KEX_NAME(KEX_GSS_GRP16_SHA512)
++	SKIP_KEX_NAME(KEX_GSS_GEX_SHA1)
++	SKIP_KEX_NAME(KEX_GSS_NISTP256_SHA256)
++	SKIP_KEX_NAME(KEX_GSS_C25519_SHA256)
++	default:
++		return GSS_C_NO_OID;
++	}
++
++#undef SKIP_KEX_NAME
++
++	while (gss_enc2oid[i].encoded != NULL &&
++	    strcmp(name, gss_enc2oid[i].encoded) != 0)
++		i++;
++
++	if (gss_enc2oid[i].oid != NULL && ctx != NULL)
++		ssh_gssapi_set_oid(ctx, gss_enc2oid[i].oid);
++
++	return gss_enc2oid[i].oid;
++}
++
+ /* Check that the OID in a data stream matches that in the context */
+ int
+ ssh_gssapi_check_oid(Gssctxt *ctx, void *data, size_t len)
+@@ -216,7 +393,7 @@ ssh_gssapi_init_ctx(Gssctxt *ctx, int deleg_creds, gss_buffer_desc *recv_tok,
+ 	}
+ 
+ 	ctx->major = gss_init_sec_context(&ctx->minor,
+-	    GSS_C_NO_CREDENTIAL, &ctx->context, ctx->name, ctx->oid,
++	    ctx->client_creds, &ctx->context, ctx->name, ctx->oid,
+ 	    GSS_C_MUTUAL_FLAG | GSS_C_INTEG_FLAG | deleg_flag,
+ 	    0, NULL, recv_tok, NULL, send_tok, flags, NULL);
+ 
+@@ -245,9 +422,43 @@ ssh_gssapi_import_name(Gssctxt *ctx, const char *host)
+ 	return (ctx->major);
+ }
+ 
++OM_uint32
++ssh_gssapi_client_identity(Gssctxt *ctx, const char *name)
++{
++	gss_buffer_desc gssbuf;
++	gss_name_t gssname;
++	OM_uint32 status;
++	gss_OID_set oidset;
++
++	gssbuf.value = (void *) name;
++	gssbuf.length = strlen(gssbuf.value);
++
++	gss_create_empty_oid_set(&status, &oidset);
++	gss_add_oid_set_member(&status, ctx->oid, &oidset);
++
++	ctx->major = gss_import_name(&ctx->minor, &gssbuf,
++	    GSS_C_NT_USER_NAME, &gssname);
++
++	if (!ctx->major)
++		ctx->major = gss_acquire_cred(&ctx->minor,
++		    gssname, 0, oidset, GSS_C_INITIATE,
++		    &ctx->client_creds, NULL, NULL);
++
++	gss_release_name(&status, &gssname);
++	gss_release_oid_set(&status, &oidset);
++
++	if (ctx->major)
++		ssh_gssapi_error(ctx);
++
++	return(ctx->major);
++}
++
+ OM_uint32
+ ssh_gssapi_sign(Gssctxt *ctx, gss_buffer_t buffer, gss_buffer_t hash)
+ {
++	if (ctx == NULL)
++		return -1;
++
+ 	if ((ctx->major = gss_get_mic(&ctx->minor, ctx->context,
+ 	    GSS_C_QOP_DEFAULT, buffer, hash)))
+ 		ssh_gssapi_error(ctx);
+@@ -255,6 +466,19 @@ ssh_gssapi_sign(Gssctxt *ctx, gss_buffer_t buffer, gss_buffer_t hash)
+ 	return (ctx->major);
+ }
+ 
++/* Priviledged when used by server */
++OM_uint32
++ssh_gssapi_checkmic(Gssctxt *ctx, gss_buffer_t gssbuf, gss_buffer_t gssmic)
++{
++	if (ctx == NULL)
++		return -1;
++
++	ctx->major = gss_verify_mic(&ctx->minor, ctx->context,
++	    gssbuf, gssmic, NULL);
++
++	return (ctx->major);
++}
++
+ void
+ ssh_gssapi_buildmic(struct sshbuf *b, const char *user, const char *service,
+     const char *context, const struct sshbuf *session_id)
+@@ -271,11 +495,16 @@ ssh_gssapi_buildmic(struct sshbuf *b, const char *user, const char *service,
+ }
+ 
+ int
+-ssh_gssapi_check_mechanism(Gssctxt **ctx, gss_OID oid, const char *host)
++ssh_gssapi_check_mechanism(Gssctxt **ctx, gss_OID oid, const char *host,
++    const char *client)
+ {
+ 	gss_buffer_desc token = GSS_C_EMPTY_BUFFER;
+ 	OM_uint32 major, minor;
+ 	gss_OID_desc spnego_oid = {6, (void *)"\x2B\x06\x01\x05\x05\x02"};
++	Gssctxt *intctx = NULL;
++
++	if (ctx == NULL)
++		ctx = &intctx;
+ 
+ 	/* RFC 4462 says we MUST NOT do SPNEGO */
+ 	if (oid->length == spnego_oid.length && 
+@@ -285,6 +514,10 @@ ssh_gssapi_check_mechanism(Gssctxt **ctx, gss_OID oid, const char *host)
+ 	ssh_gssapi_build_ctx(ctx);
+ 	ssh_gssapi_set_oid(*ctx, oid);
+ 	major = ssh_gssapi_import_name(*ctx, host);
++
++	if (!GSS_ERROR(major) && client)
++		major = ssh_gssapi_client_identity(*ctx, client);
++
+ 	if (!GSS_ERROR(major)) {
+ 		major = ssh_gssapi_init_ctx(*ctx, 0, GSS_C_NO_BUFFER, &token, 
+ 		    NULL);
+@@ -294,10 +527,66 @@ ssh_gssapi_check_mechanism(Gssctxt **ctx, gss_OID oid, const char *host)
+ 			    GSS_C_NO_BUFFER);
+ 	}
+ 
+-	if (GSS_ERROR(major)) 
++	if (GSS_ERROR(major) || intctx != NULL)
+ 		ssh_gssapi_delete_ctx(ctx);
+ 
+ 	return (!GSS_ERROR(major));
+ }
+ 
++int
++ssh_gssapi_credentials_updated(Gssctxt *ctxt) {
++	static gss_name_t saved_name = GSS_C_NO_NAME;
++	static OM_uint32 saved_lifetime = 0;
++	static gss_OID saved_mech = GSS_C_NO_OID;
++	static gss_name_t name;
++	static OM_uint32 last_call = 0;
++	OM_uint32 lifetime, now, major, minor;
++	int equal;
++
++	now = time(NULL);
++
++	if (ctxt) {
++		debug("Rekey has happened - updating saved versions");
++
++		if (saved_name != GSS_C_NO_NAME)
++			gss_release_name(&minor, &saved_name);
++
++		major = gss_inquire_cred(&minor, GSS_C_NO_CREDENTIAL,
++		    &saved_name, &saved_lifetime, NULL, NULL);
++
++		if (!GSS_ERROR(major)) {
++			saved_mech = ctxt->oid;
++		        saved_lifetime+= now;
++		} else {
++			/* Handle the error */
++		}
++		return 0;
++	}
++
++	if (now - last_call < 10)
++		return 0;
++
++	last_call = now;
++
++	if (saved_mech == GSS_C_NO_OID)
++		return 0;
++
++	major = gss_inquire_cred(&minor, GSS_C_NO_CREDENTIAL,
++	    &name, &lifetime, NULL, NULL);
++	if (major == GSS_S_CREDENTIALS_EXPIRED)
++		return 0;
++	else if (GSS_ERROR(major))
++		return 0;
++
++	major = gss_compare_name(&minor, saved_name, name, &equal);
++	gss_release_name(&minor, &name);
++	if (GSS_ERROR(major))
++		return 0;
++
++	if (equal && (saved_lifetime < lifetime + now - 10))
++		return 1;
++
++	return 0;
++}
++
+ #endif /* GSSAPI */
+diff --git a/gss-serv-krb5.c b/gss-serv-krb5.c
+index a151bc1e4..ef20401ec 100644
+--- a/gss-serv-krb5.c
++++ b/gss-serv-krb5.c
+@@ -1,7 +1,7 @@
+ /* $OpenBSD: gss-serv-krb5.c,v 1.9 2018/07/09 21:37:55 markus Exp $ */
+ 
+ /*
+- * Copyright (c) 2001-2003 Simon Wilkinson. All rights reserved.
++ * Copyright (c) 2001-2007 Simon Wilkinson. All rights reserved.
+  *
+  * Redistribution and use in source and binary forms, with or without
+  * modification, are permitted provided that the following conditions
+@@ -120,7 +120,7 @@ ssh_gssapi_krb5_storecreds(ssh_gssapi_client *client)
+ 	krb5_error_code problem;
+ 	krb5_principal princ;
+ 	OM_uint32 maj_status, min_status;
+-	int len;
++	const char *new_ccname;
+ 	const char *errmsg;
+ 
+ 	if (client->creds == NULL) {
+@@ -180,11 +180,16 @@ ssh_gssapi_krb5_storecreds(ssh_gssapi_client *client)
+ 		return;
+ 	}
+ 
+-	client->store.filename = xstrdup(krb5_cc_get_name(krb_context, ccache));
++	new_ccname = krb5_cc_get_name(krb_context, ccache);
++
+ 	client->store.envvar = "KRB5CCNAME";
+-	len = strlen(client->store.filename) + 6;
+-	client->store.envval = xmalloc(len);
+-	snprintf(client->store.envval, len, "FILE:%s", client->store.filename);
++#ifdef USE_CCAPI
++	xasprintf(&client->store.envval, "API:%s", new_ccname);
++	client->store.filename = NULL;
++#else
++	xasprintf(&client->store.envval, "FILE:%s", new_ccname);
++	client->store.filename = xstrdup(new_ccname);
++#endif
+ 
+ #ifdef USE_PAM
+ 	if (options.use_pam)
+@@ -193,9 +198,76 @@ ssh_gssapi_krb5_storecreds(ssh_gssapi_client *client)
+ 
+ 	krb5_cc_close(krb_context, ccache);
+ 
++	client->store.data = krb_context;
++
+ 	return;
+ }
+ 
++int
++ssh_gssapi_krb5_updatecreds(ssh_gssapi_ccache *store,
++    ssh_gssapi_client *client)
++{
++	krb5_ccache ccache = NULL;
++	krb5_principal principal = NULL;
++	char *name = NULL;
++	krb5_error_code problem;
++	OM_uint32 maj_status, min_status;
++
++	if ((problem = krb5_cc_resolve(krb_context, store->envval, &ccache))) {
++                logit("krb5_cc_resolve(): %.100s",
++                    krb5_get_err_text(krb_context, problem));
++                return 0;
++	}
++
++	/* Find out who the principal in this cache is */
++	if ((problem = krb5_cc_get_principal(krb_context, ccache,
++	    &principal))) {
++		logit("krb5_cc_get_principal(): %.100s",
++		    krb5_get_err_text(krb_context, problem));
++		krb5_cc_close(krb_context, ccache);
++		return 0;
++	}
++
++	if ((problem = krb5_unparse_name(krb_context, principal, &name))) {
++		logit("krb5_unparse_name(): %.100s",
++		    krb5_get_err_text(krb_context, problem));
++		krb5_free_principal(krb_context, principal);
++		krb5_cc_close(krb_context, ccache);
++		return 0;
++	}
++
++
++	if (strcmp(name,client->exportedname.value)!=0) {
++		debug("Name in local credentials cache differs. Not storing");
++		krb5_free_principal(krb_context, principal);
++		krb5_cc_close(krb_context, ccache);
++		krb5_free_unparsed_name(krb_context, name);
++		return 0;
++	}
++	krb5_free_unparsed_name(krb_context, name);
++
++	/* Name matches, so lets get on with it! */
++
++	if ((problem = krb5_cc_initialize(krb_context, ccache, principal))) {
++		logit("krb5_cc_initialize(): %.100s",
++		    krb5_get_err_text(krb_context, problem));
++		krb5_free_principal(krb_context, principal);
++		krb5_cc_close(krb_context, ccache);
++		return 0;
++	}
++
++	krb5_free_principal(krb_context, principal);
++
++	if ((maj_status = gss_krb5_copy_ccache(&min_status, client->creds,
++	    ccache))) {
++		logit("gss_krb5_copy_ccache() failed. Sorry!");
++		krb5_cc_close(krb_context, ccache);
++		return 0;
++	}
++
++	return 1;
++}
++
+ ssh_gssapi_mech gssapi_kerberos_mech = {
+ 	"toWM5Slw5Ew8Mqkay+al2g==",
+ 	"Kerberos",
+@@ -203,7 +275,8 @@ ssh_gssapi_mech gssapi_kerberos_mech = {
+ 	NULL,
+ 	&ssh_gssapi_krb5_userok,
+ 	NULL,
+-	&ssh_gssapi_krb5_storecreds
++	&ssh_gssapi_krb5_storecreds,
++	&ssh_gssapi_krb5_updatecreds
+ };
+ 
+ #endif /* KRB5 */
+diff --git a/gss-serv.c b/gss-serv.c
+index 00e3d118b..162fec447 100644
+--- a/gss-serv.c
++++ b/gss-serv.c
+@@ -1,7 +1,7 @@
+ /* $OpenBSD: gss-serv.c,v 1.32 2020/03/13 03:17:07 djm Exp $ */
+ 
+ /*
+- * Copyright (c) 2001-2003 Simon Wilkinson. All rights reserved.
++ * Copyright (c) 2001-2009 Simon Wilkinson. All rights reserved.
+  *
+  * Redistribution and use in source and binary forms, with or without
+  * modification, are permitted provided that the following conditions
+@@ -44,17 +44,19 @@
+ #include "session.h"
+ #include "misc.h"
+ #include "servconf.h"
++#include "uidswap.h"
+ 
+ #include "ssh-gss.h"
++#include "monitor_wrap.h"
+ 
+ extern ServerOptions options;
+ 
+ static ssh_gssapi_client gssapi_client =
+-    { GSS_C_EMPTY_BUFFER, GSS_C_EMPTY_BUFFER,
+-    GSS_C_NO_CREDENTIAL, NULL, {NULL, NULL, NULL, NULL}};
++    { GSS_C_EMPTY_BUFFER, GSS_C_EMPTY_BUFFER, GSS_C_NO_CREDENTIAL,
++    GSS_C_NO_NAME, NULL, {NULL, NULL, NULL, NULL, NULL}, 0, 0};
+ 
+ ssh_gssapi_mech gssapi_null_mech =
+-    { NULL, NULL, {0, NULL}, NULL, NULL, NULL, NULL};
++    { NULL, NULL, {0, NULL}, NULL, NULL, NULL, NULL, NULL};
+ 
+ #ifdef KRB5
+ extern ssh_gssapi_mech gssapi_kerberos_mech;
+@@ -140,6 +142,29 @@ ssh_gssapi_server_ctx(Gssctxt **ctx, gss_OID oid)
+ 	return (ssh_gssapi_acquire_cred(*ctx));
+ }
+ 
++/* Unprivileged */
++char *
++ssh_gssapi_server_mechanisms(void) {
++	if (supported_oids == NULL)
++		ssh_gssapi_prepare_supported_oids();
++	return (ssh_gssapi_kex_mechs(supported_oids,
++	    &ssh_gssapi_server_check_mech, NULL, NULL,
++	    options.gss_kex_algorithms));
++}
++
++/* Unprivileged */
++int
++ssh_gssapi_server_check_mech(Gssctxt **dum, gss_OID oid, const char *data,
++    const char *dummy) {
++	Gssctxt *ctx = NULL;
++	int res;
++
++	res = !GSS_ERROR(PRIVSEP(ssh_gssapi_server_ctx(&ctx, oid)));
++	ssh_gssapi_delete_ctx(&ctx);
++
++	return (res);
++}
++
+ /* Unprivileged */
+ void
+ ssh_gssapi_supported_oids(gss_OID_set *oidset)
+@@ -150,7 +175,9 @@ ssh_gssapi_supported_oids(gss_OID_set *oidset)
+ 	gss_OID_set supported;
+ 
+ 	gss_create_empty_oid_set(&min_status, oidset);
+-	gss_indicate_mechs(&min_status, &supported);
++
++	if (GSS_ERROR(gss_indicate_mechs(&min_status, &supported)))
++		return;
+ 
+ 	while (supported_mechs[i]->name != NULL) {
+ 		if (GSS_ERROR(gss_test_oid_set_member(&min_status,
+@@ -276,8 +303,48 @@ OM_uint32
+ ssh_gssapi_getclient(Gssctxt *ctx, ssh_gssapi_client *client)
+ {
+ 	int i = 0;
++	int equal = 0;
++	gss_name_t new_name = GSS_C_NO_NAME;
++	gss_buffer_desc ename = GSS_C_EMPTY_BUFFER;
++
++	if (options.gss_store_rekey && client->used && ctx->client_creds) {
++		if (client->mech->oid.length != ctx->oid->length ||
++		    (memcmp(client->mech->oid.elements,
++		     ctx->oid->elements, ctx->oid->length) !=0)) {
++			debug("Rekeyed credentials have different mechanism");
++			return GSS_S_COMPLETE;
++		}
++
++		if ((ctx->major = gss_inquire_cred_by_mech(&ctx->minor,
++		    ctx->client_creds, ctx->oid, &new_name,
++		    NULL, NULL, NULL))) {
++			ssh_gssapi_error(ctx);
++			return (ctx->major);
++		}
+ 
+-	gss_buffer_desc ename;
++		ctx->major = gss_compare_name(&ctx->minor, client->name,
++		    new_name, &equal);
++
++		if (GSS_ERROR(ctx->major)) {
++			ssh_gssapi_error(ctx);
++			return (ctx->major);
++		}
++
++		if (!equal) {
++			debug("Rekeyed credentials have different name");
++			return GSS_S_COMPLETE;
++		}
++
++		debug("Marking rekeyed credentials for export");
++
++		gss_release_name(&ctx->minor, &client->name);
++		gss_release_cred(&ctx->minor, &client->creds);
++		client->name = new_name;
++		client->creds = ctx->client_creds;
++		ctx->client_creds = GSS_C_NO_CREDENTIAL;
++		client->updated = 1;
++		return GSS_S_COMPLETE;
++	}
+ 
+ 	client->mech = NULL;
+ 
+@@ -292,6 +359,13 @@ ssh_gssapi_getclient(Gssctxt *ctx, ssh_gssapi_client *client)
+ 	if (client->mech == NULL)
+ 		return GSS_S_FAILURE;
+ 
++	if (ctx->client_creds &&
++	    (ctx->major = gss_inquire_cred_by_mech(&ctx->minor,
++	     ctx->client_creds, ctx->oid, &client->name, NULL, NULL, NULL))) {
++		ssh_gssapi_error(ctx);
++		return (ctx->major);
++	}
++
+ 	if ((ctx->major = gss_display_name(&ctx->minor, ctx->client,
+ 	    &client->displayname, NULL))) {
+ 		ssh_gssapi_error(ctx);
+@@ -309,6 +383,8 @@ ssh_gssapi_getclient(Gssctxt *ctx, ssh_gssapi_client *client)
+ 		return (ctx->major);
+ 	}
+ 
++	gss_release_buffer(&ctx->minor, &ename);
++
+ 	/* We can't copy this structure, so we just move the pointer to it */
+ 	client->creds = ctx->client_creds;
+ 	ctx->client_creds = GSS_C_NO_CREDENTIAL;
+@@ -319,11 +395,20 @@ ssh_gssapi_getclient(Gssctxt *ctx, ssh_gssapi_client *client)
+ void
+ ssh_gssapi_cleanup_creds(void)
+ {
+-	if (gssapi_client.store.filename != NULL) {
+-		/* Unlink probably isn't sufficient */
+-		debug("removing gssapi cred file\"%s\"",
+-		    gssapi_client.store.filename);
+-		unlink(gssapi_client.store.filename);
++	krb5_ccache ccache = NULL;
++	krb5_error_code problem;
++
++	if (gssapi_client.store.data != NULL) {
++		if ((problem = krb5_cc_resolve(gssapi_client.store.data, gssapi_client.store.envval, &ccache))) {
++			debug_f("krb5_cc_resolve(): %.100s",
++				krb5_get_err_text(gssapi_client.store.data, problem));
++		} else if ((problem = krb5_cc_destroy(gssapi_client.store.data, ccache))) {
++			debug_f("krb5_cc_destroy(): %.100s",
++				krb5_get_err_text(gssapi_client.store.data, problem));
++		} else {
++			krb5_free_context(gssapi_client.store.data);
++			gssapi_client.store.data = NULL;
++		}
+ 	}
+ }
+ 
+@@ -356,19 +441,23 @@ ssh_gssapi_do_child(char ***envp, u_int *envsizep)
+ 
+ /* Privileged */
+ int
+-ssh_gssapi_userok(char *user)
++ssh_gssapi_userok(char *user, struct passwd *pw, int kex)
+ {
+ 	OM_uint32 lmin;
+ 
++	(void) kex; /* used in privilege separation */
++
+ 	if (gssapi_client.exportedname.length == 0 ||
+ 	    gssapi_client.exportedname.value == NULL) {
+ 		debug("No suitable client data");
+ 		return 0;
+ 	}
+ 	if (gssapi_client.mech && gssapi_client.mech->userok)
+-		if ((*gssapi_client.mech->userok)(&gssapi_client, user))
++		if ((*gssapi_client.mech->userok)(&gssapi_client, user)) {
++			gssapi_client.used = 1;
++			gssapi_client.store.owner = pw;
+ 			return 1;
+-		else {
++		} else {
+ 			/* Destroy delegated credentials if userok fails */
+ 			gss_release_buffer(&lmin, &gssapi_client.displayname);
+ 			gss_release_buffer(&lmin, &gssapi_client.exportedname);
+@@ -382,14 +471,90 @@ ssh_gssapi_userok(char *user)
+ 	return (0);
+ }
+ 
+-/* Privileged */
+-OM_uint32
+-ssh_gssapi_checkmic(Gssctxt *ctx, gss_buffer_t gssbuf, gss_buffer_t gssmic)
++/* These bits are only used for rekeying. The unpriviledged child is running
++ * as the user, the monitor is root.
++ *
++ * In the child, we want to :
++ *    *) Ask the monitor to store our credentials into the store we specify
++ *    *) If it succeeds, maybe do a PAM update
++ */
++
++/* Stuff for PAM */
++
++#ifdef USE_PAM
++static int ssh_gssapi_simple_conv(int n, const struct pam_message **msg,
++    struct pam_response **resp, void *data)
+ {
+-	ctx->major = gss_verify_mic(&ctx->minor, ctx->context,
+-	    gssbuf, gssmic, NULL);
++	return (PAM_CONV_ERR);
++}
++#endif
+ 
+-	return (ctx->major);
++void
++ssh_gssapi_rekey_creds(void) {
++	int ok;
++#ifdef USE_PAM
++	int ret;
++	pam_handle_t *pamh = NULL;
++	struct pam_conv pamconv = {ssh_gssapi_simple_conv, NULL};
++	char *envstr;
++#endif
++
++	if (gssapi_client.store.filename == NULL &&
++	    gssapi_client.store.envval == NULL &&
++	    gssapi_client.store.envvar == NULL)
++		return;
++
++	ok = PRIVSEP(ssh_gssapi_update_creds(&gssapi_client.store));
++
++	if (!ok)
++		return;
++
++	debug("Rekeyed credentials stored successfully");
++
++	/* Actually managing to play with the ssh pam stack from here will
++	 * be next to impossible. In any case, we may want different options
++	 * for rekeying. So, use our own :)
++	 */
++#ifdef USE_PAM	
++	if (!use_privsep) {
++		debug("Not even going to try and do PAM with privsep disabled");
++		return;
++	}
++
++	ret = pam_start("sshd-rekey", gssapi_client.store.owner->pw_name,
++ 	    &pamconv, &pamh);
++	if (ret)
++		return;
++
++	xasprintf(&envstr, "%s=%s", gssapi_client.store.envvar,
++	    gssapi_client.store.envval);
++
++	ret = pam_putenv(pamh, envstr);
++	if (!ret)
++		pam_setcred(pamh, PAM_REINITIALIZE_CRED);
++	pam_end(pamh, PAM_SUCCESS);
++#endif
++}
++
++int
++ssh_gssapi_update_creds(ssh_gssapi_ccache *store) {
++	int ok = 0;
++
++	/* Check we've got credentials to store */
++	if (!gssapi_client.updated)
++		return 0;
++
++	gssapi_client.updated = 0;
++
++	temporarily_use_uid(gssapi_client.store.owner);
++	if (gssapi_client.mech && gssapi_client.mech->updatecreds)
++		ok = (*gssapi_client.mech->updatecreds)(store, &gssapi_client);
++	else
++		debug("No update function for this mechanism");
++
++	restore_uid();
++
++	return ok;
+ }
+ 
+ /* Privileged */
+diff --git a/kex.c b/kex.c
+index cbb2af596..acab53195 100644
+--- a/kex.c
++++ b/kex.c
+@@ -58,12 +58,17 @@
+ #include "dispatch.h"
+ #include "monitor.h"
+ #include "myproposal.h"
++#include "xmalloc.h"
+ 
+ #include "ssherr.h"
+ #include "sshbuf.h"
+ #include "digest.h"
+ #include "xmalloc.h"
+ 
++#ifdef GSSAPI
++#include "ssh-gss.h"
++#endif
++
+ /* prototype */
+ static int kex_choose_conf(struct ssh *, uint32_t seq);
+ static int kex_input_newkeys(int, u_int32_t, struct ssh *);
+@@ -119,15 +124,28 @@ static const struct kexalg kexalgs[] = {
+ #endif /* HAVE_EVP_SHA256 || !WITH_OPENSSL */
+ 	{ NULL, 0, -1, -1},
+ };
++static const struct kexalg gss_kexalgs[] = {
++#ifdef GSSAPI
++	{ KEX_GSS_GEX_SHA1_ID, KEX_GSS_GEX_SHA1, 0, SSH_DIGEST_SHA1 },
++	{ KEX_GSS_GRP1_SHA1_ID, KEX_GSS_GRP1_SHA1, 0, SSH_DIGEST_SHA1 },
++	{ KEX_GSS_GRP14_SHA1_ID, KEX_GSS_GRP14_SHA1, 0, SSH_DIGEST_SHA1 },
++	{ KEX_GSS_GRP14_SHA256_ID, KEX_GSS_GRP14_SHA256, 0, SSH_DIGEST_SHA256 },
++	{ KEX_GSS_GRP16_SHA512_ID, KEX_GSS_GRP16_SHA512, 0, SSH_DIGEST_SHA512 },
++	{ KEX_GSS_NISTP256_SHA256_ID, KEX_GSS_NISTP256_SHA256,
++	    NID_X9_62_prime256v1, SSH_DIGEST_SHA256 },
++	{ KEX_GSS_C25519_SHA256_ID, KEX_GSS_C25519_SHA256, 0, SSH_DIGEST_SHA256 },
++#endif
++	{ NULL, 0, -1, -1},
++};
+ 
+-char *
+-kex_alg_list(char sep)
++static char *
++kex_alg_list_internal(char sep, const struct kexalg *algs)
+ {
+ 	char *ret = NULL, *tmp;
+ 	size_t nlen, rlen = 0;
+ 	const struct kexalg *k;
+ 
+-	for (k = kexalgs; k->name != NULL; k++) {
++	for (k = algs; k->name != NULL; k++) {
+ 		if (ret != NULL)
+ 			ret[rlen++] = sep;
+ 		nlen = strlen(k->name);
+@@ -142,6 +160,18 @@ kex_alg_list(char sep)
+ 	return ret;
+ }
+ 
++char *
++kex_alg_list(char sep)
++{
++	return kex_alg_list_internal(sep, kexalgs);
++}
++
++char *
++kex_gss_alg_list(char sep)
++{
++	return kex_alg_list_internal(sep, gss_kexalgs);
++}
++
+ static const struct kexalg *
+ kex_alg_by_name(const char *name)
+ {
+@@ -151,6 +181,10 @@ kex_alg_by_name(const char *name)
+ 		if (strcmp(k->name, name) == 0)
+ 			return k;
+ 	}
++	for (k = gss_kexalgs; k->name != NULL; k++) {
++		if (strncmp(k->name, name, strlen(k->name)) == 0)
++			return k;
++	}
+ 	return NULL;
+ }
+ 
+@@ -393,6 +427,29 @@ kex_proposal_free_entries(char *prop[PROPOSAL_MAX])
+ 		free(prop[i]);
+ }
+ 
++/* Validate GSS KEX method name list */
++int
++kex_gss_names_valid(const char *names)
++{
++	char *s, *cp, *p;
++
++	if (names == NULL || *names == '\0')
++		return 0;
++	s = cp = xstrdup(names);
++	for ((p = strsep(&cp, ",")); p && *p != '\0';
++	    (p = strsep(&cp, ","))) {
++		if (strncmp(p, "gss-", 4) != 0
++		  || kex_alg_by_name(p) == NULL) {
++			error("Unsupported KEX algorithm \"%.100s\"", p);
++			free(s);
++			return 0;
++		}
++	}
++	debug3("gss kex names ok: [%s]", names);
++	free(s);
++	return 1;
++}
++
+ /* put algorithm proposal into buffer */
+ int
+ kex_prop2buf(struct sshbuf *b, char *proposal[PROPOSAL_MAX])
+@@ -964,6 +1021,9 @@ kex_free(struct kex *kex)
+ 	sshbuf_free(kex->session_id);
+ 	sshbuf_free(kex->initial_sig);
+ 	sshkey_free(kex->initial_hostkey);
++#ifdef GSSAPI
++	free(kex->gss_host);
++#endif /* GSSAPI */
+ 	free(kex->failed_choice);
+ 	free(kex->hostkey_alg);
+ 	free(kex->name);
+diff --git a/kex.h b/kex.h
+index ba3a6a4ea..faee60f16 100644
+--- a/kex.h
++++ b/kex.h
+@@ -102,6 +102,15 @@ enum kex_exchange {
+ 	KEX_ECDH_SHA2,
+ 	KEX_C25519_SHA256,
+ 	KEX_KEM_SNTRUP761X25519_SHA512,
++#ifdef GSSAPI
++	KEX_GSS_GRP1_SHA1,
++	KEX_GSS_GRP14_SHA1,
++	KEX_GSS_GRP14_SHA256,
++	KEX_GSS_GRP16_SHA512,
++	KEX_GSS_GEX_SHA1,
++	KEX_GSS_NISTP256_SHA256,
++	KEX_GSS_C25519_SHA256,
++#endif
+ 	KEX_MAX
+ };
+ 
+@@ -164,6 +173,12 @@ struct kex {
+ 	u_int	flags;
+ 	int	hash_alg;
+ 	int	ec_nid;
++#ifdef GSSAPI
++	int	gss_deleg_creds;
++	int	gss_trust_dns;
++	char    *gss_host;
++	char	*gss_client;
++#endif
+ 	char	*failed_choice;
+ 	int	(*verify_host_key)(struct sshkey *, struct ssh *);
+ 	struct sshkey *(*load_host_public_key)(int, int, struct ssh *);
+@@ -185,11 +200,13 @@ struct kex {
+ 
+ int	 kex_names_valid(const char *);
+ char	*kex_alg_list(char);
++char	*kex_gss_alg_list(char);
+ char	*kex_names_cat(const char *, const char *);
+ int	 kex_assemble_names(char **, const char *, const char *);
+ void	 kex_proposal_populate_entries(struct ssh *, char *prop[PROPOSAL_MAX],
+     const char *, const char *, const char *, const char *, const char *);
+ void	 kex_proposal_free_entries(char *prop[PROPOSAL_MAX]);
++int	 kex_gss_names_valid(const char *);
+ 
+ int	 kex_exchange_identification(struct ssh *, int, const char *);
+ 
+@@ -219,6 +236,12 @@ int	 kexgex_client(struct ssh *);
+ int	 kexgex_server(struct ssh *);
+ int	 kex_gen_client(struct ssh *);
+ int	 kex_gen_server(struct ssh *);
++#if defined(GSSAPI) && defined(WITH_OPENSSL)
++int	 kexgssgex_client(struct ssh *);
++int	 kexgssgex_server(struct ssh *);
++int	 kexgss_client(struct ssh *);
++int	 kexgss_server(struct ssh *);
++#endif
+ 
+ int	 kex_dh_keypair(struct kex *);
+ int	 kex_dh_enc(struct kex *, const struct sshbuf *, struct sshbuf **,
+@@ -251,6 +274,12 @@ int	 kexgex_hash(int, const struct sshbuf *, const struct sshbuf *,
+     const BIGNUM *, const u_char *, size_t,
+     u_char *, size_t *);
+ 
++int	 kex_gen_hash(int hash_alg, const struct sshbuf *client_version,
++    const struct sshbuf *server_version, const struct sshbuf *client_kexinit,
++    const struct sshbuf *server_kexinit, const struct sshbuf *server_host_key_blob,
++    const struct sshbuf *client_pub, const struct sshbuf *server_pub,
++    const struct sshbuf *shared_secret, u_char *hash, size_t *hashlen);
++
+ void	kexc25519_keygen(u_char key[CURVE25519_SIZE], u_char pub[CURVE25519_SIZE])
+ 	__attribute__((__bounded__(__minbytes__, 1, CURVE25519_SIZE)))
+ 	__attribute__((__bounded__(__minbytes__, 2, CURVE25519_SIZE)));
+diff --git a/kexdh.c b/kexdh.c
+index c1084f214..0faab21b0 100644
+--- a/kexdh.c
++++ b/kexdh.c
+@@ -49,13 +49,23 @@ kex_dh_keygen(struct kex *kex)
+ {
+ 	switch (kex->kex_type) {
+ 	case KEX_DH_GRP1_SHA1:
++#ifdef GSSAPI
++	case KEX_GSS_GRP1_SHA1:
++#endif
+ 		kex->dh = dh_new_group1();
+ 		break;
+ 	case KEX_DH_GRP14_SHA1:
+ 	case KEX_DH_GRP14_SHA256:
++#ifdef GSSAPI
++	case KEX_GSS_GRP14_SHA1:
++	case KEX_GSS_GRP14_SHA256:
++#endif
+ 		kex->dh = dh_new_group14();
+ 		break;
+ 	case KEX_DH_GRP16_SHA512:
++#ifdef GSSAPI
++	case KEX_GSS_GRP16_SHA512:
++#endif
+ 		kex->dh = dh_new_group16();
+ 		break;
+ 	case KEX_DH_GRP18_SHA512:
+diff --git a/kexgen.c b/kexgen.c
+index 20f3c5711..ca704844e 100644
+--- a/kexgen.c
++++ b/kexgen.c
+@@ -44,7 +44,7 @@
+ static int input_kex_gen_init(int, u_int32_t, struct ssh *);
+ static int input_kex_gen_reply(int type, u_int32_t seq, struct ssh *ssh);
+ 
+-static int
++int
+ kex_gen_hash(
+     int hash_alg,
+     const struct sshbuf *client_version,
+diff --git a/kexgssc.c b/kexgssc.c
+new file mode 100644
+index 000000000..2da431428
+--- /dev/null
++++ b/kexgssc.c
+@@ -0,0 +1,602 @@
++/*
++ * Copyright (c) 2001-2009 Simon Wilkinson. All rights reserved.
++ *
++ * Redistribution and use in source and binary forms, with or without
++ * modification, are permitted provided that the following conditions
++ * are met:
++ * 1. Redistributions of source code must retain the above copyright
++ *    notice, this list of conditions and the following disclaimer.
++ * 2. Redistributions in binary form must reproduce the above copyright
++ *    notice, this list of conditions and the following disclaimer in the
++ *    documentation and/or other materials provided with the distribution.
++ *
++ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR `AS IS'' AND ANY EXPRESS OR
++ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
++ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
++ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
++ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
++ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
++ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
++ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
++ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
++ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
++ */
++
++#include "includes.h"
++
++#if defined(GSSAPI) && defined(WITH_OPENSSL)
++
++#include "includes.h"
++
++#include <openssl/crypto.h>
++#include <openssl/bn.h>
++
++#include <string.h>
++
++#include "xmalloc.h"
++#include "sshbuf.h"
++#include "ssh2.h"
++#include "sshkey.h"
++#include "cipher.h"
++#include "kex.h"
++#include "log.h"
++#include "packet.h"
++#include "dh.h"
++#include "digest.h"
++#include "ssherr.h"
++
++#include "ssh-gss.h"
++
++int
++kexgss_client(struct ssh *ssh)
++{
++	struct kex *kex = ssh->kex;
++	gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER,
++	    recv_tok = GSS_C_EMPTY_BUFFER,
++	    gssbuf, msg_tok = GSS_C_EMPTY_BUFFER, *token_ptr;
++	Gssctxt *ctxt;
++	OM_uint32 maj_status, min_status, ret_flags;
++	struct sshbuf *server_blob = NULL;
++	struct sshbuf *shared_secret = NULL;
++	struct sshbuf *server_host_key_blob = NULL;
++	struct sshbuf *empty = NULL;
++	u_char *msg;
++	int type = 0;
++	int first = 1;
++	u_char hash[SSH_DIGEST_MAX_LENGTH];
++	size_t hashlen;
++	u_char c;
++	int r;
++
++	/* Initialise our GSSAPI world */
++	ssh_gssapi_build_ctx(&ctxt);
++	if (ssh_gssapi_id_kex(ctxt, kex->name, kex->kex_type)
++	    == GSS_C_NO_OID)
++		fatal("Couldn't identify host exchange");
++
++	if (ssh_gssapi_import_name(ctxt, kex->gss_host))
++		fatal("Couldn't import hostname");
++
++	if (kex->gss_client &&
++	    ssh_gssapi_client_identity(ctxt, kex->gss_client))
++		fatal("Couldn't acquire client credentials");
++
++	/* Step 1 */
++	switch (kex->kex_type) {
++	case KEX_GSS_GRP1_SHA1:
++	case KEX_GSS_GRP14_SHA1:
++	case KEX_GSS_GRP14_SHA256:
++	case KEX_GSS_GRP16_SHA512:
++		r = kex_dh_keypair(kex);
++		break;
++	case KEX_GSS_NISTP256_SHA256:
++		r = kex_ecdh_keypair(kex);
++		break;
++	case KEX_GSS_C25519_SHA256:
++		r = kex_c25519_keypair(kex);
++		break;
++	default:
++		fatal_f("Unexpected KEX type %d", kex->kex_type);
++	}
++	if (r != 0)
++		return r;
++
++	token_ptr = GSS_C_NO_BUFFER;
++
++	do {
++		debug("Calling gss_init_sec_context");
++
++		maj_status = ssh_gssapi_init_ctx(ctxt,
++		    kex->gss_deleg_creds, token_ptr, &send_tok,
++		    &ret_flags);
++
++		if (GSS_ERROR(maj_status)) {
++			/* XXX Useles code: Missing send? */
++			if (send_tok.length != 0) {
++				if ((r = sshpkt_start(ssh,
++				        SSH2_MSG_KEXGSS_CONTINUE)) != 0 ||
++				    (r = sshpkt_put_string(ssh, send_tok.value,
++				        send_tok.length)) != 0)
++					fatal("sshpkt failed: %s", ssh_err(r));
++			}
++			fatal("gss_init_context failed");
++		}
++
++		/* If we've got an old receive buffer get rid of it */
++		if (token_ptr != GSS_C_NO_BUFFER)
++			gss_release_buffer(&min_status, &recv_tok);
++
++		if (maj_status == GSS_S_COMPLETE) {
++			/* If mutual state flag is not true, kex fails */
++			if (!(ret_flags & GSS_C_MUTUAL_FLAG))
++				fatal("Mutual authentication failed");
++
++			/* If integ avail flag is not true kex fails */
++			if (!(ret_flags & GSS_C_INTEG_FLAG))
++				fatal("Integrity check failed");
++		}
++
++		/*
++		 * If we have data to send, then the last message that we
++		 * received cannot have been a 'complete'.
++		 */
++		if (send_tok.length != 0) {
++			if (first) {
++				if ((r = sshpkt_start(ssh, SSH2_MSG_KEXGSS_INIT)) != 0 ||
++				    (r = sshpkt_put_string(ssh, send_tok.value,
++				        send_tok.length)) != 0 ||
++				    (r = sshpkt_put_stringb(ssh, kex->client_pub)) != 0)
++					fatal("failed to construct packet: %s", ssh_err(r));
++				first = 0;
++			} else {
++				if ((r = sshpkt_start(ssh, SSH2_MSG_KEXGSS_CONTINUE)) != 0 ||
++				    (r = sshpkt_put_string(ssh, send_tok.value,
++				        send_tok.length)) != 0)
++					fatal("failed to construct packet: %s", ssh_err(r));
++			}
++			if ((r = sshpkt_send(ssh)) != 0)
++				fatal("failed to send packet: %s", ssh_err(r));
++			gss_release_buffer(&min_status, &send_tok);
++
++			/* If we've sent them data, they should reply */
++			do {
++				type = ssh_packet_read(ssh);
++				if (type == SSH2_MSG_KEXGSS_HOSTKEY) {
++					debug("Received KEXGSS_HOSTKEY");
++					if (server_host_key_blob)
++						fatal("Server host key received more than once");
++					if ((r = sshpkt_getb_froms(ssh, &server_host_key_blob)) != 0)
++						fatal("Failed to read server host key: %s", ssh_err(r));
++				}
++			} while (type == SSH2_MSG_KEXGSS_HOSTKEY);
++
++			switch (type) {
++			case SSH2_MSG_KEXGSS_CONTINUE:
++				debug("Received GSSAPI_CONTINUE");
++				if (maj_status == GSS_S_COMPLETE)
++					fatal("GSSAPI Continue received from server when complete");
++				if ((r = ssh_gssapi_sshpkt_get_buffer_desc(ssh,
++				        &recv_tok)) != 0 ||
++				    (r = sshpkt_get_end(ssh)) != 0)
++					fatal("Failed to read token: %s", ssh_err(r));
++				break;
++			case SSH2_MSG_KEXGSS_COMPLETE:
++				debug("Received GSSAPI_COMPLETE");
++				if (msg_tok.value != NULL)
++				        fatal("Received GSSAPI_COMPLETE twice?");
++				if ((r = sshpkt_getb_froms(ssh, &server_blob)) != 0 ||
++				    (r = ssh_gssapi_sshpkt_get_buffer_desc(ssh,
++				        &msg_tok)) != 0)
++					fatal("Failed to read message: %s", ssh_err(r));
++
++				/* Is there a token included? */
++				if ((r = sshpkt_get_u8(ssh, &c)) != 0)
++					fatal("sshpkt failed: %s", ssh_err(r));
++				if (c) {
++					if ((r = ssh_gssapi_sshpkt_get_buffer_desc(
++					    ssh, &recv_tok)) != 0)
++						fatal("Failed to read token: %s", ssh_err(r));
++					/* If we're already complete - protocol error */
++					if (maj_status == GSS_S_COMPLETE)
++						sshpkt_disconnect(ssh, "Protocol error: received token when complete");
++				} else {
++					/* No token included */
++					if (maj_status != GSS_S_COMPLETE)
++						sshpkt_disconnect(ssh, "Protocol error: did not receive final token");
++				}
++				if ((r = sshpkt_get_end(ssh)) != 0) {
++					fatal("Expecting end of packet.");
++				}
++				break;
++			case SSH2_MSG_KEXGSS_ERROR:
++				debug("Received Error");
++				if ((r = sshpkt_get_u32(ssh, &maj_status)) != 0 ||
++				    (r = sshpkt_get_u32(ssh, &min_status)) != 0 ||
++				    (r = sshpkt_get_string(ssh, &msg, NULL)) != 0 ||
++				    (r = sshpkt_get_string(ssh, NULL, NULL)) != 0 || /* lang tag */
++				    (r = sshpkt_get_end(ssh)) != 0)
++					fatal("sshpkt_get failed: %s", ssh_err(r));
++				fatal("GSSAPI Error: \n%.400s", msg);
++			default:
++				sshpkt_disconnect(ssh, "Protocol error: didn't expect packet type %d",
++				    type);
++			}
++			token_ptr = &recv_tok;
++		} else {
++			/* No data, and not complete */
++			if (maj_status != GSS_S_COMPLETE)
++				fatal("Not complete, and no token output");
++		}
++	} while (maj_status & GSS_S_CONTINUE_NEEDED);
++
++	/*
++	 * We _must_ have received a COMPLETE message in reply from the
++	 * server, which will have set server_blob and msg_tok
++	 */
++
++	if (type != SSH2_MSG_KEXGSS_COMPLETE)
++		fatal("Didn't receive a SSH2_MSG_KEXGSS_COMPLETE when I expected it");
++
++	/* compute shared secret */
++	switch (kex->kex_type) {
++	case KEX_GSS_GRP1_SHA1:
++	case KEX_GSS_GRP14_SHA1:
++	case KEX_GSS_GRP14_SHA256:
++	case KEX_GSS_GRP16_SHA512:
++		r = kex_dh_dec(kex, server_blob, &shared_secret);
++		break;
++	case KEX_GSS_C25519_SHA256:
++		if (sshbuf_ptr(server_blob)[sshbuf_len(server_blob)] & 0x80)
++			fatal("The received key has MSB of last octet set!");
++		r = kex_c25519_dec(kex, server_blob, &shared_secret);
++		break;
++	case KEX_GSS_NISTP256_SHA256:
++		if (sshbuf_len(server_blob) != 65)
++			fatal("The received NIST-P256 key did not match"
++			    "expected length (expected 65, got %zu)", sshbuf_len(server_blob));
++
++		if (sshbuf_ptr(server_blob)[0] != POINT_CONVERSION_UNCOMPRESSED)
++			fatal("The received NIST-P256 key does not have first octet 0x04");
++
++		r = kex_ecdh_dec(kex, server_blob, &shared_secret);
++		break;
++	default:
++		r = SSH_ERR_INVALID_ARGUMENT;
++		break;
++	}
++	if (r != 0)
++		goto out;
++
++	if ((empty = sshbuf_new()) == NULL) {
++		r = SSH_ERR_ALLOC_FAIL;
++		goto out;
++	}
++
++	hashlen = sizeof(hash);
++	if ((r = kex_gen_hash(
++	    kex->hash_alg,
++	    kex->client_version,
++	    kex->server_version,
++	    kex->my,
++	    kex->peer,
++	    (server_host_key_blob ? server_host_key_blob : empty),
++	    kex->client_pub,
++	    server_blob,
++	    shared_secret,
++	    hash, &hashlen)) != 0)
++		fatal_f("Unexpected KEX type %d", kex->kex_type);
++
++	gssbuf.value = hash;
++	gssbuf.length = hashlen;
++
++	/* Verify that the hash matches the MIC we just got. */
++	if (GSS_ERROR(ssh_gssapi_checkmic(ctxt, &gssbuf, &msg_tok)))
++		sshpkt_disconnect(ssh, "Hash's MIC didn't verify");
++
++	gss_release_buffer(&min_status, &msg_tok);
++
++	if (kex->gss_deleg_creds)
++		ssh_gssapi_credentials_updated(ctxt);
++
++	if (gss_kex_context == NULL)
++		gss_kex_context = ctxt;
++	else
++		ssh_gssapi_delete_ctx(&ctxt);
++
++	if ((r = kex_derive_keys(ssh, hash, hashlen, shared_secret)) == 0)
++		r = kex_send_newkeys(ssh);
++
++out:
++	explicit_bzero(hash, sizeof(hash));
++	explicit_bzero(kex->c25519_client_key, sizeof(kex->c25519_client_key));
++	sshbuf_free(empty);
++	sshbuf_free(server_host_key_blob);
++	sshbuf_free(server_blob);
++	sshbuf_free(shared_secret);
++	sshbuf_free(kex->client_pub);
++	kex->client_pub = NULL;
++	return r;
++}
++
++int
++kexgssgex_client(struct ssh *ssh)
++{
++	struct kex *kex = ssh->kex;
++	gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER,
++	    recv_tok = GSS_C_EMPTY_BUFFER, gssbuf,
++            msg_tok = GSS_C_EMPTY_BUFFER, *token_ptr;
++	Gssctxt *ctxt;
++	OM_uint32 maj_status, min_status, ret_flags;
++	struct sshbuf *shared_secret = NULL;
++	BIGNUM *p = NULL;
++	BIGNUM *g = NULL;
++	struct sshbuf *buf = NULL;
++	struct sshbuf *server_host_key_blob = NULL;
++	struct sshbuf *server_blob = NULL;
++	BIGNUM *dh_server_pub = NULL;
++	u_char *msg;
++	int type = 0;
++	int first = 1;
++	u_char hash[SSH_DIGEST_MAX_LENGTH];
++	size_t hashlen;
++	const BIGNUM *pub_key, *dh_p, *dh_g;
++	int nbits = 0, min = DH_GRP_MIN, max = DH_GRP_MAX;
++	struct sshbuf *empty = NULL;
++	u_char c;
++	int r;
++
++	/* Initialise our GSSAPI world */
++	ssh_gssapi_build_ctx(&ctxt);
++	if (ssh_gssapi_id_kex(ctxt, kex->name, kex->kex_type)
++	    == GSS_C_NO_OID)
++		fatal("Couldn't identify host exchange");
++
++	if (ssh_gssapi_import_name(ctxt, kex->gss_host))
++		fatal("Couldn't import hostname");
++
++	if (kex->gss_client &&
++	    ssh_gssapi_client_identity(ctxt, kex->gss_client))
++		fatal("Couldn't acquire client credentials");
++
++	debug("Doing group exchange");
++	nbits = dh_estimate(kex->dh_need * 8);
++
++	kex->min = DH_GRP_MIN;
++	kex->max = DH_GRP_MAX;
++	kex->nbits = nbits;
++	if ((r = sshpkt_start(ssh, SSH2_MSG_KEXGSS_GROUPREQ)) != 0 ||
++	    (r = sshpkt_put_u32(ssh, min)) != 0 ||
++	    (r = sshpkt_put_u32(ssh, nbits)) != 0 ||
++	    (r = sshpkt_put_u32(ssh, max)) != 0 ||
++	    (r = sshpkt_send(ssh)) != 0)
++		fatal("Failed to construct a packet: %s", ssh_err(r));
++
++	type = ssh_packet_read(ssh);
++	if (type != SSH2_MSG_KEXGSS_GROUP)
++		ssh_packet_disconnect(ssh,
++		    "Protocol error: expected packet type %d, got %d",
++		    SSH2_MSG_KEXGSS_GROUP, type);
++
++	if ((r = sshpkt_get_bignum2(ssh, &p)) != 0 ||
++	    (r = sshpkt_get_bignum2(ssh, &g)) != 0 ||
++	    (r = sshpkt_get_end(ssh)) != 0)
++		fatal("shpkt_get_bignum2 failed: %s", ssh_err(r));
++
++	if (BN_num_bits(p) < min || BN_num_bits(p) > max)
++		fatal("GSSGRP_GEX group out of range: %d !< %d !< %d",
++		    min, BN_num_bits(p), max);
++
++	if ((kex->dh = dh_new_group(g, p)) == NULL)
++		fatal("dn_new_group() failed");
++	p = g = NULL; /* belong to kex->dh now */
++
++	if ((r = dh_gen_key(kex->dh, kex->we_need * 8)) != 0)
++		goto out;
++	DH_get0_key(kex->dh, &pub_key, NULL);
++
++	token_ptr = GSS_C_NO_BUFFER;
++
++	do {
++		/* Step 2 - call GSS_Init_sec_context() */
++		debug("Calling gss_init_sec_context");
++
++		maj_status = ssh_gssapi_init_ctx(ctxt,
++		    kex->gss_deleg_creds, token_ptr, &send_tok,
++		    &ret_flags);
++
++		if (GSS_ERROR(maj_status)) {
++			/* XXX Useles code: Missing send? */
++			if (send_tok.length != 0) {
++				if ((r = sshpkt_start(ssh,
++				        SSH2_MSG_KEXGSS_CONTINUE)) != 0 ||
++				    (r = sshpkt_put_string(ssh, send_tok.value,
++				        send_tok.length)) != 0)
++					fatal("sshpkt failed: %s", ssh_err(r));
++			}
++			fatal("gss_init_context failed");
++		}
++
++		/* If we've got an old receive buffer get rid of it */
++		if (token_ptr != GSS_C_NO_BUFFER)
++			gss_release_buffer(&min_status, &recv_tok);
++
++		if (maj_status == GSS_S_COMPLETE) {
++			/* If mutual state flag is not true, kex fails */
++			if (!(ret_flags & GSS_C_MUTUAL_FLAG))
++				fatal("Mutual authentication failed");
++
++			/* If integ avail flag is not true kex fails */
++			if (!(ret_flags & GSS_C_INTEG_FLAG))
++				fatal("Integrity check failed");
++		}
++
++		/*
++		 * If we have data to send, then the last message that we
++		 * received cannot have been a 'complete'.
++		 */
++		if (send_tok.length != 0) {
++			if (first) {
++				if ((r = sshpkt_start(ssh, SSH2_MSG_KEXGSS_INIT)) != 0 ||
++				    (r = sshpkt_put_string(ssh, send_tok.value,
++				        send_tok.length)) != 0 ||
++				    (r = sshpkt_put_bignum2(ssh, pub_key)) != 0)
++					fatal("sshpkt failed: %s", ssh_err(r));
++				first = 0;
++			} else {
++				if ((r = sshpkt_start(ssh, SSH2_MSG_KEXGSS_CONTINUE)) != 0 ||
++				    (r = sshpkt_put_string(ssh,send_tok.value,
++				        send_tok.length)) != 0)
++					fatal("sshpkt failed: %s", ssh_err(r));
++			}
++			if ((r = sshpkt_send(ssh)) != 0)
++				fatal("sshpkt_send failed: %s", ssh_err(r));
++			gss_release_buffer(&min_status, &send_tok);
++
++			/* If we've sent them data, they should reply */
++			do {
++				type = ssh_packet_read(ssh);
++				if (type == SSH2_MSG_KEXGSS_HOSTKEY) {
++					debug("Received KEXGSS_HOSTKEY");
++					if (server_host_key_blob)
++						fatal("Server host key received more than once");
++					if ((r = sshpkt_getb_froms(ssh, &server_host_key_blob)) != 0)
++						fatal("sshpkt failed: %s", ssh_err(r));
++				}
++			} while (type == SSH2_MSG_KEXGSS_HOSTKEY);
++
++			switch (type) {
++			case SSH2_MSG_KEXGSS_CONTINUE:
++				debug("Received GSSAPI_CONTINUE");
++				if (maj_status == GSS_S_COMPLETE)
++					fatal("GSSAPI Continue received from server when complete");
++				if ((r = ssh_gssapi_sshpkt_get_buffer_desc(ssh,
++				        &recv_tok)) != 0 ||
++				    (r = sshpkt_get_end(ssh)) != 0)
++					fatal("sshpkt failed: %s", ssh_err(r));
++				break;
++			case SSH2_MSG_KEXGSS_COMPLETE:
++				debug("Received GSSAPI_COMPLETE");
++				if (msg_tok.value != NULL)
++				        fatal("Received GSSAPI_COMPLETE twice?");
++				if ((r = sshpkt_getb_froms(ssh, &server_blob)) != 0 ||
++				    (r = ssh_gssapi_sshpkt_get_buffer_desc(ssh,
++				        &msg_tok)) != 0)
++					fatal("sshpkt failed: %s", ssh_err(r));
++
++				/* Is there a token included? */
++				if ((r = sshpkt_get_u8(ssh, &c)) != 0)
++					fatal("sshpkt failed: %s", ssh_err(r));
++				if (c) {
++					if ((r = ssh_gssapi_sshpkt_get_buffer_desc(
++					        ssh, &recv_tok)) != 0 ||
++					    (r = sshpkt_get_end(ssh)) != 0)
++						fatal("sshpkt failed: %s", ssh_err(r));
++					/* If we're already complete - protocol error */
++					if (maj_status == GSS_S_COMPLETE)
++						sshpkt_disconnect(ssh, "Protocol error: received token when complete");
++				} else {
++					/* No token included */
++					if (maj_status != GSS_S_COMPLETE)
++						sshpkt_disconnect(ssh, "Protocol error: did not receive final token");
++				}
++				break;
++			case SSH2_MSG_KEXGSS_ERROR:
++				debug("Received Error");
++				if ((r = sshpkt_get_u32(ssh, &maj_status)) != 0 ||
++				    (r = sshpkt_get_u32(ssh, &min_status)) != 0 ||
++				    (r = sshpkt_get_string(ssh, &msg, NULL)) != 0 ||
++				    (r = sshpkt_get_string(ssh, NULL, NULL)) != 0 || /* lang tag */
++				    (r = sshpkt_get_end(ssh)) != 0)
++					fatal("sshpkt failed: %s", ssh_err(r));
++				fatal("GSSAPI Error: \n%.400s", msg);
++			default:
++				sshpkt_disconnect(ssh, "Protocol error: didn't expect packet type %d",
++				    type);
++			}
++			token_ptr = &recv_tok;
++		} else {
++			/* No data, and not complete */
++			if (maj_status != GSS_S_COMPLETE)
++				fatal("Not complete, and no token output");
++		}
++	} while (maj_status & GSS_S_CONTINUE_NEEDED);
++
++	/*
++	 * We _must_ have received a COMPLETE message in reply from the
++	 * server, which will have set dh_server_pub and msg_tok
++	 */
++
++	if (type != SSH2_MSG_KEXGSS_COMPLETE)
++		fatal("Didn't receive a SSH2_MSG_KEXGSS_COMPLETE when I expected it");
++
++	/* 7. C verifies that the key Q_S is valid */
++	/* 8. C computes shared secret */
++	if ((buf = sshbuf_new()) == NULL ||
++	    (r = sshbuf_put_stringb(buf, server_blob)) != 0 ||
++	    (r = sshbuf_get_bignum2(buf, &dh_server_pub)) != 0)
++		goto out;
++	sshbuf_free(buf);
++	buf = NULL;
++
++	if ((shared_secret = sshbuf_new()) == NULL) {
++		r = SSH_ERR_ALLOC_FAIL;
++		goto out;
++	}
++
++	if ((r = kex_dh_compute_key(kex, dh_server_pub, shared_secret)) != 0)
++		goto out;
++	if ((empty = sshbuf_new()) == NULL) {
++		r = SSH_ERR_ALLOC_FAIL;
++		goto out;
++	}
++
++	DH_get0_pqg(kex->dh, &dh_p, NULL, &dh_g);
++	hashlen = sizeof(hash);
++	if ((r = kexgex_hash(
++	    kex->hash_alg,
++	    kex->client_version,
++	    kex->server_version,
++	    kex->my,
++	    kex->peer,
++	    (server_host_key_blob ? server_host_key_blob : empty),
++ 	    kex->min, kex->nbits, kex->max,
++	    dh_p, dh_g,
++	    pub_key,
++	    dh_server_pub,
++	    sshbuf_ptr(shared_secret), sshbuf_len(shared_secret),
++	    hash, &hashlen)) != 0)
++		fatal("Failed to calculate hash: %s", ssh_err(r));
++
++	gssbuf.value = hash;
++	gssbuf.length = hashlen;
++
++	/* Verify that the hash matches the MIC we just got. */
++	if (GSS_ERROR(ssh_gssapi_checkmic(ctxt, &gssbuf, &msg_tok)))
++		sshpkt_disconnect(ssh, "Hash's MIC didn't verify");
++
++	gss_release_buffer(&min_status, &msg_tok);
++
++	if (kex->gss_deleg_creds)
++		ssh_gssapi_credentials_updated(ctxt);
++
++	if (gss_kex_context == NULL)
++		gss_kex_context = ctxt;
++	else
++		ssh_gssapi_delete_ctx(&ctxt);
++
++	/* Finally derive the keys and send them */
++	if ((r = kex_derive_keys(ssh, hash, hashlen, shared_secret)) == 0)
++		r = kex_send_newkeys(ssh);
++out:
++	sshbuf_free(buf);
++	sshbuf_free(server_blob);
++	sshbuf_free(empty);
++	explicit_bzero(hash, sizeof(hash));
++	DH_free(kex->dh);
++	kex->dh = NULL;
++	BN_clear_free(dh_server_pub);
++	sshbuf_free(shared_secret);
++	sshbuf_free(server_host_key_blob);
++	return r;
++}
++#endif /* defined(GSSAPI) && defined(WITH_OPENSSL) */
+diff --git a/kexgsss.c b/kexgsss.c
+new file mode 100644
+index 000000000..40d184170
+--- /dev/null
++++ b/kexgsss.c
+@@ -0,0 +1,478 @@
++/*
++ * Copyright (c) 2001-2009 Simon Wilkinson. All rights reserved.
++ *
++ * Redistribution and use in source and binary forms, with or without
++ * modification, are permitted provided that the following conditions
++ * are met:
++ * 1. Redistributions of source code must retain the above copyright
++ *    notice, this list of conditions and the following disclaimer.
++ * 2. Redistributions in binary form must reproduce the above copyright
++ *    notice, this list of conditions and the following disclaimer in the
++ *    documentation and/or other materials provided with the distribution.
++ *
++ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR `AS IS'' AND ANY EXPRESS OR
++ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
++ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
++ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
++ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
++ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
++ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
++ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
++ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
++ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
++ */
++
++#include "includes.h"
++
++#if defined(GSSAPI) && defined(WITH_OPENSSL)
++
++#include <string.h>
++
++#include <openssl/crypto.h>
++#include <openssl/bn.h>
++
++#include "xmalloc.h"
++#include "sshbuf.h"
++#include "ssh2.h"
++#include "sshkey.h"
++#include "cipher.h"
++#include "kex.h"
++#include "log.h"
++#include "packet.h"
++#include "dh.h"
++#include "ssh-gss.h"
++#include "monitor_wrap.h"
++#include "misc.h"      /* servconf.h needs misc.h for struct ForwardOptions */
++#include "servconf.h"
++#include "ssh-gss.h"
++#include "digest.h"
++#include "ssherr.h"
++
++extern ServerOptions options;
++
++int
++kexgss_server(struct ssh *ssh)
++{
++	struct kex *kex = ssh->kex;
++	OM_uint32 maj_status, min_status;
++
++	/*
++	 * Some GSSAPI implementations use the input value of ret_flags (an
++	 * output variable) as a means of triggering mechanism specific
++	 * features. Initializing it to zero avoids inadvertently
++	 * activating this non-standard behaviour.
++	 */
++
++	OM_uint32 ret_flags = 0;
++	gss_buffer_desc gssbuf, recv_tok, msg_tok;
++	gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
++	Gssctxt *ctxt = NULL;
++	struct sshbuf *shared_secret = NULL;
++	struct sshbuf *client_pubkey = NULL;
++	struct sshbuf *server_pubkey = NULL;
++	struct sshbuf *empty = sshbuf_new();
++	int type = 0;
++	gss_OID oid;
++	char *mechs;
++	u_char hash[SSH_DIGEST_MAX_LENGTH];
++	size_t hashlen;
++	int r;
++
++	/* Initialise GSSAPI */
++
++	/* If we're rekeying, privsep means that some of the private structures
++	 * in the GSSAPI code are no longer available. This kludges them back
++	 * into life
++	 */
++	if (!ssh_gssapi_oid_table_ok()) {
++		mechs = ssh_gssapi_server_mechanisms();
++		free(mechs);
++	}
++
++	debug2_f("Identifying %s", kex->name);
++	oid = ssh_gssapi_id_kex(NULL, kex->name, kex->kex_type);
++	if (oid == GSS_C_NO_OID)
++	   fatal("Unknown gssapi mechanism");
++
++	debug2_f("Acquiring credentials");
++
++	if (GSS_ERROR(PRIVSEP(ssh_gssapi_server_ctx(&ctxt, oid))))
++		fatal("Unable to acquire credentials for the server");
++
++	do {
++		debug("Wait SSH2_MSG_KEXGSS_INIT");
++		type = ssh_packet_read(ssh);
++		switch(type) {
++		case SSH2_MSG_KEXGSS_INIT:
++			if (client_pubkey != NULL)
++				fatal("Received KEXGSS_INIT after initialising");
++			if ((r = ssh_gssapi_sshpkt_get_buffer_desc(ssh,
++			        &recv_tok)) != 0 ||
++			    (r = sshpkt_getb_froms(ssh, &client_pubkey)) != 0 ||
++			    (r = sshpkt_get_end(ssh)) != 0)
++				fatal("sshpkt failed: %s", ssh_err(r));
++
++			switch (kex->kex_type) {
++			case KEX_GSS_GRP1_SHA1:
++			case KEX_GSS_GRP14_SHA1:
++			case KEX_GSS_GRP14_SHA256:
++			case KEX_GSS_GRP16_SHA512:
++				r = kex_dh_enc(kex, client_pubkey, &server_pubkey,
++				    &shared_secret);
++				break;
++			case KEX_GSS_NISTP256_SHA256:
++				r = kex_ecdh_enc(kex, client_pubkey, &server_pubkey,
++				    &shared_secret);
++				break;
++			case KEX_GSS_C25519_SHA256:
++				r = kex_c25519_enc(kex, client_pubkey, &server_pubkey,
++				    &shared_secret);
++				break;
++			default:
++				fatal_f("Unexpected KEX type %d", kex->kex_type);
++			}
++			if (r != 0)
++				goto out;
++
++			/* Send SSH_MSG_KEXGSS_HOSTKEY here, if we want */
++			break;
++		case SSH2_MSG_KEXGSS_CONTINUE:
++			if ((r = ssh_gssapi_sshpkt_get_buffer_desc(ssh,
++			        &recv_tok)) != 0 ||
++			    (r = sshpkt_get_end(ssh)) != 0)
++				fatal("sshpkt failed: %s", ssh_err(r));
++			break;
++		default:
++			sshpkt_disconnect(ssh,
++			    "Protocol error: didn't expect packet type %d",
++			    type);
++		}
++
++		maj_status = PRIVSEP(ssh_gssapi_accept_ctx(ctxt, &recv_tok,
++		    &send_tok, &ret_flags));
++
++		gss_release_buffer(&min_status, &recv_tok);
++
++		if (maj_status != GSS_S_COMPLETE && send_tok.length == 0)
++			fatal("Zero length token output when incomplete");
++
++		if (client_pubkey == NULL)
++			fatal("No client public key");
++
++		if (maj_status & GSS_S_CONTINUE_NEEDED) {
++			debug("Sending GSSAPI_CONTINUE");
++			if ((r = sshpkt_start(ssh, SSH2_MSG_KEXGSS_CONTINUE)) != 0 ||
++			    (r = sshpkt_put_string(ssh, send_tok.value, send_tok.length)) != 0 ||
++			    (r = sshpkt_send(ssh)) != 0)
++				fatal("sshpkt failed: %s", ssh_err(r));
++			gss_release_buffer(&min_status, &send_tok);
++		}
++	} while (maj_status & GSS_S_CONTINUE_NEEDED);
++
++	if (GSS_ERROR(maj_status)) {
++		if (send_tok.length > 0) {
++			if ((r = sshpkt_start(ssh, SSH2_MSG_KEXGSS_CONTINUE)) != 0 ||
++			    (r = sshpkt_put_string(ssh, send_tok.value, send_tok.length)) != 0 ||
++			    (r = sshpkt_send(ssh)) != 0)
++				fatal("sshpkt failed: %s", ssh_err(r));
++		}
++		fatal("accept_ctx died");
++	}
++
++	if (!(ret_flags & GSS_C_MUTUAL_FLAG))
++		fatal("Mutual Authentication flag wasn't set");
++
++	if (!(ret_flags & GSS_C_INTEG_FLAG))
++		fatal("Integrity flag wasn't set");
++
++	hashlen = sizeof(hash);
++	if ((r = kex_gen_hash(
++	    kex->hash_alg,
++	    kex->client_version,
++	    kex->server_version,
++	    kex->peer,
++	    kex->my,
++	    empty,
++	    client_pubkey,
++	    server_pubkey,
++	    shared_secret,
++	    hash, &hashlen)) != 0)
++		goto out;
++
++	gssbuf.value = hash;
++	gssbuf.length = hashlen;
++
++	if (GSS_ERROR(PRIVSEP(ssh_gssapi_sign(ctxt, &gssbuf, &msg_tok))))
++		fatal("Couldn't get MIC");
++
++	if ((r = sshpkt_start(ssh, SSH2_MSG_KEXGSS_COMPLETE)) != 0 ||
++	    (r = sshpkt_put_stringb(ssh, server_pubkey)) != 0 ||
++	    (r = sshpkt_put_string(ssh, msg_tok.value, msg_tok.length)) != 0)
++		fatal("sshpkt failed: %s", ssh_err(r));
++
++	if (send_tok.length != 0) {
++		if ((r = sshpkt_put_u8(ssh, 1)) != 0 || /* true */
++		    (r = sshpkt_put_string(ssh, send_tok.value, send_tok.length)) != 0)
++			fatal("sshpkt failed: %s", ssh_err(r));
++	} else {
++		if ((r = sshpkt_put_u8(ssh, 0)) != 0) /* false */
++			fatal("sshpkt failed: %s", ssh_err(r));
++	}
++	if ((r = sshpkt_send(ssh)) != 0)
++		fatal("sshpkt_send failed: %s", ssh_err(r));
++
++	gss_release_buffer(&min_status, &send_tok);
++	gss_release_buffer(&min_status, &msg_tok);
++
++	if (gss_kex_context == NULL)
++		gss_kex_context = ctxt;
++	else
++		ssh_gssapi_delete_ctx(&ctxt);
++
++	if ((r = kex_derive_keys(ssh, hash, hashlen, shared_secret)) == 0)
++		r = kex_send_newkeys(ssh);
++
++	/* If this was a rekey, then save out any delegated credentials we
++	 * just exchanged.  */
++	if (options.gss_store_rekey)
++		ssh_gssapi_rekey_creds();
++out:
++	sshbuf_free(empty);
++	explicit_bzero(hash, sizeof(hash));
++	sshbuf_free(shared_secret);
++	sshbuf_free(client_pubkey);
++	sshbuf_free(server_pubkey);
++	return r;
++}
++
++int
++kexgssgex_server(struct ssh *ssh)
++{
++	struct kex *kex = ssh->kex;
++	OM_uint32 maj_status, min_status;
++
++	/*
++	 * Some GSSAPI implementations use the input value of ret_flags (an
++	 * output variable) as a means of triggering mechanism specific
++	 * features. Initializing it to zero avoids inadvertently
++	 * activating this non-standard behaviour.
++	 */
++
++	OM_uint32 ret_flags = 0;
++	gss_buffer_desc gssbuf, recv_tok, msg_tok;
++	gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
++	Gssctxt *ctxt = NULL;
++	struct sshbuf *shared_secret = NULL;
++	int type = 0;
++	gss_OID oid;
++	char *mechs;
++	u_char hash[SSH_DIGEST_MAX_LENGTH];
++	size_t hashlen;
++	BIGNUM *dh_client_pub = NULL;
++	const BIGNUM *pub_key, *dh_p, *dh_g;
++	int min = -1, max = -1, nbits = -1;
++	int cmin = -1, cmax = -1; /* client proposal */
++	struct sshbuf *empty = sshbuf_new();
++	int r;
++
++	/* Initialise GSSAPI */
++
++	/* If we're rekeying, privsep means that some of the private structures
++	 * in the GSSAPI code are no longer available. This kludges them back
++	 * into life
++	 */
++	if (!ssh_gssapi_oid_table_ok())
++		if ((mechs = ssh_gssapi_server_mechanisms()))
++			free(mechs);
++
++	debug2_f("Identifying %s", kex->name);
++	oid = ssh_gssapi_id_kex(NULL, kex->name, kex->kex_type);
++	if (oid == GSS_C_NO_OID)
++	   fatal("Unknown gssapi mechanism");
++
++	debug2_f("Acquiring credentials");
++
++	if (GSS_ERROR(PRIVSEP(ssh_gssapi_server_ctx(&ctxt, oid))))
++		fatal("Unable to acquire credentials for the server");
++
++	/* 5. S generates an ephemeral key pair (do the allocations early) */
++	debug("Doing group exchange");
++	type = ssh_packet_read(ssh);
++	if (type != SSH2_MSG_KEXGSS_GROUPREQ)
++		ssh_packet_disconnect(ssh,
++		    "Protocol error: expected packet type %d, got %d",
++		    SSH2_MSG_KEXGSS_GROUPREQ, type);
++	/* store client proposal to provide valid signature */
++	if ((r = sshpkt_get_u32(ssh, &cmin)) != 0 ||
++	    (r = sshpkt_get_u32(ssh, &nbits)) != 0 ||
++	    (r = sshpkt_get_u32(ssh, &cmax)) != 0 ||
++	    (r = sshpkt_get_end(ssh)) != 0)
++		fatal("sshpkt failed: %s", ssh_err(r));
++	kex->nbits = nbits;
++	kex->min = cmin;
++	kex->max = cmax;
++	min = MAX(DH_GRP_MIN, cmin);
++	max = MIN(DH_GRP_MAX, cmax);
++	nbits = MAXIMUM(DH_GRP_MIN, nbits);
++	nbits = MINIMUM(DH_GRP_MAX, nbits);
++	if (max < min || nbits < min || max < nbits)
++		fatal("GSS_GEX, bad parameters: %d !< %d !< %d",
++		    min, nbits, max);
++	kex->dh = PRIVSEP(choose_dh(min, nbits, max));
++	if (kex->dh == NULL) {
++		sshpkt_disconnect(ssh, "Protocol error: no matching group found");
++		fatal("Protocol error: no matching group found");
++	}
++
++	DH_get0_pqg(kex->dh, &dh_p, NULL, &dh_g);
++	if ((r = sshpkt_start(ssh, SSH2_MSG_KEXGSS_GROUP)) != 0 ||
++	    (r = sshpkt_put_bignum2(ssh, dh_p)) != 0 ||
++	    (r = sshpkt_put_bignum2(ssh, dh_g)) != 0 ||
++	    (r = sshpkt_send(ssh)) != 0)
++		fatal("sshpkt failed: %s", ssh_err(r));
++
++	if ((r = ssh_packet_write_wait(ssh)) != 0)
++		fatal("ssh_packet_write_wait: %s", ssh_err(r));
++
++	/* Compute our exchange value in parallel with the client */
++	if ((r = dh_gen_key(kex->dh, kex->we_need * 8)) != 0)
++		goto out;
++
++	do {
++		debug("Wait SSH2_MSG_GSSAPI_INIT");
++		type = ssh_packet_read(ssh);
++		switch(type) {
++		case SSH2_MSG_KEXGSS_INIT:
++			if (dh_client_pub != NULL)
++				fatal("Received KEXGSS_INIT after initialising");
++			if ((r = ssh_gssapi_sshpkt_get_buffer_desc(ssh,
++			        &recv_tok)) != 0 ||
++			    (r = sshpkt_get_bignum2(ssh, &dh_client_pub)) != 0 ||
++			    (r = sshpkt_get_end(ssh)) != 0)
++				fatal("sshpkt failed: %s", ssh_err(r));
++
++			/* Send SSH_MSG_KEXGSS_HOSTKEY here, if we want */
++			break;
++		case SSH2_MSG_KEXGSS_CONTINUE:
++			if ((r = ssh_gssapi_sshpkt_get_buffer_desc(ssh,
++			        &recv_tok)) != 0 ||
++			    (r = sshpkt_get_end(ssh)) != 0)
++				fatal("sshpkt failed: %s", ssh_err(r));
++			break;
++		default:
++			sshpkt_disconnect(ssh,
++			    "Protocol error: didn't expect packet type %d",
++			    type);
++		}
++
++		maj_status = PRIVSEP(ssh_gssapi_accept_ctx(ctxt, &recv_tok,
++		    &send_tok, &ret_flags));
++
++		gss_release_buffer(&min_status, &recv_tok);
++
++		if (maj_status != GSS_S_COMPLETE && send_tok.length == 0)
++			fatal("Zero length token output when incomplete");
++
++		if (dh_client_pub == NULL)
++			fatal("No client public key");
++
++		if (maj_status & GSS_S_CONTINUE_NEEDED) {
++			debug("Sending GSSAPI_CONTINUE");
++			if ((r = sshpkt_start(ssh, SSH2_MSG_KEXGSS_CONTINUE)) != 0 ||
++			    (r = sshpkt_put_string(ssh, send_tok.value, send_tok.length)) != 0 ||
++			    (r = sshpkt_send(ssh)) != 0)
++				fatal("sshpkt failed: %s", ssh_err(r));
++			gss_release_buffer(&min_status, &send_tok);
++		}
++	} while (maj_status & GSS_S_CONTINUE_NEEDED);
++
++	if (GSS_ERROR(maj_status)) {
++		if (send_tok.length > 0) {
++			if ((r = sshpkt_start(ssh, SSH2_MSG_KEXGSS_CONTINUE)) != 0 ||
++			    (r = sshpkt_put_string(ssh, send_tok.value, send_tok.length)) != 0 ||
++			    (r = sshpkt_send(ssh)) != 0)
++				fatal("sshpkt failed: %s", ssh_err(r));
++		}
++		fatal("accept_ctx died");
++	}
++
++	if (!(ret_flags & GSS_C_MUTUAL_FLAG))
++		fatal("Mutual Authentication flag wasn't set");
++
++	if (!(ret_flags & GSS_C_INTEG_FLAG))
++		fatal("Integrity flag wasn't set");
++
++	/* calculate shared secret */
++	if ((shared_secret = sshbuf_new()) == NULL) {
++		r = SSH_ERR_ALLOC_FAIL;
++		goto out;
++	}
++	if ((r = kex_dh_compute_key(kex, dh_client_pub, shared_secret)) != 0)
++		goto out;
++
++	DH_get0_key(kex->dh, &pub_key, NULL);
++	DH_get0_pqg(kex->dh, &dh_p, NULL, &dh_g);
++	hashlen = sizeof(hash);
++	if ((r = kexgex_hash(
++	    kex->hash_alg,
++	    kex->client_version,
++	    kex->server_version,
++	    kex->peer,
++	    kex->my,
++	    empty,
++	    cmin, nbits, cmax,
++	    dh_p, dh_g,
++	    dh_client_pub,
++	    pub_key,
++	    sshbuf_ptr(shared_secret), sshbuf_len(shared_secret),
++	    hash, &hashlen)) != 0)
++		fatal("kexgex_hash failed: %s", ssh_err(r));
++
++	gssbuf.value = hash;
++	gssbuf.length = hashlen;
++
++	if (GSS_ERROR(PRIVSEP(ssh_gssapi_sign(ctxt, &gssbuf, &msg_tok))))
++		fatal("Couldn't get MIC");
++
++	if ((r = sshpkt_start(ssh, SSH2_MSG_KEXGSS_COMPLETE)) != 0 ||
++	    (r = sshpkt_put_bignum2(ssh, pub_key)) != 0 ||
++	    (r = sshpkt_put_string(ssh, msg_tok.value, msg_tok.length)) != 0)
++		fatal("sshpkt failed: %s", ssh_err(r));
++
++	if (send_tok.length != 0) {
++		if ((r = sshpkt_put_u8(ssh, 1)) != 0 || /* true */
++		    (r = sshpkt_put_string(ssh, send_tok.value, send_tok.length)) != 0)
++			fatal("sshpkt failed: %s", ssh_err(r));
++	} else {
++		if ((r = sshpkt_put_u8(ssh, 0)) != 0) /* false */
++			fatal("sshpkt failed: %s", ssh_err(r));
++	}
++	if ((r = sshpkt_send(ssh)) != 0)
++		fatal("sshpkt failed: %s", ssh_err(r));
++
++	gss_release_buffer(&min_status, &send_tok);
++	gss_release_buffer(&min_status, &msg_tok);
++
++	if (gss_kex_context == NULL)
++		gss_kex_context = ctxt;
++	else
++		ssh_gssapi_delete_ctx(&ctxt);
++
++	/* Finally derive the keys and send them */
++	if ((r = kex_derive_keys(ssh, hash, hashlen, shared_secret)) == 0)
++		r = kex_send_newkeys(ssh);
++
++	/* If this was a rekey, then save out any delegated credentials we
++	 * just exchanged.  */
++	if (options.gss_store_rekey)
++		ssh_gssapi_rekey_creds();
++out:
++	sshbuf_free(empty);
++	explicit_bzero(hash, sizeof(hash));
++	DH_free(kex->dh);
++	kex->dh = NULL;
++	BN_clear_free(dh_client_pub);
++	sshbuf_free(shared_secret);
++	return r;
++}
++#endif /* defined(GSSAPI) && defined(WITH_OPENSSL) */
+diff --git a/monitor.c b/monitor.c
+index b3ed515ed..2bc152468 100644
+--- a/monitor.c
++++ b/monitor.c
+@@ -142,6 +142,8 @@ int mm_answer_gss_setup_ctx(struct ssh *, int, struct sshbuf *);
+ int mm_answer_gss_accept_ctx(struct ssh *, int, struct sshbuf *);
+ int mm_answer_gss_userok(struct ssh *, int, struct sshbuf *);
+ int mm_answer_gss_checkmic(struct ssh *, int, struct sshbuf *);
++int mm_answer_gss_sign(struct ssh *, int, struct sshbuf *);
++int mm_answer_gss_updatecreds(struct ssh *, int, struct sshbuf *);
+ #endif
+ 
+ #ifdef SSH_AUDIT_EVENTS
+@@ -214,11 +216,18 @@ struct mon_table mon_dispatch_proto20[] = {
+     {MONITOR_REQ_GSSSTEP, 0, mm_answer_gss_accept_ctx},
+     {MONITOR_REQ_GSSUSEROK, MON_ONCE|MON_AUTHDECIDE, mm_answer_gss_userok},
+     {MONITOR_REQ_GSSCHECKMIC, MON_ONCE, mm_answer_gss_checkmic},
++    {MONITOR_REQ_GSSSIGN, MON_ONCE, mm_answer_gss_sign},
+ #endif
+     {0, 0, NULL}
+ };
+ 
+ struct mon_table mon_dispatch_postauth20[] = {
++#ifdef GSSAPI
++    {MONITOR_REQ_GSSSETUP, 0, mm_answer_gss_setup_ctx},
++    {MONITOR_REQ_GSSSTEP, 0, mm_answer_gss_accept_ctx},
++    {MONITOR_REQ_GSSSIGN, 0, mm_answer_gss_sign},
++    {MONITOR_REQ_GSSUPCREDS, 0, mm_answer_gss_updatecreds},
++#endif
+ #ifdef WITH_OPENSSL
+     {MONITOR_REQ_MODULI, 0, mm_answer_moduli},
+ #endif
+@@ -287,6 +296,10 @@ monitor_child_preauth(struct ssh *ssh, struct monitor *pmonitor)
+ 	/* Permit requests for moduli and signatures */
+ 	monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1);
+ 	monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1);
++#ifdef GSSAPI
++	/* and for the GSSAPI key exchange */
++	monitor_permit(mon_dispatch, MONITOR_REQ_GSSSETUP, 1);
++#endif
+ 
+ 	/* The first few requests do not require asynchronous access */
+ 	while (!authenticated) {
+@@ -403,6 +416,10 @@ monitor_child_postauth(struct ssh *ssh, struct monitor *pmonitor)
+ 	monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1);
+ 	monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1);
+ 	monitor_permit(mon_dispatch, MONITOR_REQ_TERM, 1);
++#ifdef GSSAPI
++	/* and for the GSSAPI key exchange */
++	monitor_permit(mon_dispatch, MONITOR_REQ_GSSSETUP, 1);
++#endif
+ 
+ 	if (auth_opts->permit_pty_flag) {
+ 		monitor_permit(mon_dispatch, MONITOR_REQ_PTY, 1);
+@@ -1745,6 +1762,17 @@ monitor_apply_keystate(struct ssh *ssh, struct monitor *pmonitor)
+ # ifdef OPENSSL_HAS_ECC
+ 	kex->kex[KEX_ECDH_SHA2] = kex_gen_server;
+ # endif
++# ifdef GSSAPI
++	if (options.gss_keyex) {
++		kex->kex[KEX_GSS_GRP1_SHA1] = kexgss_server;
++		kex->kex[KEX_GSS_GRP14_SHA1] = kexgss_server;
++		kex->kex[KEX_GSS_GRP14_SHA256] = kexgss_server;
++		kex->kex[KEX_GSS_GRP16_SHA512] = kexgss_server;
++		kex->kex[KEX_GSS_GEX_SHA1] = kexgssgex_server;
++		kex->kex[KEX_GSS_NISTP256_SHA256] = kexgss_server;
++		kex->kex[KEX_GSS_C25519_SHA256] = kexgss_server;
++	}
++# endif
+ #endif /* WITH_OPENSSL */
+ 	kex->kex[KEX_C25519_SHA256] = kex_gen_server;
+ 	kex->kex[KEX_KEM_SNTRUP761X25519_SHA512] = kex_gen_server;
+@@ -1837,8 +1865,8 @@ mm_answer_gss_setup_ctx(struct ssh *ssh, int sock, struct sshbuf *m)
+ 	u_char *p;
+ 	int r;
+ 
+-	if (!options.gss_authentication)
+-		fatal_f("GSSAPI authentication not enabled");
++	if (!options.gss_authentication && !options.gss_keyex)
++		fatal_f("GSSAPI not enabled");
+ 
+ 	if ((r = sshbuf_get_string(m, &p, &len)) != 0)
+ 		fatal_fr(r, "parse");
+@@ -1870,8 +1898,8 @@ mm_answer_gss_accept_ctx(struct ssh *ssh, int sock, struct sshbuf *m)
+ 	OM_uint32 flags = 0; /* GSI needs this */
+ 	int r;
+ 
+-	if (!options.gss_authentication)
+-		fatal_f("GSSAPI authentication not enabled");
++	if (!options.gss_authentication && !options.gss_keyex)
++		fatal_f("GSSAPI not enabled");
+ 
+ 	if ((r = ssh_gssapi_get_buffer_desc(m, &in)) != 0)
+ 		fatal_fr(r, "ssh_gssapi_get_buffer_desc");
+@@ -1891,6 +1919,7 @@ mm_answer_gss_accept_ctx(struct ssh *ssh, int sock, struct sshbuf *m)
+ 		monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 0);
+ 		monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1);
+ 		monitor_permit(mon_dispatch, MONITOR_REQ_GSSCHECKMIC, 1);
++		monitor_permit(mon_dispatch, MONITOR_REQ_GSSSIGN, 1);
+ 	}
+ 	return (0);
+ }
+@@ -1902,8 +1931,8 @@ mm_answer_gss_checkmic(struct ssh *ssh, int sock, struct sshbuf *m)
+ 	OM_uint32 ret;
+ 	int r;
+ 
+-	if (!options.gss_authentication)
+-		fatal_f("GSSAPI authentication not enabled");
++	if (!options.gss_authentication && !options.gss_keyex)
++		fatal_f("GSSAPI not enabled");
+ 
+ 	if ((r = ssh_gssapi_get_buffer_desc(m, &gssbuf)) != 0 ||
+ 	    (r = ssh_gssapi_get_buffer_desc(m, &mic)) != 0)
+@@ -1929,13 +1958,17 @@ mm_answer_gss_checkmic(struct ssh *ssh, int sock, struct sshbuf *m)
+ int
+ mm_answer_gss_userok(struct ssh *ssh, int sock, struct sshbuf *m)
+ {
+-	int r, authenticated;
++	int r, authenticated, kex;
+ 	const char *displayname;
+ 
+-	if (!options.gss_authentication)
+-		fatal_f("GSSAPI authentication not enabled");
++	if (!options.gss_authentication && !options.gss_keyex)
++		fatal_f("GSSAPI not enabled");
+ 
+-	authenticated = authctxt->valid && ssh_gssapi_userok(authctxt->user);
++	if ((r = sshbuf_get_u32(m, &kex)) != 0)
++		fatal_fr(r, "buffer error");
++
++	authenticated = authctxt->valid &&
++	    ssh_gssapi_userok(authctxt->user, authctxt->pw, kex);
+ 
+ 	sshbuf_reset(m);
+ 	if ((r = sshbuf_put_u32(m, authenticated)) != 0)
+@@ -1944,7 +1977,11 @@ mm_answer_gss_userok(struct ssh *ssh, int sock, struct sshbuf *m)
+ 	debug3_f("sending result %d", authenticated);
+ 	mm_request_send(sock, MONITOR_ANS_GSSUSEROK, m);
+ 
+-	auth_method = "gssapi-with-mic";
++	if (kex) {
++		auth_method = "gssapi-keyex";
++	} else {
++		auth_method = "gssapi-with-mic";
++	}
+ 
+ 	if ((displayname = ssh_gssapi_displayname()) != NULL)
+ 		auth2_record_info(authctxt, "%s", displayname);
+@@ -1952,5 +1989,83 @@ mm_answer_gss_userok(struct ssh *ssh, int sock, struct sshbuf *m)
+ 	/* Monitor loop will terminate if authenticated */
+ 	return (authenticated);
+ }
+-#endif /* GSSAPI */
+ 
++int
++mm_answer_gss_sign(struct ssh *ssh, int socket, struct sshbuf *m)
++{
++	gss_buffer_desc data;
++	gss_buffer_desc hash = GSS_C_EMPTY_BUFFER;
++	OM_uint32 major, minor;
++	size_t len;
++	u_char *p = NULL;
++	int r;
++
++	if (!options.gss_authentication && !options.gss_keyex)
++		fatal_f("GSSAPI not enabled");
++
++	if ((r = sshbuf_get_string(m, &p, &len)) != 0)
++		fatal_fr(r, "buffer error");
++	data.value = p;
++	data.length = len;
++	/* Lengths of SHA-1, SHA-256 and SHA-512 hashes that are used */
++	if (data.length != 20 && data.length != 32 && data.length != 64)
++		fatal_f("data length incorrect: %d", (int) data.length);
++
++	/* Save the session ID on the first time around */
++	if (session_id2_len == 0) {
++		session_id2_len = data.length;
++		session_id2 = xmalloc(session_id2_len);
++		memcpy(session_id2, data.value, session_id2_len);
++	}
++	major = ssh_gssapi_sign(gsscontext, &data, &hash);
++
++	free(data.value);
++
++	sshbuf_reset(m);
++
++	if ((r = sshbuf_put_u32(m, major)) != 0 ||
++	    (r = sshbuf_put_string(m, hash.value, hash.length)) != 0)
++		fatal_fr(r, "buffer error");
++
++	mm_request_send(socket, MONITOR_ANS_GSSSIGN, m);
++
++	gss_release_buffer(&minor, &hash);
++
++	/* Turn on getpwnam permissions */
++	monitor_permit(mon_dispatch, MONITOR_REQ_PWNAM, 1);
++
++	/* And credential updating, for when rekeying */
++	monitor_permit(mon_dispatch, MONITOR_REQ_GSSUPCREDS, 1);
++
++	return (0);
++}
++
++int
++mm_answer_gss_updatecreds(struct ssh *ssh, int socket, struct sshbuf *m) {
++	ssh_gssapi_ccache store;
++	int r, ok;
++
++	if (!options.gss_authentication && !options.gss_keyex)
++		fatal_f("GSSAPI not enabled");
++
++	if ((r = sshbuf_get_string(m, (u_char **)&store.filename, NULL)) != 0 ||
++	    (r = sshbuf_get_string(m, (u_char **)&store.envvar, NULL)) != 0 ||
++	    (r = sshbuf_get_string(m, (u_char **)&store.envval, NULL)) != 0)
++		fatal_fr(r, "buffer error");
++
++	ok = ssh_gssapi_update_creds(&store);
++
++	free(store.filename);
++	free(store.envvar);
++	free(store.envval);
++
++	sshbuf_reset(m);
++	if ((r = sshbuf_put_u32(m, ok)) != 0)
++		fatal_fr(r, "buffer error");
++
++	mm_request_send(socket, MONITOR_ANS_GSSUPCREDS, m);
++
++	return(0);
++}
++
++#endif /* GSSAPI */
+diff --git a/monitor.h b/monitor.h
+index 683e5e071..2b1a2d590 100644
+--- a/monitor.h
++++ b/monitor.h
+@@ -63,6 +63,8 @@ enum monitor_reqtype {
+ 	MONITOR_REQ_PAM_FREE_CTX = 110, MONITOR_ANS_PAM_FREE_CTX = 111,
+ 	MONITOR_REQ_AUDIT_EVENT = 112, MONITOR_REQ_AUDIT_COMMAND = 113,
+ 
++	MONITOR_REQ_GSSSIGN = 150, MONITOR_ANS_GSSSIGN = 151,
++	MONITOR_REQ_GSSUPCREDS = 152, MONITOR_ANS_GSSUPCREDS = 153,
+ };
+ 
+ struct ssh;
+diff --git a/monitor_wrap.c b/monitor_wrap.c
+index 6270d1398..189467037 100644
+--- a/monitor_wrap.c
++++ b/monitor_wrap.c
+@@ -998,13 +998,15 @@ mm_ssh_gssapi_checkmic(Gssctxt *ctx, gss_buffer_t gssbuf, gss_buffer_t gssmic)
+ }
+ 
+ int
+-mm_ssh_gssapi_userok(char *user)
++mm_ssh_gssapi_userok(char *user, struct passwd *pw, int kex)
+ {
+ 	struct sshbuf *m;
+ 	int r, authenticated = 0;
+ 
+ 	if ((m = sshbuf_new()) == NULL)
+ 		fatal_f("sshbuf_new failed");
++	if ((r = sshbuf_put_u32(m, kex)) != 0)
++		fatal_fr(r, "buffer error");
+ 
+ 	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_GSSUSEROK, m);
+ 	mm_request_receive_expect(pmonitor->m_recvfd,
+@@ -1017,4 +1019,57 @@ mm_ssh_gssapi_userok(char *user)
+ 	debug3_f("user %sauthenticated", authenticated ? "" : "not ");
+ 	return (authenticated);
+ }
++
++OM_uint32
++mm_ssh_gssapi_sign(Gssctxt *ctx, gss_buffer_desc *data, gss_buffer_desc *hash)
++{
++	struct sshbuf *m;
++	OM_uint32 major;
++	int r;
++
++	if ((m = sshbuf_new()) == NULL)
++		fatal_f("sshbuf_new failed");
++	if ((r = sshbuf_put_string(m, data->value, data->length)) != 0)
++		fatal_fr(r, "buffer error");
++
++	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_GSSSIGN, m);
++	mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_GSSSIGN, m);
++
++	if ((r = sshbuf_get_u32(m, &major)) != 0 ||
++	    (r = ssh_gssapi_get_buffer_desc(m, hash)) != 0)
++		fatal_fr(r, "buffer error");
++
++	sshbuf_free(m);
++
++	return (major);
++}
++
++int
++mm_ssh_gssapi_update_creds(ssh_gssapi_ccache *store)
++{
++	struct sshbuf *m;
++	int r, ok;
++
++	if ((m = sshbuf_new()) == NULL)
++		fatal_f("sshbuf_new failed");
++
++	if ((r = sshbuf_put_cstring(m,
++	    store->filename ? store->filename : "")) != 0 ||
++	    (r = sshbuf_put_cstring(m,
++	    store->envvar ? store->envvar : "")) != 0 ||
++	    (r = sshbuf_put_cstring(m,
++	    store->envval ? store->envval : "")) != 0)
++		fatal_fr(r, "buffer error");
++
++	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_GSSUPCREDS, m);
++	mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_GSSUPCREDS, m);
++
++	if ((r = sshbuf_get_u32(m, &ok)) != 0)
++		fatal_fr(r, "buffer error");
++
++	sshbuf_free(m);
++
++	return (ok);
++}
++
+ #endif /* GSSAPI */
+diff --git a/monitor_wrap.h b/monitor_wrap.h
+index 0df49c25b..830fdb308 100644
+--- a/monitor_wrap.h
++++ b/monitor_wrap.h
+@@ -65,8 +65,10 @@ int mm_sshkey_verify(const struct sshkey *, const u_char *, size_t,
+ OM_uint32 mm_ssh_gssapi_server_ctx(Gssctxt **, gss_OID);
+ OM_uint32 mm_ssh_gssapi_accept_ctx(Gssctxt *,
+    gss_buffer_desc *, gss_buffer_desc *, OM_uint32 *);
+-int mm_ssh_gssapi_userok(char *user);
++int mm_ssh_gssapi_userok(char *user, struct passwd *, int kex);
+ OM_uint32 mm_ssh_gssapi_checkmic(Gssctxt *, gss_buffer_t, gss_buffer_t);
++OM_uint32 mm_ssh_gssapi_sign(Gssctxt *, gss_buffer_t, gss_buffer_t);
++int mm_ssh_gssapi_update_creds(ssh_gssapi_ccache *);
+ #endif
+ 
+ #ifdef USE_PAM
+diff --git a/readconf.c b/readconf.c
+index a2282b562..ef67ab20f 100644
+--- a/readconf.c
++++ b/readconf.c
+@@ -70,6 +70,7 @@
+ #include "uidswap.h"
+ #include "myproposal.h"
+ #include "digest.h"
++#include "ssh-gss.h"
+ 
+ /* Format of the configuration file:
+ 
+@@ -164,6 +165,8 @@ typedef enum {
+ 	oClearAllForwardings, oNoHostAuthenticationForLocalhost,
+ 	oEnableSSHKeysign, oRekeyLimit, oVerifyHostKeyDNS, oConnectTimeout,
+ 	oAddressFamily, oGssAuthentication, oGssDelegateCreds,
++	oGssTrustDns, oGssKeyEx, oGssClientIdentity, oGssRenewalRekey,
++	oGssServerIdentity, oGssKexAlgorithms,
+ 	oServerAliveInterval, oServerAliveCountMax, oIdentitiesOnly,
+ 	oSendEnv, oSetEnv, oControlPath, oControlMaster, oControlPersist,
+ 	oHashKnownHosts,
+@@ -210,10 +213,22 @@ static struct {
+ 	/* Sometimes-unsupported options */
+ #if defined(GSSAPI)
+ 	{ "gssapiauthentication", oGssAuthentication },
++	{ "gssapikeyexchange", oGssKeyEx },
+ 	{ "gssapidelegatecredentials", oGssDelegateCreds },
++	{ "gssapitrustdns", oGssTrustDns },
++	{ "gssapiclientidentity", oGssClientIdentity },
++	{ "gssapiserveridentity", oGssServerIdentity },
++	{ "gssapirenewalforcesrekey", oGssRenewalRekey },
++	{ "gssapikexalgorithms", oGssKexAlgorithms },
+ # else
+ 	{ "gssapiauthentication", oUnsupported },
++	{ "gssapikeyexchange", oUnsupported },
+ 	{ "gssapidelegatecredentials", oUnsupported },
++	{ "gssapitrustdns", oUnsupported },
++	{ "gssapiclientidentity", oUnsupported },
++	{ "gssapiserveridentity", oUnsupported },
++	{ "gssapirenewalforcesrekey", oUnsupported },
++	{ "gssapikexalgorithms", oUnsupported },
+ #endif
+ #ifdef ENABLE_PKCS11
+ 	{ "pkcs11provider", oPKCS11Provider },
+@@ -1210,10 +1225,46 @@ parse_time:
+ 		intptr = &options->gss_authentication;
+ 		goto parse_flag;
+ 
++	case oGssKeyEx:
++		intptr = &options->gss_keyex;
++		goto parse_flag;
++
+ 	case oGssDelegateCreds:
+ 		intptr = &options->gss_deleg_creds;
+ 		goto parse_flag;
+ 
++	case oGssTrustDns:
++		intptr = &options->gss_trust_dns;
++		goto parse_flag;
++
++	case oGssClientIdentity:
++		charptr = &options->gss_client_identity;
++		goto parse_string;
++
++	case oGssServerIdentity:
++		charptr = &options->gss_server_identity;
++		goto parse_string;
++
++	case oGssRenewalRekey:
++		intptr = &options->gss_renewal_rekey;
++		goto parse_flag;
++
++	case oGssKexAlgorithms:
++		arg = argv_next(&ac, &av);
++		if (!arg || *arg == '\0') {
++			error("%.200s line %d: Missing argument.",
++			    filename, linenum);
++			goto out;
++		}
++		if (!kex_gss_names_valid(arg)) {
++			error("%.200s line %d: Bad GSSAPI KexAlgorithms '%s'.",
++			    filename, linenum, arg ? arg : "<NONE>");
++			goto out;
++		}
++		if (*activep && options->gss_kex_algorithms == NULL)
++			options->gss_kex_algorithms = xstrdup(arg);
++		break;
++
+ 	case oBatchMode:
+ 		intptr = &options->batch_mode;
+ 		goto parse_flag;
+@@ -2505,7 +2556,13 @@ initialize_options(Options * options)
+ 	options->fwd_opts.streamlocal_bind_unlink = -1;
+ 	options->pubkey_authentication = -1;
+ 	options->gss_authentication = -1;
++	options->gss_keyex = -1;
+ 	options->gss_deleg_creds = -1;
++	options->gss_trust_dns = -1;
++	options->gss_renewal_rekey = -1;
++	options->gss_client_identity = NULL;
++	options->gss_server_identity = NULL;
++	options->gss_kex_algorithms = NULL;
+ 	options->password_authentication = -1;
+ 	options->kbd_interactive_authentication = -1;
+ 	options->kbd_interactive_devices = NULL;
+@@ -2668,8 +2725,18 @@ fill_default_options(Options * options)
+ 		options->pubkey_authentication = SSH_PUBKEY_AUTH_ALL;
+ 	if (options->gss_authentication == -1)
+ 		options->gss_authentication = 0;
++	if (options->gss_keyex == -1)
++		options->gss_keyex = 0;
+ 	if (options->gss_deleg_creds == -1)
+ 		options->gss_deleg_creds = 0;
++	if (options->gss_trust_dns == -1)
++		options->gss_trust_dns = 0;
++	if (options->gss_renewal_rekey == -1)
++		options->gss_renewal_rekey = 0;
++#ifdef GSSAPI
++	if (options->gss_kex_algorithms == NULL)
++		options->gss_kex_algorithms = strdup(GSS_KEX_DEFAULT_KEX);
++#endif
+ 	if (options->password_authentication == -1)
+ 		options->password_authentication = 1;
+ 	if (options->kbd_interactive_authentication == -1)
+@@ -3494,7 +3561,14 @@ dump_client_config(Options *o, const char *host)
+ 	dump_cfg_fmtint(oGatewayPorts, o->fwd_opts.gateway_ports);
+ #ifdef GSSAPI
+ 	dump_cfg_fmtint(oGssAuthentication, o->gss_authentication);
++	dump_cfg_fmtint(oGssKeyEx, o->gss_keyex);
+ 	dump_cfg_fmtint(oGssDelegateCreds, o->gss_deleg_creds);
++	dump_cfg_fmtint(oGssTrustDns, o->gss_trust_dns);
++	dump_cfg_fmtint(oGssRenewalRekey, o->gss_renewal_rekey);
++	dump_cfg_string(oGssClientIdentity, o->gss_client_identity);
++	dump_cfg_string(oGssServerIdentity, o->gss_server_identity);
++	dump_cfg_string(oGssKexAlgorithms, o->gss_kex_algorithms ?
++	    o->gss_kex_algorithms : GSS_KEX_DEFAULT_KEX);
+ #endif /* GSSAPI */
+ 	dump_cfg_fmtint(oHashKnownHosts, o->hash_known_hosts);
+ 	dump_cfg_fmtint(oHostbasedAuthentication, o->hostbased_authentication);
+diff --git a/readconf.h b/readconf.h
+index ff7180cd0..0d2ad44f9 100644
+--- a/readconf.h
++++ b/readconf.h
+@@ -40,7 +40,13 @@ typedef struct {
+ 	int     pubkey_authentication;	/* Try ssh2 pubkey authentication. */
+ 	int     hostbased_authentication;	/* ssh2's rhosts_rsa */
+ 	int     gss_authentication;	/* Try GSS authentication */
++	int     gss_keyex;		/* Try GSS key exchange */
+ 	int     gss_deleg_creds;	/* Delegate GSS credentials */
++	int	gss_trust_dns;		/* Trust DNS for GSS canonicalization */
++	int	gss_renewal_rekey;	/* Credential renewal forces rekey */
++	char    *gss_client_identity;   /* Principal to initiate GSSAPI with */
++	char    *gss_server_identity;   /* GSSAPI target principal */
++	char    *gss_kex_algorithms;	/* GSSAPI kex methods to be offered by client. */
+ 	int     password_authentication;	/* Try password
+ 						 * authentication. */
+ 	int     kbd_interactive_authentication; /* Try keyboard-interactive auth. */
+diff --git a/servconf.c b/servconf.c
+index 86c297936..940e1d50a 100644
+--- a/servconf.c
++++ b/servconf.c
+@@ -68,6 +68,7 @@
+ #include "auth.h"
+ #include "myproposal.h"
+ #include "digest.h"
++#include "ssh-gss.h"
+ 
+ static void add_listen_addr(ServerOptions *, const char *,
+     const char *, int);
+@@ -134,8 +135,11 @@ initialize_server_options(ServerOptions *options)
+ 	options->kerberos_ticket_cleanup = -1;
+ 	options->kerberos_get_afs_token = -1;
+ 	options->gss_authentication=-1;
++	options->gss_keyex = -1;
+ 	options->gss_cleanup_creds = -1;
+ 	options->gss_strict_acceptor = -1;
++	options->gss_store_rekey = -1;
++	options->gss_kex_algorithms = NULL;
+ 	options->password_authentication = -1;
+ 	options->kbd_interactive_authentication = -1;
+ 	options->permit_empty_passwd = -1;
+@@ -358,10 +362,18 @@ fill_default_server_options(ServerOptions *options)
+ 		options->kerberos_get_afs_token = 0;
+ 	if (options->gss_authentication == -1)
+ 		options->gss_authentication = 0;
++	if (options->gss_keyex == -1)
++		options->gss_keyex = 0;
+ 	if (options->gss_cleanup_creds == -1)
+ 		options->gss_cleanup_creds = 1;
+ 	if (options->gss_strict_acceptor == -1)
+ 		options->gss_strict_acceptor = 1;
++	if (options->gss_store_rekey == -1)
++		options->gss_store_rekey = 0;
++#ifdef GSSAPI
++	if (options->gss_kex_algorithms == NULL)
++		options->gss_kex_algorithms = strdup(GSS_KEX_DEFAULT_KEX);
++#endif
+ 	if (options->password_authentication == -1)
+ 		options->password_authentication = 1;
+ 	if (options->kbd_interactive_authentication == -1)
+@@ -518,6 +530,7 @@ typedef enum {
+ 	sHostKeyAlgorithms, sPerSourceMaxStartups, sPerSourceNetBlockSize,
+ 	sClientAliveInterval, sClientAliveCountMax, sAuthorizedKeysFile,
+ 	sGssAuthentication, sGssCleanupCreds, sGssStrictAcceptor,
++	sGssKeyEx, sGssKexAlgorithms, sGssStoreRekey,
+ 	sAcceptEnv, sSetEnv, sPermitTunnel,
+ 	sMatch, sPermitOpen, sPermitListen, sForceCommand, sChrootDirectory,
+ 	sUsePrivilegeSeparation, sAllowAgentForwarding,
+@@ -600,12 +613,22 @@ static struct {
+ #ifdef GSSAPI
+ 	{ "gssapiauthentication", sGssAuthentication, SSHCFG_ALL },
+ 	{ "gssapicleanupcredentials", sGssCleanupCreds, SSHCFG_GLOBAL },
++	{ "gssapicleanupcreds", sGssCleanupCreds, SSHCFG_GLOBAL },
+ 	{ "gssapistrictacceptorcheck", sGssStrictAcceptor, SSHCFG_GLOBAL },
++	{ "gssapikeyexchange", sGssKeyEx, SSHCFG_GLOBAL },
++	{ "gssapistorecredentialsonrekey", sGssStoreRekey, SSHCFG_GLOBAL },
++	{ "gssapikexalgorithms", sGssKexAlgorithms, SSHCFG_GLOBAL },
+ #else
+ 	{ "gssapiauthentication", sUnsupported, SSHCFG_ALL },
+ 	{ "gssapicleanupcredentials", sUnsupported, SSHCFG_GLOBAL },
++	{ "gssapicleanupcreds", sUnsupported, SSHCFG_GLOBAL },
+ 	{ "gssapistrictacceptorcheck", sUnsupported, SSHCFG_GLOBAL },
++	{ "gssapikeyexchange", sUnsupported, SSHCFG_GLOBAL },
++	{ "gssapistorecredentialsonrekey", sUnsupported, SSHCFG_GLOBAL },
++	{ "gssapikexalgorithms", sUnsupported, SSHCFG_GLOBAL },
+ #endif
++	{ "gssusesessionccache", sUnsupported, SSHCFG_GLOBAL },
++	{ "gssapiusesessioncredcache", sUnsupported, SSHCFG_GLOBAL },
+ 	{ "passwordauthentication", sPasswordAuthentication, SSHCFG_ALL },
+ 	{ "kbdinteractiveauthentication", sKbdInteractiveAuthentication, SSHCFG_ALL },
+ 	{ "challengeresponseauthentication", sKbdInteractiveAuthentication, SSHCFG_ALL }, /* alias */
+@@ -1616,6 +1639,10 @@ process_server_config_line_depth(ServerOptions *options, char *line,
+ 		intptr = &options->gss_authentication;
+ 		goto parse_flag;
+ 
++	case sGssKeyEx:
++		intptr = &options->gss_keyex;
++		goto parse_flag;
++
+ 	case sGssCleanupCreds:
+ 		intptr = &options->gss_cleanup_creds;
+ 		goto parse_flag;
+@@ -1624,6 +1651,22 @@ process_server_config_line_depth(ServerOptions *options, char *line,
+ 		intptr = &options->gss_strict_acceptor;
+ 		goto parse_flag;
+ 
++	case sGssStoreRekey:
++		intptr = &options->gss_store_rekey;
++		goto parse_flag;
++
++	case sGssKexAlgorithms:
++		arg = argv_next(&ac, &av);
++		if (!arg || *arg == '\0')
++			fatal("%.200s line %d: Missing argument.",
++			    filename, linenum);
++		if (!kex_gss_names_valid(arg))
++			fatal("%.200s line %d: Bad GSSAPI KexAlgorithms '%s'.",
++			    filename, linenum, arg ? arg : "<NONE>");
++		if (*activep && options->gss_kex_algorithms == NULL)
++			options->gss_kex_algorithms = xstrdup(arg);
++		break;
++
+ 	case sPasswordAuthentication:
+ 		intptr = &options->password_authentication;
+ 		goto parse_flag;
+@@ -3058,6 +3101,10 @@ dump_config(ServerOptions *o)
+ #ifdef GSSAPI
+ 	dump_cfg_fmtint(sGssAuthentication, o->gss_authentication);
+ 	dump_cfg_fmtint(sGssCleanupCreds, o->gss_cleanup_creds);
++	dump_cfg_fmtint(sGssKeyEx, o->gss_keyex);
++	dump_cfg_fmtint(sGssStrictAcceptor, o->gss_strict_acceptor);
++	dump_cfg_fmtint(sGssStoreRekey, o->gss_store_rekey);
++	dump_cfg_string(sGssKexAlgorithms, o->gss_kex_algorithms);
+ #endif
+ 	dump_cfg_fmtint(sPasswordAuthentication, o->password_authentication);
+ 	dump_cfg_fmtint(sKbdInteractiveAuthentication,
+diff --git a/servconf.h b/servconf.h
+index ed7b72e8e..2ce4ae0ad 100644
+--- a/servconf.h
++++ b/servconf.h
+@@ -139,8 +139,11 @@ typedef struct {
+ 	int     kerberos_get_afs_token;		/* If true, try to get AFS token if
+ 						 * authenticated with Kerberos. */
+ 	int     gss_authentication;	/* If true, permit GSSAPI authentication */
++	int     gss_keyex;		/* If true, permit GSSAPI key exchange */
+ 	int     gss_cleanup_creds;	/* If true, destroy cred cache on logout */
+ 	int     gss_strict_acceptor;	/* If true, restrict the GSSAPI acceptor name */
++	int 	gss_store_rekey;
++	char   *gss_kex_algorithms;	/* GSSAPI kex methods to be offered by client. */
+ 	int     password_authentication;	/* If true, permit password
+ 						 * authentication. */
+ 	int     kbd_interactive_authentication;	/* If true, permit */
+diff --git a/session.c b/session.c
+index aa342e84d..f985b8177 100644
+--- a/session.c
++++ b/session.c
+@@ -2687,13 +2687,19 @@ do_cleanup(struct ssh *ssh, Authctxt *authctxt)
+ 
+ #ifdef KRB5
+ 	if (options.kerberos_ticket_cleanup &&
+-	    authctxt->krb5_ctx)
++	    authctxt->krb5_ctx) {
++		temporarily_use_uid(authctxt->pw);
+ 		krb5_cleanup_proc(authctxt);
++		restore_uid();
++	}
+ #endif
+ 
+ #ifdef GSSAPI
+-	if (options.gss_cleanup_creds)
++	if (options.gss_cleanup_creds) {
++		temporarily_use_uid(authctxt->pw);
+ 		ssh_gssapi_cleanup_creds();
++		restore_uid();
++	}
+ #endif
+ 
+ 	/* remove agent socket */
+diff --git a/ssh-gss.h b/ssh-gss.h
+index a8af117d2..6303ce185 100644
+--- a/ssh-gss.h
++++ b/ssh-gss.h
+@@ -1,6 +1,6 @@
+ /* $OpenBSD: ssh-gss.h,v 1.15 2021/01/27 10:05:28 djm Exp $ */
+ /*
+- * Copyright (c) 2001-2003 Simon Wilkinson. All rights reserved.
++ * Copyright (c) 2001-2009 Simon Wilkinson. All rights reserved.
+  *
+  * Redistribution and use in source and binary forms, with or without
+  * modification, are permitted provided that the following conditions
+@@ -61,10 +61,34 @@
+ 
+ #define SSH_GSS_OIDTYPE 0x06
+ 
++#define SSH2_MSG_KEXGSS_INIT                            30
++#define SSH2_MSG_KEXGSS_CONTINUE                        31
++#define SSH2_MSG_KEXGSS_COMPLETE                        32
++#define SSH2_MSG_KEXGSS_HOSTKEY                         33
++#define SSH2_MSG_KEXGSS_ERROR                           34
++#define SSH2_MSG_KEXGSS_GROUPREQ			40
++#define SSH2_MSG_KEXGSS_GROUP				41
++#define KEX_GSS_GRP1_SHA1_ID				"gss-group1-sha1-"
++#define KEX_GSS_GRP14_SHA1_ID				"gss-group14-sha1-"
++#define KEX_GSS_GRP14_SHA256_ID			"gss-group14-sha256-"
++#define KEX_GSS_GRP16_SHA512_ID			"gss-group16-sha512-"
++#define KEX_GSS_GEX_SHA1_ID				"gss-gex-sha1-"
++#define KEX_GSS_NISTP256_SHA256_ID			"gss-nistp256-sha256-"
++#define KEX_GSS_C25519_SHA256_ID			"gss-curve25519-sha256-"
++
++#define        GSS_KEX_DEFAULT_KEX \
++	KEX_GSS_GRP14_SHA256_ID	"," \
++	KEX_GSS_GRP16_SHA512_ID	"," \
++	KEX_GSS_NISTP256_SHA256_ID "," \
++	KEX_GSS_C25519_SHA256_ID "," \
++	KEX_GSS_GRP14_SHA1_ID "," \
++	KEX_GSS_GEX_SHA1_ID
++
+ typedef struct {
+ 	char *filename;
+ 	char *envvar;
+ 	char *envval;
++	struct passwd *owner;
+ 	void *data;
+ } ssh_gssapi_ccache;
+ 
+@@ -72,8 +96,11 @@ typedef struct {
+ 	gss_buffer_desc displayname;
+ 	gss_buffer_desc exportedname;
+ 	gss_cred_id_t creds;
++	gss_name_t name;
+ 	struct ssh_gssapi_mech_struct *mech;
+ 	ssh_gssapi_ccache store;
++	int used;
++	int updated;
+ } ssh_gssapi_client;
+ 
+ typedef struct ssh_gssapi_mech_struct {
+@@ -84,6 +111,7 @@ typedef struct ssh_gssapi_mech_struct {
+ 	int (*userok) (ssh_gssapi_client *, char *);
+ 	int (*localname) (ssh_gssapi_client *, char **);
+ 	void (*storecreds) (ssh_gssapi_client *);
++	int (*updatecreds) (ssh_gssapi_ccache *, ssh_gssapi_client *);
+ } ssh_gssapi_mech;
+ 
+ typedef struct {
+@@ -94,10 +122,11 @@ typedef struct {
+ 	gss_OID		oid; /* client */
+ 	gss_cred_id_t	creds; /* server */
+ 	gss_name_t	client; /* server */
+-	gss_cred_id_t	client_creds; /* server */
++	gss_cred_id_t	client_creds; /* both */
+ } Gssctxt;
+ 
+ extern ssh_gssapi_mech *supported_mechs[];
++extern Gssctxt *gss_kex_context;
+ 
+ int  ssh_gssapi_check_oid(Gssctxt *, void *, size_t);
+ void ssh_gssapi_set_oid_data(Gssctxt *, void *, size_t);
+@@ -109,6 +138,7 @@ OM_uint32 ssh_gssapi_test_oid_supported(OM_uint32 *, gss_OID, int *);
+ 
+ struct sshbuf;
+ int ssh_gssapi_get_buffer_desc(struct sshbuf *, gss_buffer_desc *);
++int ssh_gssapi_sshpkt_get_buffer_desc(struct ssh *, gss_buffer_desc *);
+ 
+ OM_uint32 ssh_gssapi_import_name(Gssctxt *, const char *);
+ OM_uint32 ssh_gssapi_init_ctx(Gssctxt *, int,
+@@ -123,17 +153,33 @@ void ssh_gssapi_delete_ctx(Gssctxt **);
+ OM_uint32 ssh_gssapi_sign(Gssctxt *, gss_buffer_t, gss_buffer_t);
+ void ssh_gssapi_buildmic(struct sshbuf *, const char *,
+     const char *, const char *, const struct sshbuf *);
+-int ssh_gssapi_check_mechanism(Gssctxt **, gss_OID, const char *);
++int ssh_gssapi_check_mechanism(Gssctxt **, gss_OID, const char *, const char *);
++OM_uint32 ssh_gssapi_client_identity(Gssctxt *, const char *);
++int ssh_gssapi_credentials_updated(Gssctxt *);
+ 
+ /* In the server */
++typedef int ssh_gssapi_check_fn(Gssctxt **, gss_OID, const char *,
++    const char *);
++char *ssh_gssapi_client_mechanisms(const char *, const char *, const char *);
++char *ssh_gssapi_kex_mechs(gss_OID_set, ssh_gssapi_check_fn *, const char *,
++    const char *, const char *);
++gss_OID ssh_gssapi_id_kex(Gssctxt *, char *, int);
++int ssh_gssapi_server_check_mech(Gssctxt **,gss_OID, const char *,
++    const char *);
+ OM_uint32 ssh_gssapi_server_ctx(Gssctxt **, gss_OID);
+-int ssh_gssapi_userok(char *name);
++int ssh_gssapi_userok(char *name, struct passwd *, int kex);
+ OM_uint32 ssh_gssapi_checkmic(Gssctxt *, gss_buffer_t, gss_buffer_t);
+ void ssh_gssapi_do_child(char ***, u_int *);
+ void ssh_gssapi_cleanup_creds(void);
+ void ssh_gssapi_storecreds(void);
+ const char *ssh_gssapi_displayname(void);
+ 
++char *ssh_gssapi_server_mechanisms(void);
++int ssh_gssapi_oid_table_ok(void);
++
++int ssh_gssapi_update_creds(ssh_gssapi_ccache *store);
++void ssh_gssapi_rekey_creds(void);
++
+ #endif /* GSSAPI */
+ 
+ #endif /* _SSH_GSS_H */
+diff --git a/ssh-null.c b/ssh-null.c
+new file mode 100644
+index 000000000..a934bda77
+--- /dev/null
++++ b/ssh-null.c
+@@ -0,0 +1,108 @@
++/*
++ * Copyright (c) 2023 Colin Watson.  All rights reserved.
++ *
++ * Redistribution and use in source and binary forms, with or without
++ * modification, are permitted provided that the following conditions
++ * are met:
++ * 1. Redistributions of source code must retain the above copyright
++ *    notice, this list of conditions and the following disclaimer.
++ * 2. Redistributions in binary form must reproduce the above copyright
++ *    notice, this list of conditions and the following disclaimer in the
++ *    documentation and/or other materials provided with the distribution.
++ *
++ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
++ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
++ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
++ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
++ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
++ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
++ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
++ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
++ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
++ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
++ */
++
++#include "includes.h"
++
++#ifdef GSSAPI
++
++#include "sshbuf.h"
++#include "ssherr.h"
++#include "sshkey.h"
++
++static int
++ssh_null_equal(const struct sshkey *a, const struct sshkey *b)
++{
++	return 1;
++}
++
++static int
++ssh_null_serialize_public(const struct sshkey *key, struct sshbuf *b,
++    enum sshkey_serialize_rep opts)
++{
++	return SSH_ERR_KEY_TYPE_UNKNOWN;
++}
++
++static int
++ssh_null_deserialize_public(const char *ktype, struct sshbuf *b,
++    struct sshkey *key)
++{
++	return SSH_ERR_KEY_TYPE_UNKNOWN;
++}
++
++static int
++ssh_null_serialize_private(const struct sshkey *key, struct sshbuf *b,
++    enum sshkey_serialize_rep opts)
++{
++	return SSH_ERR_KEY_TYPE_UNKNOWN;
++}
++
++static int
++ssh_null_deserialize_private(const char *ktype, struct sshbuf *b,
++    struct sshkey *key)
++{
++	return SSH_ERR_KEY_TYPE_UNKNOWN;
++}
++
++static int
++ssh_null_copy_public(const struct sshkey *from, struct sshkey *to)
++{
++	return SSH_ERR_KEY_TYPE_UNKNOWN;
++}
++
++static int
++ssh_null_verify(const struct sshkey *key, const u_char *sig, size_t siglen,
++    const u_char *data, size_t dlen, const char *alg, u_int compat,
++    struct sshkey_sig_details **detailsp)
++{
++	return SSH_ERR_KEY_TYPE_UNKNOWN;
++}
++
++static const struct sshkey_impl_funcs sshkey_null_funcs = {
++	/* .size = */		NULL,
++	/* .alloc = */		NULL,
++	/* .cleanup = */	NULL,
++	/* .equal = */		ssh_null_equal,
++	/* .ssh_serialize_public = */ ssh_null_serialize_public,
++	/* .ssh_deserialize_public = */ ssh_null_deserialize_public,
++	/* .ssh_serialize_private = */ ssh_null_serialize_private,
++	/* .ssh_deserialize_private = */ ssh_null_deserialize_private,
++	/* .generate = */	NULL,
++	/* .copy_public = */	ssh_null_copy_public,
++	/* .sign = */		NULL,
++	/* .verify = */		ssh_null_verify,
++};
++
++const struct sshkey_impl sshkey_null_impl = {
++	/* .name = */		"null",
++	/* .shortname = */	"null",
++	/* .sigalg = */		NULL,
++	/* .type = */		KEY_NULL,
++	/* .nid = */		0,
++	/* .cert = */		0,
++	/* .sigonly = */	0,
++	/* .keybits = */	0,
++	/* .funcs = */		&sshkey_null_funcs,
++};
++
++#endif /* GSSAPI */
+diff --git a/ssh.1 b/ssh.1
+index 936c995ba..877c3bc64 100644
+--- a/ssh.1
++++ b/ssh.1
+@@ -536,7 +536,13 @@ For full details of the options listed below, and their possible values, see
+ .It GatewayPorts
+ .It GlobalKnownHostsFile
+ .It GSSAPIAuthentication
++.It GSSAPIKeyExchange
++.It GSSAPIClientIdentity
+ .It GSSAPIDelegateCredentials
++.It GSSAPIKexAlgorithms
++.It GSSAPIRenewalForcesRekey
++.It GSSAPIServerIdentity
++.It GSSAPITrustDns
+ .It HashKnownHosts
+ .It Host
+ .It HostbasedAcceptedAlgorithms
+@@ -624,6 +630,8 @@ flag),
+ (supported message integrity codes),
+ .Ar kex
+ (key exchange algorithms),
++.Ar kex-gss
++(GSSAPI key exchange algorithms),
+ .Ar key
+ (key types),
+ .Ar key-ca-sign
+diff --git a/ssh.c b/ssh.c
+index 48d93ddf2..f50cecdbb 100644
+--- a/ssh.c
++++ b/ssh.c
+@@ -827,6 +827,8 @@ main(int ac, char **av)
+ 			else if (strcmp(optarg, "kex") == 0 ||
+ 			    strcasecmp(optarg, "KexAlgorithms") == 0)
+ 				cp = kex_alg_list('\n');
++			else if (strcmp(optarg, "kex-gss") == 0)
++				cp = kex_gss_alg_list('\n');
+ 			else if (strcmp(optarg, "key") == 0)
+ 				cp = sshkey_alg_list(0, 0, 0, '\n');
+ 			else if (strcmp(optarg, "key-cert") == 0)
+@@ -857,8 +859,8 @@ main(int ac, char **av)
+ 			} else if (strcmp(optarg, "help") == 0) {
+ 				cp = xstrdup(
+ 				    "cipher\ncipher-auth\ncompression\nkex\n"
+-				    "key\nkey-cert\nkey-plain\nkey-sig\nmac\n"
+-				    "protocol-version\nsig");
++				    "kex-gss\nkey\nkey-cert\nkey-plain\n"
++				    "key-sig\nmac\nprotocol-version\nsig");
+ 			}
+ 			if (cp == NULL)
+ 				fatal("Unsupported query \"%s\"", optarg);
+diff --git a/ssh_config b/ssh_config
+index cc5663562..16197d15d 100644
+--- a/ssh_config
++++ b/ssh_config
+@@ -24,6 +24,8 @@
+ #   HostbasedAuthentication no
+ #   GSSAPIAuthentication no
+ #   GSSAPIDelegateCredentials no
++#   GSSAPIKeyExchange no
++#   GSSAPITrustDNS no
+ #   BatchMode no
+ #   CheckHostIP no
+ #   AddressFamily any
+diff --git a/ssh_config.5 b/ssh_config.5
+index 4bbdfefd1..7ca72aedf 100644
+--- a/ssh_config.5
++++ b/ssh_config.5
+@@ -928,10 +928,67 @@ The default is
+ Specifies whether user authentication based on GSSAPI is allowed.
+ The default is
+ .Cm no .
++.It Cm GSSAPIClientIdentity
++If set, specifies the GSSAPI client identity that ssh should use when
++connecting to the server. The default is unset, which means that the default
++identity will be used.
+ .It Cm GSSAPIDelegateCredentials
+ Forward (delegate) credentials to the server.
+ The default is
+ .Cm no .
++.It Cm GSSAPIKeyExchange
++Specifies whether key exchange based on GSSAPI may be used. When using
++GSSAPI key exchange the server need not have a host key.
++The default is
++.Dq no .
++.It Cm GSSAPIRenewalForcesRekey
++If set to
++.Dq yes
++then renewal of the client's GSSAPI credentials will force the rekeying of the
++ssh connection. With a compatible server, this will delegate the renewed
++credentials to a session on the server.
++.Pp
++Checks are made to ensure that credentials are only propagated when the new
++credentials match the old ones on the originating client and where the
++receiving server still has the old set in its cache.
++.Pp
++The default is
++.Dq no .
++.Pp
++For this to work
++.Cm GSSAPIKeyExchange
++needs to be enabled in the server and also used by the client.
++.It Cm GSSAPIServerIdentity
++If set, specifies the GSSAPI server identity that ssh should expect when
++connecting to the server. The default is unset, which means that the
++expected GSSAPI server identity will be determined from the target
++hostname.
++.It Cm GSSAPITrustDns
++Set to
++.Dq yes
++to indicate that the DNS is trusted to securely canonicalize
++the name of the host being connected to. If
++.Dq no ,
++the hostname entered on the
++command line will be passed untouched to the GSSAPI library.
++The default is
++.Dq no .
++.It Cm GSSAPIKexAlgorithms
++The list of key exchange algorithms that are offered for GSSAPI
++key exchange. Possible values are
++.Bd -literal -offset 3n
++gss-gex-sha1-,
++gss-group1-sha1-,
++gss-group14-sha1-,
++gss-group14-sha256-,
++gss-group16-sha512-,
++gss-nistp256-sha256-,
++gss-curve25519-sha256-
++.Ed
++.Pp
++The default is
++.Dq gss-group14-sha256-,gss-group16-sha512-,gss-nistp256-sha256-,gss-curve25519-sha256-,gss-gex-sha1-,gss-group14-sha1- .
++This option only applies to connections using GSSAPI.
+ .It Cm HashKnownHosts
+ Indicates that
+ .Xr ssh 1
+diff --git a/sshconnect2.c b/sshconnect2.c
+index fab1e36be..cb584ad27 100644
+--- a/sshconnect2.c
++++ b/sshconnect2.c
+@@ -80,8 +80,6 @@
+ #endif
+ 
+ /* import */
+-extern char *client_version_string;
+-extern char *server_version_string;
+ extern Options options;
+ 
+ /*
+@@ -224,6 +222,11 @@ ssh_kex2(struct ssh *ssh, char *host, struct sockaddr *hostaddr, u_short port,
+ 	char *s, *all_key, *hkalgs = NULL;
+ 	int r, use_known_hosts_order = 0;
+ 
++#if defined(GSSAPI) && defined(WITH_OPENSSL)
++	char *orig = NULL, *gss = NULL;
++	char *gss_host = NULL;
++#endif
++
+ 	xxx_host = host;
+ 	xxx_hostaddr = hostaddr;
+ 	xxx_conn_info = cinfo;
+@@ -261,6 +264,42 @@ ssh_kex2(struct ssh *ssh, char *host, struct sockaddr *hostaddr, u_short port,
+ 
+ 	free(hkalgs);
+ 
++#if defined(GSSAPI) && defined(WITH_OPENSSL)
++	if (options.gss_keyex) {
++		/* Add the GSSAPI mechanisms currently supported on this
++		 * client to the key exchange algorithm proposal */
++		orig = myproposal[PROPOSAL_KEX_ALGS];
++
++		if (options.gss_server_identity) {
++			gss_host = xstrdup(options.gss_server_identity);
++		} else if (options.gss_trust_dns) {
++			gss_host = remote_hostname(ssh);
++			/* Fall back to specified host if we are using proxy command
++			 * and can not use DNS on that socket */
++			if (strcmp(gss_host, "UNKNOWN") == 0) {
++				free(gss_host);
++				gss_host = xstrdup(host);
++			}
++		} else {
++			gss_host = xstrdup(host);
++		}
++
++		gss = ssh_gssapi_client_mechanisms(gss_host,
++		    options.gss_client_identity, options.gss_kex_algorithms);
++		if (gss) {
++			debug("Offering GSSAPI proposal: %s", gss);
++			xasprintf(&myproposal[PROPOSAL_KEX_ALGS],
++			    "%s,%s", gss, orig);
++
++			/* If we've got GSSAPI algorithms, then we also support the
++			 * 'null' hostkey, as a last resort */
++			orig = myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS];
++			xasprintf(&myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS],
++			    "%s,null", orig);
++		}
++	}
++#endif
++
+ 	/* start key exchange */
+ 	if ((r = kex_setup(ssh, myproposal)) != 0)
+ 		fatal_r(r, "kex_setup");
+@@ -275,17 +314,47 @@ ssh_kex2(struct ssh *ssh, char *host, struct sockaddr *hostaddr, u_short port,
+ # ifdef OPENSSL_HAS_ECC
+ 	ssh->kex->kex[KEX_ECDH_SHA2] = kex_gen_client;
+ # endif
+-#endif
++# ifdef GSSAPI
++	if (options.gss_keyex) {
++		ssh->kex->kex[KEX_GSS_GRP1_SHA1] = kexgss_client;
++		ssh->kex->kex[KEX_GSS_GRP14_SHA1] = kexgss_client;
++		ssh->kex->kex[KEX_GSS_GRP14_SHA256] = kexgss_client;
++		ssh->kex->kex[KEX_GSS_GRP16_SHA512] = kexgss_client;
++		ssh->kex->kex[KEX_GSS_GEX_SHA1] = kexgssgex_client;
++		ssh->kex->kex[KEX_GSS_NISTP256_SHA256] = kexgss_client;
++		ssh->kex->kex[KEX_GSS_C25519_SHA256] = kexgss_client;
++	}
++# endif
++#endif /* WITH_OPENSSL */
+ 	ssh->kex->kex[KEX_C25519_SHA256] = kex_gen_client;
+ 	ssh->kex->kex[KEX_KEM_SNTRUP761X25519_SHA512] = kex_gen_client;
+ 	ssh->kex->verify_host_key=&verify_host_key_callback;
+ 
++#if defined(GSSAPI) && defined(WITH_OPENSSL)
++	if (options.gss_keyex) {
++		ssh->kex->gss_deleg_creds = options.gss_deleg_creds;
++		ssh->kex->gss_trust_dns = options.gss_trust_dns;
++		ssh->kex->gss_client = options.gss_client_identity;
++		ssh->kex->gss_host = gss_host;
++	}
++#endif
++
+ 	ssh_dispatch_run_fatal(ssh, DISPATCH_BLOCK, &ssh->kex->done);
+ 
+ 	/* remove ext-info from the KEX proposals for rekeying */
+ 	free(myproposal[PROPOSAL_KEX_ALGS]);
+ 	myproposal[PROPOSAL_KEX_ALGS] =
+ 	    compat_kex_proposal(ssh, options.kex_algorithms);
++#if defined(GSSAPI) && defined(WITH_OPENSSL)
++	/* repair myproposal after it was crumpled by the */
++	/* ext-info removal above */
++	if (gss) {
++		orig = myproposal[PROPOSAL_KEX_ALGS];
++		xasprintf(&myproposal[PROPOSAL_KEX_ALGS],
++		    "%s,%s", gss, orig);
++		free(gss);
++	}
++#endif
+ 	if ((r = kex_prop2buf(ssh->kex->my, myproposal)) != 0)
+ 		fatal_r(r, "kex_prop2buf");
+ 
+@@ -379,6 +448,7 @@ static int input_gssapi_response(int type, u_int32_t, struct ssh *);
+ static int input_gssapi_token(int type, u_int32_t, struct ssh *);
+ static int input_gssapi_error(int, u_int32_t, struct ssh *);
+ static int input_gssapi_errtok(int, u_int32_t, struct ssh *);
++static int userauth_gsskeyex(struct ssh *);
+ #endif
+ 
+ void	userauth(struct ssh *, char *);
+@@ -395,6 +465,11 @@ static char *authmethods_get(void);
+ 
+ Authmethod authmethods[] = {
+ #ifdef GSSAPI
++	{"gssapi-keyex",
++		userauth_gsskeyex,
++		NULL,
++		&options.gss_keyex,
++		NULL},
+ 	{"gssapi-with-mic",
+ 		userauth_gssapi,
+ 		userauth_gssapi_cleanup,
+@@ -766,12 +841,32 @@ userauth_gssapi(struct ssh *ssh)
+ 	OM_uint32 min;
+ 	int r, ok = 0;
+ 	gss_OID mech = NULL;
++	char *gss_host = NULL;
++
++	if (options.gss_server_identity) {
++		gss_host = xstrdup(options.gss_server_identity);
++	} else if (options.gss_trust_dns) {
++		gss_host = remote_hostname(ssh);
++		/* Fall back to specified host if we are using proxy command
++		 * and can not use DNS on that socket */
++		if (strcmp(gss_host, "UNKNOWN") == 0) {
++			free(gss_host);
++			gss_host = xstrdup(authctxt->host);
++		}
++	} else {
++		gss_host = xstrdup(authctxt->host);
++	}
+ 
+ 	/* Try one GSSAPI method at a time, rather than sending them all at
+ 	 * once. */
+ 
+ 	if (authctxt->gss_supported_mechs == NULL)
+-		gss_indicate_mechs(&min, &authctxt->gss_supported_mechs);
++		if (GSS_ERROR(gss_indicate_mechs(&min,
++		    &authctxt->gss_supported_mechs))) {
++			authctxt->gss_supported_mechs = NULL;
++			free(gss_host);
++			return 0;
++		}
+ 
+ 	/* Check to see whether the mechanism is usable before we offer it */
+ 	while (authctxt->mech_tried < authctxt->gss_supported_mechs->count &&
+@@ -780,13 +875,15 @@ userauth_gssapi(struct ssh *ssh)
+ 		    elements[authctxt->mech_tried];
+ 		/* My DER encoding requires length<128 */
+ 		if (mech->length < 128 && ssh_gssapi_check_mechanism(&gssctxt,
+-		    mech, authctxt->host)) {
++		    mech, gss_host, options.gss_client_identity)) {
+ 			ok = 1; /* Mechanism works */
+ 		} else {
+ 			authctxt->mech_tried++;
+ 		}
+ 	}
+ 
++	free(gss_host);
++
+ 	if (!ok || mech == NULL)
+ 		return 0;
+ 
+@@ -1020,6 +1117,55 @@ input_gssapi_error(int type, u_int32_t plen, struct ssh *ssh)
+ 	free(lang);
+ 	return r;
+ }
++
++int
++userauth_gsskeyex(struct ssh *ssh)
++{
++	struct sshbuf *b = NULL;
++	Authctxt *authctxt = ssh->authctxt;
++	gss_buffer_desc gssbuf;
++	gss_buffer_desc mic = GSS_C_EMPTY_BUFFER;
++	OM_uint32 ms;
++	int r;
++
++	static int attempt = 0;
++	if (attempt++ >= 1)
++		return (0);
++
++	if (gss_kex_context == NULL) {
++		debug("No valid Key exchange context");
++		return (0);
++	}
++
++	if ((b = sshbuf_new()) == NULL)
++		fatal_f("sshbuf_new failed");
++
++	ssh_gssapi_buildmic(b, authctxt->server_user, authctxt->service,
++	    "gssapi-keyex", ssh->kex->session_id);
++
++	if ((gssbuf.value = sshbuf_mutable_ptr(b)) == NULL)
++		fatal_f("sshbuf_mutable_ptr failed");
++	gssbuf.length = sshbuf_len(b);
++
++	if (GSS_ERROR(ssh_gssapi_sign(gss_kex_context, &gssbuf, &mic))) {
++		sshbuf_free(b);
++		return (0);
++	}
++
++	if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_REQUEST)) != 0 ||
++	    (r = sshpkt_put_cstring(ssh, authctxt->server_user)) != 0 ||
++	    (r = sshpkt_put_cstring(ssh, authctxt->service)) != 0 ||
++	    (r = sshpkt_put_cstring(ssh, authctxt->method->name)) != 0 ||
++	    (r = sshpkt_put_string(ssh, mic.value, mic.length)) != 0 ||
++	    (r = sshpkt_send(ssh)) != 0)
++		fatal_fr(r, "parsing");
++
++	sshbuf_free(b);
++	gss_release_buffer(&ms, &mic);
++
++	return (1);
++}
++
+ #endif /* GSSAPI */
+ 
+ static int
+diff --git a/sshd.c b/sshd.c
+index 9cbe92293..fee5cac64 100644
+--- a/sshd.c
++++ b/sshd.c
+@@ -798,8 +798,8 @@ notify_hostkeys(struct ssh *ssh)
+ 	}
+ 	debug3_f("sent %u hostkeys", nkeys);
+ 	if (nkeys == 0)
+-		fatal_f("no hostkeys");
+-	if ((r = sshpkt_send(ssh)) != 0)
++		debug3_f("no hostkeys");
++	else if ((r = sshpkt_send(ssh)) != 0)
+ 		sshpkt_fatal(ssh, r, "%s: send", __func__);
+ 	sshbuf_free(buf);
+ }
+@@ -1930,7 +1930,8 @@ main(int ac, char **av)
+ 		free(fp);
+ 	}
+ 	accumulate_host_timing_secret(cfg, NULL);
+-	if (!sensitive_data.have_ssh2_key) {
++	/* The GSSAPI key exchange can run without a host key */
++	if (!sensitive_data.have_ssh2_key && !options.gss_keyex) {
+ 		logit("sshd: no hostkeys available -- exiting.");
+ 		exit(1);
+ 	}
+@@ -2402,6 +2403,48 @@ do_ssh2_kex(struct ssh *ssh)
+ 
+ 	free(hkalgs);
+ 
++#if defined(GSSAPI) && defined(WITH_OPENSSL)
++	{
++	char *orig;
++	char *gss = NULL;
++	char *newstr = NULL;
++	orig = myproposal[PROPOSAL_KEX_ALGS];
++
++	/*
++	 * If we don't have a host key, then there's no point advertising
++	 * the other key exchange algorithms
++	 */
++
++	if (strlen(myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS]) == 0)
++		orig = NULL;
++
++	if (options.gss_keyex)
++		gss = ssh_gssapi_server_mechanisms();
++	else
++		gss = NULL;
++
++	if (gss && orig)
++		xasprintf(&newstr, "%s,%s", gss, orig);
++	else if (gss)
++		newstr = gss;
++	else if (orig)
++		newstr = orig;
++
++	/*
++	 * If we've got GSSAPI mechanisms, then we've got the 'null' host
++	 * key alg, but we can't tell people about it unless its the only
++	 * host key algorithm we support
++	 */
++	if (gss && (strlen(myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS])) == 0)
++		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = "null";
++
++	if (newstr)
++		myproposal[PROPOSAL_KEX_ALGS] = newstr;
++	else
++		fatal("No supported key exchange algorithms");
++	}
++#endif
++
+ 	/* start key exchange */
+ 	if ((r = kex_setup(ssh, myproposal)) != 0)
+ 		fatal_r(r, "kex_setup");
+@@ -2419,7 +2462,18 @@ do_ssh2_kex(struct ssh *ssh)
+ # ifdef OPENSSL_HAS_ECC
+ 	kex->kex[KEX_ECDH_SHA2] = kex_gen_server;
+ # endif
+-#endif
++# ifdef GSSAPI
++	if (options.gss_keyex) {
++		kex->kex[KEX_GSS_GRP1_SHA1] = kexgss_server;
++		kex->kex[KEX_GSS_GRP14_SHA1] = kexgss_server;
++		kex->kex[KEX_GSS_GRP14_SHA256] = kexgss_server;
++		kex->kex[KEX_GSS_GRP16_SHA512] = kexgss_server;
++		kex->kex[KEX_GSS_GEX_SHA1] = kexgssgex_server;
++		kex->kex[KEX_GSS_NISTP256_SHA256] = kexgss_server;
++		kex->kex[KEX_GSS_C25519_SHA256] = kexgss_server;
++	}
++# endif
++#endif /* WITH_OPENSSL */
+ 	kex->kex[KEX_C25519_SHA256] = kex_gen_server;
+ 	kex->kex[KEX_KEM_SNTRUP761X25519_SHA512] = kex_gen_server;
+ 	kex->load_host_public_key=&get_hostkey_public_by_type;
+diff --git a/sshd_config b/sshd_config
+index 36894ace5..ecfe8d026 100644
+--- a/sshd_config
++++ b/sshd_config
+@@ -69,6 +69,8 @@ AuthorizedKeysFile	.ssh/authorized_keys
+ # GSSAPI options
+ #GSSAPIAuthentication no
+ #GSSAPICleanupCredentials yes
++#GSSAPIStrictAcceptorCheck yes
++#GSSAPIKeyExchange no
+ 
+ # Set this to 'yes' to enable PAM authentication, account processing,
+ # and session processing. If this is enabled, PAM authentication will
+diff --git a/sshd_config.5 b/sshd_config.5
+index 7e1a56cd0..d2f09de9b 100644
+--- a/sshd_config.5
++++ b/sshd_config.5
+@@ -731,6 +731,11 @@ Specifies whether to automatically destroy the user's credentials cache
+ on logout.
+ The default is
+ .Cm yes .
++.It Cm GSSAPIKeyExchange
++Specifies whether key exchange based on GSSAPI is allowed. GSSAPI key exchange
++doesn't rely on ssh keys to verify host identity.
++The default is
++.Cm no .
+ .It Cm GSSAPIStrictAcceptorCheck
+ Determines whether to be strict about the identity of the GSSAPI acceptor
+ a client authenticates against.
+@@ -745,6 +750,31 @@ machine's default store.
+ This facility is provided to assist with operation on multi homed machines.
+ The default is
+ .Cm yes .
++.It Cm GSSAPIStoreCredentialsOnRekey
++Controls whether the user's GSSAPI credentials should be updated following a
++successful connection rekeying. This option can be used to accepted renewed
++or updated credentials from a compatible client. The default is
++.Dq no .
++.Pp
++For this to work
++.Cm GSSAPIKeyExchange
++needs to be enabled in the server and also used by the client.
++.It Cm GSSAPIKexAlgorithms
++The list of key exchange algorithms that are accepted by GSSAPI
++key exchange. Possible values are
++.Bd -literal -offset 3n
++gss-gex-sha1-,
++gss-group1-sha1-,
++gss-group14-sha1-,
++gss-group14-sha256-,
++gss-group16-sha512-,
++gss-nistp256-sha256-,
++gss-curve25519-sha256-
++.Ed
++.Pp
++The default is
++.Dq gss-group14-sha256-,gss-group16-sha512-,gss-nistp256-sha256-,gss-curve25519-sha256-,gss-gex-sha1-,gss-group14-sha1- .
++This option only applies to connections using GSSAPI.
+ .It Cm HostbasedAcceptedAlgorithms
+ Specifies the signature algorithms that will be accepted for hostbased
+ authentication as a list of comma-separated patterns.
+diff --git a/sshkey.c b/sshkey.c
+index 06db9b5da..1e7810337 100644
+--- a/sshkey.c
++++ b/sshkey.c
+@@ -128,6 +128,9 @@ extern const struct sshkey_impl sshkey_dsa_cert_impl;
+ extern const struct sshkey_impl sshkey_xmss_impl;
+ extern const struct sshkey_impl sshkey_xmss_cert_impl;
+ #endif
++#ifdef GSSAPI
++extern const struct sshkey_impl sshkey_null_impl;
++#endif /* GSSAPI */
+ 
+ const struct sshkey_impl * const keyimpls[] = {
+ 	&sshkey_ed25519_impl,
+@@ -165,6 +168,9 @@ const struct sshkey_impl * const keyimpls[] = {
+ 	&sshkey_xmss_impl,
+ 	&sshkey_xmss_cert_impl,
+ #endif
++#ifdef GSSAPI
++	&sshkey_null_impl,
++#endif /* GSSAPI */
+ 	NULL
+ };
+ 
+@@ -320,7 +326,7 @@ sshkey_alg_list(int certs_only, int plain_only, int include_sigonly, char sep)
+ 
+ 	for (i = 0; keyimpls[i] != NULL; i++) {
+ 		impl = keyimpls[i];
+-		if (impl->name == NULL)
++		if (impl->name == NULL || impl->type == KEY_NULL)
+ 			continue;
+ 		if (!include_sigonly && impl->sigonly)
+ 			continue;
+diff --git a/sshkey.h b/sshkey.h
+index 708f2da86..dddb40fe2 100644
+--- a/sshkey.h
++++ b/sshkey.h
+@@ -71,6 +71,7 @@ enum sshkey_types {
+ 	KEY_ECDSA_SK_CERT,
+ 	KEY_ED25519_SK,
+ 	KEY_ED25519_SK_CERT,
++	KEY_NULL,
+ 	KEY_UNSPEC
+ };
+ 
diff --git a/debian/patches/keepalive-extensions.patch b/debian/patches/keepalive-extensions.patch
new file mode 100644
index 0000000..b271f71
--- /dev/null
+++ b/debian/patches/keepalive-extensions.patch
@@ -0,0 +1,135 @@
+From 07b232eaa2b9236e66282d4f126f1023d41efc0e Mon Sep 17 00:00:00 2001
+From: Richard Kettlewell <rjk@greenend.org.uk>
+Date: Sun, 9 Feb 2014 16:09:52 +0000
+Subject: Various keepalive extensions
+
+Add compatibility aliases for ProtocolKeepAlives and SetupTimeOut, supported
+in previous versions of Debian's OpenSSH package but since superseded by
+ServerAliveInterval.  (We're probably stuck with this bit for
+compatibility.)
+
+In batch mode, default ServerAliveInterval to five minutes.
+
+Adjust documentation to match and to give some more advice on use of
+keepalives.
+
+Author: Ian Jackson <ian@chiark.greenend.org.uk>
+Author: Matthew Vernon <matthew@debian.org>
+Author: Colin Watson <cjwatson@debian.org>
+Last-Update: 2023-12-18
+
+Patch-Name: keepalive-extensions.patch
+---
+ readconf.c    | 14 ++++++++++++--
+ ssh_config.5  | 21 +++++++++++++++++++--
+ sshd_config.5 |  3 +++
+ 3 files changed, 34 insertions(+), 4 deletions(-)
+
+diff --git a/readconf.c b/readconf.c
+index 93e431d71..bd2e78ab7 100644
+--- a/readconf.c
++++ b/readconf.c
+@@ -182,6 +182,7 @@ typedef enum {
+ 	oPubkeyAcceptedAlgorithms, oCASignatureAlgorithms, oProxyJump,
+ 	oSecurityKeyProvider, oKnownHostsCommand, oRequiredRSASize,
+ 	oEnableEscapeCommandline, oObscureKeystrokeTiming, oChannelTimeout,
++	oProtocolKeepAlives, oSetupTimeOut,
+ 	oIgnore, oIgnoredUnknownOption, oDeprecated, oUnsupported
+ } OpCodes;
+ 
+@@ -345,6 +346,8 @@ static struct {
+ 	{ "enableescapecommandline", oEnableEscapeCommandline },
+ 	{ "obscurekeystroketiming", oObscureKeystrokeTiming },
+ 	{ "channeltimeout", oChannelTimeout },
++	{ "protocolkeepalives", oProtocolKeepAlives },
++	{ "setuptimeout", oSetupTimeOut },
+ 
+ 	{ NULL, oBadOption }
+ };
+@@ -1867,6 +1870,8 @@ parse_pubkey_algos:
+ 		goto parse_flag;
+ 
+ 	case oServerAliveInterval:
++	case oProtocolKeepAlives: /* Debian-specific compatibility alias */
++	case oSetupTimeOut:	  /* Debian-specific compatibility alias */
+ 		intptr = &options->server_alive_interval;
+ 		goto parse_time;
+ 
+@@ -2820,8 +2825,13 @@ fill_default_options(Options * options)
+ 		options->rekey_interval = 0;
+ 	if (options->verify_host_key_dns == -1)
+ 		options->verify_host_key_dns = 0;
+-	if (options->server_alive_interval == -1)
+-		options->server_alive_interval = 0;
++	if (options->server_alive_interval == -1) {
++		/* in batch mode, default is 5mins */
++		if (options->batch_mode == 1)
++			options->server_alive_interval = 300;
++		else
++			options->server_alive_interval = 0;
++	}
+ 	if (options->server_alive_count_max == -1)
+ 		options->server_alive_count_max = 3;
+ 	if (options->control_master == -1)
+diff --git a/ssh_config.5 b/ssh_config.5
+index 7ca72aedf..25ccbed28 100644
+--- a/ssh_config.5
++++ b/ssh_config.5
+@@ -297,9 +297,13 @@ If set to
+ .Cm yes ,
+ user interaction such as password prompts and host key confirmation requests
+ will be disabled.
++In addition, the
++.Cm ServerAliveInterval
++option will be set to 300 seconds by default (Debian-specific).
+ This option is useful in scripts and other batch jobs where no user
+ is present to interact with
+-.Xr ssh 1 .
++.Xr ssh 1 ,
++and where it is desirable to detect a broken network swiftly.
+ The argument must be
+ .Cm yes
+ or
+@@ -1913,7 +1917,14 @@ from the server,
+ will send a message through the encrypted
+ channel to request a response from the server.
+ The default
+-is 0, indicating that these messages will not be sent to the server.
++is 0, indicating that these messages will not be sent to the server,
++or 300 if the
++.Cm BatchMode
++option is set (Debian-specific).
++.Cm ProtocolKeepAlives
++and
++.Cm SetupTimeOut
++are Debian-specific compatibility aliases for this option.
+ .It Cm SessionType
+ May be used to either request invocation of a subsystem on the remote system,
+ or to prevent the execution of a remote command at all.
+@@ -2027,6 +2038,12 @@ Specifies whether the system should send TCP keepalive messages to the
+ other side.
+ If they are sent, death of the connection or crash of one
+ of the machines will be properly noticed.
++This option only uses TCP keepalives (as opposed to using ssh level
++keepalives), so takes a long time to notice when the connection dies.
++As such, you probably want
++the
++.Cm ServerAliveInterval
++option as well.
+ However, this means that
+ connections will die if the route is down temporarily, and some people
+ find it annoying.
+diff --git a/sshd_config.5 b/sshd_config.5
+index d2f09de9b..5de2fd8cf 100644
+--- a/sshd_config.5
++++ b/sshd_config.5
+@@ -1842,6 +1842,9 @@ This avoids infinitely hanging sessions.
+ .Pp
+ To disable TCP keepalive messages, the value should be set to
+ .Cm no .
++.Pp
++This option was formerly called
++.Cm KeepAlive .
+ .It Cm TrustedUserCAKeys
+ Specifies a file containing public keys of certificate authorities that are
+ trusted to sign user certificates for authentication, or
diff --git a/debian/patches/maxhostnamelen.patch b/debian/patches/maxhostnamelen.patch
new file mode 100644
index 0000000..c45fe52
--- /dev/null
+++ b/debian/patches/maxhostnamelen.patch
@@ -0,0 +1,30 @@
+From 32443f45af302ef1f1b48a06942b64b9a9bcc55a Mon Sep 17 00:00:00 2001
+From: Svante Signell <svante.signell@gmail.com>
+Date: Fri, 5 Nov 2021 23:22:53 +0000
+Subject: Define MAXHOSTNAMELEN on GNU/Hurd
+
+Bug-Debian: https://bugs.debian.org/997030
+Last-Update: 2021-11-05
+
+Patch-Name: maxhostnamelen.patch
+---
+ defines.h | 6 ++++++
+ 1 file changed, 6 insertions(+)
+
+diff --git a/defines.h b/defines.h
+index 279e509aa..7225cbfab 100644
+--- a/defines.h
++++ b/defines.h
+@@ -136,6 +136,12 @@ enum
+ # endif
+ #endif /* HOST_NAME_MAX */
+ 
++#ifndef MAXHOSTNAMELEN
++# if defined(_POSIX_HOST_NAME_MAX)
++#  define MAXHOSTNAMELEN _POSIX_HOST_NAME_MAX
++# endif
++#endif /* MAXHOSTNAMELEN */
++
+ #if defined(HAVE_DECL_MAXSYMLINKS) && HAVE_DECL_MAXSYMLINKS == 0
+ # define MAXSYMLINKS 5
+ #endif
diff --git a/debian/patches/mention-ssh-keygen-on-keychange.patch b/debian/patches/mention-ssh-keygen-on-keychange.patch
new file mode 100644
index 0000000..0aec751
--- /dev/null
+++ b/debian/patches/mention-ssh-keygen-on-keychange.patch
@@ -0,0 +1,44 @@
+From d0ff89bd8fd3212fbfaaac8e116150c82bd76ca3 Mon Sep 17 00:00:00 2001
+From: Scott Moser <smoser@ubuntu.com>
+Date: Sun, 9 Feb 2014 16:10:03 +0000
+Subject: Mention ssh-keygen in ssh fingerprint changed warning
+
+Author: Chris Lamb <lamby@debian.org>
+Bug: https://bugzilla.mindrot.org/show_bug.cgi?id=1843
+Bug-Ubuntu: https://bugs.launchpad.net/bugs/686607
+Last-Update: 2023-12-11
+
+Patch-Name: mention-ssh-keygen-on-keychange.patch
+---
+ sshconnect.c | 9 ++++++++-
+ 1 file changed, 8 insertions(+), 1 deletion(-)
+
+diff --git a/sshconnect.c b/sshconnect.c
+index 69256c354..f3096cad9 100644
+--- a/sshconnect.c
++++ b/sshconnect.c
+@@ -1277,9 +1277,13 @@ check_host_key(char *hostname, const struct ssh_conn_info *cinfo,
+ 			error("%s. This could either mean that", key_msg);
+ 			error("DNS SPOOFING is happening or the IP address for the host");
+ 			error("and its host key have changed at the same time.");
+-			if (ip_status != HOST_NEW)
++			if (ip_status != HOST_NEW) {
+ 				error("Offending key for IP in %s:%lu",
+ 				    ip_found->file, ip_found->line);
++				error("  remove with:");
++				error("  ssh-keygen -f '%s' -R '%s'",
++				    ip_found->file, ip);
++			}
+ 		}
+ 		/* The host key has changed. */
+ 		warn_changed_key(host_key);
+@@ -1291,6 +1295,9 @@ check_host_key(char *hostname, const struct ssh_conn_info *cinfo,
+ 		error("Offending %s key in %s:%lu",
+ 		    sshkey_type(host_found->key),
+ 		    host_found->file, host_found->line);
++		error("  remove with:");
++		error("  ssh-keygen -f '%s' -R '%s'",
++		    host_found->file, host);
+ 
+ 		/*
+ 		 * If strict host key checking is in use, the user will have
diff --git a/debian/patches/no-openssl-version-status.patch b/debian/patches/no-openssl-version-status.patch
new file mode 100644
index 0000000..dacefcc
--- /dev/null
+++ b/debian/patches/no-openssl-version-status.patch
@@ -0,0 +1,71 @@
+From 2c598ce2acb40df7a9275f245e375071a7fb9d7c Mon Sep 17 00:00:00 2001
+From: Kurt Roeckx <kurt@roeckx.be>
+Date: Sun, 9 Feb 2014 16:10:14 +0000
+Subject: Don't check the status field of the OpenSSL version
+
+There is no reason to check the version of OpenSSL (in Debian).  If it's
+not compatible the soname will change.  OpenSSH seems to want to do a
+check for the soname based on the version number, but wants to keep the
+status of the release the same.  Remove that check on the status since
+it doesn't tell you anything about how compatible that version is.
+
+Author: Colin Watson <cjwatson@debian.org>
+Bug-Debian: https://bugs.debian.org/93581
+Bug-Debian: https://bugs.debian.org/664383
+Bug-Debian: https://bugs.debian.org/732940
+Forwarded: not-needed
+Last-Update: 2023-09-02
+
+Patch-Name: no-openssl-version-status.patch
+---
+ openbsd-compat/openssl-compat.c         | 8 ++++----
+ openbsd-compat/regress/opensslvertest.c | 2 ++
+ 2 files changed, 6 insertions(+), 4 deletions(-)
+
+diff --git a/openbsd-compat/openssl-compat.c b/openbsd-compat/openssl-compat.c
+index 6c65003f2..30e97c464 100644
+--- a/openbsd-compat/openssl-compat.c
++++ b/openbsd-compat/openssl-compat.c
+@@ -49,18 +49,18 @@ ssh_compatible_openssl(long headerver, long libver)
+ 		return 1;
+ 
+ 	/*
+-	 * For versions >= 3.0, only the major and status must match.
++	 * For versions >= 3.0, only the major must match.
+ 	 */
+ 	if (headerver >= 0x3000000f) {
+-		mask = 0xf000000fL; /* major,status */
++		mask = 0xf0000000L; /* major */
+ 		return (headerver & mask) == (libver & mask);
+ 	}
+ 
+ 	/*
+-	 * For versions >= 1.0.0, but <3, major,minor,status must match and
++	 * For versions >= 1.0.0, but <3, major,minor must match and
+ 	 * library fix version must be equal to or newer than the header.
+ 	 */
+-	mask = 0xfff0000fL; /* major,minor,status */
++	mask = 0xfff00000L; /* major,minor */
+ 	hfix = (headerver & 0x000ff000) >> 12;
+ 	lfix = (libver & 0x000ff000) >> 12;
+ 	if ( (headerver & mask) == (libver & mask) && lfix >= hfix)
+diff --git a/openbsd-compat/regress/opensslvertest.c b/openbsd-compat/regress/opensslvertest.c
+index 99c894418..351df4374 100644
+--- a/openbsd-compat/regress/opensslvertest.c
++++ b/openbsd-compat/regress/opensslvertest.c
+@@ -28,6 +28,7 @@ struct version_test {
+ } version_tests[] = {
+ 	/* built with 1.0.1b release headers */
+ 	{ 0x1000101fL, 0x1000101fL, 1},/* exact match */
++	{ 0x1000101fL, 0x10001010L, 1}, /* different status: ok */
+ 	{ 0x1000101fL, 0x1000102fL, 1},	/* newer library patch version: ok */
+ 	{ 0x1000101fL, 0x1000100fL, 1},	/* older library patch version: ok */
+ 	{ 0x1000101fL, 0x1000201fL, 1},	/* newer library fix version: ok */
+@@ -48,6 +49,7 @@ struct version_test {
+ 
+ 	/* built with 3.0.1 release headers */
+ 	{ 0x3010101fL, 0x3010101fL, 1},/* exact match */
++	{ 0x3010101fL, 0x30101010L, 1}, /* different status: ok */
+ 	{ 0x3010101fL, 0x3010102fL, 1},	/* newer library patch version: ok */
+ 	{ 0x3010101fL, 0x3010100fL, 1},	/* older library patch version: ok */
+ 	{ 0x3010101fL, 0x3010201fL, 1},	/* newer library fix version: ok */
diff --git a/debian/patches/openbsd-docs.patch b/debian/patches/openbsd-docs.patch
new file mode 100644
index 0000000..785d181
--- /dev/null
+++ b/debian/patches/openbsd-docs.patch
@@ -0,0 +1,255 @@
+From 92fdda49286532870c424f93f3d157583a921cbe Mon Sep 17 00:00:00 2001
+From: Colin Watson <cjwatson@debian.org>
+Date: Sun, 9 Feb 2014 16:10:09 +0000
+Subject: Adjust various OpenBSD-specific references in manual pages
+
+No single bug reference for this patch, but history includes:
+ https://bugs.debian.org/154434 (login.conf(5))
+ https://bugs.debian.org/513417 (/etc/rc)
+ https://bugs.debian.org/530692 (ssl(8))
+ https://bugs.launchpad.net/bugs/456660 (ssl(8))
+ https://bugs.debian.org/998069 (rdomain(4))
+
+Forwarded: not-needed
+Last-Update: 2023-09-02
+
+Patch-Name: openbsd-docs.patch
+---
+ moduli.5      |  4 ++--
+ ssh-keygen.1  | 12 ++++--------
+ ssh.1         |  4 ++++
+ sshd.8        |  5 ++---
+ sshd_config.5 | 40 ++--------------------------------------
+ 5 files changed, 14 insertions(+), 51 deletions(-)
+
+diff --git a/moduli.5 b/moduli.5
+index 5086a6d42..6dffdc7e6 100644
+--- a/moduli.5
++++ b/moduli.5
+@@ -21,7 +21,7 @@
+ .Nd Diffie-Hellman moduli
+ .Sh DESCRIPTION
+ The
+-.Pa /etc/moduli
++.Pa /etc/ssh/moduli
+ file contains prime numbers and generators for use by
+ .Xr sshd 8
+ in the Diffie-Hellman Group Exchange key exchange method.
+@@ -110,7 +110,7 @@ first estimates the size of the modulus required to produce enough
+ Diffie-Hellman output to sufficiently key the selected symmetric cipher.
+ .Xr sshd 8
+ then randomly selects a modulus from
+-.Fa /etc/moduli
++.Fa /etc/ssh/moduli
+ that best meets the size requirement.
+ .Sh SEE ALSO
+ .Xr ssh-keygen 1 ,
+diff --git a/ssh-keygen.1 b/ssh-keygen.1
+index c392141ea..1155cf555 100644
+--- a/ssh-keygen.1
++++ b/ssh-keygen.1
+@@ -212,9 +212,7 @@ key in
+ .Pa ~/.ssh/id_ed25519_sk
+ or
+ .Pa ~/.ssh/id_rsa .
+-Additionally, the system administrator may use this to generate host keys,
+-as seen in
+-.Pa /etc/rc .
++Additionally, the system administrator may use this to generate host keys.
+ .Pp
+ Normally this program generates the key and asks for a file in which
+ to store the private key.
+@@ -279,9 +277,7 @@ If
+ .Fl f
+ has also been specified, its argument is used as a prefix to the
+ default path for the resulting host key files.
+-This is used by
+-.Pa /etc/rc
+-to generate new host keys.
++This is used by system administration scripts to generate new host keys.
+ .It Fl a Ar rounds
+ When saving a private key, this option specifies the number of KDF
+ (key derivation function, currently
+@@ -864,7 +860,7 @@ option.
+ Valid generator values are 2, 3, and 5.
+ .Pp
+ Screened DH groups may be installed in
+-.Pa /etc/moduli .
++.Pa /etc/ssh/moduli .
+ It is important that this file contains moduli of a range of bit lengths.
+ .Pp
+ A number of options are available for moduli generation and screening via the
+@@ -1322,7 +1318,7 @@ on all machines
+ where the user wishes to log in using public key authentication.
+ There is no need to keep the contents of this file secret.
+ .Pp
+-.It Pa /etc/moduli
++.It Pa /etc/ssh/moduli
+ Contains Diffie-Hellman groups used for DH-GEX.
+ The file format is described in
+ .Xr moduli 5 .
+diff --git a/ssh.1 b/ssh.1
+index 2d07c919e..60e97dc62 100644
+--- a/ssh.1
++++ b/ssh.1
+@@ -939,6 +939,10 @@ implements public key authentication protocol automatically,
+ using one of the DSA, ECDSA, Ed25519 or RSA algorithms.
+ The HISTORY section of
+ .Xr ssl 8
++(on non-OpenBSD systems, see
++.nh
++http://www.openbsd.org/cgi\-bin/man.cgi?query=ssl&sektion=8#HISTORY)
++.hy
+ contains a brief discussion of the DSA and RSA algorithms.
+ .Pp
+ The file
+diff --git a/sshd.8 b/sshd.8
+index 8efeacdf1..6527e28a3 100644
+--- a/sshd.8
++++ b/sshd.8
+@@ -64,7 +64,7 @@ over an insecure network.
+ .Nm
+ listens for connections from clients.
+ It is normally started at boot from
+-.Pa /etc/rc .
++.Pa /etc/init.d/ssh .
+ It forks a new
+ daemon for each incoming connection.
+ The forked daemons handle
+@@ -935,7 +935,7 @@ This file is for host-based authentication (see
+ .Xr ssh 1 ) .
+ It should only be writable by root.
+ .Pp
+-.It Pa /etc/moduli
++.It Pa /etc/ssh/moduli
+ Contains Diffie-Hellman groups used for the "Diffie-Hellman Group Exchange"
+ key exchange method.
+ The file format is described in
+@@ -1033,7 +1033,6 @@ The content of this file is not sensitive; it can be world-readable.
+ .Xr ssh-keyscan 1 ,
+ .Xr chroot 2 ,
+ .Xr hosts_access 5 ,
+-.Xr login.conf 5 ,
+ .Xr moduli 5 ,
+ .Xr sshd_config 5 ,
+ .Xr inetd 8 ,
+diff --git a/sshd_config.5 b/sshd_config.5
+index 630c18736..98bd201b0 100644
+--- a/sshd_config.5
++++ b/sshd_config.5
+@@ -993,9 +993,6 @@ for interactive sessions and
+ for non-interactive sessions.
+ .It Cm KbdInteractiveAuthentication
+ Specifies whether to allow keyboard-interactive authentication.
+-All authentication styles from
+-.Xr login.conf 5
+-are supported.
+ The default is
+ .Cm yes .
+ The argument to this keyword must be
+@@ -1099,45 +1096,33 @@ The following forms may be used:
+ .Sm off
+ .Ar hostname | address
+ .Sm on
+-.Op Cm rdomain Ar domain
+ .It
+ .Cm ListenAddress
+ .Sm off
+ .Ar hostname : port
+ .Sm on
+-.Op Cm rdomain Ar domain
+ .It
+ .Cm ListenAddress
+ .Sm off
+ .Ar IPv4_address : port
+ .Sm on
+-.Op Cm rdomain Ar domain
+ .It
+ .Cm ListenAddress
+ .Sm off
+ .Oo Ar hostname | address Oc : Ar port
+ .Sm on
+-.Op Cm rdomain Ar domain
+ .El
+ .Pp
+-The optional
+-.Cm rdomain
+-qualifier requests
+-.Xr sshd 8
+-listen in an explicit routing domain.
+ If
+ .Ar port
+ is not specified,
+ sshd will listen on the address and all
+ .Cm Port
+ options specified.
+-The default is to listen on all local addresses on the current default
+-routing domain.
++The default is to listen on all local addresses.
+ Multiple
+ .Cm ListenAddress
+ options are permitted.
+-For more information on routing domains, see
+-.Xr rdomain 4 .
+ .It Cm LoginGraceTime
+ The server disconnects after this time if the user has not
+ successfully logged in.
+@@ -1262,14 +1247,8 @@ The available criteria are
+ .Cm Host ,
+ .Cm LocalAddress ,
+ .Cm LocalPort ,
+-.Cm RDomain ,
+ and
+-.Cm Address
+-(with
+-.Cm RDomain
+-representing the
+-.Xr rdomain 4
+-on which the connection was received).
++.Cm Address .
+ .Pp
+ The match patterns may consist of single entries or comma-separated
+ lists and may use the wildcard and negation operators described in the
+@@ -1341,7 +1320,6 @@ Available keywords are
+ .Cm PubkeyAuthOptions ,
+ .Cm RekeyLimit ,
+ .Cm RevokedKeys ,
+-.Cm RDomain ,
+ .Cm SetEnv ,
+ .Cm StreamLocalBindMask ,
+ .Cm StreamLocalBindUnlink ,
+@@ -1736,15 +1714,6 @@ an OpenSSH Key Revocation List (KRL) as generated by
+ .Xr ssh-keygen 1 .
+ For more information on KRLs, see the KEY REVOCATION LISTS section in
+ .Xr ssh-keygen 1 .
+-.It Cm RDomain
+-Specifies an explicit routing domain that is applied after authentication
+-has completed.
+-The user session, as well as any forwarded or listening IP sockets,
+-will be bound to this
+-.Xr rdomain 4 .
+-If the routing domain is set to
+-.Cm \&%D ,
+-then the domain in which the incoming connection was received will be applied.
+ .It Cm SecurityKeyProvider
+ Specifies a path to a library that will be used when loading
+ FIDO authenticator-hosted keys, overriding the default of using
+@@ -2063,8 +2032,6 @@ A literal
+ Identifies the connection endpoints, containing
+ four space-separated values: client address, client port number,
+ server address, and server port number.
+-.It \&%D
+-The routing domain in which the incoming connection was received.
+ .It %F
+ The fingerprint of the CA key.
+ .It %f
+@@ -2103,9 +2070,6 @@ accepts the tokens %%, %h, %U, and %u.
+ .Pp
+ .Cm ChrootDirectory
+ accepts the tokens %%, %h, %U, and %u.
+-.Pp
+-.Cm RoutingDomain
+-accepts the token %D.
+ .Sh FILES
+ .Bl -tag -width Ds
+ .It Pa /etc/ssh/sshd_config
diff --git a/debian/patches/package-versioning.patch b/debian/patches/package-versioning.patch
new file mode 100644
index 0000000..7f185ed
--- /dev/null
+++ b/debian/patches/package-versioning.patch
@@ -0,0 +1,47 @@
+From 7cb16dcd8f8ef171515f125b3557d01712f58bbb Mon Sep 17 00:00:00 2001
+From: Matthew Vernon <matthew@debian.org>
+Date: Sun, 9 Feb 2014 16:10:05 +0000
+Subject: Include the Debian version in our identification
+
+This makes it easier to audit networks for versions patched against security
+vulnerabilities.  It has little detrimental effect, as attackers will
+generally just try attacks rather than bothering to scan for
+vulnerable-looking version strings.  (However, see debian-banner.patch.)
+
+Forwarded: not-needed
+Last-Update: 2023-12-18
+
+Patch-Name: package-versioning.patch
+---
+ kex.c     | 2 +-
+ version.h | 7 ++++++-
+ 2 files changed, 7 insertions(+), 2 deletions(-)
+
+diff --git a/kex.c b/kex.c
+index acab53195..a532d8cb0 100644
+--- a/kex.c
++++ b/kex.c
+@@ -1540,7 +1540,7 @@ kex_exchange_identification(struct ssh *ssh, int timeout_ms,
+ 	if (version_addendum != NULL && *version_addendum == '\0')
+ 		version_addendum = NULL;
+ 	if ((r = sshbuf_putf(our_version, "SSH-%d.%d-%s%s%s\r\n",
+-	    PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2, SSH_VERSION,
++	    PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2, SSH_RELEASE,
+ 	    version_addendum == NULL ? "" : " ",
+ 	    version_addendum == NULL ? "" : version_addendum)) != 0) {
+ 		oerrno = errno;
+diff --git a/version.h b/version.h
+index a4b7b594c..9e9ab037f 100644
+--- a/version.h
++++ b/version.h
+@@ -3,4 +3,9 @@
+ #define SSH_VERSION	"OpenSSH_9.6"
+ 
+ #define SSH_PORTABLE	"p1"
+-#define SSH_RELEASE	SSH_VERSION SSH_PORTABLE
++#define SSH_RELEASE_MINIMUM	SSH_VERSION SSH_PORTABLE
++#ifdef SSH_EXTRAVERSION
++#define SSH_RELEASE	SSH_RELEASE_MINIMUM " " SSH_EXTRAVERSION
++#else
++#define SSH_RELEASE	SSH_RELEASE_MINIMUM
++#endif
diff --git a/debian/patches/restore-authorized_keys2.patch b/debian/patches/restore-authorized_keys2.patch
new file mode 100644
index 0000000..910e606
--- /dev/null
+++ b/debian/patches/restore-authorized_keys2.patch
@@ -0,0 +1,35 @@
+From 0d37b950036d682883ed4b3c2d07946649698123 Mon Sep 17 00:00:00 2001
+From: Colin Watson <cjwatson@debian.org>
+Date: Sun, 5 Mar 2017 02:02:11 +0000
+Subject: Restore reading authorized_keys2 by default
+
+Upstream seems to intend to gradually phase this out, so don't assume
+that this will remain the default forever.  However, we were late in
+adopting the upstream sshd_config changes, so it makes sense to extend
+the grace period.
+
+Bug-Debian: https://bugs.debian.org/852320
+Forwarded: not-needed
+Last-Update: 2017-03-05
+
+Patch-Name: restore-authorized_keys2.patch
+---
+ sshd_config | 5 ++---
+ 1 file changed, 2 insertions(+), 3 deletions(-)
+
+diff --git a/sshd_config b/sshd_config
+index 677f97d5d..d500d18cd 100644
+--- a/sshd_config
++++ b/sshd_config
+@@ -38,9 +38,8 @@ Include /etc/ssh/sshd_config.d/*.conf
+ 
+ #PubkeyAuthentication yes
+ 
+-# The default is to check both .ssh/authorized_keys and .ssh/authorized_keys2
+-# but this is overridden so installations will only check .ssh/authorized_keys
+-AuthorizedKeysFile	.ssh/authorized_keys
++# Expect .ssh/authorized_keys2 to be disregarded by default in future.
++#AuthorizedKeysFile	.ssh/authorized_keys .ssh/authorized_keys2
+ 
+ #AuthorizedPrincipalsFile none
+ 
diff --git a/debian/patches/restore-tcp-wrappers.patch b/debian/patches/restore-tcp-wrappers.patch
new file mode 100644
index 0000000..0e6df41
--- /dev/null
+++ b/debian/patches/restore-tcp-wrappers.patch
@@ -0,0 +1,172 @@
+From e79b4cebc0d5e1b8fb5083aed781df70c4db021d Mon Sep 17 00:00:00 2001
+From: Colin Watson <cjwatson@debian.org>
+Date: Tue, 7 Oct 2014 13:22:41 +0100
+Subject: Restore TCP wrappers support
+
+Support for TCP wrappers was dropped in OpenSSH 6.7.  See this message
+and thread:
+
+  https://lists.mindrot.org/pipermail/openssh-unix-dev/2014-April/032497.html
+
+It is true that this reduces preauth attack surface in sshd.  On the
+other hand, this support seems to be quite widely used, and abruptly
+dropping it (from the perspective of users who don't read
+openssh-unix-dev) could easily cause more serious problems in practice.
+
+It's not entirely clear what the right long-term answer for Debian is,
+but it at least probably doesn't involve dropping this feature shortly
+before a freeze.
+
+Forwarded: not-needed
+Last-Update: 2022-02-23
+
+Patch-Name: restore-tcp-wrappers.patch
+---
+ configure.ac | 57 ++++++++++++++++++++++++++++++++++++++++++++++++++++
+ sshd.8       |  7 +++++++
+ sshd.c       | 25 +++++++++++++++++++++++
+ 3 files changed, 89 insertions(+)
+
+diff --git a/configure.ac b/configure.ac
+index 2aeab040c..badfacf8f 100644
+--- a/configure.ac
++++ b/configure.ac
+@@ -1677,6 +1677,62 @@ else
+ 	AC_MSG_RESULT([no])
+ fi
+ 
++# Check whether user wants TCP wrappers support
++TCPW_MSG="no"
++AC_ARG_WITH([tcp-wrappers],
++	[  --with-tcp-wrappers[[=PATH]] Enable tcpwrappers support (optionally in PATH)],
++	[
++		if test "x$withval" != "xno" ; then
++			saved_LIBS="$LIBS"
++			saved_LDFLAGS="$LDFLAGS"
++			saved_CPPFLAGS="$CPPFLAGS"
++			if test -n "${withval}" && \
++			    test "x${withval}" != "xyes"; then
++				if test -d "${withval}/lib"; then
++					if test -n "${need_dash_r}"; then
++						LDFLAGS="-L${withval}/lib -R${withval}/lib ${LDFLAGS}"
++					else
++						LDFLAGS="-L${withval}/lib ${LDFLAGS}"
++					fi
++				else
++					if test -n "${need_dash_r}"; then
++						LDFLAGS="-L${withval} -R${withval} ${LDFLAGS}"
++					else
++						LDFLAGS="-L${withval} ${LDFLAGS}"
++					fi
++				fi
++				if test -d "${withval}/include"; then
++					CPPFLAGS="-I${withval}/include ${CPPFLAGS}"
++				else
++					CPPFLAGS="-I${withval} ${CPPFLAGS}"
++				fi
++			fi
++			LIBS="-lwrap $LIBS"
++			AC_MSG_CHECKING([for libwrap])
++			AC_LINK_IFELSE([AC_LANG_PROGRAM([[
++#include <sys/types.h>
++#include <sys/socket.h>
++#include <netinet/in.h>
++#include <tcpd.h>
++int deny_severity = 0, allow_severity = 0;
++				]], [[
++	hosts_access(0);
++				]])], [
++					AC_MSG_RESULT([yes])
++					AC_DEFINE([LIBWRAP], [1],
++						[Define if you want
++						TCP Wrappers support])
++					SSHDLIBS="$SSHDLIBS -lwrap"
++					TCPW_MSG="yes"
++				], [
++					AC_MSG_ERROR([*** libwrap missing])
++				
++			])
++			LIBS="$saved_LIBS"
++		fi
++	]
++)
++
+ # Check whether user wants to use ldns
+ LDNS_MSG="no"
+ AC_ARG_WITH(ldns,
+@@ -5669,6 +5725,7 @@ echo "                       PAM support: $PAM_MSG"
+ echo "                   OSF SIA support: $SIA_MSG"
+ echo "                 KerberosV support: $KRB5_MSG"
+ echo "                   SELinux support: $SELINUX_MSG"
++echo "              TCP Wrappers support: $TCPW_MSG"
+ echo "                   libedit support: $LIBEDIT_MSG"
+ echo "                   libldns support: $LDNS_MSG"
+ echo "  Solaris process contract support: $SPC_MSG"
+diff --git a/sshd.8 b/sshd.8
+index 73d5e9232..8efeacdf1 100644
+--- a/sshd.8
++++ b/sshd.8
+@@ -924,6 +924,12 @@ the user's home directory becomes accessible.
+ This file should be writable only by the user, and need not be
+ readable by anyone else.
+ .Pp
++.It Pa /etc/hosts.allow
++.It Pa /etc/hosts.deny
++Access controls that should be enforced by tcp-wrappers are defined here.
++Further details are described in
++.Xr hosts_access 5 .
++.Pp
+ .It Pa /etc/hosts.equiv
+ This file is for host-based authentication (see
+ .Xr ssh 1 ) .
+@@ -1026,6 +1032,7 @@ The content of this file is not sensitive; it can be world-readable.
+ .Xr ssh-keygen 1 ,
+ .Xr ssh-keyscan 1 ,
+ .Xr chroot 2 ,
++.Xr hosts_access 5 ,
+ .Xr login.conf 5 ,
+ .Xr moduli 5 ,
+ .Xr sshd_config 5 ,
+diff --git a/sshd.c b/sshd.c
+index fee5cac64..c57ab9628 100644
+--- a/sshd.c
++++ b/sshd.c
+@@ -128,6 +128,13 @@
+ #include "srclimit.h"
+ #include "dh.h"
+ 
++#ifdef LIBWRAP
++#include <tcpd.h>
++#include <syslog.h>
++int allow_severity;
++int deny_severity;
++#endif /* LIBWRAP */
++
+ /* Re-exec fds */
+ #define REEXEC_DEVCRYPTO_RESERVED_FD	(STDERR_FILENO + 1)
+ #define REEXEC_STARTUP_PIPE_FD		(STDERR_FILENO + 2)
+@@ -2200,6 +2207,24 @@ main(int ac, char **av)
+ #ifdef SSH_AUDIT_EVENTS
+ 	audit_connection_from(remote_ip, remote_port);
+ #endif
++#ifdef LIBWRAP
++	allow_severity = options.log_facility|LOG_INFO;
++	deny_severity = options.log_facility|LOG_WARNING;
++	/* Check whether logins are denied from this host. */
++	if (ssh_packet_connection_is_on_socket(ssh)) {
++		struct request_info req;
++
++		request_init(&req, RQ_DAEMON, __progname, RQ_FILE, sock_in, 0);
++		fromhost(&req);
++
++		if (!hosts_access(&req)) {
++			debug("Connection refused by tcp wrapper");
++			refuse(&req);
++			/* NOTREACHED */
++			fatal("libwrap refuse returns");
++		}
++	}
++#endif /* LIBWRAP */
+ 
+ 	rdomain = ssh_packet_rdomain_in(ssh);
+ 
diff --git a/debian/patches/revert-ipqos-defaults.patch b/debian/patches/revert-ipqos-defaults.patch
new file mode 100644
index 0000000..204f524
--- /dev/null
+++ b/debian/patches/revert-ipqos-defaults.patch
@@ -0,0 +1,93 @@
+From fc28a869ee5cedb1122d6171049fd3373e74a169 Mon Sep 17 00:00:00 2001
+From: Colin Watson <cjwatson@debian.org>
+Date: Mon, 8 Apr 2019 10:46:29 +0100
+Subject: Revert "upstream: Update default IPQoS in ssh(1), sshd(8) to DSCP
+ AF21 for"
+
+This reverts commit 5ee8448ad7c306f05a9f56769f95336a8269f379.
+
+The IPQoS default changes have some unfortunate interactions with
+iptables (see https://bugs.debian.org/923880) and VMware, so I'm
+temporarily reverting them until those have been fixed.
+
+Bug-Debian: https://bugs.debian.org/923879
+Bug-Debian: https://bugs.debian.org/926229
+Bug-Ubuntu: https://bugs.launchpad.net/bugs/1822370
+Last-Update: 2019-04-08
+
+Patch-Name: revert-ipqos-defaults.patch
+---
+ readconf.c    | 4 ++--
+ servconf.c    | 4 ++--
+ ssh_config.5  | 6 ++----
+ sshd_config.5 | 6 ++----
+ 4 files changed, 8 insertions(+), 12 deletions(-)
+
+diff --git a/readconf.c b/readconf.c
+index 2e6d3e726..95517f15f 100644
+--- a/readconf.c
++++ b/readconf.c
+@@ -2852,9 +2852,9 @@ fill_default_options(Options * options)
+ 	if (options->visual_host_key == -1)
+ 		options->visual_host_key = 0;
+ 	if (options->ip_qos_interactive == -1)
+-		options->ip_qos_interactive = IPTOS_DSCP_AF21;
++		options->ip_qos_interactive = IPTOS_LOWDELAY;
+ 	if (options->ip_qos_bulk == -1)
+-		options->ip_qos_bulk = IPTOS_DSCP_CS1;
++		options->ip_qos_bulk = IPTOS_THROUGHPUT;
+ 	if (options->request_tty == -1)
+ 		options->request_tty = REQUEST_TTY_AUTO;
+ 	if (options->session_type == -1)
+diff --git a/servconf.c b/servconf.c
+index cecbef9a1..ab6198e6e 100644
+--- a/servconf.c
++++ b/servconf.c
+@@ -439,9 +439,9 @@ fill_default_server_options(ServerOptions *options)
+ 	if (options->permit_tun == -1)
+ 		options->permit_tun = SSH_TUNMODE_NO;
+ 	if (options->ip_qos_interactive == -1)
+-		options->ip_qos_interactive = IPTOS_DSCP_AF21;
++		options->ip_qos_interactive = IPTOS_LOWDELAY;
+ 	if (options->ip_qos_bulk == -1)
+-		options->ip_qos_bulk = IPTOS_DSCP_CS1;
++		options->ip_qos_bulk = IPTOS_THROUGHPUT;
+ 	if (options->version_addendum == NULL)
+ 		options->version_addendum = xstrdup("");
+ 	if (options->fwd_opts.streamlocal_bind_mask == (mode_t)-1)
+diff --git a/ssh_config.5 b/ssh_config.5
+index 4ec34d1a3..fe144ce29 100644
+--- a/ssh_config.5
++++ b/ssh_config.5
+@@ -1313,11 +1313,9 @@ If one argument is specified, it is used as the packet class unconditionally.
+ If two values are specified, the first is automatically selected for
+ interactive sessions and the second for non-interactive sessions.
+ The default is
+-.Cm af21
+-(Low-Latency Data)
++.Cm lowdelay
+ for interactive sessions and
+-.Cm cs1
+-(Lower Effort)
++.Cm throughput
+ for non-interactive sessions.
+ .It Cm KbdInteractiveAuthentication
+ Specifies whether to use keyboard-interactive authentication.
+diff --git a/sshd_config.5 b/sshd_config.5
+index d0bf6d641..7cc68f4d4 100644
+--- a/sshd_config.5
++++ b/sshd_config.5
+@@ -1014,11 +1014,9 @@ If one argument is specified, it is used as the packet class unconditionally.
+ If two values are specified, the first is automatically selected for
+ interactive sessions and the second for non-interactive sessions.
+ The default is
+-.Cm af21
+-(Low-Latency Data)
++.Cm lowdelay
+ for interactive sessions and
+-.Cm cs1
+-(Lower Effort)
++.Cm throughput
+ for non-interactive sessions.
+ .It Cm KbdInteractiveAuthentication
+ Specifies whether to allow keyboard-interactive authentication.
diff --git a/debian/patches/scp-quoting.patch b/debian/patches/scp-quoting.patch
new file mode 100644
index 0000000..d6d0b5d
--- /dev/null
+++ b/debian/patches/scp-quoting.patch
@@ -0,0 +1,41 @@
+From 50542fa19bcac94a20d86470324a878c19e4e726 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Nicolas=20Valc=C3=A1rcel?= <nvalcarcel@ubuntu.com>
+Date: Sun, 9 Feb 2014 16:09:59 +0000
+Subject: Adjust scp quoting in verbose mode
+
+Tweak scp's reporting of filenames in verbose mode to be a bit less
+confusing with spaces.
+
+This should be revised to mimic real shell quoting.
+
+Bug-Ubuntu: https://bugs.launchpad.net/bugs/89945
+Last-Update: 2010-02-27
+
+Patch-Name: scp-quoting.patch
+---
+ scp.c | 12 ++++++++++--
+ 1 file changed, 10 insertions(+), 2 deletions(-)
+
+diff --git a/scp.c b/scp.c
+index 492dace12..49c86b66c 100644
+--- a/scp.c
++++ b/scp.c
+@@ -239,8 +239,16 @@ do_local_cmd(arglist *a)
+ 
+ 	if (verbose_mode) {
+ 		fprintf(stderr, "Executing:");
+-		for (i = 0; i < a->num; i++)
+-			fmprintf(stderr, " %s", a->list[i]);
++		for (i = 0; i < a->num; i++) {
++			if (i == 0)
++				fmprintf(stderr, " %s", a->list[i]);
++			else
++				/*
++				 * TODO: misbehaves if a->list[i] contains a
++				 * single quote
++				 */
++				fmprintf(stderr, " '%s'", a->list[i]);
++		}
+ 		fprintf(stderr, "\n");
+ 	}
+ 	if ((pid = fork()) == -1)
diff --git a/debian/patches/selinux-role.patch b/debian/patches/selinux-role.patch
new file mode 100644
index 0000000..063ed7d
--- /dev/null
+++ b/debian/patches/selinux-role.patch
@@ -0,0 +1,471 @@
+From 42e6d9d59082e75efe0ce7fca91c4297137cfb93 Mon Sep 17 00:00:00 2001
+From: Manoj Srivastava <srivasta@debian.org>
+Date: Sun, 9 Feb 2014 16:09:49 +0000
+Subject: Handle SELinux authorisation roles
+
+Rejected upstream due to discomfort with magic usernames; a better approach
+will need an SSH protocol change.  In the meantime, this came from Debian's
+SELinux maintainer, so we'll keep it until we have something better.
+
+Bug: https://bugzilla.mindrot.org/show_bug.cgi?id=1641
+Bug-Debian: http://bugs.debian.org/394795
+Last-Update: 2021-11-05
+
+Patch-Name: selinux-role.patch
+---
+ auth.h                      |  1 +
+ auth2.c                     | 10 ++++++++--
+ monitor.c                   | 36 +++++++++++++++++++++++++++++++++---
+ monitor.h                   |  2 ++
+ monitor_wrap.c              | 27 ++++++++++++++++++++++++---
+ monitor_wrap.h              |  3 ++-
+ openbsd-compat/port-linux.c | 21 ++++++++++++++-------
+ openbsd-compat/port-linux.h |  4 ++--
+ platform.c                  |  4 ++--
+ platform.h                  |  2 +-
+ session.c                   | 10 +++++-----
+ session.h                   |  2 +-
+ sshd.c                      |  2 +-
+ sshpty.c                    |  4 ++--
+ sshpty.h                    |  2 +-
+ 15 files changed, 99 insertions(+), 31 deletions(-)
+
+diff --git a/auth.h b/auth.h
+index 6d2d39762..d16dc66b8 100644
+--- a/auth.h
++++ b/auth.h
+@@ -65,6 +65,7 @@ struct Authctxt {
+ 	char		*service;
+ 	struct passwd	*pw;		/* set if 'valid' */
+ 	char		*style;
++	char		*role;
+ 
+ 	/* Method lists for multiple authentication */
+ 	char		**auth_methods;	/* modified from server config */
+diff --git a/auth2.c b/auth2.c
+index 514a697ca..12210c043 100644
+--- a/auth2.c
++++ b/auth2.c
+@@ -272,7 +272,7 @@ input_userauth_request(int type, u_int32_t seq, struct ssh *ssh)
+ {
+ 	Authctxt *authctxt = ssh->authctxt;
+ 	Authmethod *m = NULL;
+-	char *user = NULL, *service = NULL, *method = NULL, *style = NULL;
++	char *user = NULL, *service = NULL, *method = NULL, *style = NULL, *role = NULL;
+ 	int r, authenticated = 0;
+ 	double tstart = monotime_double();
+ 
+@@ -286,8 +286,13 @@ input_userauth_request(int type, u_int32_t seq, struct ssh *ssh)
+ 	debug("userauth-request for user %s service %s method %s", user, service, method);
+ 	debug("attempt %d failures %d", authctxt->attempt, authctxt->failures);
+ 
++	if ((role = strchr(user, '/')) != NULL)
++		*role++ = 0;
++
+ 	if ((style = strchr(user, ':')) != NULL)
+ 		*style++ = 0;
++	else if (role && (style = strchr(role, ':')) != NULL)
++		*style++ = '\0';
+ 
+ 	if (authctxt->attempt >= 1024)
+ 		auth_maxtries_exceeded(ssh);
+@@ -316,8 +321,9 @@ input_userauth_request(int type, u_int32_t seq, struct ssh *ssh)
+ 		    use_privsep ? " [net]" : "");
+ 		authctxt->service = xstrdup(service);
+ 		authctxt->style = style ? xstrdup(style) : NULL;
++		authctxt->role = role ? xstrdup(role) : NULL;
+ 		if (use_privsep)
+-			mm_inform_authserv(service, style);
++			mm_inform_authserv(service, style, role);
+ 		userauth_banner(ssh);
+ 		if ((r = kex_server_update_ext_info(ssh)) != 0)
+ 			fatal_fr(r, "kex_server_update_ext_info failed");
+diff --git a/monitor.c b/monitor.c
+index 2bc152468..c7e6f25d7 100644
+--- a/monitor.c
++++ b/monitor.c
+@@ -117,6 +117,7 @@ int mm_answer_sign(struct ssh *, int, struct sshbuf *);
+ int mm_answer_pwnamallow(struct ssh *, int, struct sshbuf *);
+ int mm_answer_auth2_read_banner(struct ssh *, int, struct sshbuf *);
+ int mm_answer_authserv(struct ssh *, int, struct sshbuf *);
++int mm_answer_authrole(struct ssh *, int, struct sshbuf *);
+ int mm_answer_authpassword(struct ssh *, int, struct sshbuf *);
+ int mm_answer_bsdauthquery(struct ssh *, int, struct sshbuf *);
+ int mm_answer_bsdauthrespond(struct ssh *, int, struct sshbuf *);
+@@ -192,6 +193,7 @@ struct mon_table mon_dispatch_proto20[] = {
+     {MONITOR_REQ_SIGN, MON_ONCE, mm_answer_sign},
+     {MONITOR_REQ_PWNAM, MON_ONCE, mm_answer_pwnamallow},
+     {MONITOR_REQ_AUTHSERV, MON_ONCE, mm_answer_authserv},
++    {MONITOR_REQ_AUTHROLE, MON_ONCE, mm_answer_authrole},
+     {MONITOR_REQ_AUTH2_READ_BANNER, MON_ONCE, mm_answer_auth2_read_banner},
+     {MONITOR_REQ_AUTHPASSWORD, MON_AUTH, mm_answer_authpassword},
+ #ifdef USE_PAM
+@@ -817,6 +819,7 @@ mm_answer_pwnamallow(struct ssh *ssh, int sock, struct sshbuf *m)
+ 
+ 	/* Allow service/style information on the auth context */
+ 	monitor_permit(mon_dispatch, MONITOR_REQ_AUTHSERV, 1);
++	monitor_permit(mon_dispatch, MONITOR_REQ_AUTHROLE, 1);
+ 	monitor_permit(mon_dispatch, MONITOR_REQ_AUTH2_READ_BANNER, 1);
+ 
+ #ifdef USE_PAM
+@@ -850,15 +853,42 @@ mm_answer_authserv(struct ssh *ssh, int sock, struct sshbuf *m)
+ 	monitor_permit_authentications(1);
+ 
+ 	if ((r = sshbuf_get_cstring(m, &authctxt->service, NULL)) != 0 ||
+-	    (r = sshbuf_get_cstring(m, &authctxt->style, NULL)) != 0)
++	    (r = sshbuf_get_cstring(m, &authctxt->style, NULL)) != 0 ||
++	    (r = sshbuf_get_cstring(m, &authctxt->role, NULL)) != 0)
+ 		fatal_fr(r, "parse");
+-	debug3_f("service=%s, style=%s", authctxt->service, authctxt->style);
++	debug3_f("service=%s, style=%s, role=%s",
++	    authctxt->service, authctxt->style, authctxt->role);
+ 
+ 	if (strlen(authctxt->style) == 0) {
+ 		free(authctxt->style);
+ 		authctxt->style = NULL;
+ 	}
+ 
++	if (strlen(authctxt->role) == 0) {
++		free(authctxt->role);
++		authctxt->role = NULL;
++	}
++
++	return (0);
++}
++
++int
++mm_answer_authrole(struct ssh *ssh, int sock, struct sshbuf *m)
++{
++	int r;
++
++	monitor_permit_authentications(1);
++
++	if ((r = sshbuf_get_cstring(m, &authctxt->role, NULL)) != 0)
++		fatal("%s: buffer error: %s", __func__, ssh_err(r));
++	debug3("%s: role=%s",
++	    __func__, authctxt->role);
++
++	if (strlen(authctxt->role) == 0) {
++		free(authctxt->role);
++		authctxt->role = NULL;
++	}
++
+ 	return (0);
+ }
+ 
+@@ -1579,7 +1609,7 @@ mm_answer_pty(struct ssh *ssh, int sock, struct sshbuf *m)
+ 	res = pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty));
+ 	if (res == 0)
+ 		goto error;
+-	pty_setowner(authctxt->pw, s->tty);
++	pty_setowner(authctxt->pw, s->tty, authctxt->role);
+ 
+ 	if ((r = sshbuf_put_u32(m, 1)) != 0 ||
+ 	    (r = sshbuf_put_cstring(m, s->tty)) != 0)
+diff --git a/monitor.h b/monitor.h
+index 2b1a2d590..4d87284aa 100644
+--- a/monitor.h
++++ b/monitor.h
+@@ -65,6 +65,8 @@ enum monitor_reqtype {
+ 
+ 	MONITOR_REQ_GSSSIGN = 150, MONITOR_ANS_GSSSIGN = 151,
+ 	MONITOR_REQ_GSSUPCREDS = 152, MONITOR_ANS_GSSUPCREDS = 153,
++
++	MONITOR_REQ_AUTHROLE = 154,
+ };
+ 
+ struct ssh;
+diff --git a/monitor_wrap.c b/monitor_wrap.c
+index 189467037..4b986ded6 100644
+--- a/monitor_wrap.c
++++ b/monitor_wrap.c
+@@ -375,10 +375,10 @@ mm_auth2_read_banner(void)
+ 	return (banner);
+ }
+ 
+-/* Inform the privileged process about service and style */
++/* Inform the privileged process about service, style, and role */
+ 
+ void
+-mm_inform_authserv(char *service, char *style)
++mm_inform_authserv(char *service, char *style, char *role)
+ {
+ 	struct sshbuf *m;
+ 	int r;
+@@ -388,7 +388,8 @@ mm_inform_authserv(char *service, char *style)
+ 	if ((m = sshbuf_new()) == NULL)
+ 		fatal_f("sshbuf_new failed");
+ 	if ((r = sshbuf_put_cstring(m, service)) != 0 ||
+-	    (r = sshbuf_put_cstring(m, style ? style : "")) != 0)
++	    (r = sshbuf_put_cstring(m, style ? style : "")) != 0 ||
++	    (r = sshbuf_put_cstring(m, role ? role : "")) != 0)
+ 		fatal_fr(r, "assemble");
+ 
+ 	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_AUTHSERV, m);
+@@ -396,6 +397,26 @@ mm_inform_authserv(char *service, char *style)
+ 	sshbuf_free(m);
+ }
+ 
++/* Inform the privileged process about role */
++
++void
++mm_inform_authrole(char *role)
++{
++	struct sshbuf *m;
++	int r;
++
++	debug3("%s entering", __func__);
++
++	if ((m = sshbuf_new()) == NULL)
++		fatal("%s: sshbuf_new failed", __func__);
++	if ((r = sshbuf_put_cstring(m, role ? role : "")) != 0)
++		fatal("%s: buffer error: %s", __func__, ssh_err(r));
++
++	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_AUTHROLE, m);
++
++	sshbuf_free(m);
++}
++
+ /* Do the password authentication */
+ int
+ mm_auth_password(struct ssh *ssh, char *password)
+diff --git a/monitor_wrap.h b/monitor_wrap.h
+index 830fdb308..c84f96d0c 100644
+--- a/monitor_wrap.h
++++ b/monitor_wrap.h
+@@ -48,7 +48,8 @@ DH *mm_choose_dh(int, int, int);
+ int mm_sshkey_sign(struct ssh *, struct sshkey *, u_char **, size_t *,
+     const u_char *, size_t, const char *, const char *,
+     const char *, u_int compat);
+-void mm_inform_authserv(char *, char *);
++void mm_inform_authserv(char *, char *, char *);
++void mm_inform_authrole(char *);
+ struct passwd *mm_getpwnamallow(struct ssh *, const char *);
+ char *mm_auth2_read_banner(void);
+ int mm_auth_password(struct ssh *, char *);
+diff --git a/openbsd-compat/port-linux.c b/openbsd-compat/port-linux.c
+index 0457e28d0..0394f4808 100644
+--- a/openbsd-compat/port-linux.c
++++ b/openbsd-compat/port-linux.c
+@@ -57,7 +57,7 @@ ssh_selinux_enabled(void)
+ 
+ /* Return the default security context for the given username */
+ static char *
+-ssh_selinux_getctxbyname(char *pwname)
++ssh_selinux_getctxbyname(char *pwname, const char *role)
+ {
+ 	char *sc = NULL, *sename = NULL, *lvl = NULL;
+ 	int r;
+@@ -71,9 +71,16 @@ ssh_selinux_getctxbyname(char *pwname)
+ #endif
+ 
+ #ifdef HAVE_GET_DEFAULT_CONTEXT_WITH_LEVEL
+-	r = get_default_context_with_level(sename, lvl, NULL, &sc);
++	if (role != NULL && role[0])
++		r = get_default_context_with_rolelevel(sename, role, lvl, NULL,
++						       &sc);
++	else
++		r = get_default_context_with_level(sename, lvl, NULL, &sc);
+ #else
+-	r = get_default_context(sename, NULL, &sc);
++	if (role != NULL && role[0])
++		r = get_default_context_with_role(sename, role, NULL, &sc);
++	else
++		r = get_default_context(sename, NULL, &sc);
+ #endif
+ 
+ 	if (r != 0) {
+@@ -103,7 +110,7 @@ ssh_selinux_getctxbyname(char *pwname)
+ 
+ /* Set the execution context to the default for the specified user */
+ void
+-ssh_selinux_setup_exec_context(char *pwname)
++ssh_selinux_setup_exec_context(char *pwname, const char *role)
+ {
+ 	char *user_ctx = NULL;
+ 
+@@ -112,7 +119,7 @@ ssh_selinux_setup_exec_context(char *pwname)
+ 
+ 	debug3("%s: setting execution context", __func__);
+ 
+-	user_ctx = ssh_selinux_getctxbyname(pwname);
++	user_ctx = ssh_selinux_getctxbyname(pwname, role);
+ 	if (setexeccon(user_ctx) != 0) {
+ 		switch (security_getenforce()) {
+ 		case -1:
+@@ -134,7 +141,7 @@ ssh_selinux_setup_exec_context(char *pwname)
+ 
+ /* Set the TTY context for the specified user */
+ void
+-ssh_selinux_setup_pty(char *pwname, const char *tty)
++ssh_selinux_setup_pty(char *pwname, const char *tty, const char *role)
+ {
+ 	char *new_tty_ctx = NULL, *user_ctx = NULL, *old_tty_ctx = NULL;
+ 	security_class_t chrclass;
+@@ -144,7 +151,7 @@ ssh_selinux_setup_pty(char *pwname, const char *tty)
+ 
+ 	debug3("%s: setting TTY context on %s", __func__, tty);
+ 
+-	user_ctx = ssh_selinux_getctxbyname(pwname);
++	user_ctx = ssh_selinux_getctxbyname(pwname, role);
+ 
+ 	/* XXX: should these calls fatal() upon failure in enforcing mode? */
+ 
+diff --git a/openbsd-compat/port-linux.h b/openbsd-compat/port-linux.h
+index 3c22a854d..c88129428 100644
+--- a/openbsd-compat/port-linux.h
++++ b/openbsd-compat/port-linux.h
+@@ -19,8 +19,8 @@
+ 
+ #ifdef WITH_SELINUX
+ int ssh_selinux_enabled(void);
+-void ssh_selinux_setup_pty(char *, const char *);
+-void ssh_selinux_setup_exec_context(char *);
++void ssh_selinux_setup_pty(char *, const char *, const char *);
++void ssh_selinux_setup_exec_context(char *, const char *);
+ void ssh_selinux_change_context(const char *);
+ void ssh_selinux_setfscreatecon(const char *);
+ #endif
+diff --git a/platform.c b/platform.c
+index 4fe8744ee..70c3a9b58 100644
+--- a/platform.c
++++ b/platform.c
+@@ -144,7 +144,7 @@ platform_setusercontext(struct passwd *pw)
+  * called if sshd is running as root.
+  */
+ void
+-platform_setusercontext_post_groups(struct passwd *pw)
++platform_setusercontext_post_groups(struct passwd *pw, const char *role)
+ {
+ #if !defined(HAVE_LOGIN_CAP) && defined(USE_PAM)
+ 	/*
+@@ -185,7 +185,7 @@ platform_setusercontext_post_groups(struct passwd *pw)
+ 	}
+ #endif /* HAVE_SETPCRED */
+ #ifdef WITH_SELINUX
+-	ssh_selinux_setup_exec_context(pw->pw_name);
++	ssh_selinux_setup_exec_context(pw->pw_name, role);
+ #endif
+ }
+ 
+diff --git a/platform.h b/platform.h
+index 7fef8c983..027fdfb51 100644
+--- a/platform.h
++++ b/platform.h
+@@ -25,7 +25,7 @@ void platform_post_fork_parent(pid_t child_pid);
+ void platform_post_fork_child(void);
+ int  platform_privileged_uidswap(void);
+ void platform_setusercontext(struct passwd *);
+-void platform_setusercontext_post_groups(struct passwd *);
++void platform_setusercontext_post_groups(struct passwd *, const char *);
+ char *platform_get_krb5_client(const char *);
+ char *platform_krb5_get_principal_name(const char *);
+ int platform_locked_account(struct passwd *);
+diff --git a/session.c b/session.c
+index f985b8177..cc6b6714d 100644
+--- a/session.c
++++ b/session.c
+@@ -1355,7 +1355,7 @@ safely_chroot(const char *path, uid_t uid)
+ 
+ /* Set login name, uid, gid, and groups. */
+ void
+-do_setusercontext(struct passwd *pw)
++do_setusercontext(struct passwd *pw, const char *role)
+ {
+ 	char uidstr[32], *chroot_path, *tmp;
+ 
+@@ -1383,7 +1383,7 @@ do_setusercontext(struct passwd *pw)
+ 		endgrent();
+ #endif
+ 
+-		platform_setusercontext_post_groups(pw);
++		platform_setusercontext_post_groups(pw, role);
+ 
+ 		if (!in_chroot && options.chroot_directory != NULL &&
+ 		    strcasecmp(options.chroot_directory, "none") != 0) {
+@@ -1527,7 +1527,7 @@ do_child(struct ssh *ssh, Session *s, const char *command)
+ 
+ 	/* Force a password change */
+ 	if (s->authctxt->force_pwchange) {
+-		do_setusercontext(pw);
++		do_setusercontext(pw, s->authctxt->role);
+ 		child_close_fds(ssh);
+ 		do_pwchange(s);
+ 		exit(1);
+@@ -1545,7 +1545,7 @@ do_child(struct ssh *ssh, Session *s, const char *command)
+ 	/* When PAM is enabled we rely on it to do the nologin check */
+ 	if (!options.use_pam)
+ 		do_nologin(pw);
+-	do_setusercontext(pw);
++	do_setusercontext(pw, s->authctxt->role);
+ 	/*
+ 	 * PAM session modules in do_setusercontext may have
+ 	 * generated messages, so if this in an interactive
+@@ -1941,7 +1941,7 @@ session_pty_req(struct ssh *ssh, Session *s)
+ 		sshpkt_fatal(ssh, r, "%s: parse packet", __func__);
+ 
+ 	if (!use_privsep)
+-		pty_setowner(s->pw, s->tty);
++		pty_setowner(s->pw, s->tty, s->authctxt->role);
+ 
+ 	/* Set window size from the packet. */
+ 	pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
+diff --git a/session.h b/session.h
+index 344a1ddf9..20ea822a7 100644
+--- a/session.h
++++ b/session.h
+@@ -77,7 +77,7 @@ void	 session_pty_cleanup2(Session *);
+ Session	*session_new(void);
+ Session	*session_by_tty(char *);
+ void	 session_close(struct ssh *, Session *);
+-void	 do_setusercontext(struct passwd *);
++void	 do_setusercontext(struct passwd *, const char *);
+ 
+ const char	*session_get_remote_name_or_ip(struct ssh *, u_int, int);
+ 
+diff --git a/sshd.c b/sshd.c
+index c57ab9628..1895a9972 100644
+--- a/sshd.c
++++ b/sshd.c
+@@ -579,7 +579,7 @@ privsep_postauth(struct ssh *ssh, Authctxt *authctxt)
+ 	reseed_prngs();
+ 
+ 	/* Drop privileges */
+-	do_setusercontext(authctxt->pw);
++	do_setusercontext(authctxt->pw, authctxt->role);
+ 
+  skip:
+ 	/* It is safe now to apply the key state */
+diff --git a/sshpty.c b/sshpty.c
+index cae0b977a..7870c6482 100644
+--- a/sshpty.c
++++ b/sshpty.c
+@@ -163,7 +163,7 @@ pty_change_window_size(int ptyfd, u_int row, u_int col,
+ }
+ 
+ void
+-pty_setowner(struct passwd *pw, const char *tty)
++pty_setowner(struct passwd *pw, const char *tty, const char *role)
+ {
+ 	struct group *grp;
+ 	gid_t gid;
+@@ -187,7 +187,7 @@ pty_setowner(struct passwd *pw, const char *tty)
+ 		    strerror(errno));
+ 
+ #ifdef WITH_SELINUX
+-	ssh_selinux_setup_pty(pw->pw_name, tty);
++	ssh_selinux_setup_pty(pw->pw_name, tty, role);
+ #endif
+ 
+ 	if (st.st_uid != pw->pw_uid || st.st_gid != gid) {
+diff --git a/sshpty.h b/sshpty.h
+index 9ec7e9a15..de7e000ae 100644
+--- a/sshpty.h
++++ b/sshpty.h
+@@ -24,5 +24,5 @@ int	 pty_allocate(int *, int *, char *, size_t);
+ void	 pty_release(const char *);
+ void	 pty_make_controlling_tty(int *, const char *);
+ void	 pty_change_window_size(int, u_int, u_int, u_int, u_int);
+-void	 pty_setowner(struct passwd *, const char *);
++void	 pty_setowner(struct passwd *, const char *, const char *);
+ void	 disconnect_controlling_tty(void);
diff --git a/debian/patches/series b/debian/patches/series
new file mode 100644
index 0000000..2170a6a
--- /dev/null
+++ b/debian/patches/series
@@ -0,0 +1,28 @@
+gssapi.patch
+restore-tcp-wrappers.patch
+selinux-role.patch
+ssh-vulnkey-compat.patch
+keepalive-extensions.patch
+syslog-level-silent.patch
+user-group-modes.patch
+scp-quoting.patch
+shell-path.patch
+dnssec-sshfp.patch
+mention-ssh-keygen-on-keychange.patch
+package-versioning.patch
+debian-banner.patch
+authorized-keys-man-symlink.patch
+openbsd-docs.patch
+ssh-argv0.patch
+doc-hash-tab-completion.patch
+ssh-agent-setgid.patch
+no-openssl-version-status.patch
+gnome-ssh-askpass2-icon.patch
+systemd-readiness.patch
+debian-config.patch
+restore-authorized_keys2.patch
+revert-ipqos-defaults.patch
+maxhostnamelen.patch
+conch-ssh-rsa.patch
+systemd-socket-activation.patch
+broken-zero-call-used-regs.patch
diff --git a/debian/patches/shell-path.patch b/debian/patches/shell-path.patch
new file mode 100644
index 0000000..381122e
--- /dev/null
+++ b/debian/patches/shell-path.patch
@@ -0,0 +1,39 @@
+From b2e4df6aa3245d06c318d8977612d863ee427289 Mon Sep 17 00:00:00 2001
+From: Colin Watson <cjwatson@debian.org>
+Date: Sun, 9 Feb 2014 16:10:00 +0000
+Subject: Look for $SHELL on the path for ProxyCommand/LocalCommand
+
+There's some debate on the upstream bug about whether POSIX requires this.
+I (Colin Watson) agree with Vincent and think it does.
+
+Bug: https://bugzilla.mindrot.org/show_bug.cgi?id=1494
+Bug-Debian: http://bugs.debian.org/492728
+Last-Update: 2020-02-21
+
+Patch-Name: shell-path.patch
+---
+ sshconnect.c | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+diff --git a/sshconnect.c b/sshconnect.c
+index bd077c75c..69256c354 100644
+--- a/sshconnect.c
++++ b/sshconnect.c
+@@ -247,7 +247,7 @@ ssh_proxy_connect(struct ssh *ssh, const char *host, const char *host_arg,
+ 		 * extra privileges above.
+ 		 */
+ 		ssh_signal(SIGPIPE, SIG_DFL);
+-		execv(argv[0], argv);
++		execvp(argv[0], argv);
+ 		perror(argv[0]);
+ 		exit(1);
+ 	}
+@@ -1678,7 +1678,7 @@ ssh_local_cmd(const char *args)
+ 	if (pid == 0) {
+ 		ssh_signal(SIGPIPE, SIG_DFL);
+ 		debug3("Executing %s -c \"%s\"", shell, args);
+-		execl(shell, shell, "-c", args, (char *)NULL);
++		execlp(shell, shell, "-c", args, (char *)NULL);
+ 		error("Couldn't execute %s -c \"%s\": %s",
+ 		    shell, args, strerror(errno));
+ 		_exit(1);
diff --git a/debian/patches/ssh-agent-setgid.patch b/debian/patches/ssh-agent-setgid.patch
new file mode 100644
index 0000000..b126b41
--- /dev/null
+++ b/debian/patches/ssh-agent-setgid.patch
@@ -0,0 +1,40 @@
+From 3ca56081fc6ec90eea7f20e36b281a8fd0cf43f2 Mon Sep 17 00:00:00 2001
+From: Colin Watson <cjwatson@debian.org>
+Date: Sun, 9 Feb 2014 16:10:13 +0000
+Subject: Document consequences of ssh-agent being setgid in ssh-agent(1)
+
+Bug-Debian: http://bugs.debian.org/711623
+Forwarded: no
+Last-Update: 2020-02-21
+
+Patch-Name: ssh-agent-setgid.patch
+---
+ ssh-agent.1 | 15 +++++++++++++++
+ 1 file changed, 15 insertions(+)
+
+diff --git a/ssh-agent.1 b/ssh-agent.1
+index 0b93d03a3..1ab7d729d 100644
+--- a/ssh-agent.1
++++ b/ssh-agent.1
+@@ -248,6 +248,21 @@ socket and stores its pathname in this variable.
+ It is accessible only to the current user,
+ but is easily abused by root or another instance of the same user.
+ .El
++.Pp
++In Debian,
++.Nm
++is installed with the set-group-id bit set, to prevent
++.Xr ptrace 2
++attacks retrieving private key material.
++This has the side-effect of causing the run-time linker to remove certain
++environment variables which might have security implications for set-id
++programs, including
++.Ev LD_PRELOAD ,
++.Ev LD_LIBRARY_PATH ,
++and
++.Ev TMPDIR .
++If you need to set any of these environment variables, you will need to do
++so in the program executed by ssh-agent.
+ .Sh FILES
+ .Bl -tag -width Ds
+ .It Pa $TMPDIR/ssh-XXXXXXXXXX/agent.<ppid>
diff --git a/debian/patches/ssh-argv0.patch b/debian/patches/ssh-argv0.patch
new file mode 100644
index 0000000..78946ad
--- /dev/null
+++ b/debian/patches/ssh-argv0.patch
@@ -0,0 +1,31 @@
+From ba303e6c64ee2abd705de92b5155d4fc8ba4d4d3 Mon Sep 17 00:00:00 2001
+From: Colin Watson <cjwatson@debian.org>
+Date: Sun, 9 Feb 2014 16:10:10 +0000
+Subject: ssh(1): Refer to ssh-argv0(1)
+
+Old versions of OpenSSH (up to 2.5 or thereabouts) allowed creating symlinks
+to ssh with the name of the host you want to connect to.  Debian ships an
+ssh-argv0 script restoring this feature; this patch refers to its manual
+page from ssh(1).
+
+Bug-Debian: http://bugs.debian.org/111341
+Forwarded: not-needed
+Last-Update: 2013-09-14
+
+Patch-Name: ssh-argv0.patch
+---
+ ssh.1 | 1 +
+ 1 file changed, 1 insertion(+)
+
+diff --git a/ssh.1 b/ssh.1
+index 60e97dc62..0d56f3dc1 100644
+--- a/ssh.1
++++ b/ssh.1
+@@ -1681,6 +1681,7 @@ if an error occurred.
+ .Xr sftp 1 ,
+ .Xr ssh-add 1 ,
+ .Xr ssh-agent 1 ,
++.Xr ssh-argv0 1 ,
+ .Xr ssh-keygen 1 ,
+ .Xr ssh-keyscan 1 ,
+ .Xr tun 4 ,
diff --git a/debian/patches/ssh-vulnkey-compat.patch b/debian/patches/ssh-vulnkey-compat.patch
new file mode 100644
index 0000000..7ec9870
--- /dev/null
+++ b/debian/patches/ssh-vulnkey-compat.patch
@@ -0,0 +1,42 @@
+From 9c36b0b02fe0e6af1553e93bdc7c2e6e97e6514c Mon Sep 17 00:00:00 2001
+From: Colin Watson <cjwatson@ubuntu.com>
+Date: Sun, 9 Feb 2014 16:09:50 +0000
+Subject: Accept obsolete ssh-vulnkey configuration options
+
+These options were used as part of Debian's response to CVE-2008-0166.
+Nearly six years later, we no longer need to continue carrying the bulk
+of that patch, but we do need to avoid failing when the associated
+configuration options are still present.
+
+Last-Update: 2014-02-09
+
+Patch-Name: ssh-vulnkey-compat.patch
+---
+ readconf.c | 1 +
+ servconf.c | 1 +
+ 2 files changed, 2 insertions(+)
+
+diff --git a/readconf.c b/readconf.c
+index ef67ab20f..93e431d71 100644
+--- a/readconf.c
++++ b/readconf.c
+@@ -197,6 +197,7 @@ static struct {
+ 	{ "fallbacktorsh", oDeprecated },
+ 	{ "globalknownhostsfile2", oDeprecated },
+ 	{ "rhostsauthentication", oDeprecated },
++	{ "useblacklistedkeys", oDeprecated },
+ 	{ "userknownhostsfile2", oDeprecated },
+ 	{ "useroaming", oDeprecated },
+ 	{ "usersh", oDeprecated },
+diff --git a/servconf.c b/servconf.c
+index 940e1d50a..b61295758 100644
+--- a/servconf.c
++++ b/servconf.c
+@@ -649,6 +649,7 @@ static struct {
+ 	{ "x11uselocalhost", sX11UseLocalhost, SSHCFG_ALL },
+ 	{ "xauthlocation", sXAuthLocation, SSHCFG_GLOBAL },
+ 	{ "strictmodes", sStrictModes, SSHCFG_GLOBAL },
++	{ "permitblacklistedkeys", sDeprecated, SSHCFG_GLOBAL },
+ 	{ "permitemptypasswords", sEmptyPasswd, SSHCFG_ALL },
+ 	{ "permituserenvironment", sPermitUserEnvironment, SSHCFG_GLOBAL },
+ 	{ "uselogin", sDeprecated, SSHCFG_GLOBAL },
diff --git a/debian/patches/syslog-level-silent.patch b/debian/patches/syslog-level-silent.patch
new file mode 100644
index 0000000..db8b789
--- /dev/null
+++ b/debian/patches/syslog-level-silent.patch
@@ -0,0 +1,47 @@
+From 4e61619999ed5b3822b81773693d5b773858b927 Mon Sep 17 00:00:00 2001
+From: Natalie Amery <nmamery@chiark.greenend.org.uk>
+Date: Sun, 9 Feb 2014 16:09:54 +0000
+Subject: "LogLevel SILENT" compatibility
+
+"LogLevel SILENT" (-qq) was introduced in Debian openssh 1:3.0.1p1-1 to
+match the behaviour of non-free SSH, in which -q does not suppress fatal
+errors.  However, this was unintentionally broken in 1:4.6p1-2 and nobody
+complained, so we've dropped most of it.  The parts that remain are basic
+configuration file compatibility, and an adjustment to "Pseudo-terminal will
+not be allocated ..." which should be split out into a separate patch.
+
+Author: Matthew Vernon <matthew@debian.org>
+Author: Colin Watson <cjwatson@debian.org>
+Last-Update: 2013-09-14
+
+Patch-Name: syslog-level-silent.patch
+---
+ log.c | 1 +
+ ssh.c | 2 +-
+ 2 files changed, 2 insertions(+), 1 deletion(-)
+
+diff --git a/log.c b/log.c
+index 9fc1a2e2e..6a8b1fc4a 100644
+--- a/log.c
++++ b/log.c
+@@ -96,6 +96,7 @@ static struct {
+ 	LogLevel val;
+ } log_levels[] =
+ {
++	{ "SILENT",	SYSLOG_LEVEL_QUIET }, /* compatibility */
+ 	{ "QUIET",	SYSLOG_LEVEL_QUIET },
+ 	{ "FATAL",	SYSLOG_LEVEL_FATAL },
+ 	{ "ERROR",	SYSLOG_LEVEL_ERROR },
+diff --git a/ssh.c b/ssh.c
+index f50cecdbb..160c403c8 100644
+--- a/ssh.c
++++ b/ssh.c
+@@ -1412,7 +1412,7 @@ main(int ac, char **av)
+ 	/* Do not allocate a tty if stdin is not a tty. */
+ 	if ((!isatty(fileno(stdin)) || options.stdin_null) &&
+ 	    options.request_tty != REQUEST_TTY_FORCE) {
+-		if (tty_flag)
++		if (tty_flag && options.log_level != SYSLOG_LEVEL_QUIET)
+ 			logit("Pseudo-terminal will not be allocated because "
+ 			    "stdin is not a terminal.");
+ 		tty_flag = 0;
diff --git a/debian/patches/systemd-readiness.patch b/debian/patches/systemd-readiness.patch
new file mode 100644
index 0000000..59f63ab
--- /dev/null
+++ b/debian/patches/systemd-readiness.patch
@@ -0,0 +1,84 @@
+From 997c7d972b8ad436dff3b9a482f7ce988b50114c Mon Sep 17 00:00:00 2001
+From: Michael Biebl <biebl@debian.org>
+Date: Mon, 21 Dec 2015 16:08:47 +0000
+Subject: Add systemd readiness notification support
+
+Bug-Debian: https://bugs.debian.org/778913
+Forwarded: no
+Last-Update: 2017-08-22
+
+Patch-Name: systemd-readiness.patch
+---
+ configure.ac | 24 ++++++++++++++++++++++++
+ sshd.c       |  9 +++++++++
+ 2 files changed, 33 insertions(+)
+
+diff --git a/configure.ac b/configure.ac
+index badfacf8f..5662c9e3a 100644
+--- a/configure.ac
++++ b/configure.ac
+@@ -4922,6 +4922,29 @@ AC_SUBST([GSSLIBS])
+ AC_SUBST([K5LIBS])
+ AC_SUBST([CHANNELLIBS])
+ 
++# Check whether user wants systemd support
++SYSTEMD_MSG="no"
++AC_ARG_WITH(systemd,
++	[  --with-systemd          Enable systemd support],
++	[ if test "x$withval" != "xno" ; then
++		AC_PATH_TOOL([PKGCONFIG], [pkg-config], [no])
++		if test "$PKGCONFIG" != "no"; then
++			AC_MSG_CHECKING([for libsystemd])
++			if $PKGCONFIG --exists libsystemd; then
++				SYSTEMD_CFLAGS=`$PKGCONFIG --cflags libsystemd`
++				SYSTEMD_LIBS=`$PKGCONFIG --libs libsystemd`
++				CPPFLAGS="$CPPFLAGS $SYSTEMD_CFLAGS"
++				SSHDLIBS="$SSHDLIBS $SYSTEMD_LIBS"
++				AC_MSG_RESULT([yes])
++				AC_DEFINE(HAVE_SYSTEMD, 1, [Define if you want systemd support.])
++				SYSTEMD_MSG="yes"
++			else
++				AC_MSG_RESULT([no])
++			fi
++		fi
++	fi ]
++)
++
+ # Looking for programs, paths and files
+ 
+ PRIVSEP_PATH=/var/empty
+@@ -5731,6 +5754,7 @@ echo "                   libldns support: $LDNS_MSG"
+ echo "  Solaris process contract support: $SPC_MSG"
+ echo "           Solaris project support: $SP_MSG"
+ echo "         Solaris privilege support: $SPP_MSG"
++echo "                   systemd support: $SYSTEMD_MSG"
+ echo "       IP address in \$DISPLAY hack: $DISPLAY_HACK_MSG"
+ echo "           Translate v4 in v6 hack: $IPV4_IN6_HACK_MSG"
+ echo "                  BSD Auth support: $BSD_AUTH_MSG"
+diff --git a/sshd.c b/sshd.c
+index d56ba490b..356bd6c02 100644
+--- a/sshd.c
++++ b/sshd.c
+@@ -88,6 +88,10 @@
+ #include <prot.h>
+ #endif
+ 
++#ifdef HAVE_SYSTEMD
++#include <systemd/sd-daemon.h>
++#endif
++
+ #include "xmalloc.h"
+ #include "ssh.h"
+ #include "ssh2.h"
+@@ -2101,6 +2105,11 @@ main(int ac, char **av)
+ 			}
+ 		}
+ 
++#ifdef HAVE_SYSTEMD
++		/* Signal systemd that we are ready to accept connections */
++		sd_notify(0, "READY=1");
++#endif
++
+ 		/* Accept a connection and return in a forked child */
+ 		server_accept_loop(&sock_in, &sock_out,
+ 		    &newsock, config_s);
diff --git a/debian/patches/systemd-socket-activation.patch b/debian/patches/systemd-socket-activation.patch
new file mode 100644
index 0000000..73afb88
--- /dev/null
+++ b/debian/patches/systemd-socket-activation.patch
@@ -0,0 +1,138 @@
+From 7fa10262be3c7d9fd2fca9c9710ac4ef3f788b08 Mon Sep 17 00:00:00 2001
+From: Steve Langasek <steve.langasek@ubuntu.com>
+Date: Thu, 1 Sep 2022 16:03:37 +0100
+Subject: Support systemd socket activation
+
+Unlike inetd socket activation, with systemd socket activation the
+supervisor passes the listened-on socket to the child process and lets
+the child process handle the accept().  This lets us do delayed start
+of the sshd daemon without becoming incompatible with config options
+like ClientAliveCountMax.
+
+Last-Update: 2022-09-01
+
+Patch-Name: systemd-socket-activation.patch
+---
+ sshd.c | 89 +++++++++++++++++++++++++++++++++++++++++++++++++---------
+ 1 file changed, 75 insertions(+), 14 deletions(-)
+
+diff --git a/sshd.c b/sshd.c
+index 356bd6c02..6dfa5fffe 100644
+--- a/sshd.c
++++ b/sshd.c
+@@ -140,10 +140,16 @@ int deny_severity;
+ #endif /* LIBWRAP */
+ 
+ /* Re-exec fds */
+-#define REEXEC_DEVCRYPTO_RESERVED_FD	(STDERR_FILENO + 1)
+-#define REEXEC_STARTUP_PIPE_FD		(STDERR_FILENO + 2)
+-#define REEXEC_CONFIG_PASS_FD		(STDERR_FILENO + 3)
+-#define REEXEC_MIN_FREE_FD		(STDERR_FILENO + 4)
++#ifdef HAVE_SYSTEMD
++#define SYSTEMD_OFFSET sd_listen_fds(0)
++#else
++#define SYSTEMD_OFFSET 0
++#endif
++
++#define REEXEC_DEVCRYPTO_RESERVED_FD	(STDERR_FILENO + 1 + SYSTEMD_OFFSET)
++#define REEXEC_STARTUP_PIPE_FD		(STDERR_FILENO + 2 + SYSTEMD_OFFSET)
++#define REEXEC_CONFIG_PASS_FD		(STDERR_FILENO + 3 + SYSTEMD_OFFSET)
++#define REEXEC_MIN_FREE_FD		(STDERR_FILENO + 4 + SYSTEMD_OFFSET)
+ 
+ extern char *__progname;
+ 
+@@ -1020,6 +1026,48 @@ server_accept_inetd(int *sock_in, int *sock_out)
+ 	debug("inetd sockets after dupping: %d, %d", *sock_in, *sock_out);
+ }
+ 
++#ifdef HAVE_SYSTEMD
++/*
++ * Configure our socket fds that were passed from systemd
++ */
++static void
++setup_systemd_socket(int listen_sock)
++{
++	int ret;
++	struct sockaddr_storage addr;
++	socklen_t len = sizeof(addr);
++	char ntop[NI_MAXHOST], strport[NI_MAXSERV];
++
++	if (getsockname(listen_sock, (struct sockaddr *)&addr, &len) != 0)
++		return;
++
++	if (((struct sockaddr *)&addr)->sa_family != AF_INET
++	    && ((struct sockaddr *)&addr)->sa_family != AF_INET6)
++		return;
++	if (num_listen_socks >= MAX_LISTEN_SOCKS)
++		fatal("Too many listen sockets. "
++		    "Enlarge MAX_LISTEN_SOCKS");
++	if ((ret = getnameinfo((struct sockaddr *)&addr, len, ntop,
++	                       sizeof(ntop), strport, sizeof(strport),
++	                       NI_NUMERICHOST|NI_NUMERICSERV)) != 0) {
++		error("getnameinfo failed: %.100s",
++		    ssh_gai_strerror(ret));
++		return;
++	}
++	if (set_nonblock(listen_sock) == -1) {
++		close(listen_sock);
++		return;
++	}
++	/* Socket options */
++	set_reuseaddr(listen_sock);
++
++	listen_socks[num_listen_socks] = listen_sock;
++	num_listen_socks++;
++
++	logit("Server listening on %s port %s.", ntop, strport);
++}
++#endif
++
+ /*
+  * Listen for TCP connections
+  */
+@@ -1099,22 +1147,35 @@ static void
+ server_listen(void)
+ {
+ 	u_int i;
++#ifdef HAVE_SYSTEMD
++	int systemd_socket_count;
++#endif
+ 
+ 	/* Initialise per-source limit tracking. */
+ 	srclimit_init(options.max_startups, options.per_source_max_startups,
+ 	    options.per_source_masklen_ipv4, options.per_source_masklen_ipv6);
+ 
+-	for (i = 0; i < options.num_listen_addrs; i++) {
+-		listen_on_addrs(&options.listen_addrs[i]);
+-		freeaddrinfo(options.listen_addrs[i].addrs);
+-		free(options.listen_addrs[i].rdomain);
+-		memset(&options.listen_addrs[i], 0,
+-		    sizeof(options.listen_addrs[i]));
++#ifdef HAVE_SYSTEMD
++	systemd_socket_count = sd_listen_fds(0);
++	if (systemd_socket_count > 0)
++	{
++		int i;
++		for (i = 0; i < systemd_socket_count; i++)
++			setup_systemd_socket(SD_LISTEN_FDS_START + i);
++	} else
++#endif
++	{
++		for (i = 0; i < options.num_listen_addrs; i++) {
++			listen_on_addrs(&options.listen_addrs[i]);
++			freeaddrinfo(options.listen_addrs[i].addrs);
++			free(options.listen_addrs[i].rdomain);
++			memset(&options.listen_addrs[i], 0,
++			    sizeof(options.listen_addrs[i]));
++		}
++		free(options.listen_addrs);
++		options.listen_addrs = NULL;
++		options.num_listen_addrs = 0;
+ 	}
+-	free(options.listen_addrs);
+-	options.listen_addrs = NULL;
+-	options.num_listen_addrs = 0;
+-
+ 	if (!num_listen_socks)
+ 		fatal("Cannot bind any address.");
+ }
diff --git a/debian/patches/user-group-modes.patch b/debian/patches/user-group-modes.patch
new file mode 100644
index 0000000..42d5b18
--- /dev/null
+++ b/debian/patches/user-group-modes.patch
@@ -0,0 +1,210 @@
+From 44f9b28b1c8adaf00af6e011928141cfbd729b9a Mon Sep 17 00:00:00 2001
+From: Colin Watson <cjwatson@debian.org>
+Date: Sun, 9 Feb 2014 16:09:58 +0000
+Subject: Allow harmless group-writability
+
+Allow secure files (~/.ssh/config, ~/.ssh/authorized_keys, etc.) to be
+group-writable, provided that the group in question contains only the file's
+owner.  Rejected upstream for IMO incorrect reasons (e.g. a misunderstanding
+about the contents of gr->gr_mem).  Given that per-user groups and umask 002
+are the default setup in Debian (for good reasons - this makes operating in
+setgid directories with other groups much easier), we need to permit this by
+default.
+
+Bug: https://bugzilla.mindrot.org/show_bug.cgi?id=1060
+Bug-Debian: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=314347
+Last-Update: 2022-02-23
+
+Patch-Name: user-group-modes.patch
+---
+ auth-rhosts.c |  6 ++----
+ auth.c        |  3 +--
+ misc.c        | 57 ++++++++++++++++++++++++++++++++++++++++++++++-----
+ misc.h        |  2 ++
+ readconf.c    |  3 +--
+ ssh.1         |  2 ++
+ ssh_config.5  |  2 ++
+ 7 files changed, 62 insertions(+), 13 deletions(-)
+
+diff --git a/auth-rhosts.c b/auth-rhosts.c
+index 56724677a..e15f5bc5a 100644
+--- a/auth-rhosts.c
++++ b/auth-rhosts.c
+@@ -266,8 +266,7 @@ auth_rhosts2(struct passwd *pw, const char *client_user, const char *hostname,
+ 		return 0;
+ 	}
+ 	if (options.strict_modes &&
+-	    ((st.st_uid != 0 && st.st_uid != pw->pw_uid) ||
+-	    (st.st_mode & 022) != 0)) {
++	    !secure_permissions(&st, pw->pw_uid)) {
+ 		logit("Rhosts authentication refused for %.100s: "
+ 		    "bad ownership or modes for home directory.", pw->pw_name);
+ 		auth_debug_add("Rhosts authentication refused for %.100s: "
+@@ -296,8 +295,7 @@ auth_rhosts2(struct passwd *pw, const char *client_user, const char *hostname,
+ 		 * allowing access to their account by anyone.
+ 		 */
+ 		if (options.strict_modes &&
+-		    ((st.st_uid != 0 && st.st_uid != pw->pw_uid) ||
+-		    (st.st_mode & 022) != 0)) {
++		    !secure_permissions(&st, pw->pw_uid)) {
+ 			logit("Rhosts authentication refused for %.100s: "
+ 			    "bad modes for %.200s", pw->pw_name, path);
+ 			auth_debug_add("Bad file modes for %.200s", path);
+diff --git a/auth.c b/auth.c
+index 8ccf06370..08a75fc4e 100644
+--- a/auth.c
++++ b/auth.c
+@@ -431,8 +431,7 @@ check_key_in_hostfiles(struct passwd *pw, struct sshkey *key, const char *host,
+ 		user_hostfile = tilde_expand_filename(userfile, pw->pw_uid);
+ 		if (options.strict_modes &&
+ 		    (stat(user_hostfile, &st) == 0) &&
+-		    ((st.st_uid != 0 && st.st_uid != pw->pw_uid) ||
+-		    (st.st_mode & 022) != 0)) {
++		    !secure_permissions(&st, pw->pw_uid)) {
+ 			logit("Authentication refused for %.100s: "
+ 			    "bad owner or modes for %.200s",
+ 			    pw->pw_name, user_hostfile);
+diff --git a/misc.c b/misc.c
+index 3db2e4d0b..f667a99f8 100644
+--- a/misc.c
++++ b/misc.c
+@@ -62,9 +62,9 @@
+ #include <netdb.h>
+ #ifdef HAVE_PATHS_H
+ # include <paths.h>
++#endif
+ #include <pwd.h>
+ #include <grp.h>
+-#endif
+ #ifdef SSH_TUN_OPENBSD
+ #include <net/if.h>
+ #endif
+@@ -1414,6 +1414,55 @@ percent_dollar_expand(const char *string, ...)
+ 	return ret;
+ }
+ 
++int
++secure_permissions(struct stat *st, uid_t uid)
++{
++	if (!platform_sys_dir_uid(st->st_uid) && st->st_uid != uid)
++		return 0;
++	if ((st->st_mode & 002) != 0)
++		return 0;
++	if ((st->st_mode & 020) != 0) {
++		/* If the file is group-writable, the group in question must
++		 * have exactly one member, namely the file's owner.
++		 * (Zero-member groups are typically used by setgid
++		 * binaries, and are unlikely to be suitable.)
++		 */
++		struct passwd *pw;
++		struct group *gr;
++		int members = 0;
++
++		gr = getgrgid(st->st_gid);
++		if (!gr)
++			return 0;
++
++		/* Check primary group memberships. */
++		while ((pw = getpwent()) != NULL) {
++			if (pw->pw_gid == gr->gr_gid) {
++				++members;
++				if (pw->pw_uid != uid)
++					return 0;
++			}
++		}
++		endpwent();
++
++		pw = getpwuid(st->st_uid);
++		if (!pw)
++			return 0;
++
++		/* Check supplementary group memberships. */
++		if (gr->gr_mem[0]) {
++			++members;
++			if (strcmp(pw->pw_name, gr->gr_mem[0]) ||
++			    gr->gr_mem[1])
++				return 0;
++		}
++
++		if (!members)
++			return 0;
++	}
++	return 1;
++}
++
+ int
+ tun_open(int tun, int mode, char **ifname)
+ {
+@@ -2223,8 +2272,7 @@ safe_path(const char *name, struct stat *stp, const char *pw_dir,
+ 		snprintf(err, errlen, "%s is not a regular file", buf);
+ 		return -1;
+ 	}
+-	if ((!platform_sys_dir_uid(stp->st_uid) && stp->st_uid != uid) ||
+-	    (stp->st_mode & 022) != 0) {
++	if (!secure_permissions(stp, uid)) {
+ 		snprintf(err, errlen, "bad ownership or modes for file %s",
+ 		    buf);
+ 		return -1;
+@@ -2239,8 +2287,7 @@ safe_path(const char *name, struct stat *stp, const char *pw_dir,
+ 		strlcpy(buf, cp, sizeof(buf));
+ 
+ 		if (stat(buf, &st) == -1 ||
+-		    (!platform_sys_dir_uid(st.st_uid) && st.st_uid != uid) ||
+-		    (st.st_mode & 022) != 0) {
++		    !secure_permissions(&st, uid)) {
+ 			snprintf(err, errlen,
+ 			    "bad ownership or modes for directory %s", buf);
+ 			return -1;
+diff --git a/misc.h b/misc.h
+index 74c6f832c..0aabe84ad 100644
+--- a/misc.h
++++ b/misc.h
+@@ -237,6 +237,8 @@ struct notifier_ctx *notify_start(int, const char *, ...)
+ void	notify_complete(struct notifier_ctx *, const char *, ...)
+ 	__attribute__((format(printf, 2, 3)));
+ 
++int	 secure_permissions(struct stat *st, uid_t uid);
++
+ #define MINIMUM(a, b)	(((a) < (b)) ? (a) : (b))
+ #define MAXIMUM(a, b)	(((a) > (b)) ? (a) : (b))
+ #define ROUNDUP(x, y)   ((((x)+((y)-1))/(y))*(y))
+diff --git a/readconf.c b/readconf.c
+index bd2e78ab7..6cf3612e7 100644
+--- a/readconf.c
++++ b/readconf.c
+@@ -2481,8 +2481,7 @@ read_config_file_depth(const char *filename, struct passwd *pw,
+ 
+ 		if (fstat(fileno(f), &sb) == -1)
+ 			fatal("fstat %s: %s", filename, strerror(errno));
+-		if (((sb.st_uid != 0 && sb.st_uid != getuid()) ||
+-		    (sb.st_mode & 022) != 0))
++		if (!secure_permissions(&sb, getuid()))
+ 			fatal("Bad owner or permissions on %s", filename);
+ 	}
+ 
+diff --git a/ssh.1 b/ssh.1
+index 877c3bc64..2d07c919e 100644
+--- a/ssh.1
++++ b/ssh.1
+@@ -1577,6 +1577,8 @@ The file format and configuration options are described in
+ .Xr ssh_config 5 .
+ Because of the potential for abuse, this file must have strict permissions:
+ read/write for the user, and not writable by others.
++It may be group-writable provided that the group in question contains only
++the user.
+ .Pp
+ .It Pa ~/.ssh/environment
+ Contains additional definitions for environment variables; see
+diff --git a/ssh_config.5 b/ssh_config.5
+index 25ccbed28..bebfe1cee 100644
+--- a/ssh_config.5
++++ b/ssh_config.5
+@@ -2395,6 +2395,8 @@ The format of this file is described above.
+ This file is used by the SSH client.
+ Because of the potential for abuse, this file must have strict permissions:
+ read/write for the user, and not writable by others.
++It may be group-writable provided that the group in question contains only
++the user.
+ .It Pa /etc/ssh/ssh_config
+ Systemwide configuration file.
+ This file provides defaults for those
author	Daniel Baumann <daniel.baumann@progress-linux.org>	2024-04-10 19:49:47 +0000
committer	Daniel Baumann <daniel.baumann@progress-linux.org>	2024-04-10 19:49:47 +0000
commit	9c5dd847393c7c0f37ef557d7a0d402deedd8d2a (patch)
tree	dcb9b4740181f58a5d235e8ca52f9855494f486e /debian/patches
parent	Adding upstream version 1:9.6p1. (diff)
download	openssh-9c5dd847393c7c0f37ef557d7a0d402deedd8d2a.tar.xz openssh-9c5dd847393c7c0f37ef557d7a0d402deedd8d2a.zip