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-rw-r--r--debian/patches/gssapi.patch3353
1 files changed, 3353 insertions, 0 deletions
diff --git a/debian/patches/gssapi.patch b/debian/patches/gssapi.patch
new file mode 100644
index 0000000..f62bf66
--- /dev/null
+++ b/debian/patches/gssapi.patch
@@ -0,0 +1,3353 @@
+From 72b1d308e6400194ef6e4e7dd45bfa48fa39b5e6 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.
+
+Bug: https://bugzilla.mindrot.org/show_bug.cgi?id=1242
+Last-Updated: 2018-10-20
+
+Patch-Name: gssapi.patch
+---
+ ChangeLog.gssapi | 113 ++++++++++++++++
+ Makefile.in | 3 +-
+ auth-krb5.c | 17 ++-
+ auth.c | 96 +------------
+ auth2-gss.c | 54 +++++++-
+ auth2.c | 2 +
+ canohost.c | 93 +++++++++++++
+ canohost.h | 3 +
+ clientloop.c | 15 ++-
+ config.h.in | 6 +
+ configure.ac | 24 ++++
+ gss-genr.c | 280 +++++++++++++++++++++++++++++++++++++-
+ gss-serv-krb5.c | 85 +++++++++++-
+ gss-serv.c | 184 +++++++++++++++++++++++--
+ kex.c | 19 +++
+ kex.h | 14 ++
+ kexgssc.c | 341 +++++++++++++++++++++++++++++++++++++++++++++++
+ kexgsss.c | 300 +++++++++++++++++++++++++++++++++++++++++
+ monitor.c | 122 +++++++++++++++--
+ monitor.h | 3 +
+ monitor_wrap.c | 53 +++++++-
+ monitor_wrap.h | 4 +-
+ opacket.c | 2 +-
+ opacket.h | 2 +-
+ readconf.c | 43 ++++++
+ readconf.h | 5 +
+ servconf.c | 26 ++++
+ servconf.h | 2 +
+ ssh-gss.h | 41 +++++-
+ ssh_config | 2 +
+ ssh_config.5 | 32 +++++
+ sshconnect2.c | 133 +++++++++++++++++-
+ sshd.c | 110 +++++++++++++++
+ sshd_config | 2 +
+ sshd_config.5 | 10 ++
+ sshkey.c | 3 +-
+ sshkey.h | 1 +
+ 37 files changed, 2099 insertions(+), 146 deletions(-)
+ create mode 100644 ChangeLog.gssapi
+ create mode 100644 kexgssc.c
+ create mode 100644 kexgsss.c
+
+diff --git a/ChangeLog.gssapi b/ChangeLog.gssapi
+new file mode 100644
+index 000000000..f117a336a
+--- /dev/null
++++ b/ChangeLog.gssapi
+@@ -0,0 +1,113 @@
++20110101
++ - Finally update for OpenSSH 5.6p1
++ - Add GSSAPIServerIdentity option from Jim Basney
++
++20100308
++ - [ Makefile.in, key.c, key.h ]
++ Updates for OpenSSH 5.4p1
++ - [ servconf.c ]
++ Include GSSAPI options in the sshd -T configuration dump, and flag
++ some older configuration options as being unsupported. Thanks to Colin
++ Watson.
++ -
++
++20100124
++ - [ sshconnect2.c ]
++ Adapt to deal with additional element in Authmethod structure. Thanks to
++ Colin Watson
++
++20090615
++ - [ gss-genr.c gss-serv.c kexgssc.c kexgsss.c monitor.c sshconnect2.c
++ sshd.c ]
++ Fix issues identified by Greg Hudson following a code review
++ Check return value of gss_indicate_mechs
++ Protect GSSAPI calls in monitor, so they can only be used if enabled
++ Check return values of bignum functions in key exchange
++ Use BN_clear_free to clear other side's DH value
++ Make ssh_gssapi_id_kex more robust
++ Only configure kex table pointers if GSSAPI is enabled
++ Don't leak mechanism list, or gss mechanism list
++ Cast data.length before printing
++ If serverkey isn't provided, use an empty string, rather than NULL
++
++20090201
++ - [ gss-genr.c gss-serv.c kex.h kexgssc.c readconf.c readconf.h ssh-gss.h
++ ssh_config.5 sshconnet2.c ]
++ Add support for the GSSAPIClientIdentity option, which allows the user
++ to specify which GSSAPI identity to use to contact a given server
++
++20080404
++ - [ gss-serv.c ]
++ Add code to actually implement GSSAPIStrictAcceptCheck, which had somehow
++ been omitted from a previous version of this patch. Reported by Borislav
++ Stoichkov
++
++20070317
++ - [ gss-serv-krb5.c ]
++ Remove C99ism, where new_ccname was being declared in the middle of a
++ function
++
++20061220
++ - [ servconf.c ]
++ Make default for GSSAPIStrictAcceptorCheck be Yes, to match previous, and
++ documented, behaviour. Reported by Dan Watson.
++
++20060910
++ - [ gss-genr.c kexgssc.c kexgsss.c kex.h monitor.c sshconnect2.c sshd.c
++ ssh-gss.h ]
++ add support for gss-group14-sha1 key exchange mechanisms
++ - [ gss-serv.c servconf.c servconf.h sshd_config sshd_config.5 ]
++ Add GSSAPIStrictAcceptorCheck option to allow the disabling of
++ acceptor principal checking on multi-homed machines.
++ <Bugzilla #928>
++ - [ sshd_config ssh_config ]
++ Add settings for GSSAPIKeyExchange and GSSAPITrustDNS to the sample
++ configuration files
++ - [ kexgss.c kegsss.c sshconnect2.c sshd.c ]
++ Code cleanup. Replace strlen/xmalloc/snprintf sequences with xasprintf()
++ Limit length of error messages displayed by client
++
++20060909
++ - [ gss-genr.c gss-serv.c ]
++ move ssh_gssapi_acquire_cred() and ssh_gssapi_server_ctx to be server
++ only, where they belong
++ <Bugzilla #1225>
++
++20060829
++ - [ gss-serv-krb5.c ]
++ Fix CCAPI credentials cache name when creating KRB5CCNAME environment
++ variable
++
++20060828
++ - [ gss-genr.c ]
++ Avoid Heimdal context freeing problem
++ <Fixed upstream 20060829>
++
++20060818
++ - [ gss-genr.c ssh-gss.h sshconnect2.c ]
++ Make sure that SPENGO is disabled
++ <Bugzilla #1218 - Fixed upstream 20060818>
++
++20060421
++ - [ gssgenr.c, sshconnect2.c ]
++ a few type changes (signed versus unsigned, int versus size_t) to
++ fix compiler errors/warnings
++ (from jbasney AT ncsa.uiuc.edu)
++ - [ kexgssc.c, sshconnect2.c ]
++ fix uninitialized variable warnings
++ (from jbasney AT ncsa.uiuc.edu)
++ - [ gssgenr.c ]
++ pass oid to gss_display_status (helpful when using GSSAPI mechglue)
++ (from jbasney AT ncsa.uiuc.edu)
++ <Bugzilla #1220 >
++ - [ gss-serv-krb5.c ]
++ #ifdef HAVE_GSSAPI_KRB5 should be #ifdef HAVE_GSSAPI_KRB5_H
++ (from jbasney AT ncsa.uiuc.edu)
++ <Fixed upstream 20060304>
++ - [ readconf.c, readconf.h, ssh_config.5, sshconnect2.c
++ add client-side GssapiKeyExchange option
++ (from jbasney AT ncsa.uiuc.edu)
++ - [ sshconnect2.c ]
++ add support for GssapiTrustDns option for gssapi-with-mic
++ (from jbasney AT ncsa.uiuc.edu)
++ <gssapi-with-mic support is Bugzilla #1008>
+diff --git a/Makefile.in b/Makefile.in
+index 126b2c742..70050ffb6 100644
+--- a/Makefile.in
++++ b/Makefile.in
+@@ -100,6 +100,7 @@ LIBSSH_OBJS=${LIBOPENSSH_OBJS} \
+ kex.o kexdh.o kexgex.o kexecdh.o kexc25519.o \
+ kexdhc.o kexgexc.o kexecdhc.o kexc25519c.o \
+ kexdhs.o kexgexs.o kexecdhs.o kexc25519s.o \
++ kexgssc.o \
+ platform-pledge.o platform-tracing.o platform-misc.o
+
+ SSHOBJS= ssh.o readconf.o clientloop.o sshtty.o \
+@@ -113,7 +114,7 @@ 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 \
+ 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 md5crypt.o \
+ sftp-server.o sftp-common.o \
+ sandbox-null.o sandbox-rlimit.o sandbox-systrace.o sandbox-darwin.o \
+diff --git a/auth-krb5.c b/auth-krb5.c
+index 3096f1c8e..204752e1b 100644
+--- a/auth-krb5.c
++++ b/auth-krb5.c
+@@ -182,8 +182,13 @@ auth_krb5_password(Authctxt *authctxt, const char *password)
+
+ len = strlen(authctxt->krb5_ticket_file) + 6;
+ authctxt->krb5_ccname = xmalloc(len);
++#ifdef USE_CCAPI
++ snprintf(authctxt->krb5_ccname, len, "API:%s",
++ authctxt->krb5_ticket_file);
++#else
+ snprintf(authctxt->krb5_ccname, len, "FILE:%s",
+ authctxt->krb5_ticket_file);
++#endif
+
+ #ifdef USE_PAM
+ if (options.use_pam)
+@@ -240,15 +245,22 @@ krb5_cleanup_proc(Authctxt *authctxt)
+ #ifndef HEIMDAL
+ krb5_error_code
+ ssh_krb5_cc_gen(krb5_context ctx, krb5_ccache *ccache) {
+- int tmpfd, ret, oerrno;
++ int ret, oerrno;
+ char ccname[40];
+ mode_t old_umask;
++#ifdef USE_CCAPI
++ char cctemplate[] = "API:krb5cc_%d";
++#else
++ char cctemplate[] = "FILE:/tmp/krb5cc_%d_XXXXXXXXXX";
++ int tmpfd;
++#endif
+
+ ret = snprintf(ccname, sizeof(ccname),
+- "FILE:/tmp/krb5cc_%d_XXXXXXXXXX", geteuid());
++ cctemplate, geteuid());
+ if (ret < 0 || (size_t)ret >= sizeof(ccname))
+ return ENOMEM;
+
++#ifndef USE_CCAPI
+ old_umask = umask(0177);
+ tmpfd = mkstemp(ccname + strlen("FILE:"));
+ oerrno = errno;
+@@ -265,6 +277,7 @@ ssh_krb5_cc_gen(krb5_context ctx, krb5_ccache *ccache) {
+ return oerrno;
+ }
+ close(tmpfd);
++#endif
+
+ return (krb5_cc_resolve(ctx, ccname, ccache));
+ }
+diff --git a/auth.c b/auth.c
+index 3ca3762cc..d8e6b4a3d 100644
+--- a/auth.c
++++ b/auth.c
+@@ -399,7 +399,8 @@ 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:
+@@ -737,99 +738,6 @@ 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 legacy rhosts-style authentication.
+- * XXX is RhostsRSAAuthentication vulnerable to these?
+- * XXX Can we remove these checks? (or if not, remove RhostsRSAAuthentication?)
+- */
+-
+-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) < 0) {
+- debug("getpeername failed: %.100s", strerror(errno));
+- return strdup(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 strdup(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 strdup(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 strdup(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 strdup(ntop);
+- }
+- return strdup(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 9351e0428..1f12bb113 100644
+--- a/auth2-gss.c
++++ b/auth2-gss.c
+@@ -1,7 +1,7 @@
+ /* $OpenBSD: auth2-gss.c,v 1.29 2018/07/31 03:10:27 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
+@@ -54,6 +54,46 @@ 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;
++ 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("%s: %s", __func__, ssh_err(r));
++ if ((b = sshbuf_new()) == NULL)
++ fatal("%s: sshbuf_new failed", __func__);
++ mic.value = p;
++ mic.length = len;
++
++ ssh_gssapi_buildmic(b, authctxt->user, authctxt->service,
++ "gssapi-keyex");
++
++ if ((gssbuf.value = sshbuf_mutable_ptr(b)) == NULL)
++ fatal("%s: sshbuf_mutable_ptr failed", __func__);
++ 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));
++
++ 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)
+@@ -260,7 +300,8 @@ input_gssapi_exchange_complete(int type, u_int32_t plen, struct ssh *ssh)
+ if ((r = sshpkt_get_end(ssh)) != 0)
+ fatal("%s: %s", __func__, ssh_err(r));
+
+- authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));
++ authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user,
++ authctxt->pw));
+
+ if ((!use_privsep || mm_is_monitor()) &&
+ (displayname = ssh_gssapi_displayname()) != NULL)
+@@ -306,7 +347,8 @@ 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));
+ else
+ logit("GSSAPI MIC check failed");
+
+@@ -326,6 +368,12 @@ 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",
+ userauth_gssapi,
+diff --git a/auth2.c b/auth2.c
+index 4d19957a6..a77742819 100644
+--- a/auth2.c
++++ b/auth2.c
+@@ -74,6 +74,7 @@ extern Authmethod method_passwd;
+ extern Authmethod method_kbdint;
+ extern Authmethod method_hostbased;
+ #ifdef GSSAPI
++extern Authmethod method_gsskeyex;
+ extern Authmethod method_gssapi;
+ #endif
+
+@@ -81,6 +82,7 @@ Authmethod *authmethods[] = {
+ &method_none,
+ &method_pubkey,
+ #ifdef GSSAPI
++ &method_gsskeyex,
+ &method_gssapi,
+ #endif
+ &method_passwd,
+diff --git a/canohost.c b/canohost.c
+index f71a08568..404731d24 100644
+--- a/canohost.c
++++ b/canohost.c
+@@ -35,6 +35,99 @@
+ #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.
++ * XXX is RhostsRSAAuthentication vulnerable to these?
++ * XXX Can we remove these checks? (or if not, remove RhostsRSAAuthentication?)
++ */
++
++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) < 0) {
++ debug("getpeername failed: %.100s", strerror(errno));
++ return strdup(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 strdup(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 strdup(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 strdup(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 strdup(ntop);
++ }
++ return strdup(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 8d312cdaa..1464634b0 100644
+--- a/clientloop.c
++++ b/clientloop.c
+@@ -112,6 +112,10 @@
+ #include "ssherr.h"
+ #include "hostfile.h"
+
++#ifdef GSSAPI
++#include "ssh-gss.h"
++#endif
++
+ /* import options */
+ extern Options options;
+
+@@ -1370,9 +1374,18 @@ client_loop(struct ssh *ssh, int have_pty, int escape_char_arg,
+ break;
+
+ /* Do channel operations unless rekeying in progress. */
+- if (!ssh_packet_is_rekeying(ssh))
++ if (!ssh_packet_is_rekeying(ssh)) {
+ channel_after_select(ssh, readset, writeset);
+
++#ifdef GSSAPI
++ if (options.gss_renewal_rekey &&
++ ssh_gssapi_credentials_updated(NULL)) {
++ debug("credentials updated - forcing rekey");
++ need_rekeying = 1;
++ }
++#endif
++ }
++
+ /* Buffer input from the connection. */
+ client_process_net_input(readset);
+
+diff --git a/config.h.in b/config.h.in
+index 91b65db8f..209760c7c 100644
+--- a/config.h.in
++++ b/config.h.in
+@@ -1845,6 +1845,9 @@
+ /* Use btmp to log bad logins */
+ #undef USE_BTMP
+
++/* platform uses an in-memory credentials cache */
++#undef USE_CCAPI
++
+ /* Use libedit for sftp */
+ #undef USE_LIBEDIT
+
+@@ -1860,6 +1863,9 @@
+ /* Use PIPES instead of a socketpair() */
+ #undef USE_PIPES
+
++/* platform has the Security Authorization Session API */
++#undef USE_SECURITY_SESSION_API
++
+ /* Define if you have Solaris privileges */
+ #undef USE_SOLARIS_PRIVS
+
+diff --git a/configure.ac b/configure.ac
+index 7379ab358..023e7cc55 100644
+--- a/configure.ac
++++ b/configure.ac
+@@ -664,6 +664,30 @@ main() { 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 d56257b4a..491e62cee 100644
+--- a/gss-genr.c
++++ b/gss-genr.c
+@@ -1,7 +1,7 @@
+ /* $OpenBSD: gss-genr.c,v 1.26 2018/07/10 09:13:30 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
+@@ -39,14 +39,37 @@
+ #include "xmalloc.h"
+ #include "ssherr.h"
+ #include "sshbuf.h"
++#include "sshkey.h"
+ #include "log.h"
+ #include "ssh2.h"
++#include "cipher.h"
++#include "kex.h"
++#include "digest.h"
+
+ #include "ssh-gss.h"
+
+ extern u_char *session_id2;
+ extern u_int session_id2_len;
+
++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)
+@@ -62,6 +85,143 @@ ssh_gssapi_get_buffer_desc(struct sshbuf *b, gss_buffer_desc *g)
+ 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) {
++ gss_OID_set gss_supported;
++ 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));
++}
++
++char *
++ssh_gssapi_kex_mechs(gss_OID_set gss_supported, ssh_gssapi_check_fn *check,
++ const char *host, const char *client) {
++ struct sshbuf *buf;
++ size_t i;
++ int r, oidpos, enclen;
++ char *mechs, *encoded;
++ u_char digest[SSH_DIGEST_MAX_LENGTH];
++ char deroid[2];
++ struct ssh_digest_ctx *md;
++
++ 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("%s: sshbuf_new failed", __func__);
++
++ oidpos = 0;
++ 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 ||
++ ssh_digest_update(md, deroid, 2) != 0 ||
++ ssh_digest_update(md,
++ gss_supported->elements[i].elements,
++ gss_supported->elements[i].length) != 0 ||
++ ssh_digest_final(md, digest, sizeof(digest)) != 0)
++ fatal("%s: digest failed", __func__);
++
++ 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);
++
++ if (oidpos != 0) {
++ if ((r = sshbuf_put_u8(buf, ',')) != 0)
++ fatal("%s: buffer error: %s",
++ __func__, ssh_err(r));
++ }
++
++ if ((r = sshbuf_put(buf, KEX_GSS_GEX_SHA1_ID,
++ sizeof(KEX_GSS_GEX_SHA1_ID) - 1)) != 0 ||
++ (r = sshbuf_put(buf, encoded, enclen)) != 0 ||
++ (r = sshbuf_put_u8(buf, ',')) != 0 ||
++ (r = sshbuf_put(buf, KEX_GSS_GRP1_SHA1_ID,
++ sizeof(KEX_GSS_GRP1_SHA1_ID) - 1)) != 0 ||
++ (r = sshbuf_put(buf, encoded, enclen)) != 0 ||
++ (r = sshbuf_put_u8(buf, ',')) != 0 ||
++ (r = sshbuf_put(buf, KEX_GSS_GRP14_SHA1_ID,
++ sizeof(KEX_GSS_GRP14_SHA1_ID) - 1)) != 0 ||
++ (r = sshbuf_put(buf, encoded, enclen)) != 0)
++ fatal("%s: buffer error: %s",
++ __func__, ssh_err(r));
++
++ gss_enc2oid[oidpos].oid = &(gss_supported->elements[i]);
++ gss_enc2oid[oidpos].encoded = encoded;
++ oidpos++;
++ }
++ }
++ gss_enc2oid[oidpos].oid = NULL;
++ gss_enc2oid[oidpos].encoded = NULL;
++
++ if ((mechs = sshbuf_dup_string(buf)) == NULL)
++ fatal("%s: sshbuf_dup_string failed", __func__);
++
++ 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;
++
++ switch (kex_type) {
++ case KEX_GSS_GRP1_SHA1:
++ if (strlen(name) < sizeof(KEX_GSS_GRP1_SHA1_ID))
++ return GSS_C_NO_OID;
++ name += sizeof(KEX_GSS_GRP1_SHA1_ID) - 1;
++ break;
++ case KEX_GSS_GRP14_SHA1:
++ if (strlen(name) < sizeof(KEX_GSS_GRP14_SHA1_ID))
++ return GSS_C_NO_OID;
++ name += sizeof(KEX_GSS_GRP14_SHA1_ID) - 1;
++ break;
++ case KEX_GSS_GEX_SHA1:
++ if (strlen(name) < sizeof(KEX_GSS_GEX_SHA1_ID))
++ return GSS_C_NO_OID;
++ name += sizeof(KEX_GSS_GEX_SHA1_ID) - 1;
++ break;
++ default:
++ return GSS_C_NO_OID;
++ }
++
++ 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)
+@@ -218,7 +378,7 @@ 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);
+
+@@ -247,9 +407,43 @@ 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);
+@@ -257,6 +451,19 @@ 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)
+@@ -273,11 +480,16 @@ 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 &&
+@@ -287,6 +499,10 @@ 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);
+@@ -296,10 +512,66 @@ 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..90f8692f5 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
+@@ -120,8 +120,8 @@ 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 *errmsg;
++ const char *new_ccname;
+
+ if (client->creds == NULL) {
+ debug("No credentials stored");
+@@ -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)
+@@ -196,6 +201,71 @@ ssh_gssapi_krb5_storecreds(ssh_gssapi_client *client)
+ 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 +273,8 @@ 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 ab3a15f0f..6c087a1b1 100644
+--- a/gss-serv.c
++++ b/gss-serv.c
+@@ -1,7 +1,7 @@
+ /* $OpenBSD: gss-serv.c,v 1.31 2018/07/09 21:37:55 markus 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 +44,22 @@
+ #include "session.h"
+ #include "misc.h"
+ #include "servconf.h"
++#include "uidswap.h"
+
+ #include "ssh-gss.h"
++#include "monitor_wrap.h"
++
++extern ServerOptions options;
+
+ 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_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 +145,28 @@ 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));
++}
++
++/* 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 +177,9 @@ 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 +305,48 @@ 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);
++ }
++
++ 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;
++ }
+
+- gss_buffer_desc ename;
++ 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 +361,13 @@ 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 +385,8 @@ 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;
+@@ -356,7 +434,7 @@ ssh_gssapi_do_child(char ***envp, u_int *envsizep)
+
+ /* Privileged */
+ int
+-ssh_gssapi_userok(char *user)
++ssh_gssapi_userok(char *user, struct passwd *pw)
+ {
+ OM_uint32 lmin;
+
+@@ -366,9 +444,11 @@ ssh_gssapi_userok(char *user)
+ 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 +462,90 @@ 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;
++ int ret;
++#ifdef USE_PAM
++ 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 25f9f66f6..fb5bfaea5 100644
+--- a/kex.c
++++ b/kex.c
+@@ -54,6 +54,10 @@
+ #include "sshbuf.h"
+ #include "digest.h"
+
++#ifdef GSSAPI
++#include "ssh-gss.h"
++#endif
++
+ /* prototype */
+ static int kex_choose_conf(struct ssh *);
+ static int kex_input_newkeys(int, u_int32_t, struct ssh *);
+@@ -105,6 +109,14 @@ static const struct kexalg kexalgs[] = {
+ #endif /* HAVE_EVP_SHA256 || !WITH_OPENSSL */
+ { NULL, -1, -1, -1},
+ };
++static const struct kexalg kexalg_prefixes[] = {
++#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 },
++#endif
++ { NULL, -1, -1, -1 },
++};
+
+ char *
+ kex_alg_list(char sep)
+@@ -137,6 +149,10 @@ kex_alg_by_name(const char *name)
+ if (strcmp(k->name, name) == 0)
+ return k;
+ }
++ for (k = kexalg_prefixes; k->name != NULL; k++) {
++ if (strncmp(k->name, name, strlen(k->name)) == 0)
++ return k;
++ }
+ return NULL;
+ }
+
+@@ -653,6 +669,9 @@ kex_free(struct kex *kex)
+ sshbuf_free(kex->peer);
+ sshbuf_free(kex->my);
+ free(kex->session_id);
++#ifdef GSSAPI
++ free(kex->gss_host);
++#endif /* GSSAPI */
+ free(kex->client_version_string);
+ free(kex->server_version_string);
+ free(kex->failed_choice);
+diff --git a/kex.h b/kex.h
+index 593de1208..4e5ead839 100644
+--- a/kex.h
++++ b/kex.h
+@@ -100,6 +100,9 @@ enum kex_exchange {
+ KEX_DH_GEX_SHA256,
+ KEX_ECDH_SHA2,
+ KEX_C25519_SHA256,
++ KEX_GSS_GRP1_SHA1,
++ KEX_GSS_GRP14_SHA1,
++ KEX_GSS_GEX_SHA1,
+ KEX_MAX
+ };
+
+@@ -148,6 +151,12 @@ 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 *client_version_string;
+ char *server_version_string;
+ char *failed_choice;
+@@ -198,6 +207,11 @@ int kexecdh_server(struct ssh *);
+ int kexc25519_client(struct ssh *);
+ int kexc25519_server(struct ssh *);
+
++#ifdef GSSAPI
++int kexgss_client(struct ssh *);
++int kexgss_server(struct ssh *);
++#endif
++
+ int kex_dh_hash(int, const char *, const char *,
+ const u_char *, size_t, const u_char *, size_t, const u_char *, size_t,
+ const BIGNUM *, const BIGNUM *, const BIGNUM *, u_char *, size_t *);
+diff --git a/kexgssc.c b/kexgssc.c
+new file mode 100644
+index 000000000..3c8ae08dd
+--- /dev/null
++++ b/kexgssc.c
+@@ -0,0 +1,341 @@
++/*
++ * 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"
++
++#ifdef GSSAPI
++
++#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 "ssh-gss.h"
++
++int
++kexgss_client(struct ssh *ssh) {
++ gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
++ gss_buffer_desc recv_tok, gssbuf, msg_tok, *token_ptr;
++ Gssctxt *ctxt;
++ OM_uint32 maj_status, min_status, ret_flags;
++ u_int klen, kout, slen = 0, strlen;
++ DH *dh;
++ BIGNUM *dh_server_pub = NULL;
++ BIGNUM *shared_secret = NULL;
++ const BIGNUM *pub_key, *dh_p, *dh_g;
++ BIGNUM *p = NULL;
++ BIGNUM *g = NULL;
++ u_char *kbuf;
++ u_char *serverhostkey = NULL;
++ u_char *empty = "";
++ char *msg;
++ int type = 0;
++ int first = 1;
++ int nbits = 0, min = DH_GRP_MIN, max = DH_GRP_MAX;
++ u_char hash[SSH_DIGEST_MAX_LENGTH];
++ size_t hashlen;
++
++ /* Initialise our GSSAPI world */
++ ssh_gssapi_build_ctx(&ctxt);
++ if (ssh_gssapi_id_kex(ctxt, ssh->kex->name, ssh->kex->kex_type)
++ == GSS_C_NO_OID)
++ fatal("Couldn't identify host exchange");
++
++ if (ssh_gssapi_import_name(ctxt, ssh->kex->gss_host))
++ fatal("Couldn't import hostname");
++
++ if (ssh->kex->gss_client &&
++ ssh_gssapi_client_identity(ctxt, ssh->kex->gss_client))
++ fatal("Couldn't acquire client credentials");
++
++ switch (ssh->kex->kex_type) {
++ case KEX_GSS_GRP1_SHA1:
++ dh = dh_new_group1();
++ break;
++ case KEX_GSS_GRP14_SHA1:
++ dh = dh_new_group14();
++ break;
++ case KEX_GSS_GEX_SHA1:
++ debug("Doing group exchange\n");
++ nbits = dh_estimate(ssh->kex->we_need * 8);
++ packet_start(SSH2_MSG_KEXGSS_GROUPREQ);
++ packet_put_int(min);
++ packet_put_int(nbits);
++ packet_put_int(max);
++
++ packet_send();
++
++ packet_read_expect(SSH2_MSG_KEXGSS_GROUP);
++
++ if ((p = BN_new()) == NULL)
++ fatal("BN_new() failed");
++ packet_get_bignum2(p);
++ if ((g = BN_new()) == NULL)
++ fatal("BN_new() failed");
++ packet_get_bignum2(g);
++ packet_check_eom();
++
++ 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);
++
++ dh = dh_new_group(g, p);
++ break;
++ default:
++ fatal("%s: Unexpected KEX type %d", __func__, ssh->kex->kex_type);
++ }
++
++ /* Step 1 - e is dh->pub_key */
++ dh_gen_key(dh, ssh->kex->we_need * 8);
++ DH_get0_key(dh, &pub_key, NULL);
++ DH_get0_pqg(dh, &dh_p, NULL, &dh_g);
++
++ /* This is f, we initialise it now to make life easier */
++ dh_server_pub = BN_new();
++ if (dh_server_pub == NULL)
++ fatal("dh_server_pub == NULL");
++
++ token_ptr = GSS_C_NO_BUFFER;
++
++ do {
++ debug("Calling gss_init_sec_context");
++
++ maj_status = ssh_gssapi_init_ctx(ctxt,
++ ssh->kex->gss_deleg_creds, token_ptr, &send_tok,
++ &ret_flags);
++
++ if (GSS_ERROR(maj_status)) {
++ if (send_tok.length != 0) {
++ packet_start(SSH2_MSG_KEXGSS_CONTINUE);
++ packet_put_string(send_tok.value,
++ send_tok.length);
++ }
++ fatal("gss_init_context failed");
++ }
++
++ /* If we've got an old receive buffer get rid of it */
++ if (token_ptr != GSS_C_NO_BUFFER)
++ free(recv_tok.value);
++
++ 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) {
++ packet_start(SSH2_MSG_KEXGSS_INIT);
++ packet_put_string(send_tok.value,
++ send_tok.length);
++ packet_put_bignum2(pub_key);
++ first = 0;
++ } else {
++ packet_start(SSH2_MSG_KEXGSS_CONTINUE);
++ packet_put_string(send_tok.value,
++ send_tok.length);
++ }
++ packet_send();
++ gss_release_buffer(&min_status, &send_tok);
++
++ /* If we've sent them data, they should reply */
++ do {
++ type = packet_read();
++ if (type == SSH2_MSG_KEXGSS_HOSTKEY) {
++ debug("Received KEXGSS_HOSTKEY");
++ if (serverhostkey)
++ fatal("Server host key received more than once");
++ serverhostkey =
++ packet_get_string(&slen);
++ }
++ } 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");
++ recv_tok.value = packet_get_string(&strlen);
++ recv_tok.length = strlen;
++ break;
++ case SSH2_MSG_KEXGSS_COMPLETE:
++ debug("Received GSSAPI_COMPLETE");
++ packet_get_bignum2(dh_server_pub);
++ msg_tok.value = packet_get_string(&strlen);
++ msg_tok.length = strlen;
++
++ /* Is there a token included? */
++ if (packet_get_char()) {
++ recv_tok.value=
++ packet_get_string(&strlen);
++ recv_tok.length = strlen;
++ /* If we're already complete - protocol error */
++ if (maj_status == GSS_S_COMPLETE)
++ packet_disconnect("Protocol error: received token when complete");
++ } else {
++ /* No token included */
++ if (maj_status != GSS_S_COMPLETE)
++ packet_disconnect("Protocol error: did not receive final token");
++ }
++ break;
++ case SSH2_MSG_KEXGSS_ERROR:
++ debug("Received Error");
++ maj_status = packet_get_int();
++ min_status = packet_get_int();
++ msg = packet_get_string(NULL);
++ (void) packet_get_string_ptr(NULL);
++ fatal("GSSAPI Error: \n%.400s",msg);
++ default:
++ packet_disconnect("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");
++
++ /* Check f in range [1, p-1] */
++ if (!dh_pub_is_valid(dh, dh_server_pub))
++ packet_disconnect("bad server public DH value");
++
++ /* compute K=f^x mod p */
++ klen = DH_size(dh);
++ kbuf = xmalloc(klen);
++ kout = DH_compute_key(kbuf, dh_server_pub, dh);
++ if (kout < 0)
++ fatal("DH_compute_key: failed");
++
++ shared_secret = BN_new();
++ if (shared_secret == NULL)
++ fatal("kexgss_client: BN_new failed");
++
++ if (BN_bin2bn(kbuf, kout, shared_secret) == NULL)
++ fatal("kexdh_client: BN_bin2bn failed");
++
++ memset(kbuf, 0, klen);
++ free(kbuf);
++
++ hashlen = sizeof(hash);
++ switch (ssh->kex->kex_type) {
++ case KEX_GSS_GRP1_SHA1:
++ case KEX_GSS_GRP14_SHA1:
++ kex_dh_hash(
++ ssh->kex->hash_alg,
++ ssh->kex->client_version_string,
++ ssh->kex->server_version_string,
++ sshbuf_ptr(ssh->kex->my), sshbuf_len(ssh->kex->my),
++ sshbuf_ptr(ssh->kex->peer), sshbuf_len(ssh->kex->peer),
++ (serverhostkey ? serverhostkey : empty), slen,
++ pub_key, /* e */
++ dh_server_pub, /* f */
++ shared_secret, /* K */
++ hash, &hashlen
++ );
++ break;
++ case KEX_GSS_GEX_SHA1:
++ kexgex_hash(
++ ssh->kex->hash_alg,
++ ssh->kex->client_version_string,
++ ssh->kex->server_version_string,
++ sshbuf_ptr(ssh->kex->my), sshbuf_len(ssh->kex->my),
++ sshbuf_ptr(ssh->kex->peer), sshbuf_len(ssh->kex->peer),
++ (serverhostkey ? serverhostkey : empty), slen,
++ min, nbits, max,
++ dh_p, dh_g,
++ pub_key,
++ dh_server_pub,
++ shared_secret,
++ hash, &hashlen
++ );
++ break;
++ default:
++ fatal("%s: Unexpected KEX type %d", __func__, ssh->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)))
++ packet_disconnect("Hash's MIC didn't verify");
++
++ free(msg_tok.value);
++
++ DH_free(dh);
++ free(serverhostkey);
++ BN_clear_free(dh_server_pub);
++
++ /* save session id */
++ if (ssh->kex->session_id == NULL) {
++ ssh->kex->session_id_len = hashlen;
++ ssh->kex->session_id = xmalloc(ssh->kex->session_id_len);
++ memcpy(ssh->kex->session_id, hash, ssh->kex->session_id_len);
++ }
++
++ if (ssh->kex->gss_deleg_creds)
++ ssh_gssapi_credentials_updated(ctxt);
++
++ if (gss_kex_context == NULL)
++ gss_kex_context = ctxt;
++ else
++ ssh_gssapi_delete_ctx(&ctxt);
++
++ kex_derive_keys_bn(ssh, hash, hashlen, shared_secret);
++ BN_clear_free(shared_secret);
++ return kex_send_newkeys(ssh);
++}
++
++#endif /* GSSAPI */
+diff --git a/kexgsss.c b/kexgsss.c
+new file mode 100644
+index 000000000..18070f1d7
+--- /dev/null
++++ b/kexgsss.c
+@@ -0,0 +1,300 @@
++/*
++ * 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"
++
++#ifdef GSSAPI
++
++#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"
++#include "servconf.h"
++#include "digest.h"
++
++extern ServerOptions options;
++
++int
++kexgss_server(struct ssh *ssh)
++{
++ 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;
++ u_int slen, klen, kout;
++ u_char *kbuf;
++ DH *dh;
++ int min = -1, max = -1, nbits = -1;
++ const BIGNUM *pub_key, *dh_p, *dh_g;
++ BIGNUM *shared_secret = NULL;
++ BIGNUM *dh_client_pub = NULL;
++ int type = 0;
++ gss_OID oid;
++ char *mechs;
++ u_char hash[SSH_DIGEST_MAX_LENGTH];
++ size_t hashlen;
++
++ /* 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("%s: Identifying %s", __func__, ssh->kex->name);
++ oid = ssh_gssapi_id_kex(NULL, ssh->kex->name, ssh->kex->kex_type);
++ if (oid == GSS_C_NO_OID)
++ fatal("Unknown gssapi mechanism");
++
++ debug2("%s: Acquiring credentials", __func__);
++
++ if (GSS_ERROR(PRIVSEP(ssh_gssapi_server_ctx(&ctxt, oid))))
++ fatal("Unable to acquire credentials for the server");
++
++ switch (ssh->kex->kex_type) {
++ case KEX_GSS_GRP1_SHA1:
++ dh = dh_new_group1();
++ break;
++ case KEX_GSS_GRP14_SHA1:
++ dh = dh_new_group14();
++ break;
++ case KEX_GSS_GEX_SHA1:
++ debug("Doing group exchange");
++ packet_read_expect(SSH2_MSG_KEXGSS_GROUPREQ);
++ min = packet_get_int();
++ nbits = packet_get_int();
++ max = packet_get_int();
++ packet_check_eom();
++ if (max < min || nbits < min || max < nbits)
++ fatal("GSS_GEX, bad parameters: %d !< %d !< %d",
++ min, nbits, max);
++ dh = PRIVSEP(choose_dh(MAX(DH_GRP_MIN, min),
++ nbits, MIN(DH_GRP_MAX, max)));
++ if (dh == NULL)
++ packet_disconnect("Protocol error: no matching group found");
++ DH_get0_pqg(dh, &dh_p, NULL, &dh_g);
++
++ packet_start(SSH2_MSG_KEXGSS_GROUP);
++ packet_put_bignum2(dh_p);
++ packet_put_bignum2(dh_g);
++ packet_send();
++
++ packet_write_wait();
++ break;
++ default:
++ fatal("%s: Unexpected KEX type %d", __func__, ssh->kex->kex_type);
++ }
++
++ dh_gen_key(dh, ssh->kex->we_need * 8);
++
++ do {
++ debug("Wait SSH2_MSG_GSSAPI_INIT");
++ type = packet_read();
++ switch(type) {
++ case SSH2_MSG_KEXGSS_INIT:
++ if (dh_client_pub != NULL)
++ fatal("Received KEXGSS_INIT after initialising");
++ recv_tok.value = packet_get_string(&slen);
++ recv_tok.length = slen;
++
++ if ((dh_client_pub = BN_new()) == NULL)
++ fatal("dh_client_pub == NULL");
++
++ packet_get_bignum2(dh_client_pub);
++
++ /* Send SSH_MSG_KEXGSS_HOSTKEY here, if we want */
++ break;
++ case SSH2_MSG_KEXGSS_CONTINUE:
++ recv_tok.value = packet_get_string(&slen);
++ recv_tok.length = slen;
++ break;
++ default:
++ packet_disconnect(
++ "Protocol error: didn't expect packet type %d",
++ type);
++ }
++
++ maj_status = PRIVSEP(ssh_gssapi_accept_ctx(ctxt, &recv_tok,
++ &send_tok, &ret_flags));
++
++ free(recv_tok.value);
++
++ 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");
++ packet_start(SSH2_MSG_KEXGSS_CONTINUE);
++ packet_put_string(send_tok.value, send_tok.length);
++ packet_send();
++ gss_release_buffer(&min_status, &send_tok);
++ }
++ } while (maj_status & GSS_S_CONTINUE_NEEDED);
++
++ if (GSS_ERROR(maj_status)) {
++ if (send_tok.length > 0) {
++ packet_start(SSH2_MSG_KEXGSS_CONTINUE);
++ packet_put_string(send_tok.value, send_tok.length);
++ packet_send();
++ }
++ 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");
++
++ if (!dh_pub_is_valid(dh, dh_client_pub))
++ packet_disconnect("bad client public DH value");
++
++ klen = DH_size(dh);
++ kbuf = xmalloc(klen);
++ kout = DH_compute_key(kbuf, dh_client_pub, dh);
++ if (kout < 0)
++ fatal("DH_compute_key: failed");
++
++ shared_secret = BN_new();
++ if (shared_secret == NULL)
++ fatal("kexgss_server: BN_new failed");
++
++ if (BN_bin2bn(kbuf, kout, shared_secret) == NULL)
++ fatal("kexgss_server: BN_bin2bn failed");
++
++ memset(kbuf, 0, klen);
++ free(kbuf);
++
++ DH_get0_key(dh, &pub_key, NULL);
++ DH_get0_pqg(dh, &dh_p, NULL, &dh_g);
++
++ hashlen = sizeof(hash);
++ switch (ssh->kex->kex_type) {
++ case KEX_GSS_GRP1_SHA1:
++ case KEX_GSS_GRP14_SHA1:
++ kex_dh_hash(
++ ssh->kex->hash_alg,
++ ssh->kex->client_version_string, ssh->kex->server_version_string,
++ sshbuf_ptr(ssh->kex->peer), sshbuf_len(ssh->kex->peer),
++ sshbuf_ptr(ssh->kex->my), sshbuf_len(ssh->kex->my),
++ NULL, 0, /* Change this if we start sending host keys */
++ dh_client_pub, pub_key, shared_secret,
++ hash, &hashlen
++ );
++ break;
++ case KEX_GSS_GEX_SHA1:
++ kexgex_hash(
++ ssh->kex->hash_alg,
++ ssh->kex->client_version_string, ssh->kex->server_version_string,
++ sshbuf_ptr(ssh->kex->peer), sshbuf_len(ssh->kex->peer),
++ sshbuf_ptr(ssh->kex->my), sshbuf_len(ssh->kex->my),
++ NULL, 0,
++ min, nbits, max,
++ dh_p, dh_g,
++ dh_client_pub,
++ pub_key,
++ shared_secret,
++ hash, &hashlen
++ );
++ break;
++ default:
++ fatal("%s: Unexpected KEX type %d", __func__, ssh->kex->kex_type);
++ }
++
++ BN_clear_free(dh_client_pub);
++
++ if (ssh->kex->session_id == NULL) {
++ ssh->kex->session_id_len = hashlen;
++ ssh->kex->session_id = xmalloc(ssh->kex->session_id_len);
++ memcpy(ssh->kex->session_id, hash, ssh->kex->session_id_len);
++ }
++
++ gssbuf.value = hash;
++ gssbuf.length = hashlen;
++
++ if (GSS_ERROR(PRIVSEP(ssh_gssapi_sign(ctxt,&gssbuf,&msg_tok))))
++ fatal("Couldn't get MIC");
++
++ packet_start(SSH2_MSG_KEXGSS_COMPLETE);
++ packet_put_bignum2(pub_key);
++ packet_put_string(msg_tok.value,msg_tok.length);
++
++ if (send_tok.length != 0) {
++ packet_put_char(1); /* true */
++ packet_put_string(send_tok.value, send_tok.length);
++ } else {
++ packet_put_char(0); /* false */
++ }
++ packet_send();
++
++ 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);
++
++ DH_free(dh);
++
++ kex_derive_keys_bn(ssh, hash, hashlen, shared_secret);
++ BN_clear_free(shared_secret);
++ 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();
++ return 0;
++}
++#endif /* GSSAPI */
+diff --git a/monitor.c b/monitor.c
+index 531b2993a..eabc1e89b 100644
+--- a/monitor.c
++++ b/monitor.c
+@@ -145,6 +145,8 @@ int mm_answer_gss_setup_ctx(int, struct sshbuf *);
+ int mm_answer_gss_accept_ctx(int, struct sshbuf *);
+ int mm_answer_gss_userok(int, struct sshbuf *);
+ int mm_answer_gss_checkmic(int, struct sshbuf *);
++int mm_answer_gss_sign(int, struct sshbuf *);
++int mm_answer_gss_updatecreds(int, struct sshbuf *);
+ #endif
+
+ #ifdef SSH_AUDIT_EVENTS
+@@ -215,11 +217,18 @@ 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
+@@ -289,6 +298,10 @@ monitor_child_preauth(Authctxt *_authctxt, 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) {
+@@ -401,6 +414,10 @@ monitor_child_postauth(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);
+@@ -1666,6 +1683,13 @@ monitor_apply_keystate(struct monitor *pmonitor)
+ # endif
+ #endif /* WITH_OPENSSL */
+ kex->kex[KEX_C25519_SHA256] = kexc25519_server;
++#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_GEX_SHA1] = kexgss_server;
++ }
++#endif
+ kex->load_host_public_key=&get_hostkey_public_by_type;
+ kex->load_host_private_key=&get_hostkey_private_by_type;
+ kex->host_key_index=&get_hostkey_index;
+@@ -1756,8 +1780,8 @@ mm_answer_gss_setup_ctx(int sock, struct sshbuf *m)
+ u_char *p;
+ int r;
+
+- if (!options.gss_authentication)
+- fatal("%s: GSSAPI authentication not enabled", __func__);
++ if (!options.gss_authentication && !options.gss_keyex)
++ fatal("%s: GSSAPI not enabled", __func__);
+
+ if ((r = sshbuf_get_string(m, &p, &len)) != 0)
+ fatal("%s: buffer error: %s", __func__, ssh_err(r));
+@@ -1789,8 +1813,8 @@ mm_answer_gss_accept_ctx(int sock, struct sshbuf *m)
+ OM_uint32 flags = 0; /* GSI needs this */
+ int r;
+
+- if (!options.gss_authentication)
+- fatal("%s: GSSAPI authentication not enabled", __func__);
++ if (!options.gss_authentication && !options.gss_keyex)
++ fatal("%s: GSSAPI not enabled", __func__);
+
+ if ((r = ssh_gssapi_get_buffer_desc(m, &in)) != 0)
+ fatal("%s: buffer error: %s", __func__, ssh_err(r));
+@@ -1810,6 +1834,7 @@ mm_answer_gss_accept_ctx(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);
+ }
+@@ -1821,8 +1846,8 @@ mm_answer_gss_checkmic(int sock, struct sshbuf *m)
+ OM_uint32 ret;
+ int r;
+
+- if (!options.gss_authentication)
+- fatal("%s: GSSAPI authentication not enabled", __func__);
++ if (!options.gss_authentication && !options.gss_keyex)
++ fatal("%s: GSSAPI not enabled", __func__);
+
+ if ((r = ssh_gssapi_get_buffer_desc(m, &gssbuf)) != 0 ||
+ (r = ssh_gssapi_get_buffer_desc(m, &mic)) != 0)
+@@ -1851,10 +1876,11 @@ mm_answer_gss_userok(int sock, struct sshbuf *m)
+ int r, authenticated;
+ const char *displayname;
+
+- if (!options.gss_authentication)
+- fatal("%s: GSSAPI authentication not enabled", __func__);
++ if (!options.gss_authentication && !options.gss_keyex)
++ fatal("%s: GSSAPI not enabled", __func__);
+
+- authenticated = authctxt->valid && ssh_gssapi_userok(authctxt->user);
++ authenticated = authctxt->valid &&
++ ssh_gssapi_userok(authctxt->user, authctxt->pw);
+
+ sshbuf_reset(m);
+ if ((r = sshbuf_put_u32(m, authenticated)) != 0)
+@@ -1871,5 +1897,83 @@ mm_answer_gss_userok(int sock, struct sshbuf *m)
+ /* Monitor loop will terminate if authenticated */
+ return (authenticated);
+ }
++
++int
++mm_answer_gss_sign(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;
++ int r;
++
++ if (!options.gss_authentication && !options.gss_keyex)
++ fatal("%s: GSSAPI not enabled", __func__);
++
++ if ((r = sshbuf_get_string(m, &p, &len)) != 0)
++ fatal("%s: buffer error: %s", __func__, ssh_err(r));
++ data.value = p;
++ data.length = len;
++ if (data.length != 20)
++ fatal("%s: data length incorrect: %d", __func__,
++ (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("%s: buffer error: %s", __func__, ssh_err(r));
++
++ 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(int socket, struct sshbuf *m) {
++ ssh_gssapi_ccache store;
++ int r, ok;
++
++ if (!options.gss_authentication && !options.gss_keyex)
++ fatal("%s: GSSAPI not enabled", __func__);
++
++ if ((r = sshbuf_get_cstring(m, &store.filename, NULL)) != 0 ||
++ (r = sshbuf_get_cstring(m, &store.envvar, NULL)) != 0 ||
++ (r = sshbuf_get_cstring(m, &store.envval, NULL)) != 0)
++ fatal("%s: buffer error: %s", __func__, ssh_err(r));
++
++ 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("%s: buffer error: %s", __func__, ssh_err(r));
++
++ mm_request_send(socket, MONITOR_ANS_GSSUPCREDS, m);
++
++ return(0);
++}
++
+ #endif /* GSSAPI */
+
+diff --git a/monitor.h b/monitor.h
+index 16047299f..44fbed589 100644
+--- a/monitor.h
++++ b/monitor.h
+@@ -63,6 +63,9 @@ 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 monitor {
+diff --git a/monitor_wrap.c b/monitor_wrap.c
+index 732fb3476..1865a122a 100644
+--- a/monitor_wrap.c
++++ b/monitor_wrap.c
+@@ -984,7 +984,7 @@ 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)
+ {
+ struct sshbuf *m;
+ int r, authenticated = 0;
+@@ -1003,4 +1003,55 @@ mm_ssh_gssapi_userok(char *user)
+ debug3("%s: user %sauthenticated",__func__, 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("%s: sshbuf_new failed", __func__);
++ if ((r = sshbuf_put_string(m, data->value, data->length)) != 0)
++ fatal("%s: buffer error: %s", __func__, ssh_err(r));
++
++ 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("%s: buffer error: %s", __func__, ssh_err(r));
++
++ 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("%s: sshbuf_new failed", __func__);
++ 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("%s: buffer error: %s", __func__, ssh_err(r));
++
++ 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("%s: buffer error: %s", __func__, ssh_err(r));
++ sshbuf_free(m);
++
++ return (ok);
++}
++
+ #endif /* GSSAPI */
+diff --git a/monitor_wrap.h b/monitor_wrap.h
+index 644da081d..7f93144ff 100644
+--- a/monitor_wrap.h
++++ b/monitor_wrap.h
+@@ -60,8 +60,10 @@ 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 *);
+ 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/opacket.c b/opacket.c
+index e637d7a71..7672c0b59 100644
+--- a/opacket.c
++++ b/opacket.c
+@@ -80,7 +80,7 @@ ssh_packet_put_raw(struct ssh *ssh, const void *buf, u_int len)
+
+ #ifdef WITH_OPENSSL
+ void
+-ssh_packet_put_bignum2(struct ssh *ssh, BIGNUM * value)
++ssh_packet_put_bignum2(struct ssh *ssh, const BIGNUM * value)
+ {
+ int r;
+
+diff --git a/opacket.h b/opacket.h
+index f92fe586e..1cf66a2d3 100644
+--- a/opacket.h
++++ b/opacket.h
+@@ -7,7 +7,7 @@ void ssh_packet_start(struct ssh *, u_char);
+ void ssh_packet_put_char(struct ssh *, int ch);
+ void ssh_packet_put_int(struct ssh *, u_int value);
+ void ssh_packet_put_int64(struct ssh *, u_int64_t value);
+-void ssh_packet_put_bignum2(struct ssh *, BIGNUM * value);
++void ssh_packet_put_bignum2(struct ssh *, const BIGNUM * value);
+ void ssh_packet_put_ecpoint(struct ssh *, const EC_GROUP *, const EC_POINT *);
+ void ssh_packet_put_string(struct ssh *, const void *buf, u_int len);
+ void ssh_packet_put_cstring(struct ssh *, const char *str);
+diff --git a/readconf.c b/readconf.c
+index 433811521..36bc5e59a 100644
+--- a/readconf.c
++++ b/readconf.c
+@@ -161,6 +161,8 @@ typedef enum {
+ oClearAllForwardings, oNoHostAuthenticationForLocalhost,
+ oEnableSSHKeysign, oRekeyLimit, oVerifyHostKeyDNS, oConnectTimeout,
+ oAddressFamily, oGssAuthentication, oGssDelegateCreds,
++ oGssTrustDns, oGssKeyEx, oGssClientIdentity, oGssRenewalRekey,
++ oGssServerIdentity,
+ oServerAliveInterval, oServerAliveCountMax, oIdentitiesOnly,
+ oSendEnv, oSetEnv, oControlPath, oControlMaster, oControlPersist,
+ oHashKnownHosts,
+@@ -201,10 +203,20 @@ static struct {
+ /* Sometimes-unsupported options */
+ #if defined(GSSAPI)
+ { "gssapiauthentication", oGssAuthentication },
++ { "gssapikeyexchange", oGssKeyEx },
+ { "gssapidelegatecredentials", oGssDelegateCreds },
++ { "gssapitrustdns", oGssTrustDns },
++ { "gssapiclientidentity", oGssClientIdentity },
++ { "gssapiserveridentity", oGssServerIdentity },
++ { "gssapirenewalforcesrekey", oGssRenewalRekey },
+ # else
+ { "gssapiauthentication", oUnsupported },
++ { "gssapikeyexchange", oUnsupported },
+ { "gssapidelegatecredentials", oUnsupported },
++ { "gssapitrustdns", oUnsupported },
++ { "gssapiclientidentity", oUnsupported },
++ { "gssapiserveridentity", oUnsupported },
++ { "gssapirenewalforcesrekey", oUnsupported },
+ #endif
+ #ifdef ENABLE_PKCS11
+ { "smartcarddevice", oPKCS11Provider },
+@@ -974,10 +986,30 @@ 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 oBatchMode:
+ intptr = &options->batch_mode;
+ goto parse_flag;
+@@ -1842,7 +1874,12 @@ initialize_options(Options * options)
+ options->pubkey_authentication = -1;
+ options->challenge_response_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->password_authentication = -1;
+ options->kbd_interactive_authentication = -1;
+ options->kbd_interactive_devices = NULL;
+@@ -1988,8 +2025,14 @@ fill_default_options(Options * options)
+ options->challenge_response_authentication = 1;
+ 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;
+ if (options->password_authentication == -1)
+ options->password_authentication = 1;
+ if (options->kbd_interactive_authentication == -1)
+diff --git a/readconf.h b/readconf.h
+index fc7e38251..8e4900d01 100644
+--- a/readconf.h
++++ b/readconf.h
+@@ -40,7 +40,12 @@ typedef struct {
+ int challenge_response_authentication;
+ /* Try S/Key or TIS, authentication. */
+ 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 */
+ int password_authentication; /* Try password
+ * authentication. */
+ int kbd_interactive_authentication; /* Try keyboard-interactive auth. */
+diff --git a/servconf.c b/servconf.c
+index 932d363bb..4668b8a45 100644
+--- a/servconf.c
++++ b/servconf.c
+@@ -124,8 +124,10 @@ 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->password_authentication = -1;
+ options->kbd_interactive_authentication = -1;
+ options->challenge_response_authentication = -1;
+@@ -337,10 +339,14 @@ 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;
+ if (options->password_authentication == -1)
+ options->password_authentication = 1;
+ if (options->kbd_interactive_authentication == -1)
+@@ -485,6 +491,7 @@ typedef enum {
+ sHostKeyAlgorithms,
+ sClientAliveInterval, sClientAliveCountMax, sAuthorizedKeysFile,
+ sGssAuthentication, sGssCleanupCreds, sGssStrictAcceptor,
++ sGssKeyEx, sGssStoreRekey,
+ sAcceptEnv, sSetEnv, sPermitTunnel,
+ sMatch, sPermitOpen, sPermitListen, sForceCommand, sChrootDirectory,
+ sUsePrivilegeSeparation, sAllowAgentForwarding,
+@@ -559,12 +566,20 @@ 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 },
+ #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 },
+ #endif
++ { "gssusesessionccache", sUnsupported, SSHCFG_GLOBAL },
++ { "gssapiusesessioncredcache", sUnsupported, SSHCFG_GLOBAL },
+ { "passwordauthentication", sPasswordAuthentication, SSHCFG_ALL },
+ { "kbdinteractiveauthentication", sKbdInteractiveAuthentication, SSHCFG_ALL },
+ { "challengeresponseauthentication", sChallengeResponseAuthentication, SSHCFG_GLOBAL },
+@@ -1468,6 +1483,10 @@ process_server_config_line(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;
+@@ -1476,6 +1495,10 @@ process_server_config_line(ServerOptions *options, char *line,
+ intptr = &options->gss_strict_acceptor;
+ goto parse_flag;
+
++ case sGssStoreRekey:
++ intptr = &options->gss_store_rekey;
++ goto parse_flag;
++
+ case sPasswordAuthentication:
+ intptr = &options->password_authentication;
+ goto parse_flag;
+@@ -2560,7 +2583,10 @@ dump_config(ServerOptions *o)
+ #endif
+ #ifdef GSSAPI
+ dump_cfg_fmtint(sGssAuthentication, o->gss_authentication);
++ dump_cfg_fmtint(sGssKeyEx, o->gss_keyex);
+ dump_cfg_fmtint(sGssCleanupCreds, o->gss_cleanup_creds);
++ dump_cfg_fmtint(sGssStrictAcceptor, o->gss_strict_acceptor);
++ dump_cfg_fmtint(sGssStoreRekey, o->gss_store_rekey);
+ #endif
+ dump_cfg_fmtint(sPasswordAuthentication, o->password_authentication);
+ dump_cfg_fmtint(sKbdInteractiveAuthentication,
+diff --git a/servconf.h b/servconf.h
+index 0175e00e8..3b76da816 100644
+--- a/servconf.h
++++ b/servconf.h
+@@ -125,8 +125,10 @@ 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;
+ int password_authentication; /* If true, permit password
+ * authentication. */
+ int kbd_interactive_authentication; /* If true, permit */
+diff --git a/ssh-gss.h b/ssh-gss.h
+index 36180d07a..350ce7882 100644
+--- a/ssh-gss.h
++++ b/ssh-gss.h
+@@ -1,6 +1,6 @@
+ /* $OpenBSD: ssh-gss.h,v 1.14 2018/07/10 09:13:30 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 +61,22 @@
+
+ #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_GEX_SHA1_ID "gss-gex-sha1-"
++
+ typedef struct {
+ char *filename;
+ char *envvar;
+ char *envval;
++ struct passwd *owner;
+ void *data;
+ } ssh_gssapi_ccache;
+
+@@ -72,8 +84,11 @@ 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 +99,7 @@ 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 +110,11 @@ 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);
+@@ -123,17 +140,33 @@ 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 *);
+-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 *);
++char *ssh_gssapi_kex_mechs(gss_OID_set, ssh_gssapi_check_fn *, 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 *);
+ 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_config b/ssh_config
+index c12f5ef52..bcb9f153d 100644
+--- a/ssh_config
++++ b/ssh_config
+@@ -24,6 +24,8 @@
+ # HostbasedAuthentication no
+ # GSSAPIAuthentication no
+ # GSSAPIDelegateCredentials no
++# GSSAPIKeyExchange no
++# GSSAPITrustDNS no
+ # BatchMode no
+ # CheckHostIP yes
+ # AddressFamily any
+diff --git a/ssh_config.5 b/ssh_config.5
+index 4d5b01d3e..16c79368a 100644
+--- a/ssh_config.5
++++ b/ssh_config.5
+@@ -736,10 +736,42 @@ The default is
+ Specifies whether user authentication based on GSSAPI is allowed.
+ 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
++.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 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 GSSAPIDelegateCredentials
+ Forward (delegate) credentials to the server.
+ The default is
+ .Cm no .
++.It Cm GSSAPIRenewalForcesRekey
++If set to
++.Cm yes
++then renewal of the client's GSSAPI credentials will force the rekeying of the
++ssh connection. With a compatible server, this can delegate the renewed
++credentials to a session on the server.
++The default is
++.Cm no .
++.It Cm GSSAPITrustDns
++Set to
++.Cm yes
++to indicate that the DNS is trusted to securely canonicalize
++the name of the host being connected to. If
++.Cm no ,
++the hostname entered on the
++command line will be passed untouched to the GSSAPI library.
++The default is
++.Cm no .
+ .It Cm HashKnownHosts
+ Indicates that
+ .Xr ssh 1
+diff --git a/sshconnect2.c b/sshconnect2.c
+index 1675f3935..8c872a4fb 100644
+--- a/sshconnect2.c
++++ b/sshconnect2.c
+@@ -162,6 +162,11 @@ ssh_kex2(char *host, struct sockaddr *hostaddr, u_short port)
+ struct kex *kex;
+ int r;
+
++#ifdef GSSAPI
++ char *orig = NULL, *gss = NULL;
++ char *gss_host = NULL;
++#endif
++
+ xxx_host = host;
+ xxx_hostaddr = hostaddr;
+
+@@ -194,6 +199,35 @@ ssh_kex2(char *host, struct sockaddr *hostaddr, u_short port)
+ order_hostkeyalgs(host, hostaddr, port));
+ }
+
++#ifdef GSSAPI
++ 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(active_state);
++ else
++ gss_host = xstrdup(host);
++
++ gss = ssh_gssapi_client_mechanisms(gss_host,
++ options.gss_client_identity);
++ 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
++
+ if (options.rekey_limit || options.rekey_interval)
+ packet_set_rekey_limits(options.rekey_limit,
+ options.rekey_interval);
+@@ -215,15 +249,41 @@ ssh_kex2(char *host, struct sockaddr *hostaddr, u_short port)
+ # endif
+ #endif
+ kex->kex[KEX_C25519_SHA256] = kexc25519_client;
++#ifdef GSSAPI
++ if (options.gss_keyex) {
++ kex->kex[KEX_GSS_GRP1_SHA1] = kexgss_client;
++ kex->kex[KEX_GSS_GRP14_SHA1] = kexgss_client;
++ kex->kex[KEX_GSS_GEX_SHA1] = kexgss_client;
++ }
++#endif
+ kex->client_version_string=client_version_string;
+ kex->server_version_string=server_version_string;
+ kex->verify_host_key=&verify_host_key_callback;
+
++#ifdef GSSAPI
++ if (options.gss_keyex) {
++ kex->gss_deleg_creds = options.gss_deleg_creds;
++ kex->gss_trust_dns = options.gss_trust_dns;
++ kex->gss_client = options.gss_client_identity;
++ kex->gss_host = gss_host;
++ }
++#endif
++
+ ssh_dispatch_run_fatal(active_state, DISPATCH_BLOCK, &kex->done);
+
+ /* remove ext-info from the KEX proposals for rekeying */
+ myproposal[PROPOSAL_KEX_ALGS] =
+ compat_kex_proposal(options.kex_algorithms);
++#ifdef GSSAPI
++ /* 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(kex->my, myproposal)) != 0)
+ fatal("kex_prop2buf: %s", ssh_err(r));
+
+@@ -314,6 +374,7 @@ int input_gssapi_token(int type, u_int32_t, struct ssh *);
+ int input_gssapi_hash(int type, u_int32_t, struct ssh *);
+ int input_gssapi_error(int, u_int32_t, struct ssh *);
+ int input_gssapi_errtok(int, u_int32_t, struct ssh *);
++int userauth_gsskeyex(Authctxt *authctxt);
+ #endif
+
+ void userauth(Authctxt *, char *);
+@@ -330,6 +391,11 @@ static char *authmethods_get(void);
+
+ Authmethod authmethods[] = {
+ #ifdef GSSAPI
++ {"gssapi-keyex",
++ userauth_gsskeyex,
++ NULL,
++ &options.gss_authentication,
++ NULL},
+ {"gssapi-with-mic",
+ userauth_gssapi,
+ NULL,
+@@ -686,25 +752,40 @@ userauth_gssapi(Authctxt *authctxt)
+ static u_int mech = 0;
+ OM_uint32 min;
+ int r, ok = 0;
++ char *gss_host;
++
++ if (options.gss_server_identity)
++ gss_host = xstrdup(options.gss_server_identity);
++ else if (options.gss_trust_dns)
++ gss_host = remote_hostname(active_state);
++ else
++ gss_host = xstrdup(authctxt->host);
+
+ /* Try one GSSAPI method at a time, rather than sending them all at
+ * once. */
+
+ if (gss_supported == NULL)
+- gss_indicate_mechs(&min, &gss_supported);
++ if (GSS_ERROR(gss_indicate_mechs(&min, &gss_supported))) {
++ gss_supported = NULL;
++ free(gss_host);
++ return 0;
++ }
+
+ /* Check to see if the mechanism is usable before we offer it */
+ while (mech < gss_supported->count && !ok) {
+ /* My DER encoding requires length<128 */
+ if (gss_supported->elements[mech].length < 128 &&
+ ssh_gssapi_check_mechanism(&gssctxt,
+- &gss_supported->elements[mech], authctxt->host)) {
++ &gss_supported->elements[mech], gss_host,
++ options.gss_client_identity)) {
+ ok = 1; /* Mechanism works */
+ } else {
+ mech++;
+ }
+ }
+
++ free(gss_host);
++
+ if (!ok)
+ return 0;
+
+@@ -935,6 +1016,54 @@ input_gssapi_error(int type, u_int32_t plen, struct ssh *ssh)
+ free(lang);
+ return r;
+ }
++
++int
++userauth_gsskeyex(Authctxt *authctxt)
++{
++ struct ssh *ssh = active_state; /* XXX */
++ struct sshbuf *b;
++ 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("%s: sshbuf_new failed", __func__);
++ ssh_gssapi_buildmic(b, authctxt->server_user, authctxt->service,
++ "gssapi-keyex");
++
++ if ((gssbuf.value = sshbuf_mutable_ptr(b)) == NULL)
++ fatal("%s: sshbuf_mutable_ptr failed", __func__);
++ 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("%s: %s", __func__, ssh_err(r));
++
++ sshbuf_free(b);
++ gss_release_buffer(&ms, &mic);
++
++ return (1);
++}
++
+ #endif /* GSSAPI */
+
+ int
+diff --git a/sshd.c b/sshd.c
+index ba26287ba..539a000fd 100644
+--- a/sshd.c
++++ b/sshd.c
+@@ -123,6 +123,10 @@
+ #include "version.h"
+ #include "ssherr.h"
+
++#ifdef USE_SECURITY_SESSION_API
++#include <Security/AuthSession.h>
++#endif
++
+ /* Re-exec fds */
+ #define REEXEC_DEVCRYPTO_RESERVED_FD (STDERR_FILENO + 1)
+ #define REEXEC_STARTUP_PIPE_FD (STDERR_FILENO + 2)
+@@ -1810,10 +1814,13 @@ main(int ac, char **av)
+ free(fp);
+ }
+ accumulate_host_timing_secret(cfg, NULL);
++#ifndef GSSAPI
++ /* The GSSAPI key exchange can run without a host key */
+ if (!sensitive_data.have_ssh2_key) {
+ logit("sshd: no hostkeys available -- exiting.");
+ exit(1);
+ }
++#endif
+
+ /*
+ * Load certificates. They are stored in an array at identical
+@@ -2104,6 +2111,60 @@ main(int ac, char **av)
+ rdomain == NULL ? "" : "\"");
+ free(laddr);
+
++#ifdef USE_SECURITY_SESSION_API
++ /*
++ * Create a new security session for use by the new user login if
++ * the current session is the root session or we are not launched
++ * by inetd (eg: debugging mode or server mode). We do not
++ * necessarily need to create a session if we are launched from
++ * inetd because Panther xinetd will create a session for us.
++ *
++ * The only case where this logic will fail is if there is an
++ * inetd running in a non-root session which is not creating
++ * new sessions for us. Then all the users will end up in the
++ * same session (bad).
++ *
++ * When the client exits, the session will be destroyed for us
++ * automatically.
++ *
++ * We must create the session before any credentials are stored
++ * (including AFS pags, which happens a few lines below).
++ */
++ {
++ OSStatus err = 0;
++ SecuritySessionId sid = 0;
++ SessionAttributeBits sattrs = 0;
++
++ err = SessionGetInfo(callerSecuritySession, &sid, &sattrs);
++ if (err)
++ error("SessionGetInfo() failed with error %.8X",
++ (unsigned) err);
++ else
++ debug("Current Session ID is %.8X / Session Attributes are %.8X",
++ (unsigned) sid, (unsigned) sattrs);
++
++ if (inetd_flag && !(sattrs & sessionIsRoot))
++ debug("Running in inetd mode in a non-root session... "
++ "assuming inetd created the session for us.");
++ else {
++ debug("Creating new security session...");
++ err = SessionCreate(0, sessionHasTTY | sessionIsRemote);
++ if (err)
++ error("SessionCreate() failed with error %.8X",
++ (unsigned) err);
++
++ err = SessionGetInfo(callerSecuritySession, &sid,
++ &sattrs);
++ if (err)
++ error("SessionGetInfo() failed with error %.8X",
++ (unsigned) err);
++ else
++ debug("New Session ID is %.8X / Session Attributes are %.8X",
++ (unsigned) sid, (unsigned) sattrs);
++ }
++ }
++#endif
++
+ /*
+ * We don't want to listen forever unless the other side
+ * successfully authenticates itself. So we set up an alarm which is
+@@ -2287,6 +2348,48 @@ do_ssh2_kex(void)
+ myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = compat_pkalg_proposal(
+ list_hostkey_types());
+
++#ifdef GSSAPI
++ {
++ 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(active_state, myproposal)) != 0)
+ fatal("kex_setup: %s", ssh_err(r));
+@@ -2304,6 +2407,13 @@ do_ssh2_kex(void)
+ # endif
+ #endif
+ kex->kex[KEX_C25519_SHA256] = kexc25519_server;
++#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_GEX_SHA1] = kexgss_server;
++ }
++#endif
+ kex->server = 1;
+ kex->client_version_string=client_version_string;
+ kex->server_version_string=server_version_string;
+diff --git a/sshd_config b/sshd_config
+index 19b7c91a1..2c48105f8 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 c6484370b..985eef5a2 100644
+--- a/sshd_config.5
++++ b/sshd_config.5
+@@ -648,6 +648,11 @@ The default is
+ Specifies whether user authentication based on GSSAPI is allowed.
+ The default is
+ .Cm no .
++.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 GSSAPICleanupCredentials
+ Specifies whether to automatically destroy the user's credentials cache
+ on logout.
+@@ -667,6 +672,11 @@ 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
++.Cm no .
+ .It Cm HostbasedAcceptedKeyTypes
+ Specifies the key types that will be accepted for hostbased authentication
+ as a list of comma-separated patterns.
+diff --git a/sshkey.c b/sshkey.c
+index 6555c5ef8..a85c185fc 100644
+--- a/sshkey.c
++++ b/sshkey.c
+@@ -135,6 +135,7 @@ static const struct keytype keytypes[] = {
+ # endif /* OPENSSL_HAS_NISTP521 */
+ # endif /* OPENSSL_HAS_ECC */
+ #endif /* WITH_OPENSSL */
++ { "null", "null", NULL, KEY_NULL, 0, 0, 0 },
+ { NULL, NULL, NULL, -1, -1, 0, 0 }
+ };
+
+@@ -223,7 +224,7 @@ sshkey_alg_list(int certs_only, int plain_only, int include_sigonly, char sep)
+ const struct keytype *kt;
+
+ for (kt = keytypes; kt->type != -1; kt++) {
+- if (kt->name == NULL)
++ if (kt->name == NULL || kt->type == KEY_NULL)
+ continue;
+ if (!include_sigonly && kt->sigonly)
+ continue;
+diff --git a/sshkey.h b/sshkey.h
+index f6a007fdf..f54deb0c0 100644
+--- a/sshkey.h
++++ b/sshkey.h
+@@ -64,6 +64,7 @@ enum sshkey_types {
+ KEY_ED25519_CERT,
+ KEY_XMSS,
+ KEY_XMSS_CERT,
++ KEY_NULL,
+ KEY_UNSPEC
+ };
+