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Diffstat (limited to 'compat.c')
| -rw-r--r-- | compat.c | 166 |
1 files changed, 166 insertions, 0 deletions
diff --git a/compat.c b/compat.c new file mode 100644 index 0000000..b59f0bf --- /dev/null +++ b/compat.c @@ -0,0 +1,166 @@ +/* $OpenBSD: compat.c,v 1.126 2023/03/06 12:14:48 dtucker Exp $ */ +/* + * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. 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" + +#include <sys/types.h> + +#include <stdlib.h> +#include <string.h> +#include <stdarg.h> + +#include "xmalloc.h" +#include "packet.h" +#include "compat.h" +#include "log.h" +#include "match.h" + +/* determine bug flags from SSH protocol banner */ +void +compat_banner(struct ssh *ssh, const char *version) +{ + int i; + static struct { + char *pat; + int bugs; + } check[] = { + { "OpenSSH_2.*," + "OpenSSH_3.0*," + "OpenSSH_3.1*", SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR| + SSH_BUG_SIGTYPE}, + { "OpenSSH_3.*", SSH_OLD_FORWARD_ADDR|SSH_BUG_SIGTYPE }, + { "Sun_SSH_1.0*", SSH_BUG_NOREKEY|SSH_BUG_EXTEOF| + SSH_BUG_SIGTYPE}, + { "OpenSSH_2*," + "OpenSSH_3*," + "OpenSSH_4*", SSH_BUG_SIGTYPE }, + { "OpenSSH_5*", SSH_NEW_OPENSSH|SSH_BUG_DYNAMIC_RPORT| + SSH_BUG_SIGTYPE}, + { "OpenSSH_6.6.1*", SSH_NEW_OPENSSH|SSH_BUG_SIGTYPE}, + { "OpenSSH_6.5*," + "OpenSSH_6.6*", SSH_NEW_OPENSSH|SSH_BUG_CURVE25519PAD| + SSH_BUG_SIGTYPE}, + { "OpenSSH_7.4*", SSH_NEW_OPENSSH|SSH_BUG_SIGTYPE| + SSH_BUG_SIGTYPE74}, + { "OpenSSH_7.0*," + "OpenSSH_7.1*," + "OpenSSH_7.2*," + "OpenSSH_7.3*," + "OpenSSH_7.5*," + "OpenSSH_7.6*," + "OpenSSH_7.7*", SSH_NEW_OPENSSH|SSH_BUG_SIGTYPE}, + { "OpenSSH*", SSH_NEW_OPENSSH }, + { "*MindTerm*", 0 }, + { "3.0.*", SSH_BUG_DEBUG }, + { "3.0 SecureCRT*", SSH_OLD_SESSIONID }, + { "1.7 SecureFX*", SSH_OLD_SESSIONID }, + { "Cisco-1.*", SSH_BUG_DHGEX_LARGE| + SSH_BUG_HOSTKEYS }, + { "*SSH_Version_Mapper*", + SSH_BUG_SCANNER }, + { "PuTTY_Local:*," /* dev versions < Sep 2014 */ + "PuTTY-Release-0.5*," /* 0.50-0.57, DH-GEX in >=0.52 */ + "PuTTY_Release_0.5*," /* 0.58-0.59 */ + "PuTTY_Release_0.60*," + "PuTTY_Release_0.61*," + "PuTTY_Release_0.62*," + "PuTTY_Release_0.63*," + "PuTTY_Release_0.64*", + SSH_OLD_DHGEX }, + { "FuTTY*", SSH_OLD_DHGEX }, /* Putty Fork */ + { "Probe-*", + SSH_BUG_PROBE }, + { "TeraTerm SSH*," + "TTSSH/1.5.*," + "TTSSH/2.1*," + "TTSSH/2.2*," + "TTSSH/2.3*," + "TTSSH/2.4*," + "TTSSH/2.5*," + "TTSSH/2.6*," + "TTSSH/2.70*," + "TTSSH/2.71*," + "TTSSH/2.72*", SSH_BUG_HOSTKEYS }, + { "WinSCP_release_4*," + "WinSCP_release_5.0*," + "WinSCP_release_5.1," + "WinSCP_release_5.1.*," + "WinSCP_release_5.5," + "WinSCP_release_5.5.*," + "WinSCP_release_5.6," + "WinSCP_release_5.6.*," + "WinSCP_release_5.7," + "WinSCP_release_5.7.1," + "WinSCP_release_5.7.2," + "WinSCP_release_5.7.3," + "WinSCP_release_5.7.4", + SSH_OLD_DHGEX }, + { "ConfD-*", + SSH_BUG_UTF8TTYMODE }, + { "Twisted_*", 0 }, + { "Twisted*", SSH_BUG_DEBUG }, + { NULL, 0 } + }; + + /* process table, return first match */ + ssh->compat = 0; + for (i = 0; check[i].pat; i++) { + if (match_pattern_list(version, check[i].pat, 0) == 1) { + debug_f("match: %s pat %s compat 0x%08x", + version, check[i].pat, check[i].bugs); + ssh->compat = check[i].bugs; + return; + } + } + debug_f("no match: %s", version); +} + +/* Always returns pointer to allocated memory, caller must free. */ +char * +compat_kex_proposal(struct ssh *ssh, const char *p) +{ + char *cp = NULL, *cp2 = NULL; + + if ((ssh->compat & (SSH_BUG_CURVE25519PAD|SSH_OLD_DHGEX)) == 0) + return xstrdup(p); + debug2_f("original KEX proposal: %s", p); + if ((ssh->compat & SSH_BUG_CURVE25519PAD) != 0) + if ((cp = match_filter_denylist(p, + "curve25519-sha256@libssh.org")) == NULL) + fatal("match_filter_denylist failed"); + if ((ssh->compat & SSH_OLD_DHGEX) != 0) { + if ((cp2 = match_filter_denylist(cp ? cp : p, + "diffie-hellman-group-exchange-sha256," + "diffie-hellman-group-exchange-sha1")) == NULL) + fatal("match_filter_denylist failed"); + free(cp); + cp = cp2; + } + if (cp == NULL || *cp == '\0') + fatal("No supported key exchange algorithms found"); + debug2_f("compat KEX proposal: %s", cp); + return cp; +} + |