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- /* $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;
- }
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