Coverage Report

Created: 2025-06-20 06:24

/src/openssh/compat.c
Line
Count
Source (jump to first uncovered line)
1
/* $OpenBSD: compat.c,v 1.126 2023/03/06 12:14:48 dtucker Exp $ */
2
/*
3
 * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl.  All rights reserved.
4
 *
5
 * Redistribution and use in source and binary forms, with or without
6
 * modification, are permitted provided that the following conditions
7
 * are met:
8
 * 1. Redistributions of source code must retain the above copyright
9
 *    notice, this list of conditions and the following disclaimer.
10
 * 2. Redistributions in binary form must reproduce the above copyright
11
 *    notice, this list of conditions and the following disclaimer in the
12
 *    documentation and/or other materials provided with the distribution.
13
 *
14
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
15
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
18
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24
 */
25
26
#include "includes.h"
27
28
#include <sys/types.h>
29
30
#include <stdlib.h>
31
#include <string.h>
32
#include <stdarg.h>
33
34
#include "xmalloc.h"
35
#include "packet.h"
36
#include "compat.h"
37
#include "log.h"
38
#include "match.h"
39
40
/* determine bug flags from SSH protocol banner */
41
void
42
compat_banner(struct ssh *ssh, const char *version)
43
91.4k
{
44
91.4k
  int i;
45
91.4k
  static struct {
46
91.4k
    char  *pat;
47
91.4k
    int bugs;
48
91.4k
  } check[] = {
49
91.4k
    { "OpenSSH_2.*,"
50
91.4k
      "OpenSSH_3.0*,"
51
91.4k
      "OpenSSH_3.1*", SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR|
52
91.4k
          SSH_BUG_SIGTYPE},
53
91.4k
    { "OpenSSH_3.*",  SSH_OLD_FORWARD_ADDR|SSH_BUG_SIGTYPE },
54
91.4k
    { "Sun_SSH_1.0*", SSH_BUG_NOREKEY|SSH_BUG_EXTEOF|
55
91.4k
          SSH_BUG_SIGTYPE},
56
91.4k
    { "OpenSSH_2*,"
57
91.4k
      "OpenSSH_3*,"
58
91.4k
      "OpenSSH_4*",   SSH_BUG_SIGTYPE },
59
91.4k
    { "OpenSSH_5*",   SSH_NEW_OPENSSH|SSH_BUG_DYNAMIC_RPORT|
60
91.4k
          SSH_BUG_SIGTYPE},
61
91.4k
    { "OpenSSH_6.6.1*", SSH_NEW_OPENSSH|SSH_BUG_SIGTYPE},
62
91.4k
    { "OpenSSH_6.5*,"
63
91.4k
      "OpenSSH_6.6*", SSH_NEW_OPENSSH|SSH_BUG_CURVE25519PAD|
64
91.4k
          SSH_BUG_SIGTYPE},
65
91.4k
    { "OpenSSH_7.4*", SSH_NEW_OPENSSH|SSH_BUG_SIGTYPE|
66
91.4k
          SSH_BUG_SIGTYPE74},
67
91.4k
    { "OpenSSH_7.0*,"
68
91.4k
      "OpenSSH_7.1*,"
69
91.4k
      "OpenSSH_7.2*,"
70
91.4k
      "OpenSSH_7.3*,"
71
91.4k
      "OpenSSH_7.5*,"
72
91.4k
      "OpenSSH_7.6*,"
73
91.4k
      "OpenSSH_7.7*", SSH_NEW_OPENSSH|SSH_BUG_SIGTYPE},
74
91.4k
    { "OpenSSH*",   SSH_NEW_OPENSSH },
75
91.4k
    { "*MindTerm*",   0 },
76
91.4k
    { "3.0.*",    SSH_BUG_DEBUG },
77
91.4k
    { "3.0 SecureCRT*", SSH_OLD_SESSIONID },
78
91.4k
    { "1.7 SecureFX*",  SSH_OLD_SESSIONID },
79
91.4k
    { "Cisco-1.*",    SSH_BUG_DHGEX_LARGE|
80
91.4k
          SSH_BUG_HOSTKEYS },
81
91.4k
    { "*SSH_Version_Mapper*",
82
91.4k
          SSH_BUG_SCANNER },
83
91.4k
    { "PuTTY_Local:*,"  /* dev versions < Sep 2014 */
84
91.4k
      "PuTTY-Release-0.5*," /* 0.50-0.57, DH-GEX in >=0.52 */
85
91.4k
      "PuTTY_Release_0.5*," /* 0.58-0.59 */
86
91.4k
      "PuTTY_Release_0.60*,"
87
91.4k
      "PuTTY_Release_0.61*,"
88
91.4k
      "PuTTY_Release_0.62*,"
89
91.4k
      "PuTTY_Release_0.63*,"
90
91.4k
      "PuTTY_Release_0.64*",
91
91.4k
          SSH_OLD_DHGEX },
92
91.4k
    { "FuTTY*",   SSH_OLD_DHGEX }, /* Putty Fork */
93
91.4k
    { "Probe-*",
94
91.4k
          SSH_BUG_PROBE },
95
91.4k
    { "TeraTerm SSH*,"
96
91.4k
      "TTSSH/1.5.*,"
97
91.4k
      "TTSSH/2.1*,"
98
91.4k
      "TTSSH/2.2*,"
99
91.4k
      "TTSSH/2.3*,"
100
91.4k
      "TTSSH/2.4*,"
101
91.4k
      "TTSSH/2.5*,"
102
91.4k
      "TTSSH/2.6*,"
103
91.4k
      "TTSSH/2.70*,"
104
91.4k
      "TTSSH/2.71*,"
105
91.4k
      "TTSSH/2.72*",  SSH_BUG_HOSTKEYS },
106
91.4k
    { "WinSCP_release_4*,"
107
91.4k
      "WinSCP_release_5.0*,"
108
91.4k
      "WinSCP_release_5.1,"
109
91.4k
      "WinSCP_release_5.1.*,"
110
91.4k
      "WinSCP_release_5.5,"
111
91.4k
      "WinSCP_release_5.5.*,"
112
91.4k
      "WinSCP_release_5.6,"
113
91.4k
      "WinSCP_release_5.6.*,"
114
91.4k
      "WinSCP_release_5.7,"
115
91.4k
      "WinSCP_release_5.7.1,"
116
91.4k
      "WinSCP_release_5.7.2,"
117
91.4k
      "WinSCP_release_5.7.3,"
118
91.4k
      "WinSCP_release_5.7.4",
119
91.4k
          SSH_OLD_DHGEX },
120
91.4k
    { "ConfD-*",
121
91.4k
          SSH_BUG_UTF8TTYMODE },
122
91.4k
    { "Twisted_*",    0 },
123
91.4k
    { "Twisted*",   SSH_BUG_DEBUG },
124
91.4k
    { NULL,     0 }
125
91.4k
  };
126
127
  /* process table, return first match */
128
91.4k
  ssh->compat = 0;
129
2.08M
  for (i = 0; check[i].pat; i++) {
130
2.00M
    if (match_pattern_list(version, check[i].pat, 0) == 1) {
131
13.0k
      debug_f("match: %s pat %s compat 0x%08x",
132
13.0k
          version, check[i].pat, check[i].bugs);
133
13.0k
      ssh->compat = check[i].bugs;
134
13.0k
      return;
135
13.0k
    }
136
2.00M
  }
137
78.4k
  debug_f("no match: %s", version);
138
78.4k
}
139
140
/* Always returns pointer to allocated memory, caller must free. */
141
char *
142
compat_kex_proposal(struct ssh *ssh, const char *p)
143
179k
{
144
179k
  char *cp = NULL, *cp2 = NULL;
145
146
179k
  if ((ssh->compat & (SSH_BUG_CURVE25519PAD|SSH_OLD_DHGEX)) == 0)
147
179k
    return xstrdup(p);
148
0
  debug2_f("original KEX proposal: %s", p);
149
0
  if ((ssh->compat & SSH_BUG_CURVE25519PAD) != 0)
150
0
    if ((cp = match_filter_denylist(p,
151
0
        "curve25519-sha256@libssh.org")) == NULL)
152
0
      fatal("match_filter_denylist failed");
153
0
  if ((ssh->compat & SSH_OLD_DHGEX) != 0) {
154
0
    if ((cp2 = match_filter_denylist(cp ? cp : p,
155
0
        "diffie-hellman-group-exchange-sha256,"
156
0
        "diffie-hellman-group-exchange-sha1")) == NULL)
157
0
      fatal("match_filter_denylist failed");
158
0
    free(cp);
159
0
    cp = cp2;
160
0
  }
161
0
  if (cp == NULL || *cp == '\0')
162
0
    fatal("No supported key exchange algorithms found");
163
0
  debug2_f("compat KEX proposal: %s", cp);
164
0
  return cp;
165
0
}
166