Annotation of src/usr.bin/ssh/compat.c, Revision 1.117
1.117 ! djm 1: /* $OpenBSD: compat.c,v 1.116 2020/10/18 11:32:01 djm Exp $ */
1.5 markus 2: /*
1.61 markus 3: * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved.
1.5 markus 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:
1.76 deraadt 26: #include <sys/types.h>
1.74 stevesk 27:
1.75 stevesk 28: #include <stdlib.h>
1.74 stevesk 29: #include <string.h>
1.76 deraadt 30: #include <stdarg.h>
1.2 markus 31:
1.76 deraadt 32: #include "xmalloc.h"
1.6 markus 33: #include "packet.h"
1.10 markus 34: #include "compat.h"
1.34 markus 35: #include "log.h"
1.55 markus 36: #include "match.h"
1.100 djm 37: #include "kex.h"
1.1 markus 38:
1.117 ! djm 39: /* determine bug flags from SSH protocol banner */
! 40: void
! 41: compat_banner(struct ssh *ssh, const char *version)
1.6 markus 42: {
1.55 markus 43: int i;
1.24 markus 44: static struct {
45: char *pat;
1.13 markus 46: int bugs;
47: } check[] = {
1.62 markus 48: { "OpenSSH_2.*,"
49: "OpenSSH_3.0*,"
1.108 djm 50: "OpenSSH_3.1*", SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR|
51: SSH_BUG_SIGTYPE},
52: { "OpenSSH_3.*", SSH_OLD_FORWARD_ADDR|SSH_BUG_SIGTYPE },
53: { "Sun_SSH_1.0*", SSH_BUG_NOREKEY|SSH_BUG_EXTEOF|
54: SSH_BUG_SIGTYPE},
1.105 djm 55: { "OpenSSH_2*,"
56: "OpenSSH_3*,"
1.108 djm 57: "OpenSSH_4*", SSH_BUG_SIGTYPE },
58: { "OpenSSH_5*", SSH_NEW_OPENSSH|SSH_BUG_DYNAMIC_RPORT|
59: SSH_BUG_SIGTYPE},
60: { "OpenSSH_6.6.1*", SSH_NEW_OPENSSH|SSH_BUG_SIGTYPE},
1.83 djm 61: { "OpenSSH_6.5*,"
1.108 djm 62: "OpenSSH_6.6*", SSH_NEW_OPENSSH|SSH_BUG_CURVE25519PAD|
63: SSH_BUG_SIGTYPE},
64: { "OpenSSH_7.0*,"
65: "OpenSSH_7.1*,"
66: "OpenSSH_7.2*,"
67: "OpenSSH_7.3*,"
68: "OpenSSH_7.4*,"
69: "OpenSSH_7.5*,"
1.109 djm 70: "OpenSSH_7.6*,"
71: "OpenSSH_7.7*", SSH_NEW_OPENSSH|SSH_BUG_SIGTYPE},
1.78 markus 72: { "OpenSSH*", SSH_NEW_OPENSSH },
1.55 markus 73: { "*MindTerm*", 0 },
74: { "3.0.*", SSH_BUG_DEBUG },
75: { "3.0 SecureCRT*", SSH_OLD_SESSIONID },
76: { "1.7 SecureFX*", SSH_OLD_SESSIONID },
77: { "1.2.18*,"
78: "1.2.19*,"
79: "1.2.20*,"
80: "1.2.21*,"
1.69 markus 81: "1.2.22*", SSH_BUG_IGNOREMSG },
1.63 markus 82: { "1.3.2*", /* F-Secure */
1.69 markus 83: SSH_BUG_IGNOREMSG },
1.96 djm 84: { "Cisco-1.*", SSH_BUG_DHGEX_LARGE|
85: SSH_BUG_HOSTKEYS },
1.55 markus 86: { "*SSH Compatible Server*", /* Netscreen */
1.38 deraadt 87: SSH_BUG_PASSWORDPAD },
1.56 deraadt 88: { "*OSU_0*,"
1.55 markus 89: "OSU_1.0*,"
90: "OSU_1.1*,"
91: "OSU_1.2*,"
92: "OSU_1.3*,"
93: "OSU_1.4*,"
94: "OSU_1.5alpha1*,"
95: "OSU_1.5alpha2*,"
96: "OSU_1.5alpha3*", SSH_BUG_PASSWORDPAD },
97: { "*SSH_Version_Mapper*",
1.39 deraadt 98: SSH_BUG_SCANNER },
1.95 dtucker 99: { "PuTTY_Local:*," /* dev versions < Sep 2014 */
100: "PuTTY-Release-0.5*," /* 0.50-0.57, DH-GEX in >=0.52 */
1.93 dtucker 101: "PuTTY_Release_0.5*," /* 0.58-0.59 */
102: "PuTTY_Release_0.60*,"
103: "PuTTY_Release_0.61*,"
104: "PuTTY_Release_0.62*,"
105: "PuTTY_Release_0.63*,"
106: "PuTTY_Release_0.64*",
107: SSH_OLD_DHGEX },
1.97 djm 108: { "FuTTY*", SSH_OLD_DHGEX }, /* Putty Fork */
1.65 mickey 109: { "Probe-*",
110: SSH_BUG_PROBE },
1.89 dtucker 111: { "TeraTerm SSH*,"
112: "TTSSH/1.5.*,"
113: "TTSSH/2.1*,"
114: "TTSSH/2.2*,"
115: "TTSSH/2.3*,"
116: "TTSSH/2.4*,"
117: "TTSSH/2.5*,"
118: "TTSSH/2.6*,"
119: "TTSSH/2.70*,"
120: "TTSSH/2.71*,"
121: "TTSSH/2.72*", SSH_BUG_HOSTKEYS },
1.97 djm 122: { "WinSCP_release_4*,"
123: "WinSCP_release_5.0*,"
1.104 dtucker 124: "WinSCP_release_5.1,"
125: "WinSCP_release_5.1.*,"
126: "WinSCP_release_5.5,"
127: "WinSCP_release_5.5.*,"
128: "WinSCP_release_5.6,"
129: "WinSCP_release_5.6.*,"
1.97 djm 130: "WinSCP_release_5.7,"
131: "WinSCP_release_5.7.1,"
132: "WinSCP_release_5.7.2,"
133: "WinSCP_release_5.7.3,"
134: "WinSCP_release_5.7.4",
135: SSH_OLD_DHGEX },
1.106 dtucker 136: { "ConfD-*",
137: SSH_BUG_UTF8TTYMODE },
1.107 djm 138: { "Twisted_*", 0 },
139: { "Twisted*", SSH_BUG_DEBUG },
1.25 markus 140: { NULL, 0 }
1.6 markus 141: };
1.55 markus 142:
1.21 markus 143: /* process table, return first match */
1.117 ! djm 144: ssh->compat = 0;
1.24 markus 145: for (i = 0; check[i].pat; i++) {
1.91 djm 146: if (match_pattern_list(version, check[i].pat, 0) == 1) {
1.117 ! djm 147: debug_f("match: %s pat %s compat 0x%08x",
1.87 markus 148: version, check[i].pat, check[i].bugs);
1.117 ! djm 149: ssh->compat = check[i].bugs;
! 150: return;
1.6 markus 151: }
152: }
1.117 ! djm 153: debug_f("no match: %s", version);
1.40 djm 154: }
155:
1.82 djm 156: char *
1.117 ! djm 157: compat_cipher_proposal(struct ssh *ssh, char *cipher_prop)
1.82 djm 158: {
1.117 ! djm 159: if (!(ssh->compat & SSH_BUG_BIGENDIANAES))
1.82 djm 160: return cipher_prop;
1.116 djm 161: debug2_f("original cipher proposal: %s", cipher_prop);
1.115 djm 162: if ((cipher_prop = match_filter_denylist(cipher_prop, "aes*")) == NULL)
163: fatal("match_filter_denylist failed");
1.116 djm 164: debug2_f("compat cipher proposal: %s", cipher_prop);
1.82 djm 165: if (*cipher_prop == '\0')
166: fatal("No supported ciphers found");
167: return cipher_prop;
168: }
169:
170: char *
1.117 ! djm 171: compat_pkalg_proposal(struct ssh *ssh, char *pkalg_prop)
1.82 djm 172: {
1.117 ! djm 173: if (!(ssh->compat & SSH_BUG_RSASIGMD5))
1.82 djm 174: return pkalg_prop;
1.116 djm 175: debug2_f("original public key proposal: %s", pkalg_prop);
1.115 djm 176: if ((pkalg_prop = match_filter_denylist(pkalg_prop, "ssh-rsa")) == NULL)
177: fatal("match_filter_denylist failed");
1.116 djm 178: debug2_f("compat public key proposal: %s", pkalg_prop);
1.82 djm 179: if (*pkalg_prop == '\0')
180: fatal("No supported PK algorithms found");
181: return pkalg_prop;
1.83 djm 182: }
183:
184: char *
1.117 ! djm 185: compat_kex_proposal(struct ssh *ssh, char *p)
1.83 djm 186: {
1.117 ! djm 187: if ((ssh->compat & (SSH_BUG_CURVE25519PAD|SSH_OLD_DHGEX)) == 0)
1.113 djm 188: return p;
1.116 djm 189: debug2_f("original KEX proposal: %s", p);
1.117 ! djm 190: if ((ssh->compat & SSH_BUG_CURVE25519PAD) != 0)
1.115 djm 191: if ((p = match_filter_denylist(p,
1.100 djm 192: "curve25519-sha256@libssh.org")) == NULL)
1.115 djm 193: fatal("match_filter_denylist failed");
1.117 ! djm 194: if ((ssh->compat & SSH_OLD_DHGEX) != 0) {
1.115 djm 195: if ((p = match_filter_denylist(p,
1.100 djm 196: "diffie-hellman-group-exchange-sha256,"
197: "diffie-hellman-group-exchange-sha1")) == NULL)
1.115 djm 198: fatal("match_filter_denylist failed");
1.90 djm 199: }
1.116 djm 200: debug2_f("compat KEX proposal: %s", p);
1.113 djm 201: if (*p == '\0')
1.83 djm 202: fatal("No supported key exchange algorithms found");
1.113 djm 203: return p;
1.82 djm 204: }
205: