Annotation of src/usr.bin/ssh/compat.c, Revision 1.122
1.122 ! dtucker 1: /* $OpenBSD: compat.c,v 1.121 2023/02/02 12:10:05 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},
1.118 djm 64: { "OpenSSH_7.4*", SSH_NEW_OPENSSH|SSH_BUG_SIGTYPE|
65: SSH_BUG_SIGTYPE74},
1.108 djm 66: { "OpenSSH_7.0*,"
67: "OpenSSH_7.1*,"
68: "OpenSSH_7.2*,"
69: "OpenSSH_7.3*,"
70: "OpenSSH_7.5*,"
1.109 djm 71: "OpenSSH_7.6*,"
72: "OpenSSH_7.7*", SSH_NEW_OPENSSH|SSH_BUG_SIGTYPE},
1.78 markus 73: { "OpenSSH*", SSH_NEW_OPENSSH },
1.55 markus 74: { "*MindTerm*", 0 },
75: { "3.0.*", SSH_BUG_DEBUG },
76: { "3.0 SecureCRT*", SSH_OLD_SESSIONID },
77: { "1.7 SecureFX*", SSH_OLD_SESSIONID },
1.96 djm 78: { "Cisco-1.*", SSH_BUG_DHGEX_LARGE|
79: SSH_BUG_HOSTKEYS },
1.55 markus 80: { "*SSH Compatible Server*", /* Netscreen */
1.38 deraadt 81: SSH_BUG_PASSWORDPAD },
1.56 deraadt 82: { "*OSU_0*,"
1.55 markus 83: "OSU_1.0*,"
84: "OSU_1.1*,"
85: "OSU_1.2*,"
86: "OSU_1.3*,"
87: "OSU_1.4*,"
88: "OSU_1.5alpha1*,"
89: "OSU_1.5alpha2*,"
90: "OSU_1.5alpha3*", SSH_BUG_PASSWORDPAD },
91: { "*SSH_Version_Mapper*",
1.39 deraadt 92: SSH_BUG_SCANNER },
1.95 dtucker 93: { "PuTTY_Local:*," /* dev versions < Sep 2014 */
94: "PuTTY-Release-0.5*," /* 0.50-0.57, DH-GEX in >=0.52 */
1.93 dtucker 95: "PuTTY_Release_0.5*," /* 0.58-0.59 */
96: "PuTTY_Release_0.60*,"
97: "PuTTY_Release_0.61*,"
98: "PuTTY_Release_0.62*,"
99: "PuTTY_Release_0.63*,"
100: "PuTTY_Release_0.64*",
101: SSH_OLD_DHGEX },
1.97 djm 102: { "FuTTY*", SSH_OLD_DHGEX }, /* Putty Fork */
1.65 mickey 103: { "Probe-*",
104: SSH_BUG_PROBE },
1.89 dtucker 105: { "TeraTerm SSH*,"
106: "TTSSH/1.5.*,"
107: "TTSSH/2.1*,"
108: "TTSSH/2.2*,"
109: "TTSSH/2.3*,"
110: "TTSSH/2.4*,"
111: "TTSSH/2.5*,"
112: "TTSSH/2.6*,"
113: "TTSSH/2.70*,"
114: "TTSSH/2.71*,"
115: "TTSSH/2.72*", SSH_BUG_HOSTKEYS },
1.97 djm 116: { "WinSCP_release_4*,"
117: "WinSCP_release_5.0*,"
1.104 dtucker 118: "WinSCP_release_5.1,"
119: "WinSCP_release_5.1.*,"
120: "WinSCP_release_5.5,"
121: "WinSCP_release_5.5.*,"
122: "WinSCP_release_5.6,"
123: "WinSCP_release_5.6.*,"
1.97 djm 124: "WinSCP_release_5.7,"
125: "WinSCP_release_5.7.1,"
126: "WinSCP_release_5.7.2,"
127: "WinSCP_release_5.7.3,"
128: "WinSCP_release_5.7.4",
129: SSH_OLD_DHGEX },
1.106 dtucker 130: { "ConfD-*",
131: SSH_BUG_UTF8TTYMODE },
1.107 djm 132: { "Twisted_*", 0 },
133: { "Twisted*", SSH_BUG_DEBUG },
1.25 markus 134: { NULL, 0 }
1.6 markus 135: };
1.55 markus 136:
1.21 markus 137: /* process table, return first match */
1.117 djm 138: ssh->compat = 0;
1.24 markus 139: for (i = 0; check[i].pat; i++) {
1.91 djm 140: if (match_pattern_list(version, check[i].pat, 0) == 1) {
1.117 djm 141: debug_f("match: %s pat %s compat 0x%08x",
1.87 markus 142: version, check[i].pat, check[i].bugs);
1.117 djm 143: ssh->compat = check[i].bugs;
144: return;
1.6 markus 145: }
146: }
1.117 djm 147: debug_f("no match: %s", version);
1.40 djm 148: }
149:
1.120 dtucker 150: /* Always returns pointer to allocated memory, caller must free. */
1.82 djm 151: char *
1.117 djm 152: compat_cipher_proposal(struct ssh *ssh, char *cipher_prop)
1.82 djm 153: {
1.117 djm 154: if (!(ssh->compat & SSH_BUG_BIGENDIANAES))
1.120 dtucker 155: return xstrdup(cipher_prop);
1.116 djm 156: debug2_f("original cipher proposal: %s", cipher_prop);
1.115 djm 157: if ((cipher_prop = match_filter_denylist(cipher_prop, "aes*")) == NULL)
158: fatal("match_filter_denylist failed");
1.116 djm 159: debug2_f("compat cipher proposal: %s", cipher_prop);
1.82 djm 160: if (*cipher_prop == '\0')
161: fatal("No supported ciphers found");
162: return cipher_prop;
163: }
164:
1.120 dtucker 165: /* Always returns pointer to allocated memory, caller must free. */
1.82 djm 166: char *
1.117 djm 167: compat_pkalg_proposal(struct ssh *ssh, char *pkalg_prop)
1.82 djm 168: {
1.117 djm 169: if (!(ssh->compat & SSH_BUG_RSASIGMD5))
1.120 dtucker 170: return xstrdup(pkalg_prop);
1.116 djm 171: debug2_f("original public key proposal: %s", pkalg_prop);
1.115 djm 172: if ((pkalg_prop = match_filter_denylist(pkalg_prop, "ssh-rsa")) == NULL)
173: fatal("match_filter_denylist failed");
1.116 djm 174: debug2_f("compat public key proposal: %s", pkalg_prop);
1.82 djm 175: if (*pkalg_prop == '\0')
176: fatal("No supported PK algorithms found");
177: return pkalg_prop;
1.83 djm 178: }
179:
1.120 dtucker 180: /* Always returns pointer to allocated memory, caller must free. */
1.83 djm 181: char *
1.117 djm 182: compat_kex_proposal(struct ssh *ssh, char *p)
1.83 djm 183: {
1.121 djm 184: char *cp = NULL, *cp2 = NULL;
1.120 dtucker 185:
1.117 djm 186: if ((ssh->compat & (SSH_BUG_CURVE25519PAD|SSH_OLD_DHGEX)) == 0)
1.120 dtucker 187: return xstrdup(p);
1.116 djm 188: debug2_f("original KEX proposal: %s", p);
1.117 djm 189: if ((ssh->compat & SSH_BUG_CURVE25519PAD) != 0)
1.121 djm 190: if ((cp = match_filter_denylist(p,
1.100 djm 191: "curve25519-sha256@libssh.org")) == NULL)
1.115 djm 192: fatal("match_filter_denylist failed");
1.117 djm 193: if ((ssh->compat & SSH_OLD_DHGEX) != 0) {
1.121 djm 194: if ((cp2 = match_filter_denylist(cp ? cp : p,
1.100 djm 195: "diffie-hellman-group-exchange-sha256,"
196: "diffie-hellman-group-exchange-sha1")) == NULL)
1.115 djm 197: fatal("match_filter_denylist failed");
1.120 dtucker 198: free(cp);
1.121 djm 199: cp = cp2;
1.90 djm 200: }
1.121 djm 201: if (cp == NULL || *cp == '\0')
1.83 djm 202: fatal("No supported key exchange algorithms found");
1.121 djm 203: debug2_f("compat KEX proposal: %s", cp);
204: return cp;
1.82 djm 205: }
206: