Annotation of src/usr.bin/ssh/compat.c, Revision 1.91
1.91 ! djm 1: /* $OpenBSD: compat.c,v 1.90 2015/04/13 02:04:08 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"
1.57 markus 33: #include "buffer.h"
1.6 markus 34: #include "packet.h"
1.10 markus 35: #include "compat.h"
1.34 markus 36: #include "log.h"
1.55 markus 37: #include "match.h"
1.1 markus 38:
1.4 markus 39: int compat13 = 0;
1.6 markus 40: int compat20 = 0;
41: int datafellows = 0;
1.4 markus 42:
1.11 markus 43: void
1.6 markus 44: enable_compat20(void)
45: {
1.80 djm 46: if (compat20)
47: return;
1.64 stevesk 48: debug("Enabling compatibility mode for protocol 2.0");
1.7 markus 49: compat20 = 1;
1.6 markus 50: }
1.11 markus 51: void
1.4 markus 52: enable_compat13(void)
53: {
1.64 stevesk 54: debug("Enabling compatibility mode for protocol 1.3");
1.4 markus 55: compat13 = 1;
1.6 markus 56: }
57: /* datafellows bug compatibility */
1.87 markus 58: u_int
1.6 markus 59: compat_datafellows(const char *version)
60: {
1.55 markus 61: int i;
1.24 markus 62: static struct {
63: char *pat;
1.13 markus 64: int bugs;
65: } check[] = {
1.55 markus 66: { "OpenSSH-2.0*,"
67: "OpenSSH-2.1*,"
68: "OpenSSH_2.1*,"
69: "OpenSSH_2.2*", SSH_OLD_SESSIONID|SSH_BUG_BANNER|
1.62 markus 70: SSH_OLD_DHGEX|SSH_BUG_NOREKEY|
1.71 djm 71: SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR},
1.55 markus 72: { "OpenSSH_2.3.0*", SSH_BUG_BANNER|SSH_BUG_BIGENDIANAES|
1.62 markus 73: SSH_OLD_DHGEX|SSH_BUG_NOREKEY|
1.71 djm 74: SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR},
1.55 markus 75: { "OpenSSH_2.3.*", SSH_BUG_BIGENDIANAES|SSH_OLD_DHGEX|
1.71 djm 76: SSH_BUG_NOREKEY|SSH_BUG_EXTEOF|
77: SSH_OLD_FORWARD_ADDR},
1.55 markus 78: { "OpenSSH_2.5.0p1*,"
79: "OpenSSH_2.5.1p1*",
1.45 markus 80: SSH_BUG_BIGENDIANAES|SSH_OLD_DHGEX|
1.71 djm 81: SSH_BUG_NOREKEY|SSH_BUG_EXTEOF|
82: SSH_OLD_FORWARD_ADDR},
1.55 markus 83: { "OpenSSH_2.5.0*,"
84: "OpenSSH_2.5.1*,"
1.62 markus 85: "OpenSSH_2.5.2*", SSH_OLD_DHGEX|SSH_BUG_NOREKEY|
1.71 djm 86: SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR},
87: { "OpenSSH_2.5.3*", SSH_BUG_NOREKEY|SSH_BUG_EXTEOF|
88: SSH_OLD_FORWARD_ADDR},
1.62 markus 89: { "OpenSSH_2.*,"
90: "OpenSSH_3.0*,"
1.71 djm 91: "OpenSSH_3.1*", SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR},
92: { "OpenSSH_3.*", SSH_OLD_FORWARD_ADDR },
1.62 markus 93: { "Sun_SSH_1.0*", SSH_BUG_NOREKEY|SSH_BUG_EXTEOF},
1.78 markus 94: { "OpenSSH_4*", 0 },
1.79 markus 95: { "OpenSSH_5*", SSH_NEW_OPENSSH|SSH_BUG_DYNAMIC_RPORT},
1.85 djm 96: { "OpenSSH_6.6.1*", SSH_NEW_OPENSSH},
1.83 djm 97: { "OpenSSH_6.5*,"
1.84 djm 98: "OpenSSH_6.6*", SSH_NEW_OPENSSH|SSH_BUG_CURVE25519PAD},
1.78 markus 99: { "OpenSSH*", SSH_NEW_OPENSSH },
1.55 markus 100: { "*MindTerm*", 0 },
101: { "2.1.0*", SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
1.41 markus 102: SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
1.66 markus 103: SSH_BUG_RSASIGMD5|SSH_BUG_HBSERVICE|
104: SSH_BUG_FIRSTKEX },
1.55 markus 105: { "2.1 *", SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
1.41 markus 106: SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
1.66 markus 107: SSH_BUG_RSASIGMD5|SSH_BUG_HBSERVICE|
108: SSH_BUG_FIRSTKEX },
1.56 deraadt 109: { "2.0.13*,"
110: "2.0.14*,"
111: "2.0.15*,"
112: "2.0.16*,"
113: "2.0.17*,"
114: "2.0.18*,"
1.55 markus 115: "2.0.19*", SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
1.31 markus 116: SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
1.37 markus 117: SSH_BUG_PKSERVICE|SSH_BUG_X11FWD|
1.47 markus 118: SSH_BUG_PKOK|SSH_BUG_RSASIGMD5|
1.53 markus 119: SSH_BUG_HBSERVICE|SSH_BUG_OPENFAILURE|
1.66 markus 120: SSH_BUG_DUMMYCHAN|SSH_BUG_FIRSTKEX },
1.56 deraadt 121: { "2.0.11*,"
1.55 markus 122: "2.0.12*", SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
1.49 markus 123: SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
124: SSH_BUG_PKSERVICE|SSH_BUG_X11FWD|
125: SSH_BUG_PKAUTH|SSH_BUG_PKOK|
1.53 markus 126: SSH_BUG_RSASIGMD5|SSH_BUG_OPENFAILURE|
1.66 markus 127: SSH_BUG_DUMMYCHAN|SSH_BUG_FIRSTKEX },
1.55 markus 128: { "2.0.*", SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
1.31 markus 129: SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
130: SSH_BUG_PKSERVICE|SSH_BUG_X11FWD|
1.41 markus 131: SSH_BUG_PKAUTH|SSH_BUG_PKOK|
1.49 markus 132: SSH_BUG_RSASIGMD5|SSH_BUG_OPENFAILURE|
1.66 markus 133: SSH_BUG_DERIVEKEY|SSH_BUG_DUMMYCHAN|
134: SSH_BUG_FIRSTKEX },
1.55 markus 135: { "2.2.0*,"
136: "2.3.0*", SSH_BUG_HMAC|SSH_BUG_DEBUG|
1.66 markus 137: SSH_BUG_RSASIGMD5|SSH_BUG_FIRSTKEX },
138: { "2.3.*", SSH_BUG_DEBUG|SSH_BUG_RSASIGMD5|
139: SSH_BUG_FIRSTKEX },
1.55 markus 140: { "2.4", SSH_OLD_SESSIONID }, /* Van Dyke */
1.77 djm 141: { "2.*", SSH_BUG_DEBUG|SSH_BUG_FIRSTKEX|
142: SSH_BUG_RFWD_ADDR },
1.55 markus 143: { "3.0.*", SSH_BUG_DEBUG },
144: { "3.0 SecureCRT*", SSH_OLD_SESSIONID },
145: { "1.7 SecureFX*", SSH_OLD_SESSIONID },
146: { "1.2.18*,"
147: "1.2.19*,"
148: "1.2.20*,"
149: "1.2.21*,"
1.69 markus 150: "1.2.22*", SSH_BUG_IGNOREMSG },
1.63 markus 151: { "1.3.2*", /* F-Secure */
1.69 markus 152: SSH_BUG_IGNOREMSG },
1.55 markus 153: { "*SSH Compatible Server*", /* Netscreen */
1.38 deraadt 154: SSH_BUG_PASSWORDPAD },
1.56 deraadt 155: { "*OSU_0*,"
1.55 markus 156: "OSU_1.0*,"
157: "OSU_1.1*,"
158: "OSU_1.2*,"
159: "OSU_1.3*,"
160: "OSU_1.4*,"
161: "OSU_1.5alpha1*,"
162: "OSU_1.5alpha2*,"
163: "OSU_1.5alpha3*", SSH_BUG_PASSWORDPAD },
164: { "*SSH_Version_Mapper*",
1.39 deraadt 165: SSH_BUG_SCANNER },
1.90 djm 166: { "PuTTY*", SSH_OLD_DHGEX },
1.65 mickey 167: { "Probe-*",
168: SSH_BUG_PROBE },
1.89 dtucker 169: { "TeraTerm SSH*,"
170: "TTSSH/1.5.*,"
171: "TTSSH/2.1*,"
172: "TTSSH/2.2*,"
173: "TTSSH/2.3*,"
174: "TTSSH/2.4*,"
175: "TTSSH/2.5*,"
176: "TTSSH/2.6*,"
177: "TTSSH/2.70*,"
178: "TTSSH/2.71*,"
179: "TTSSH/2.72*", SSH_BUG_HOSTKEYS },
1.25 markus 180: { NULL, 0 }
1.6 markus 181: };
1.55 markus 182:
1.21 markus 183: /* process table, return first match */
1.24 markus 184: for (i = 0; check[i].pat; i++) {
1.91 ! djm 185: if (match_pattern_list(version, check[i].pat, 0) == 1) {
1.82 djm 186: debug("match: %s pat %s compat 0x%08x",
1.87 markus 187: version, check[i].pat, check[i].bugs);
188: datafellows = check[i].bugs; /* XXX for now */
189: return check[i].bugs;
1.6 markus 190: }
191: }
1.24 markus 192: debug("no match: %s", version);
1.87 markus 193: return 0;
1.10 markus 194: }
195:
196: #define SEP ","
197: int
198: proto_spec(const char *spec)
199: {
1.18 provos 200: char *s, *p, *q;
1.10 markus 201: int ret = SSH_PROTO_UNKNOWN;
202:
1.14 markus 203: if (spec == NULL)
204: return ret;
1.87 markus 205: q = s = strdup(spec);
206: if (s == NULL)
207: return ret;
1.19 ho 208: for ((p = strsep(&q, SEP)); p && *p != '\0'; (p = strsep(&q, SEP))) {
1.54 deraadt 209: switch (atoi(p)) {
1.10 markus 210: case 1:
1.88 djm 211: #ifdef WITH_SSH1
1.10 markus 212: if (ret == SSH_PROTO_UNKNOWN)
213: ret |= SSH_PROTO_1_PREFERRED;
214: ret |= SSH_PROTO_1;
1.88 djm 215: #endif
1.10 markus 216: break;
217: case 2:
218: ret |= SSH_PROTO_2;
219: break;
220: default:
1.67 itojun 221: logit("ignoring bad proto spec: '%s'.", p);
1.10 markus 222: break;
223: }
224: }
1.81 djm 225: free(s);
1.10 markus 226: return ret;
1.40 djm 227: }
228:
1.82 djm 229: /*
230: * Filters a proposal string, excluding any algorithm matching the 'filter'
231: * pattern list.
232: */
233: static char *
234: filter_proposal(char *proposal, const char *filter)
1.40 djm 235: {
1.57 markus 236: Buffer b;
1.82 djm 237: char *orig_prop, *fix_prop;
1.40 djm 238: char *cp, *tmp;
239:
1.57 markus 240: buffer_init(&b);
1.82 djm 241: tmp = orig_prop = xstrdup(proposal);
1.54 deraadt 242: while ((cp = strsep(&tmp, ",")) != NULL) {
1.91 ! djm 243: if (match_pattern_list(cp, filter, 0) != 1) {
1.57 markus 244: if (buffer_len(&b) > 0)
245: buffer_append(&b, ",", 1);
246: buffer_append(&b, cp, strlen(cp));
1.82 djm 247: } else
248: debug2("Compat: skipping algorithm \"%s\"", cp);
1.40 djm 249: }
1.57 markus 250: buffer_append(&b, "\0", 1);
1.86 djm 251: fix_prop = xstrdup((char *)buffer_ptr(&b));
1.57 markus 252: buffer_free(&b);
1.81 djm 253: free(orig_prop);
1.40 djm 254:
1.82 djm 255: return fix_prop;
1.1 markus 256: }
1.82 djm 257:
258: char *
259: compat_cipher_proposal(char *cipher_prop)
260: {
261: if (!(datafellows & SSH_BUG_BIGENDIANAES))
262: return cipher_prop;
263: debug2("%s: original cipher proposal: %s", __func__, cipher_prop);
264: cipher_prop = filter_proposal(cipher_prop, "aes*");
265: debug2("%s: compat cipher proposal: %s", __func__, cipher_prop);
266: if (*cipher_prop == '\0')
267: fatal("No supported ciphers found");
268: return cipher_prop;
269: }
270:
271: char *
272: compat_pkalg_proposal(char *pkalg_prop)
273: {
274: if (!(datafellows & SSH_BUG_RSASIGMD5))
275: return pkalg_prop;
276: debug2("%s: original public key proposal: %s", __func__, pkalg_prop);
277: pkalg_prop = filter_proposal(pkalg_prop, "ssh-rsa");
278: debug2("%s: compat public key proposal: %s", __func__, pkalg_prop);
279: if (*pkalg_prop == '\0')
280: fatal("No supported PK algorithms found");
281: return pkalg_prop;
1.83 djm 282: }
283:
284: char *
1.90 djm 285: compat_kex_proposal(char *p)
1.83 djm 286: {
1.90 djm 287: if ((datafellows & (SSH_BUG_CURVE25519PAD|SSH_OLD_DHGEX)) == 0)
288: return p;
289: debug2("%s: original KEX proposal: %s", __func__, p);
290: if ((datafellows & SSH_BUG_CURVE25519PAD) != 0)
291: p = filter_proposal(p, "curve25519-sha256@libssh.org");
292: if ((datafellows & SSH_OLD_DHGEX) != 0) {
293: p = filter_proposal(p, "diffie-hellman-group-exchange-sha256");
294: p = filter_proposal(p, "diffie-hellman-group-exchange-sha1");
295: }
296: debug2("%s: compat KEX proposal: %s", __func__, p);
297: if (*p == '\0')
1.83 djm 298: fatal("No supported key exchange algorithms found");
1.90 djm 299: return p;
1.82 djm 300: }
301:
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