/* $OpenBSD: compat.c,v 1.92 2015/05/05 10:17:49 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 #include #include #include #include "xmalloc.h" #include "buffer.h" #include "packet.h" #include "compat.h" #include "log.h" #include "match.h" int compat13 = 0; int compat20 = 0; int datafellows = 0; void enable_compat20(void) { if (compat20) return; debug("Enabling compatibility mode for protocol 2.0"); compat20 = 1; } void enable_compat13(void) { debug("Enabling compatibility mode for protocol 1.3"); compat13 = 1; } /* datafellows bug compatibility */ u_int compat_datafellows(const char *version) { int i; static struct { char *pat; int bugs; } check[] = { { "OpenSSH-2.0*," "OpenSSH-2.1*," "OpenSSH_2.1*," "OpenSSH_2.2*", SSH_OLD_SESSIONID|SSH_BUG_BANNER| SSH_OLD_DHGEX|SSH_BUG_NOREKEY| SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR}, { "OpenSSH_2.3.0*", SSH_BUG_BANNER|SSH_BUG_BIGENDIANAES| SSH_OLD_DHGEX|SSH_BUG_NOREKEY| SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR}, { "OpenSSH_2.3.*", SSH_BUG_BIGENDIANAES|SSH_OLD_DHGEX| SSH_BUG_NOREKEY|SSH_BUG_EXTEOF| SSH_OLD_FORWARD_ADDR}, { "OpenSSH_2.5.0p1*," "OpenSSH_2.5.1p1*", SSH_BUG_BIGENDIANAES|SSH_OLD_DHGEX| SSH_BUG_NOREKEY|SSH_BUG_EXTEOF| SSH_OLD_FORWARD_ADDR}, { "OpenSSH_2.5.0*," "OpenSSH_2.5.1*," "OpenSSH_2.5.2*", SSH_OLD_DHGEX|SSH_BUG_NOREKEY| SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR}, { "OpenSSH_2.5.3*", SSH_BUG_NOREKEY|SSH_BUG_EXTEOF| SSH_OLD_FORWARD_ADDR}, { "OpenSSH_2.*," "OpenSSH_3.0*," "OpenSSH_3.1*", SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR}, { "OpenSSH_3.*", SSH_OLD_FORWARD_ADDR }, { "Sun_SSH_1.0*", SSH_BUG_NOREKEY|SSH_BUG_EXTEOF}, { "OpenSSH_4*", 0 }, { "OpenSSH_5*", SSH_NEW_OPENSSH|SSH_BUG_DYNAMIC_RPORT}, { "OpenSSH_6.6.1*", SSH_NEW_OPENSSH}, { "OpenSSH_6.5*," "OpenSSH_6.6*", SSH_NEW_OPENSSH|SSH_BUG_CURVE25519PAD}, { "OpenSSH*", SSH_NEW_OPENSSH }, { "*MindTerm*", 0 }, { "2.1.0*", SSH_BUG_SIGBLOB|SSH_BUG_HMAC| SSH_OLD_SESSIONID|SSH_BUG_DEBUG| SSH_BUG_RSASIGMD5|SSH_BUG_HBSERVICE| SSH_BUG_FIRSTKEX }, { "2.1 *", SSH_BUG_SIGBLOB|SSH_BUG_HMAC| SSH_OLD_SESSIONID|SSH_BUG_DEBUG| SSH_BUG_RSASIGMD5|SSH_BUG_HBSERVICE| SSH_BUG_FIRSTKEX }, { "2.0.13*," "2.0.14*," "2.0.15*," "2.0.16*," "2.0.17*," "2.0.18*," "2.0.19*", SSH_BUG_SIGBLOB|SSH_BUG_HMAC| SSH_OLD_SESSIONID|SSH_BUG_DEBUG| SSH_BUG_PKSERVICE|SSH_BUG_X11FWD| SSH_BUG_PKOK|SSH_BUG_RSASIGMD5| SSH_BUG_HBSERVICE|SSH_BUG_OPENFAILURE| SSH_BUG_DUMMYCHAN|SSH_BUG_FIRSTKEX }, { "2.0.11*," "2.0.12*", SSH_BUG_SIGBLOB|SSH_BUG_HMAC| SSH_OLD_SESSIONID|SSH_BUG_DEBUG| SSH_BUG_PKSERVICE|SSH_BUG_X11FWD| SSH_BUG_PKAUTH|SSH_BUG_PKOK| SSH_BUG_RSASIGMD5|SSH_BUG_OPENFAILURE| SSH_BUG_DUMMYCHAN|SSH_BUG_FIRSTKEX }, { "2.0.*", SSH_BUG_SIGBLOB|SSH_BUG_HMAC| SSH_OLD_SESSIONID|SSH_BUG_DEBUG| SSH_BUG_PKSERVICE|SSH_BUG_X11FWD| SSH_BUG_PKAUTH|SSH_BUG_PKOK| SSH_BUG_RSASIGMD5|SSH_BUG_OPENFAILURE| SSH_BUG_DERIVEKEY|SSH_BUG_DUMMYCHAN| SSH_BUG_FIRSTKEX }, { "2.2.0*," "2.3.0*", SSH_BUG_HMAC|SSH_BUG_DEBUG| SSH_BUG_RSASIGMD5|SSH_BUG_FIRSTKEX }, { "2.3.*", SSH_BUG_DEBUG|SSH_BUG_RSASIGMD5| SSH_BUG_FIRSTKEX }, { "2.4", SSH_OLD_SESSIONID }, /* Van Dyke */ { "2.*", SSH_BUG_DEBUG|SSH_BUG_FIRSTKEX| SSH_BUG_RFWD_ADDR }, { "3.0.*", SSH_BUG_DEBUG }, { "3.0 SecureCRT*", SSH_OLD_SESSIONID }, { "1.7 SecureFX*", SSH_OLD_SESSIONID }, { "1.2.18*," "1.2.19*," "1.2.20*," "1.2.21*," "1.2.22*", SSH_BUG_IGNOREMSG }, { "1.3.2*", /* F-Secure */ SSH_BUG_IGNOREMSG }, { "*SSH Compatible Server*", /* Netscreen */ SSH_BUG_PASSWORDPAD }, { "*OSU_0*," "OSU_1.0*," "OSU_1.1*," "OSU_1.2*," "OSU_1.3*," "OSU_1.4*," "OSU_1.5alpha1*," "OSU_1.5alpha2*," "OSU_1.5alpha3*", SSH_BUG_PASSWORDPAD }, { "*SSH_Version_Mapper*", SSH_BUG_SCANNER }, { "PuTTY*", SSH_OLD_DHGEX }, { "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*", SSH_OLD_DHGEX }, { NULL, 0 } }; /* process table, return first match */ for (i = 0; check[i].pat; i++) { if (match_pattern_list(version, check[i].pat, strlen(check[i].pat), 0) == 1) { debug("match: %s pat %s compat 0x%08x", version, check[i].pat, check[i].bugs); datafellows = check[i].bugs; /* XXX for now */ return check[i].bugs; } } debug("no match: %s", version); return 0; } #define SEP "," int proto_spec(const char *spec) { char *s, *p, *q; int ret = SSH_PROTO_UNKNOWN; if (spec == NULL) return ret; q = s = strdup(spec); if (s == NULL) return ret; for ((p = strsep(&q, SEP)); p && *p != '\0'; (p = strsep(&q, SEP))) { switch (atoi(p)) { case 1: #ifdef WITH_SSH1 if (ret == SSH_PROTO_UNKNOWN) ret |= SSH_PROTO_1_PREFERRED; ret |= SSH_PROTO_1; #endif break; case 2: ret |= SSH_PROTO_2; break; default: logit("ignoring bad proto spec: '%s'.", p); break; } } free(s); return ret; } /* * Filters a proposal string, excluding any algorithm matching the 'filter' * pattern list. */ static char * filter_proposal(char *proposal, const char *filter) { Buffer b; char *orig_prop, *fix_prop; char *cp, *tmp; buffer_init(&b); tmp = orig_prop = xstrdup(proposal); while ((cp = strsep(&tmp, ",")) != NULL) { if (match_pattern_list(cp, filter, strlen(cp), 0) != 1) { if (buffer_len(&b) > 0) buffer_append(&b, ",", 1); buffer_append(&b, cp, strlen(cp)); } else debug2("Compat: skipping algorithm \"%s\"", cp); } buffer_append(&b, "\0", 1); fix_prop = xstrdup((char *)buffer_ptr(&b)); buffer_free(&b); free(orig_prop); return fix_prop; } char * compat_cipher_proposal(char *cipher_prop) { if (!(datafellows & SSH_BUG_BIGENDIANAES)) return cipher_prop; debug2("%s: original cipher proposal: %s", __func__, cipher_prop); cipher_prop = filter_proposal(cipher_prop, "aes*"); debug2("%s: compat cipher proposal: %s", __func__, cipher_prop); if (*cipher_prop == '\0') fatal("No supported ciphers found"); return cipher_prop; } char * compat_pkalg_proposal(char *pkalg_prop) { if (!(datafellows & SSH_BUG_RSASIGMD5)) return pkalg_prop; debug2("%s: original public key proposal: %s", __func__, pkalg_prop); pkalg_prop = filter_proposal(pkalg_prop, "ssh-rsa"); debug2("%s: compat public key proposal: %s", __func__, pkalg_prop); if (*pkalg_prop == '\0') fatal("No supported PK algorithms found"); return pkalg_prop; } char * compat_kex_proposal(char *p) { if ((datafellows & (SSH_BUG_CURVE25519PAD|SSH_OLD_DHGEX)) == 0) return p; debug2("%s: original KEX proposal: %s", __func__, p); if ((datafellows & SSH_BUG_CURVE25519PAD) != 0) p = filter_proposal(p, "curve25519-sha256@libssh.org"); if ((datafellows & SSH_OLD_DHGEX) != 0) { p = filter_proposal(p, "diffie-hellman-group-exchange-sha256"); p = filter_proposal(p, "diffie-hellman-group-exchange-sha1"); } debug2("%s: compat KEX proposal: %s", __func__, p); if (*p == '\0') fatal("No supported key exchange algorithms found"); return p; }