diff options
| -rw-r--r-- | ChangeLog | 11 | ||||
| -rw-r--r-- | bufaux.c | 5 | ||||
| -rw-r--r-- | compat.c | 17 | ||||
| -rw-r--r-- | compat.h | 2 | ||||
| -rw-r--r-- | sshconnect2.c | 2 | ||||
| -rw-r--r-- | sshd.c | 3 | ||||
| -rw-r--r-- | version.h | 2 |
7 files changed, 39 insertions, 3 deletions
@@ -1,3 +1,14 @@ +20140420 + - (djm) [bufaux.c compat.c compat.h sshconnect2.c sshd.c version.h] + OpenSSH 6.5 and 6.6 sometimes encode a value used in the curve25519 + key exchange incorrectly, causing connection failures about 0.2% of + the time when this method is used against a peer that implements + the method properly. + + Fix the problem and disable the curve25519 KEX when speaking to + OpenSSH 6.5 or 6.6. This version will identify itself as 6.6.1 + to enable the compatability code. + 20140313 - (djm) Release OpenSSH 6.6 @@ -1,4 +1,4 @@ -/* $OpenBSD: bufaux.c,v 1.56 2014/02/02 03:44:31 djm Exp $ */ +/* $OpenBSD: bufaux.c,v 1.57 2014/04/16 23:22:45 djm Exp $ */ /* * Author: Tatu Ylonen <ylo@cs.hut.fi> * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland @@ -372,6 +372,9 @@ buffer_put_bignum2_from_string(Buffer *buffer, const u_char *s, u_int l) if (l > 8 * 1024) fatal("%s: length %u too long", __func__, l); + /* Skip leading zero bytes */ + for (; l > 0 && *s == 0; l--, s++) + ; p = buf = xmalloc(l + 1); /* * If most significant bit is set then prepend a zero byte to @@ -95,6 +95,9 @@ compat_datafellows(const char *version) { "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| @@ -251,7 +254,6 @@ compat_cipher_proposal(char *cipher_prop) return cipher_prop; } - char * compat_pkalg_proposal(char *pkalg_prop) { @@ -265,3 +267,16 @@ compat_pkalg_proposal(char *pkalg_prop) return pkalg_prop; } +char * +compat_kex_proposal(char *kex_prop) +{ + if (!(datafellows & SSH_BUG_CURVE25519PAD)) + return kex_prop; + debug2("%s: original KEX proposal: %s", __func__, kex_prop); + kex_prop = filter_proposal(kex_prop, "curve25519-sha256@libssh.org"); + debug2("%s: compat KEX proposal: %s", __func__, kex_prop); + if (*kex_prop == '\0') + fatal("No supported key exchange algorithms found"); + return kex_prop; +} + @@ -59,6 +59,7 @@ #define SSH_BUG_RFWD_ADDR 0x02000000 #define SSH_NEW_OPENSSH 0x04000000 #define SSH_BUG_DYNAMIC_RPORT 0x08000000 +#define SSH_BUG_CURVE25519PAD 0x10000000 void enable_compat13(void); void enable_compat20(void); @@ -66,6 +67,7 @@ void compat_datafellows(const char *); int proto_spec(const char *); char *compat_cipher_proposal(char *); char *compat_pkalg_proposal(char *); +char *compat_kex_proposal(char *); extern int compat13; extern int compat20; diff --git a/sshconnect2.c b/sshconnect2.c index 7f4ff418..ec3ad6a5 100644 --- a/sshconnect2.c +++ b/sshconnect2.c @@ -195,6 +195,8 @@ ssh_kex2(char *host, struct sockaddr *hostaddr, u_short port) } if (options.kex_algorithms != NULL) myproposal[PROPOSAL_KEX_ALGS] = options.kex_algorithms; + myproposal[PROPOSAL_KEX_ALGS] = compat_kex_proposal( + myproposal[PROPOSAL_KEX_ALGS]); if (options.rekey_limit || options.rekey_interval) packet_set_rekey_limits((u_int32_t)options.rekey_limit, @@ -2462,6 +2462,9 @@ do_ssh2_kex(void) if (options.kex_algorithms != NULL) myproposal[PROPOSAL_KEX_ALGS] = options.kex_algorithms; + myproposal[PROPOSAL_KEX_ALGS] = compat_kex_proposal( + myproposal[PROPOSAL_KEX_ALGS]); + if (options.rekey_limit || options.rekey_interval) packet_set_rekey_limits((u_int32_t)options.rekey_limit, (time_t)options.rekey_interval); @@ -1,6 +1,6 @@ /* $OpenBSD: version.h,v 1.70 2014/02/27 22:57:40 djm Exp $ */ -#define SSH_VERSION "OpenSSH_6.6" +#define SSH_VERSION "OpenSSH_6.6.1" #define SSH_PORTABLE "p1" #define SSH_RELEASE SSH_VERSION SSH_PORTABLE |