diff options
author | Colin Watson <cjwatson@debian.org> | 2010-01-01 23:53:30 +0000 |
---|---|---|
committer | Colin Watson <cjwatson@debian.org> | 2010-01-01 23:53:30 +0000 |
commit | df03186a4f9e0c2ece398b5c0571cb6263d7a752 (patch) | |
tree | 1aab079441dff9615274769b19f2d734ddf508dd /kexgexs.c | |
parent | 6ad6994c288662fca6949f42bf91fec2aff00bca (diff) | |
parent | 99b402ea4c8457b0a3cafff37f5b3410a8dc6476 (diff) |
* New upstream release (closes: #536182). Yes, I know 5.3p1 has been out
for a while, but there's no GSSAPI patch available for it yet.
- Change the default cipher order to prefer the AES CTR modes and the
revised "arcfour256" mode to CBC mode ciphers that are susceptible to
CPNI-957037 "Plaintext Recovery Attack Against SSH".
- Add countermeasures to mitigate CPNI-957037-style attacks against the
SSH protocol's use of CBC-mode ciphers. Upon detection of an invalid
packet length or Message Authentication Code, ssh/sshd will continue
reading up to the maximum supported packet length rather than
immediately terminating the connection. This eliminates most of the
known differences in behaviour that leaked information about the
plaintext of injected data which formed the basis of this attack
(closes: #506115, LP: #379329).
- ForceCommand directive now accepts commandline arguments for the
internal-sftp server (closes: #524423, LP: #362511).
- Add AllowAgentForwarding to available Match keywords list (closes:
#540623).
- Make ssh(1) send the correct channel number for
SSH2_MSG_CHANNEL_SUCCESS and SSH2_MSG_CHANNEL_FAILURE messages to
avoid triggering 'Non-public channel' error messages on sshd(8) in
openssh-5.1.
- Avoid printing 'Non-public channel' warnings in sshd(8), since the
ssh(1) has sent incorrect channel numbers since ~2004 (this reverts a
behaviour introduced in openssh-5.1; closes: #496017).
* Update to GSSAPI patch from
http://www.sxw.org.uk/computing/patches/openssh-5.2p1-gsskex-all-20090726.patch,
including cascading credentials support (LP: #416958).
Diffstat (limited to 'kexgexs.c')
-rw-r--r-- | kexgexs.c | 27 |
1 files changed, 15 insertions, 12 deletions
@@ -1,4 +1,4 @@ | |||
1 | /* $OpenBSD: kexgexs.c,v 1.10 2006/11/06 21:25:28 markus Exp $ */ | 1 | /* $OpenBSD: kexgexs.c,v 1.11 2009/01/01 21:17:36 djm Exp $ */ |
2 | /* | 2 | /* |
3 | * Copyright (c) 2000 Niels Provos. All rights reserved. | 3 | * Copyright (c) 2000 Niels Provos. All rights reserved. |
4 | * Copyright (c) 2001 Markus Friedl. All rights reserved. | 4 | * Copyright (c) 2001 Markus Friedl. All rights reserved. |
@@ -56,7 +56,8 @@ kexgex_server(Kex *kex) | |||
56 | DH *dh; | 56 | DH *dh; |
57 | u_char *kbuf, *hash, *signature = NULL, *server_host_key_blob = NULL; | 57 | u_char *kbuf, *hash, *signature = NULL, *server_host_key_blob = NULL; |
58 | u_int sbloblen, klen, slen, hashlen; | 58 | u_int sbloblen, klen, slen, hashlen; |
59 | int min = -1, max = -1, nbits = -1, type, kout; | 59 | int omin = -1, min = -1, omax = -1, max = -1, onbits = -1, nbits = -1; |
60 | int type, kout; | ||
60 | 61 | ||
61 | if (kex->load_host_key == NULL) | 62 | if (kex->load_host_key == NULL) |
62 | fatal("Cannot load hostkey"); | 63 | fatal("Cannot load hostkey"); |
@@ -68,27 +69,29 @@ kexgex_server(Kex *kex) | |||
68 | switch (type) { | 69 | switch (type) { |
69 | case SSH2_MSG_KEX_DH_GEX_REQUEST: | 70 | case SSH2_MSG_KEX_DH_GEX_REQUEST: |
70 | debug("SSH2_MSG_KEX_DH_GEX_REQUEST received"); | 71 | debug("SSH2_MSG_KEX_DH_GEX_REQUEST received"); |
71 | min = packet_get_int(); | 72 | omin = min = packet_get_int(); |
72 | nbits = packet_get_int(); | 73 | onbits = nbits = packet_get_int(); |
73 | max = packet_get_int(); | 74 | omax = max = packet_get_int(); |
74 | min = MAX(DH_GRP_MIN, min); | 75 | min = MAX(DH_GRP_MIN, min); |
75 | max = MIN(DH_GRP_MAX, max); | 76 | max = MIN(DH_GRP_MAX, max); |
77 | nbits = MAX(DH_GRP_MIN, nbits); | ||
78 | nbits = MIN(DH_GRP_MAX, nbits); | ||
76 | break; | 79 | break; |
77 | case SSH2_MSG_KEX_DH_GEX_REQUEST_OLD: | 80 | case SSH2_MSG_KEX_DH_GEX_REQUEST_OLD: |
78 | debug("SSH2_MSG_KEX_DH_GEX_REQUEST_OLD received"); | 81 | debug("SSH2_MSG_KEX_DH_GEX_REQUEST_OLD received"); |
79 | nbits = packet_get_int(); | 82 | onbits = nbits = packet_get_int(); |
80 | min = DH_GRP_MIN; | ||
81 | max = DH_GRP_MAX; | ||
82 | /* unused for old GEX */ | 83 | /* unused for old GEX */ |
84 | omin = min = DH_GRP_MIN; | ||
85 | omax = max = DH_GRP_MAX; | ||
83 | break; | 86 | break; |
84 | default: | 87 | default: |
85 | fatal("protocol error during kex, no DH_GEX_REQUEST: %d", type); | 88 | fatal("protocol error during kex, no DH_GEX_REQUEST: %d", type); |
86 | } | 89 | } |
87 | packet_check_eom(); | 90 | packet_check_eom(); |
88 | 91 | ||
89 | if (max < min || nbits < min || max < nbits) | 92 | if (omax < omin || onbits < omin || omax < onbits) |
90 | fatal("DH_GEX_REQUEST, bad parameters: %d !< %d !< %d", | 93 | fatal("DH_GEX_REQUEST, bad parameters: %d !< %d !< %d", |
91 | min, nbits, max); | 94 | omin, onbits, omax); |
92 | 95 | ||
93 | /* Contact privileged parent */ | 96 | /* Contact privileged parent */ |
94 | dh = PRIVSEP(choose_dh(min, nbits, max)); | 97 | dh = PRIVSEP(choose_dh(min, nbits, max)); |
@@ -149,7 +152,7 @@ kexgex_server(Kex *kex) | |||
149 | key_to_blob(server_host_key, &server_host_key_blob, &sbloblen); | 152 | key_to_blob(server_host_key, &server_host_key_blob, &sbloblen); |
150 | 153 | ||
151 | if (type == SSH2_MSG_KEX_DH_GEX_REQUEST_OLD) | 154 | if (type == SSH2_MSG_KEX_DH_GEX_REQUEST_OLD) |
152 | min = max = -1; | 155 | omin = min = omax = max = -1; |
153 | 156 | ||
154 | /* calc H */ | 157 | /* calc H */ |
155 | kexgex_hash( | 158 | kexgex_hash( |
@@ -159,7 +162,7 @@ kexgex_server(Kex *kex) | |||
159 | buffer_ptr(&kex->peer), buffer_len(&kex->peer), | 162 | buffer_ptr(&kex->peer), buffer_len(&kex->peer), |
160 | buffer_ptr(&kex->my), buffer_len(&kex->my), | 163 | buffer_ptr(&kex->my), buffer_len(&kex->my), |
161 | server_host_key_blob, sbloblen, | 164 | server_host_key_blob, sbloblen, |
162 | min, nbits, max, | 165 | omin, onbits, omax, |
163 | dh->p, dh->g, | 166 | dh->p, dh->g, |
164 | dh_client_pub, | 167 | dh_client_pub, |
165 | dh->pub_key, | 168 | dh->pub_key, |