diff options
| author | Damien Miller <djm@cvs.openbsd.org> | 2016-09-28 16:33:08 +0000 |
|---|---|---|
| committer | Damien Miller <djm@cvs.openbsd.org> | 2016-09-28 16:33:08 +0000 |
| commit | f4b6c59a19ea18647a82e8c459b91dc700e5c638 (patch) | |
| tree | 6fdabc4550dba6bda519ef09206f28c2bb8631fa /usr.bin/ssh/sshconnect2.c | |
| parent | b49895b6f2c6e9132d9df1fc5041151d6e735862 (diff) | |
Remove support for pre-authentication compression. Doing compression
early in the protocol probably seemed reasonable in the 1990s, but
today it's clearly a bad idea in terms of both cryptography (cf.
multiple compression oracle attacks in TLS) and attack surface.
Moreover, to support it across privilege-separation zlib needed
the assistance of a complex shared-memory manager that made the
required attack surface considerably larger.
Prompted by Guido Vranken pointing out a compiler-elided security
check in the shared memory manager found by Stack
(http://css.csail.mit.edu/stack/); ok deraadt@ markus@
NB. pre-auth authentication has been disabled by default in sshd
for >10 years.
Diffstat (limited to 'usr.bin/ssh/sshconnect2.c')
| -rw-r--r-- | usr.bin/ssh/sshconnect2.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/usr.bin/ssh/sshconnect2.c b/usr.bin/ssh/sshconnect2.c index e7d39840e7c..f975accacdc 100644 --- a/usr.bin/ssh/sshconnect2.c +++ b/usr.bin/ssh/sshconnect2.c @@ -1,4 +1,4 @@ -/* $OpenBSD: sshconnect2.c,v 1.248 2016/09/22 02:29:57 dtucker Exp $ */ +/* $OpenBSD: sshconnect2.c,v 1.249 2016/09/28 16:33:07 djm Exp $ */ /* * Copyright (c) 2000 Markus Friedl. All rights reserved. * Copyright (c) 2008 Damien Miller. All rights reserved. @@ -168,7 +168,7 @@ ssh_kex2(char *host, struct sockaddr *hostaddr, u_short port) compat_cipher_proposal(options.ciphers); myproposal[PROPOSAL_COMP_ALGS_CTOS] = myproposal[PROPOSAL_COMP_ALGS_STOC] = options.compression ? - "zlib@openssh.com,zlib,none" : "none,zlib@openssh.com,zlib"; + "zlib@openssh.com,none" : "none,zlib@openssh.com"; myproposal[PROPOSAL_MAC_ALGS_CTOS] = myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; if (options.hostkeyalgorithms != NULL) { |