diff options
author | Damien Miller <djm@mindrot.org> | 2014-04-20 13:23:43 +1000 |
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committer | Damien Miller <djm@mindrot.org> | 2014-04-20 13:23:43 +1000 |
commit | 7d6a9fb660c808882d064e152d6070ffc3844c3f (patch) | |
tree | b3ba326eb0853c005d9c9d4c91b1c0f8dac8855e /sshconnect.c | |
parent | fcd62c0b66b8415405ed0af29c236329eb88cc0f (diff) | |
download | openssh-git-7d6a9fb660c808882d064e152d6070ffc3844c3f.tar.gz |
- djm@cvs.openbsd.org 2014/04/01 03:34:10
[sshconnect.c]
When using VerifyHostKeyDNS with a DNSSEC resolver, down-convert any
certificate keys to plain keys and attempt SSHFP resolution.
Prevents a server from skipping SSHFP lookup and forcing a new-hostkey
dialog by offering only certificate keys.
Reported by mcv21 AT cam.ac.uk
Diffstat (limited to 'sshconnect.c')
-rw-r--r-- | sshconnect.c | 44 |
1 files changed, 27 insertions, 17 deletions
diff --git a/sshconnect.c b/sshconnect.c index 573d7a8e..ca6e4cc9 100644 --- a/sshconnect.c +++ b/sshconnect.c @@ -1,4 +1,4 @@ -/* $OpenBSD: sshconnect.c,v 1.246 2014/02/06 22:21:01 djm Exp $ */ +/* $OpenBSD: sshconnect.c,v 1.247 2014/04/01 03:34:10 djm Exp $ */ /* * Author: Tatu Ylonen <ylo@cs.hut.fi> * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland @@ -1219,29 +1219,39 @@ verify_host_key(char *host, struct sockaddr *hostaddr, Key *host_key) { int flags = 0; char *fp; + Key *plain = NULL; fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX); debug("Server host key: %s %s", key_type(host_key), fp); free(fp); - /* XXX certs are not yet supported for DNS */ - if (!key_is_cert(host_key) && options.verify_host_key_dns && - verify_host_key_dns(host, hostaddr, host_key, &flags) == 0) { - if (flags & DNS_VERIFY_FOUND) { - - if (options.verify_host_key_dns == 1 && - flags & DNS_VERIFY_MATCH && - flags & DNS_VERIFY_SECURE) - return 0; - - if (flags & DNS_VERIFY_MATCH) { - matching_host_key_dns = 1; - } else { - warn_changed_key(host_key); - error("Update the SSHFP RR in DNS with the new " - "host key to get rid of this message."); + if (options.verify_host_key_dns) { + /* + * XXX certs are not yet supported for DNS, so downgrade + * them and try the plain key. + */ + plain = key_from_private(host_key); + if (key_is_cert(plain)) + key_drop_cert(plain); + if (verify_host_key_dns(host, hostaddr, plain, &flags) == 0) { + if (flags & DNS_VERIFY_FOUND) { + if (options.verify_host_key_dns == 1 && + flags & DNS_VERIFY_MATCH && + flags & DNS_VERIFY_SECURE) { + key_free(plain); + return 0; + } + if (flags & DNS_VERIFY_MATCH) { + matching_host_key_dns = 1; + } else { + warn_changed_key(plain); + error("Update the SSHFP RR in DNS " + "with the new host key to get rid " + "of this message."); + } } } + key_free(plain); } return check_host_key(host, hostaddr, options.port, host_key, RDRW, |