diff options
| author | Damien Miller <djm@cvs.openbsd.org> | 2014-04-01 03:34:11 +0000 |
|---|---|---|
| committer | Damien Miller <djm@cvs.openbsd.org> | 2014-04-01 03:34:11 +0000 |
| commit | 83772facb851f895f7e23ce7ef575a87e96f16d8 (patch) | |
| tree | ae9641f6a96b06c7592ac0ca5b71374d86741601 | |
| parent | 17932ead16c61151eda168cd52ed6bea3e19df1f (diff) | |
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
| -rw-r--r-- | usr.bin/ssh/sshconnect.c | 44 |
1 files changed, 27 insertions, 17 deletions
diff --git a/usr.bin/ssh/sshconnect.c b/usr.bin/ssh/sshconnect.c index 8c38b16b8be..f01fb856e26 100644 --- a/usr.bin/ssh/sshconnect.c +++ b/usr.bin/ssh/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 @@ -1193,29 +1193,39 @@ 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, |