Reject vulnerable keys to mitigate Debian OpenSSL flaw

In 2008, Debian (and derived distributions such as Ubuntu) shipped an
OpenSSL package with a flawed random number generator, causing OpenSSH to
generate only a very limited set of keys which were subject to private half
precomputation.  To mitigate this, this patch checks key authentications
against a blacklist of known-vulnerable keys, and adds a new ssh-vulnkey
program which can be used to explicitly check keys against that blacklist.
See CVE-2008-0166.

Bug: https://bugzilla.mindrot.org/show_bug.cgi?id=1469
Last-Update: 2013-09-14

Patch-Name: ssh-vulnkey.patch

1 files changed, 3 insertions, 2 deletions

diff --git a/auth2-pubkey.c b/auth2-pubkey.c
index 2b3ecb104..12eb8a6b2 100644
--- a/auth2-pubkey.c
+++ b/auth2-pubkey.c
@@ -647,9 +647,10 @@ user_key_allowed(struct passwd *pw, Key *key)
         u_int success, i;
         char *file;
 
-        if (auth_key_is_revoked(key))
+        if (auth_key_is_revoked(key, 0))
                 return 0;
-        if (key_is_cert(key) && auth_key_is_revoked(key->cert->signature_key))
+        if (key_is_cert(key) &&
+            auth_key_is_revoked(key->cert->signature_key, 0))
                 return 0;
 
         success = user_cert_trusted_ca(pw, key);