* Mitigate OpenSSL security vulnerability:

  - Add key blacklisting support. Keys listed in
    /etc/ssh/blacklist.TYPE-LENGTH will be rejected for authentication by
    sshd, unless "PermitBlacklistedKeys yes" is set in
    /etc/ssh/sshd_config.
  - Add a new program, ssh-vulnkey, which can be used to check keys
    against these blacklists.
  - Depend on openssh-blacklist.
  - Force dependencies on libssl0.9.8 / libcrypto0.9.8-udeb to at least
    0.9.8g-9.
  - Automatically regenerate known-compromised host keys, with a
    critical-priority debconf note. (I regret that there was no time to
    gather translations.)

1 files changed, 16 insertions, 0 deletions

diff --git a/auth-rh-rsa.c b/auth-rh-rsa.c
index eca750275..093461e83 100644
--- a/auth-rh-rsa.c
+++ b/auth-rh-rsa.c
@@ -20,6 +20,7 @@
 #include <pwd.h>
 #include <stdarg.h>
 
+#include "xmalloc.h"
 #include "packet.h"
 #include "uidswap.h"
 #include "log.h"
@@ -27,6 +28,7 @@
 #include "servconf.h"
 #include "key.h"
 #include "hostfile.h"
+#include "authfile.h"
 #include "pathnames.h"
 #include "auth.h"
 #include "canohost.h"
@@ -42,8 +44,22 @@ int
 auth_rhosts_rsa_key_allowed(struct passwd *pw, char *cuser, char *chost,
     Key *client_host_key)
 {
+        char *fp;
         HostStatus host_status;
 
+        if (blacklisted_key(client_host_key)) {
+                fp = key_fingerprint(client_host_key, SSH_FP_MD5, SSH_FP_HEX);
+                if (options.permit_blacklisted_keys)
+                        logit("Public key %s blacklisted (see "
+                            "ssh-vulnkey(1)); continuing anyway", fp);
+                else
+                        logit("Public key %s blacklisted (see "
+                            "ssh-vulnkey(1))", fp);
+                xfree(fp);
+                if (!options.permit_blacklisted_keys)
+                        return 0;
+        }
+
         /* Check if we would accept it using rhosts authentication. */
         if (!auth_rhosts(pw, cuser))
                 return 0;