Reject invalid PSS parameters.

Fix a bug where invalid PSS parameters are not rejected resulting in a
NULL pointer exception. This can be triggered during certificate
verification so could be a DoS attack against a client or a server
enabling client authentication.

Thanks to Brian Carpenter for reporting this issues.

CVE-2015-0208

Reviewed-by: Tim Hudson <tjh@openssl.org>

diff --git a/crypto/rsa/rsa_ameth.c b/crypto/rsa/rsa_ameth.c
index c7106a313097bb470576e1dc38eef608e6cbeb64..ca3922e6c298314f234a2bc972afa863c261b002 100644 (file)
--- a/crypto/rsa/rsa_ameth.c
+++ b/crypto/rsa/rsa_ameth.c
@@ -698,9 +698,10 @@ static int rsa_item_verify(EVP_MD_CTX *ctx, const ASN1_ITEM *it, void *asn,
         RSAerr(RSA_F_RSA_ITEM_VERIFY, RSA_R_UNSUPPORTED_SIGNATURE_TYPE);
         return -1;
     }
         RSAerr(RSA_F_RSA_ITEM_VERIFY, RSA_R_UNSUPPORTED_SIGNATURE_TYPE);
         return -1;
     }

-    if (rsa_pss_to_ctx(ctx, NULL, sigalg, pkey))
+    if (rsa_pss_to_ctx(ctx, NULL, sigalg, pkey) > 0) {

         /* Carry on */
         return 2;
         /* Carry on */
         return 2;

+    }

     return -1;
 }
 
     return -1;
 }