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 5e8701ac0ab6b8a73ba5a58e2630cb626c390b1b..6f4c1048588da9b388fd995c4fd47709b690cf0f 100644 (file)
--- a/crypto/rsa/rsa_ameth.c
+++ b/crypto/rsa/rsa_ameth.c
@@ -703,9 +703,10 @@ 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;
     }
-    if (rsa_pss_to_ctx(ctx, NULL, sigalg, pkey))
+    if (rsa_pss_to_ctx(ctx, NULL, sigalg, pkey) > 0) {
         /* Carry on */
         return 2;
+    }
     return -1;
 }