Submitted by: Martin Kaiser

Reject PSS signatures with unsupported trailer value.

diff --git a/crypto/rsa/rsa_ameth.c b/crypto/rsa/rsa_ameth.c
index 4daeca18a99df60524ed46e4d5a2a89c05720645..6f790c2548c1b625b4b4c5ca72acfaf7acddde70 100644 (file)
--- a/crypto/rsa/rsa_ameth.c
+++ b/crypto/rsa/rsa_ameth.c
@@ -530,6 +530,15 @@ static int rsa_item_verify(EVP_MD_CTX *ctx, const ASN1_ITEM *it, void *asn,
        else
                saltlen = 20;
 
+       /* low-level routines support only trailer field 0xbc (value 1)
+        * and PKCS#1 says we should reject any other value anyway.
+        */
+       if (pss->trailerField && ASN1_INTEGER_get(pss->trailerField) != 1)
+               {
+               RSAerr(RSA_F_RSA_ITEM_VERIFY, RSA_R_INVALID_TRAILER);
+               goto err;
+               }
+
        /* We have all parameters now set up context */
 
        if (!EVP_DigestVerifyInit(ctx, &pkctx, md, NULL, pkey))