Do not match RFC 5114 groups without q as it is significant

Reviewed-by: Paul Dale <pauli@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/14189)

diff --git a/crypto/ffc/ffc_dh.c b/crypto/ffc/ffc_dh.c
index 313466b0eac3345f2d725d0964027eb2ff1a6b57..948c61d988ba9eff1b8e4c87d73dbefd4f856573 100644 (file)
--- a/crypto/ffc/ffc_dh.c
+++ b/crypto/ffc/ffc_dh.c
@@ -110,7 +110,9 @@ const DH_NAMED_GROUP *ossl_ffc_numbers_to_dh_named_group(const BIGNUM *p,
         if (BN_cmp(p, dh_named_groups[i].p) == 0
             && BN_cmp(g, dh_named_groups[i].g) == 0
             /* Verify q is correct if it exists */
-            && (q == NULL || BN_cmp(q, dh_named_groups[i].q) == 0))
+            && ((q != NULL && BN_cmp(q, dh_named_groups[i].q) == 0)
+                /* Do not match RFC 5114 groups without q */
+                || (q == NULL && dh_named_groups[i].uid > 3)))
             return &dh_named_groups[i];
     }
     return NULL;