EDH >= 1024 bits even at security level 0

Reviewed-by: Rich Salz <rsalz@openssl.org>
Reviewed-by: Richard Levitte <levitte@openssl.org>

ssl/ssl_cert.c

diff --git a/ssl/ssl_cert.c b/ssl/ssl_cert.c
index 7f01bcc..75ccc72 100644
--- a/ssl/ssl_cert.c
+++ b/ssl/ssl_cert.c
@@ -1062,9 +1062,16 @@
         level = SSL_CTX_get_security_level(ctx);
     else
         level = SSL_get_security_level(s);
-    /* Level 0: anything goes */
-    if (level <= 0)
+
+    if (level <= 0) {
+        /*
+         * No EDH keys weaker than 1024-bits even at level 0, otherwise,
+         * anything goes.
+         */
+        if (op == SSL_SECOP_TMP_DH && bits < 80)
+            return 0;
         return 1;
+    }
     if (level > 5)
         level = 5;
     minbits = minbits_table[level - 1];