Fix TLS 1.2 and no sigalgs.

For TLS 1.2 if we have no signature algorithms extension then lookup
using the complete table instead of (empty) shared signature algorithms
list so we pick up defaults.

Reviewed-by: Richard Levitte <levitte@openssl.org>
Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2301)

diff --git a/ssl/t1_lib.c b/ssl/t1_lib.c
index dbd0fb6cc6c556da974ada1c0648ceecd0a2a961..6f7ef965be36b1400a69a6a58495edb021212562 100644 (file)
--- a/ssl/t1_lib.c
+++ b/ssl/t1_lib.c
@@ -1278,6 +1278,7 @@ int tls12_get_sigandhash(SSL *s, WPACKET *pkt, const EVP_PKEY *pk,
 {
     int md_id, sig_id;
     size_t i;
+    const SIGALG_LOOKUP *curr;
 
     if (md == NULL)
         return 0;
@@ -1289,8 +1290,25 @@ int tls12_get_sigandhash(SSL *s, WPACKET *pkt, const EVP_PKEY *pk,
     if (SSL_IS_TLS13(s) && sig_id == EVP_PKEY_RSA)
         sig_id = EVP_PKEY_RSA_PSS;
 
+    if (s->s3->tmp.peer_sigalgs == NULL) {
+        /* Should never happen: we abort if no sigalgs extension and TLS 1.3 */
+        if (SSL_IS_TLS13(s))
+            return 0;
+        /* For TLS 1.2 and no sigalgs lookup using complete table */
+        for (i = 0, curr = sigalg_lookup_tbl; i < OSSL_NELEM(sigalg_lookup_tbl);
+             i++, curr++) {
+            if (curr->hash == md_id && curr->sig == sig_id) {
+                if (!WPACKET_put_bytes_u16(pkt, curr->sigalg))
+                    return 0;
+                *ispss = curr->sig == EVP_PKEY_RSA_PSS;
+                return 1;
+            }
+        }
+        return 0;
+    }
+
     for (i = 0; i < s->cert->shared_sigalgslen; i++) {
-        const SIGALG_LOOKUP *curr = s->cert->shared_sigalgs[i];
+        curr = s->cert->shared_sigalgs[i];
 
         /*
          * Look for matching key and hash. If key type is RSA also match PSS