commit 703bcee021790d33e07809c9b07fd51d2b4b5474
author Matt Caswell <matt@openssl.org> Wed Dec 14 14:31:21 2016 +0000
committer Matt Caswell <matt@openssl.org> Tue Jan 10 23:02:50 2017 +0000
tree 329bdc88314a202c2d53896b5e1901e15de2b3f2
parent 5f9b64a2fdfd0ccf04d58c8b04d576f13950d63f

Convert Sigalgs processing to use ints

In TLSv1.2 an individual sig alg is represented by 1 byte for the hash
and 1 byte for the signature. In TLSv1.3 each sig alg is represented by
two bytes, where the two bytes together represent a single hash and
signature combination. This converts the internal representation of sigalgs
to use a single int for the pair, rather than a pair of bytes.

Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2157)

ssl/statem/statem_clnt.c

diff --git a/ssl/statem/statem_clnt.c b/ssl/statem/statem_clnt.c
index ff57e92..432dc91 100644
--- a/ssl/statem/statem_clnt.c
+++ b/ssl/statem/statem_clnt.c
@@ -1880,14 +1880,15 @@
         }
 
         if (SSL_USE_SIGALGS(s)) {
-            const unsigned char *sigalgs;
+            unsigned int sigalg;
             int rv;
-            if (!PACKET_get_bytes(pkt, &sigalgs, 2)) {
+
+            if (!PACKET_get_net_2(pkt, &sigalg)) {
                 al = SSL_AD_DECODE_ERROR;
                 SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, SSL_R_LENGTH_TOO_SHORT);
                 goto err;
             }
-            rv = tls12_check_peer_sigalg(&md, s, sigalgs, pkey);
+            rv = tls12_check_peer_sigalg(&md, s, sigalg, pkey);
             if (rv == -1) {
                 al = SSL_AD_INTERNAL_ERROR;
                 goto err;
@@ -2026,8 +2027,9 @@
         s->s3->tmp.ctype[i] = data[i];
 
     if (SSL_USE_SIGALGS(s)) {
-        if (!PACKET_get_net_2(pkt, &list_len)
-            || !PACKET_get_bytes(pkt, &data, list_len)) {
+        PACKET sigalgs;
+
+        if (!PACKET_get_length_prefixed_2(pkt, &sigalgs)) {
             ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
             SSLerr(SSL_F_TLS_PROCESS_CERTIFICATE_REQUEST,
                    SSL_R_LENGTH_MISMATCH);
@@ -2039,7 +2041,7 @@
             s->s3->tmp.md[i] = NULL;
             s->s3->tmp.valid_flags[i] = 0;
         }
-        if ((list_len & 1) || !tls1_save_sigalgs(s, data, list_len)) {
+        if (!tls1_save_sigalgs(s, &sigalgs)) {
             ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
             SSLerr(SSL_F_TLS_PROCESS_CERTIFICATE_REQUEST,
                    SSL_R_SIGNATURE_ALGORITHMS_ERROR);