commit 8f12296e2356a0daf751cbc00aed14d4c31a2476
author Dr. Stephen Henson <steve@openssl.org> Fri Mar 03 02:44:18 2017 +0000
committer Dr. Stephen Henson <steve@openssl.org> Fri Mar 03 21:58:33 2017 +0000
tree e7b884fd24ca39d75866fab404ef1f4de4fb045f
parent 224b4e37c075f5bbe1573a90a1dc5e5d9a91d9c1

Disallow zero length signature algorithms

Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2840)

ssl/statem/statem_srvr.c

diff --git a/ssl/statem/statem_srvr.c b/ssl/statem/statem_srvr.c
index 7414c19..6c007a1 100644
--- a/ssl/statem/statem_srvr.c
+++ b/ssl/statem/statem_srvr.c
@@ -2497,6 +2497,7 @@
         size_t nl = tls12_get_psigalgs(s, 1, &psigs);
 
         if (!WPACKET_start_sub_packet_u16(pkt)
+                || !WPACKET_set_flags(pkt, WPACKET_FLAGS_NON_ZERO_LENGTH)
                 || !tls12_copy_sigalgs(s, pkt, psigs, nl)
                 || !WPACKET_close(pkt)) {
             SSLerr(SSL_F_TLS_CONSTRUCT_CERTIFICATE_REQUEST,

ssl/t1_lib.c

diff --git a/ssl/t1_lib.c b/ssl/t1_lib.c
index 87ef620..93a8cfe 100644
--- a/ssl/t1_lib.c
+++ b/ssl/t1_lib.c
@@ -1563,7 +1563,7 @@
     size = PACKET_remaining(pkt);
 
     /* Invalid data length */
-    if ((size & 1) != 0)
+    if (size == 0 || (size & 1) != 0)
         return 0;
 
     size >>= 1;