Convert ssl_parse_serverhello_use_srtp_ext to CBS.

ok miod@ jsing@

1 files changed, 15 insertions, 10 deletions

diff --git a/src/lib/libssl/d1_srtp.c b/src/lib/libssl/d1_srtp.c
index 8f05c4abc8..2974691e3c 100644
--- a/src/lib/libssl/d1_srtp.c
+++ b/src/lib/libssl/d1_srtp.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: d1_srtp.c,v 1.13 2015/07/15 21:52:02 beck Exp $ */
+/* $OpenBSD: d1_srtp.c,v 1.14 2015/07/17 17:36:24 doug Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -404,32 +404,37 @@ ssl_add_serverhello_use_srtp_ext(SSL *s, unsigned char *p, int *len, int maxlen)
 
 
 int
-ssl_parse_serverhello_use_srtp_ext(SSL *s, unsigned char *d, int len, int *al)
+ssl_parse_serverhello_use_srtp_ext(SSL *s, const unsigned char *d, int len, int *al)
 {
         STACK_OF(SRTP_PROTECTION_PROFILE) *clnt;
         SRTP_PROTECTION_PROFILE *prof;
-        unsigned id;
         int i;
-        int ct;
+        uint16_t id;
+        CBS cbs, profile_ids, mki;
 
-        if (len != 5) {
+        if (len < 0) {
                 SSLerr(SSL_F_SSL_PARSE_SERVERHELLO_USE_SRTP_EXT,
                     SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST);
                 *al = SSL_AD_DECODE_ERROR;
                 return 1;
         }
 
-        n2s(d, ct);
-        if (ct != 2) {
+        CBS_init(&cbs, d, len);
+
+        /*
+         * As per RFC 5764 section 4.1.1, server response MUST be a single
+         * profile id.
+         */
+        if (!CBS_get_u16_length_prefixed(&cbs, &profile_ids) ||
+            !CBS_get_u16(&profile_ids, &id) || CBS_len(&profile_ids) != 0) {
                 SSLerr(SSL_F_SSL_PARSE_SERVERHELLO_USE_SRTP_EXT,
                     SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST);
                 *al = SSL_AD_DECODE_ERROR;
                 return 1;
         }
 
-        n2s(d, id);
-        if (*d) {
-                /* Must be no MKI, since we never offer one. */
+        /* Must be no MKI, since we never offer one. */
+        if (!CBS_get_u8_length_prefixed(&cbs, &mki) || CBS_len(&mki) != 0) {
                 SSLerr(SSL_F_SSL_PARSE_SERVERHELLO_USE_SRTP_EXT,
                     SSL_R_BAD_SRTP_MKI_VALUE);
                 *al = SSL_AD_ILLEGAL_PARAMETER;