Merged revisions 372710 via svnmerge from

file:///srv/subversion/repos/asterisk/branches/10

................
  r372710 | mjordan | 2012-09-08 20:24:36 -0500 (Sat, 08 Sep 2012) | 24 lines

  Only re-create an SRTP session when needed

  In r356604, SRTP handling was fixed to accomodate multiple crypto keys in an
  SDP offer and the ability to re-create an SRTP session when the crypto keys
  changed.  In certain circumstances - most notably when a phone is put on
  hold after having been bridged for a significant amount of time - the act
  of re-creating the SRTP session causes problems for certain models of phones.
  The patch committed in r356604 always re-created the SRTP session regardless
  of whether or not the cryptographic keys changed.  Since this is technically
  not necessary, this patch modifies the behavior to only re-create the SRTP
  session if Asterisk detects that the remote key has changed.  This allows
  models of phones that do not handle the SRTP session changing to continue
  to work, while also providing the behavior needed for those phones that do
  re-negotiate cryptographic keys.

  (issue ASTERISK-20194)
  Reported by: Nicolo Mazzon
  Tested by: Nicolo Mazzon

  Review: https://reviewboard.asterisk.org/r/2099
  ........

  Merged revisions 372709 from http://svn.asterisk.org/svn/asterisk/branches/1.8
................

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/10-digiumphones@372735 65c4cc65-6c06-0410-ace0-fbb531ad65f3

diff --git a/channels/sip/sdp_crypto.c b/channels/sip/sdp_crypto.c
index 1342d079d02b1012e9577033c0c77e88e9fd78eb..0372e7caf6d25b48781f2d92133a920689b142ae 100644 (file)
--- a/channels/sip/sdp_crypto.c
+++ b/channels/sip/sdp_crypto.c
@@ -50,6 +50,7 @@ struct sdp_crypto {
        char *a_crypto;
        unsigned char local_key[SRTP_MASTER_LEN];
        char local_key64[SRTP_MASTER_LEN64];
+       unsigned char remote_key[SRTP_MASTER_LEN];
 };
 
 static int set_crypto_policy(struct ast_srtp_policy *policy, int suite_val, const unsigned char *master_key, unsigned long ssrc, int inbound);
@@ -260,12 +261,17 @@ int sdp_crypto_process(struct sdp_crypto *p, const char *attr, struct ast_rtp_in
                return -1;
        }
 
-
        if ((key_len = ast_base64decode(remote_key, key_salt, sizeof(remote_key))) != SRTP_MASTER_LEN) {
-               ast_log(LOG_WARNING, "SRTP sdescriptions key %d != %d\n", key_len, SRTP_MASTER_LEN);
+               ast_log(LOG_WARNING, "SRTP descriptions key %d != %d\n", key_len, SRTP_MASTER_LEN);
                return -1;
        }
 
+       if (!memcmp(p->remote_key, remote_key, sizeof(p->remote_key))) {
+               ast_debug(1, "SRTP remote key unchanged; maintaining current policy\n");
+               return 0;
+       }
+       memcpy(p->remote_key, remote_key, sizeof(p->remote_key));
+
        if (sdp_crypto_activate(p, suite_val, remote_key, rtp) < 0) {
                return -1;
        }