chan_sip: Reject calls without prior SDP on 200 OK

If we receive a 200 OK without SDP, we will now check to see if
the remote address has been established for that channel's RTP
session and if the to tag for that channel has changed from
the most recent to tag in a response less than 200.
If either a change has been made since the last to-tag was
received or the remote address is unset, then we will drop
the call.

(closes issue ASTERISK-22424)
Reported by: Jonathan Rose
Review: https://reviewboard.asterisk.org/r/2827/diff/#index_header

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.8@398835 65c4cc65-6c06-0410-ace0-fbb531ad65f3

diff --git a/channels/chan_sip.c b/channels/chan_sip.c
index cd7c70e03c31c5c145c2d92ca7a66aeff1452f48..612b9dc239e89fe6103aee4cd1d13cdbb7f3a482 100644 (file)
--- a/channels/chan_sip.c
+++ b/channels/chan_sip.c
@@ -20907,6 +20907,15 @@ static void handle_response_invite(struct sip_pvt *p, int resp, const char *rest
                                        ast_set_flag(&p->flags[0], SIP_PENDINGBYE);
                                }
                        ast_rtp_instance_activate(p->rtp);
+               } else if (!reinvite) {
+                       struct ast_sockaddr remote_address = {{0,}};
+
+                       ast_rtp_instance_get_remote_address(p->rtp, &remote_address);
+                       if (ast_sockaddr_isnull(&remote_address) || (!ast_strlen_zero(p->theirprovtag) && strcmp(p->theirtag, p->theirprovtag))) {
+                               ast_log(LOG_WARNING, "Received response: \"200 OK\" from '%s' without SDP\n", p->relatedpeer->name);
+                               ast_set_flag(&p->flags[0], SIP_PENDINGBYE);
+                               ast_rtp_instance_activate(p->rtp);
+                       }
                }
 
                if (!req->ignore && p->owner) {
@@ -21762,7 +21771,11 @@ static void handle_response(struct sip_pvt *p, int resp, const char *rest, struc
 
                gettag(req, "To", tag, sizeof(tag));
                ast_string_field_set(p, theirtag, tag);
+       } else {
+               /* Store theirtag to track for changes when 200 responses to invites are received without SDP */
+               ast_string_field_set(p, theirprovtag, p->theirtag);
        }
+
        /* This needs to be configurable on a channel/peer level,
           not mandatory for all communication. Sadly enough, NAT implementations
           are not so stable so we can always rely on these headers.

diff --git a/channels/sip/include/sip.h b/channels/sip/include/sip.h
index 75730e60e06165e24b6aa525092403ab8b5a9f1b..ec9984616a60dd031f3c40a6b0de3aaa8f856548 100644 (file)
--- a/channels/sip/include/sip.h
+++ b/channels/sip/include/sip.h
@@ -967,6 +967,7 @@ struct sip_pvt {
                AST_STRING_FIELD(rdnis);        /*!< Referring DNIS */
                AST_STRING_FIELD(redircause);   /*!< Referring cause */
                AST_STRING_FIELD(theirtag);     /*!< Their tag */
+               AST_STRING_FIELD(theirprovtag); /*!< Provisional their tag, used when evaluating responses to invites */
                AST_STRING_FIELD(tag);          /*!< Our tag for this session */
                AST_STRING_FIELD(username);     /*!< [user] name */
                AST_STRING_FIELD(peername);     /*!< [peer] name, not set if [user] */