Fixed crash from orphaned MWI subscriptions in chan_sip
authorMatthew Jordan <mjordan@digium.com>
Tue, 6 Dec 2011 17:34:35 +0000 (17:34 +0000)
committerMatthew Jordan <mjordan@digium.com>
Tue, 6 Dec 2011 17:34:35 +0000 (17:34 +0000)
This patch resolves the issue where MWI subscriptions are orphaned
by subsequent SIP SUBSCRIBE messages.  When a peer is removed, either
by pruning realtime SIP peers or by unloading / loading chan_sip, the
MWI subscriptions that were orphaned would still be on the event engine
list of valid subscriptions but have a pointer to a peer that no longer
was valid.  When an MWI event would occur, this would cause a seg fault.

(closes issue ASTERISK-18663)
Reported by: Ross Beer
Tested by: Ross Beer, Matt Jordan
Patches:
  blf_mwi_diff_12_06_11.txt uploaded by Matt Jordan (license 6283)

Review: https://reviewboard.asterisk.org/r/1610/
........

Merged revisions 347058 from http://svn.asterisk.org/svn/asterisk/branches/1.8
........

Merged revisions 347068 from http://svn.asterisk.org/svn/asterisk/branches/10

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@347069 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/chan_sip.c

index a10106d..ab25f1c 100644 (file)
@@ -24940,11 +24940,21 @@ static int handle_request_publish(struct sip_pvt *p, struct sip_request *req, st
        return handler_result;
 }
 
+/*! \internal \brief Subscribe to MWI events for the specified peer
+ * \note The peer cannot be locked during this method.  sip_send_mwi_peer will
+ * attempt to lock the peer after the event subscription lock is held; if the peer is locked during
+ * this method then we will attempt to lock the event subscription lock but after the peer, creating
+ * a locking inversion.
+ */
 static void add_peer_mwi_subs(struct sip_peer *peer)
 {
        struct sip_mailbox *mailbox;
 
        AST_LIST_TRAVERSE(&peer->mailboxes, mailbox, entry) {
+               if (mailbox->event_sub) {
+                       ast_event_unsubscribe(mailbox->event_sub);
+               }
+
                mailbox->event_sub = ast_event_subscribe(AST_EVENT_MWI, mwi_event_cb, "SIP mbox event", peer,
                        AST_EVENT_IE_MAILBOX, AST_EVENT_IE_PLTYPE_STR, mailbox->mailbox,
                        AST_EVENT_IE_CONTEXT, AST_EVENT_IE_PLTYPE_STR, S_OR(mailbox->context, "default"),
@@ -25098,7 +25108,7 @@ static int handle_request_subscribe(struct sip_pvt *p, struct sip_request *req,
                /* if an authentication response was sent, we are done here */
                if (res == AUTH_CHALLENGE_SENT) /* authpeer = NULL here */
                        return 0;
-               if (res < 0) {
+               if (res != AUTH_SUCCESSFUL) {
                        if (res == AUTH_FAKE_AUTH) {
                                ast_log(LOG_NOTICE, "Sending fake auth rejection for device %s\n", sip_get_header(req, "From"));
                                transmit_fake_auth_response(p, SIP_SUBSCRIBE, req, XMIT_UNRELIABLE);
@@ -25112,17 +25122,17 @@ static int handle_request_subscribe(struct sip_pvt *p, struct sip_request *req,
                }
        }
 
-       /* At this point, authpeer cannot be NULL. Remember we hold a reference,
-        * so we must release it when done.
-        * XXX must remove all the checks for authpeer == NULL.
+       /* At this point, we hold a reference to authpeer (if not NULL).  It
+        * must be released when done.
         */
 
        /* Check if this device  is allowed to subscribe at all */
        if (!ast_test_flag(&p->flags[1], SIP_PAGE2_ALLOWSUBSCRIBE)) {
                transmit_response(p, "403 Forbidden (policy)", req);
                pvt_set_needdestroy(p, "subscription not allowed");
-               if (authpeer)
+               if (authpeer) {
                        sip_unref_peer(authpeer, "sip_unref_peer, from handle_request_subscribe (authpeer 1)");
+               }
                return 0;
        }
 
@@ -25142,8 +25152,9 @@ static int handle_request_subscribe(struct sip_pvt *p, struct sip_request *req,
                        transmit_response(p, "404 Not Found", req);
                }
                pvt_set_needdestroy(p, "subscription target not found");
-               if (authpeer)
+               if (authpeer) {
                        sip_unref_peer(authpeer, "sip_unref_peer, from handle_request_subscribe (authpeer 2)");
+               }
                return 0;
        }
 
@@ -25158,9 +25169,6 @@ static int handle_request_subscribe(struct sip_pvt *p, struct sip_request *req,
                enum subscriptiontype subscribed = NONE;
                const char *unknown_acceptheader = NULL;
 
-               if (authpeer)   /* We do not need the authpeer any more */
-                       authpeer = sip_unref_peer(authpeer, "sip_unref_peer, from handle_request_subscribe (authpeer 2)");
-
                /* Header from Xten Eye-beam Accept: multipart/related, application/rlmi+xml, application/pidf+xml, application/xpidf+xml */
                accept = __get_header(req, "Accept", &start);
                while ((subscribed == NONE) && !ast_strlen_zero(accept)) {
@@ -25198,6 +25206,9 @@ static int handle_request_subscribe(struct sip_pvt *p, struct sip_request *req,
                                        p->subscribecontext,
                                        p->subscribeuri);
                                pvt_set_needdestroy(p, "no Accept header");
+                               if (authpeer) {
+                                       sip_unref_peer(authpeer, "sip_unref_peer, from handle_request_subscribe (authpeer 2)");
+                               }
                                return 0;
                        }
                        /* if p->subscribed is non-zero, then accept is not obligatory; according to rfc 3265 section 3.1.3, at least.
@@ -25222,6 +25233,9 @@ static int handle_request_subscribe(struct sip_pvt *p, struct sip_request *req,
                                p->subscribecontext,
                                p->subscribeuri);
                        pvt_set_needdestroy(p, "unrecognized format");
+                       if (authpeer) {
+                               sip_unref_peer(authpeer, "sip_unref_peer, from handle_request_subscribe (authpeer 2)");
+                       }
                        return 0;
                } else {
                        p->subscribed = subscribed;
@@ -25244,8 +25258,9 @@ static int handle_request_subscribe(struct sip_pvt *p, struct sip_request *req,
                        transmit_response(p, "406 Not Acceptable", req);
                        ast_debug(2, "Received SIP mailbox subscription for unknown format: %s\n", acceptheader);
                        pvt_set_needdestroy(p, "unknown format");
-                       if (authpeer)
+                       if (authpeer) {
                                sip_unref_peer(authpeer, "sip_unref_peer, from handle_request_subscribe (authpeer 3)");
+                       }
                        return 0;
                }
                /* Looks like they actually want a mailbox status
@@ -25254,11 +25269,17 @@ static int handle_request_subscribe(struct sip_pvt *p, struct sip_request *req,
                  In most devices, this is configurable to the voicemailmain extension you use
                */
                if (!authpeer || AST_LIST_EMPTY(&authpeer->mailboxes)) {
-                       transmit_response(p, "404 Not found (no mailbox)", req);
+                       if (!authpeer) {
+                               transmit_response(p, "404 Not found", req);
+                       } else {
+                               transmit_response(p, "404 Not found (no mailbox)", req);
+                               ast_log(LOG_NOTICE, "Received SIP subscribe for peer without mailbox: %s\n", S_OR(authpeer->name, ""));
+                       }
                        pvt_set_needdestroy(p, "received 404 response");
-                       ast_log(LOG_NOTICE, "Received SIP subscribe for peer without mailbox: %s\n", S_OR(authpeer->name, ""));
-                       if (authpeer)
-                               sip_unref_peer(authpeer, "sip_unref_peer, from handle_request_subscribe (authpeer 4)");
+
+                       if (authpeer) {
+                               sip_unref_peer(authpeer, "sip_unref_peer, from handle_request_subscribe (authpeer 3)");
+                       }
                        return 0;
                }
 
@@ -25268,18 +25289,21 @@ static int handle_request_subscribe(struct sip_pvt *p, struct sip_request *req,
                        add_peer_mwi_subs(authpeer);
                        ao2_lock(p);
                }
-               if (authpeer->mwipvt && authpeer->mwipvt != p) {        /* Destroy old PVT if this is a new one */
+               if (authpeer->mwipvt != p) {    /* Destroy old PVT if this is a new one */
                        /* We only allow one subscription per peer */
-                       dialog_unlink_all(authpeer->mwipvt);
-                       authpeer->mwipvt = dialog_unref(authpeer->mwipvt, "unref dialog authpeer->mwipvt");
-                       /* sip_destroy(authpeer->mwipvt); */
-               }
-               if (authpeer->mwipvt)
-                       dialog_unref(authpeer->mwipvt, "Unref previously stored mwipvt dialog pointer");
-               authpeer->mwipvt = dialog_ref(p, "setting peers' mwipvt to p");         /* Link from peer to pvt UH- should this be dialog_ref()? */
-               if (p->relatedpeer)
-                       sip_unref_peer(p->relatedpeer, "Unref previously stored relatedpeer ptr");
-               p->relatedpeer = sip_ref_peer(authpeer, "setting dialog's relatedpeer pointer");        /* already refcounted...Link from pvt to peer UH- should this be dialog_ref()? */
+                       if (authpeer->mwipvt) {
+                               dialog_unlink_all(authpeer->mwipvt);
+                               authpeer->mwipvt = dialog_unref(authpeer->mwipvt, "unref dialog authpeer->mwipvt");
+                       }
+                       authpeer->mwipvt = dialog_ref(p, "setting peers' mwipvt to p");
+               }
+
+               if (p->relatedpeer != authpeer) {
+                       if (p->relatedpeer) {
+                               sip_unref_peer(p->relatedpeer, "Unref previously stored relatedpeer ptr");
+                       }
+                       p->relatedpeer = sip_ref_peer(authpeer, "setting dialog's relatedpeer pointer");
+               }
                /* Do not release authpeer here */
        } else if (!strcmp(event, "call-completion")) {
                handle_cc_subscribe(p, req);
@@ -25287,16 +25311,12 @@ static int handle_request_subscribe(struct sip_pvt *p, struct sip_request *req,
                transmit_response(p, "489 Bad Event", req);
                ast_debug(2, "Received SIP subscribe for unknown event package: %s\n", event);
                pvt_set_needdestroy(p, "unknown event package");
-               if (authpeer)
+               if (authpeer) {
                        sip_unref_peer(authpeer, "sip_unref_peer, from handle_request_subscribe (authpeer 5)");
+               }
                return 0;
        }
 
-       /* At this point, if we have an authpeer we should unref it. */
-       if (authpeer) {
-               authpeer = sip_unref_peer(authpeer, "unref pointer into (*authpeer)");
-       }
-
        /* Add subscription for extension state from the PBX core */
        if (p->subscribed != MWI_NOTIFICATION  && p->subscribed != CALL_COMPLETION && !resubscribe) {
                if (p->stateid > -1) {
@@ -25321,6 +25341,9 @@ static int handle_request_subscribe(struct sip_pvt *p, struct sip_request *req,
                                "with Expire header less that 'minexpire' limit. Received \"Expire: %d\" min is %d\n",
                                p->exten, p->context, p->expiry, min_expiry);
                        pvt_set_needdestroy(p, "Expires is less that the min expires allowed.");
+                       if (authpeer) {
+                               sip_unref_peer(authpeer, "sip_unref_peer, from handle_request_subscribe (authpeer 6)");
+                       }
                        return 0;
                }
 
@@ -25356,6 +25379,9 @@ static int handle_request_subscribe(struct sip_pvt *p, struct sip_request *req,
                                ast_log(LOG_NOTICE, "Got SUBSCRIBE for extension %s@%s from %s, but there is no hint for that extension.\n", p->exten, p->context, ast_sockaddr_stringify(&p->sa));
                                transmit_response(p, "404 Not found", req);
                                pvt_set_needdestroy(p, "no extension for SUBSCRIBE");
+                               if (authpeer) {
+                                       sip_unref_peer(authpeer, "sip_unref_peer, from handle_request_subscribe (authpeer 6)");
+                               }
                                return 0;
                        }
                        ast_set_flag(&p->flags[1], SIP_PAGE2_DIALOG_ESTABLISHED);
@@ -25371,6 +25397,10 @@ static int handle_request_subscribe(struct sip_pvt *p, struct sip_request *req,
                        pvt_set_needdestroy(p, "forcing expiration");
                }
        }
+
+       if (authpeer) {
+               sip_unref_peer(authpeer, "unref pointer into (*authpeer)");
+       }
        return 1;
 }
 
@@ -26088,7 +26118,7 @@ static int get_cached_mwi(struct sip_peer *peer, int *new, int *old)
  */
 static int sip_send_mwi_to_peer(struct sip_peer *peer, int cache_only)
 {
-       /* Called with peerl lock, but releases it */
+       /* Called with peer lock, but releases it */
        struct sip_pvt *p;
        int newmsgs = 0, oldmsgs = 0;
        const char *vmexten = NULL;