Prevent exhaustion of system resources through exploitation of event cache

This patch changes res_xmpp to no longer cache events under certain circumstances.

(issue ASTERISK-20175)
Reported by: Russell Bryant, Leif Madsen, Joshua Colp
Tested by: kmoore
........

Merged revisions 378411 from http://svn.asterisk.org/svn/asterisk/branches/11

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@378412 65c4cc65-6c06-0410-ace0-fbb531ad65f3

diff --git a/res/res_xmpp.c b/res/res_xmpp.c
index d490ee5..1e130e7 100644 (file)
--- a/res/res_xmpp.c
+++ b/res/res_xmpp.c
@@ -928,7 +928,7 @@ static iks* xmpp_pubsub_iq_create(struct ast_xmpp_client *client, const char *ty
  * \return iks *
  */
 static iks* xmpp_pubsub_build_publish_skeleton(struct ast_xmpp_client *client, const char *node,
-                                              const char *event_type)
+                                              const char *event_type, unsigned int cachable)
 {
        RAII_VAR(struct xmpp_config *, cfg, ao2_global_obj_ref(globals), ao2_cleanup);
        iks *request, *pubsub, *publish, *item;
@@ -944,6 +944,22 @@ static iks* xmpp_pubsub_build_publish_skeleton(struct ast_xmpp_client *client, c
        item = iks_insert(publish, "item");
        iks_insert_attrib(item, "id", node);
 
+       if (cachable == AST_DEVSTATE_NOT_CACHABLE) {
+               iks *options, *x, *field_form_type, *field_persist;
+
+               options = iks_insert(pubsub, "publish-options");
+               x = iks_insert(options, "x");
+               iks_insert_attrib(x, "xmlns", "jabber:x:data");
+               iks_insert_attrib(x, "type", "submit");
+               field_form_type = iks_insert(x, "field");
+               iks_insert_attrib(field_form_type, "var", "FORM_TYPE");
+               iks_insert_attrib(field_form_type, "type", "hidden");
+               iks_insert_cdata(iks_insert(field_form_type, "value"), "http://jabber.org/protocol/pubsub#publish-options", 0);
+               field_persist = iks_insert(x, "field");
+               iks_insert_attrib(field_persist, "var", "pubsub#persist_items");
+               iks_insert_cdata(iks_insert(field_persist, "value"), "0", 1);
+       }
+
        return item;
 
 }
@@ -1120,7 +1136,7 @@ static void xmpp_pubsub_publish_mwi(struct ast_xmpp_client *client, const char *
 
        snprintf(full_mailbox, sizeof(full_mailbox), "%s@%s", mailbox, context);
 
-       if (!(request = xmpp_pubsub_build_publish_skeleton(client, full_mailbox, "message_waiting"))) {
+       if (!(request = xmpp_pubsub_build_publish_skeleton(client, full_mailbox, "message_waiting", AST_DEVSTATE_CACHABLE))) {
                return;
        }
 
@@ -1144,13 +1160,13 @@ static void xmpp_pubsub_publish_mwi(struct ast_xmpp_client *client, const char *
  * \return void
  */
 static void xmpp_pubsub_publish_device_state(struct ast_xmpp_client *client, const char *device,
-                                            const char *device_state)
+                                            const char *device_state, unsigned int cachable)
 {
        RAII_VAR(struct xmpp_config *, cfg, ao2_global_obj_ref(globals), ao2_cleanup);
        iks *request, *state;
-       char eid_str[20];
+       char eid_str[20], cachable_str[2];
 
-       if (!cfg || !cfg->global || !(request = xmpp_pubsub_build_publish_skeleton(client, device, "device_state"))) {
+       if (!cfg || !cfg->global || !(request = xmpp_pubsub_build_publish_skeleton(client, device, "device_state", cachable))) {
                return;
        }
 
@@ -1166,6 +1182,8 @@ static void xmpp_pubsub_publish_device_state(struct ast_xmpp_client *client, con
        state = iks_insert(request, "state");
        iks_insert_attrib(state, "xmlns", "http://asterisk.org");
        iks_insert_attrib(state, "eid", eid_str);
+       snprintf(cachable_str, sizeof(cachable_str), "%u", cachable);
+       iks_insert_attrib(state, "cachable", cachable_str);
        iks_insert_cdata(state, device_state, strlen(device_state));
        ast_xmpp_client_send(client, iks_root(request));
        iks_delete(request);
@@ -1208,6 +1226,7 @@ static void xmpp_pubsub_devstate_cb(const struct ast_event *ast_event, void *dat
 {
        struct ast_xmpp_client *client = data;
        const char *device, *device_state;
+       unsigned int cachable;
 
        if (ast_eid_cmp(&ast_eid_default, ast_event_get_ie_raw(ast_event, AST_EVENT_IE_EID))) {
                /* If the event didn't originate from this server, don't send it back out. */
@@ -1217,7 +1236,8 @@ static void xmpp_pubsub_devstate_cb(const struct ast_event *ast_event, void *dat
 
        device = ast_event_get_ie_str(ast_event, AST_EVENT_IE_DEVICE);
        device_state = ast_devstate_str(ast_event_get_ie_uint(ast_event, AST_EVENT_IE_STATE));
-       xmpp_pubsub_publish_device_state(client, device, device_state);
+       cachable = ast_event_get_ie_uint(ast_event, AST_EVENT_IE_CACHABLE);
+       xmpp_pubsub_publish_device_state(client, device, device_state, cachable);
 }
 
 /*!
@@ -1301,11 +1321,12 @@ static void xmpp_pubsub_subscribe(struct ast_xmpp_client *client, const char *no
  */
 static int xmpp_pubsub_handle_event(void *data, ikspak *pak)
 {
-       char *item_id, *device_state, *context;
+       char *item_id, *device_state, *context, *cachable_str;
        int oldmsgs, newmsgs;
        iks *item, *item_content;
        struct ast_eid pubsub_eid;
        struct ast_event *event;
+       unsigned int cachable = AST_DEVSTATE_CACHABLE;
        item = iks_find(iks_find(iks_find(pak->x, "event"), "items"), "item");
        if (!item) {
                ast_log(LOG_ERROR, "Could not parse incoming PubSub event\n");
@@ -1320,6 +1341,9 @@ static int xmpp_pubsub_handle_event(void *data, ikspak *pak)
        }
        if (!strcasecmp(iks_name(item_content), "state")) {
                device_state = iks_find_cdata(item, "state");
+               if ((cachable_str = iks_find_cdata(item, "cachable"))) {
+                       sscanf(cachable_str, "%30d", &cachable);
+               }
                if (!(event = ast_event_new(AST_EVENT_DEVICE_STATE_CHANGE,
                                            AST_EVENT_IE_DEVICE, AST_EVENT_IE_PLTYPE_STR, item_id, AST_EVENT_IE_STATE,
                                            AST_EVENT_IE_PLTYPE_UINT, ast_devstate_val(device_state), AST_EVENT_IE_EID,
@@ -1344,7 +1368,13 @@ static int xmpp_pubsub_handle_event(void *data, ikspak *pak)
                          iks_name(item_content));
                return IKS_FILTER_EAT;
        }
-       ast_event_queue_and_cache(event);
+
+       if (cachable == AST_DEVSTATE_CACHABLE) {
+               ast_event_queue_and_cache(event);
+       } else {
+               ast_event_queue(event);
+       }
+
        return IKS_FILTER_EAT;
 }