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chan_sip: Fix crash involving the bogus peer during sip reload. 

A crash happens sometimes when performing a CLI "sip reload".  The bogus
peer gets refreshed while it is in use by a new call which can cause the
crash.

* Protected the global bogus peer object with an ao2 global object
container.

ASTERISK-25610 #close

Change-Id: I5b528c742195681abcf713c6e1011ea65354eeed
This commit is contained in:
Richard Mudgett 2015-12-04 15:36:45 -06:00
parent 48c065e46d
commit 65c8147952
1 changed files with 21 additions and 12 deletions
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33
channels/chan_sip.c
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@ -997,9 +997,9 @@ static struct ao2_container *threadt;
static struct ao2_container *peers;
static struct ao2_container *peers_by_ip;
/*! \brief A bogus peer, to be used when authentication should fail */
static struct sip_peer *bogus_peer;
/*! \brief We can recognise the bogus peer by this invalid MD5 hash */
/*! \brief A bogus peer, to be used when authentication should fail */
static AO2_GLOBAL_OBJ_STATIC(g_bogus_peer);
/*! \brief We can recognize the bogus peer by this invalid MD5 hash */
#define BOGUS_PEER_MD5SECRET "intentionally_invalid_md5_string"
/*! \brief The register list: Other SIP proxies we register with and receive calls from */
@ -17228,8 +17228,7 @@ static enum check_auth_result register_verify(struct sip_pvt *p, struct ast_sock
/* If we don't want username disclosure, use the bogus_peer when a user
* is not found. */
if (!peer && sip_cfg.alwaysauthreject && sip_cfg.autocreatepeer == AUTOPEERS_DISABLED) {
peer = bogus_peer;
sip_ref_peer(peer, "register_verify: ref the bogus_peer");
peer = ao2_t_global_obj_ref(g_bogus_peer, "register_verify: Get the bogus peer.");
}
if (!(peer && ast_apply_acl(peer->acl, addr, "SIP Peer ACL: "))) {
@ -18482,6 +18481,7 @@ static enum check_auth_result check_peer_ok(struct sip_pvt *p, char *of,
enum check_auth_result res;
int debug = sip_debug_test_addr(addr);
struct sip_peer *peer;
struct sip_peer *bogus_peer;
if (sipmethod == SIP_SUBSCRIBE) {
/* For subscribes, match on device name only; for other methods,
@ -18521,8 +18521,13 @@ static enum check_auth_result check_peer_ok(struct sip_pvt *p, char *of,
/* If you do mind, we use a peer that will never authenticate.
* This ensures that we follow the same code path as regular
* auth: less chance for username disclosure. */
peer = bogus_peer;
sip_ref_peer(peer, "sip_ref_peer: check_peer_ok: must ref bogus_peer so unreffing it does not fail");
peer = ao2_t_global_obj_ref(g_bogus_peer, "check_peer_ok: Get the bogus peer.");
if (!peer) {
return AUTH_DONT_KNOW;
}
bogus_peer = peer;
} else {
bogus_peer = NULL;
}
/* build_peer, called through sip_find_peer, is not able to check the
@ -33194,7 +33199,7 @@ static int sip_do_reload(enum channelreloadreason reason)
/*! \brief Force reload of module from cli */
static char *sip_reload(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
{
static struct sip_peer *tmp_peer, *new_peer;
static struct sip_peer *new_peer;
switch (cmd) {
case CLI_INIT:
@ -33217,13 +33222,13 @@ static char *sip_reload(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a
ast_mutex_unlock(&sip_reload_lock);
restart_monitor();
tmp_peer = bogus_peer;
/* Create new bogus peer possibly with new global settings. */
if ((new_peer = temp_peer("(bogus_peer)"))) {
ast_string_field_set(new_peer, md5secret, BOGUS_PEER_MD5SECRET);
ast_clear_flag(&new_peer->flags[0], SIP_INSECURE);
bogus_peer = new_peer;
ao2_t_ref(tmp_peer, -1, "unref the old bogus_peer during reload");
ao2_t_global_obj_replace_unref(g_bogus_peer, new_peer,
"Replacing the old bogus peer during reload.");
ao2_t_ref(new_peer, -1, "done with new_peer");
} else {
ast_log(LOG_ERROR, "Could not update the fake authentication peer.\n");
/* You probably have bigger (memory?) issues to worry about though.. */
@ -34474,6 +34479,8 @@ static int unload_module(void);
*/
static int load_module(void)
{
struct sip_peer *bogus_peer;
ast_verbose("SIP channel loading...\n");
if (STASIS_MESSAGE_TYPE_INIT(session_timeout_type)) {
@ -34545,6 +34552,8 @@ static int load_module(void)
/* Make sure the auth will always fail. */
ast_string_field_set(bogus_peer, md5secret, BOGUS_PEER_MD5SECRET);
ast_clear_flag(&bogus_peer->flags[0], SIP_INSECURE);
ao2_t_global_obj_replace_unref(g_bogus_peer, bogus_peer, "Set the initial bogus peer.");
ao2_t_ref(bogus_peer, -1, "Module load is done with the bogus peer.");
/* Prepare the version that does not require DTMF BEGIN frames.
* We need to use tricks such as memcpy and casts because the variable
@ -34829,7 +34838,7 @@ static int unload_module(void)
ast_debug(2, "TCP/TLS thread container did not become empty :(\n");
}
ao2_t_cleanup(bogus_peer, "unref the bogus_peer");
ao2_t_global_obj_release(g_bogus_peer, "Release the bogus peer.");
ao2_t_cleanup(peers, "unref the peers table");
ao2_t_cleanup(peers_by_ip, "unref the peers_by_ip table");