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b2b_entities: fix crashes due to races when deleting entity
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An entity might have been deleted and freed while the lock has been released
when running the entity storage callbacks.

Related to #3110
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@rvlad-patrascu
rvlad-patrascu committed Jun 30, 2023
1 parent b787802 commit 22bd818
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Showing 3 changed files with 81 additions and 40 deletions.
26 changes: 21 additions & 5 deletions modules/b2b_entities/b2be_clustering.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -567,9 +567,12 @@ int receive_entity_update(bin_packet_t *packet)
unpack_update_fields(packet, dlg);

htable[hash_index].locked_by = process_no;
b2b_run_cb(dlg, hash_index, type, B2BCB_RECV_EVENT,
if ((rc = b2b_run_cb(dlg, hash_index, type, B2BCB_RECV_EVENT,
packet->type == REPL_ENTITY_UPDATE ? B2B_EVENT_UPDATE : B2B_EVENT_ACK,
packet, B2BCB_BACKEND_CLUSTER);
packet, B2BCB_BACKEND_CLUSTER)) != 0) {
lock_release(&htable[hash_index].lock);
return rc == -1 ? -1 : 0;
}
htable[hash_index].locked_by = -1;
} else {
rc = recv_b2bl_param_update(packet, dlg);
Expand All @@ -592,6 +595,7 @@ int receive_entity_delete(bin_packet_t *packet)
str *b2be_key;
b2b_table htable;
str callid, tag0, tag1;
int rc;

bin_pop_int(packet, &type);
bin_pop_str(packet, &tag0);
Expand Down Expand Up @@ -625,8 +629,12 @@ int receive_entity_delete(bin_packet_t *packet)
}

htable[hash_index].locked_by = process_no;
b2b_run_cb(dlg, hash_index, type, B2BCB_RECV_EVENT, B2B_EVENT_DELETE, packet,
B2BCB_BACKEND_CLUSTER);
if ((rc = b2b_run_cb(dlg, hash_index, type, B2BCB_RECV_EVENT, B2B_EVENT_DELETE,
packet, B2BCB_BACKEND_CLUSTER)) != 0) {
htable[hash_index].locked_by = -1;
lock_release(&htable[hash_index].lock);
return rc == -1 ? -1 : 0;
}
htable[hash_index].locked_by = -1;

b2b_entity_db_delete(type, dlg);
Expand Down Expand Up @@ -687,6 +695,7 @@ static int pack_entities_sync(bin_packet_t **sync_packet, int node_id,
int i;
b2b_dlg_t *dlg;
str storage_cnt_buf;
int rc;

storage->buffer.s = NULL;

Expand All @@ -709,8 +718,15 @@ static int pack_entities_sync(bin_packet_t **sync_packet, int node_id,
return -1;
}

b2b_run_cb(dlg, i, etype, B2BCB_TRIGGER_EVENT, B2B_EVENT_CREATE,
rc = b2b_run_cb(dlg, i, etype, B2BCB_TRIGGER_EVENT, B2B_EVENT_CREATE,
storage, serialize_backend);
if (rc == -1) {
lock_release(&htable[i].lock);
return -1;
} else if (rc == 1) {
lock_release(&htable[i].lock);
continue;
}

bin_pack_entity(*sync_packet, dlg, etype);

Expand Down
93 changes: 59 additions & 34 deletions modules/b2b_entities/dlg.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -531,11 +531,13 @@ b2b_dlg_t* b2bl_search_iteratively(str* callid, str* from_tag, str* ruri,
return dlg;
}

void b2b_run_cb(b2b_dlg_t *dlg, unsigned int hash_index, int entity_type,
int b2b_run_cb(b2b_dlg_t *dlg, unsigned int hash_index, int entity_type,
int cbs_type, int event_type, bin_packet_t *storage, int backend)
{
struct b2b_callback *cb;
str st;
b2b_dlg_t *aux_dlg;
b2b_table table = entity_type == B2B_SERVER ? server_htable:client_htable;

/* search for the callback registered by the module that
* this entity belongs to */
Expand All @@ -553,17 +555,17 @@ void b2b_run_cb(b2b_dlg_t *dlg, unsigned int hash_index, int entity_type,
if (cbs_type == B2BCB_TRIGGER_EVENT) {
if (!cb) {
storage->buffer.s = NULL;
return;
return 0;
}

if (bin_init(storage, &storage_cap, B2BE_STORAGE_BIN_TYPE,
B2BE_STORAGE_BIN_VERS, 0) < 0) {
LM_ERR("Failed to init entity storage buffer\n");
return;
return -1;
}
} else { /* B2BCB_RECV_EVENT */
if (!cb)
return;
return 0;

if (bin_get_content_pos(storage, &st) > 0) {
if (b2be_db_mode != NO_DB && event_type != B2B_EVENT_DELETE) {
Expand All @@ -576,7 +578,7 @@ void b2b_run_cb(b2b_dlg_t *dlg, unsigned int hash_index, int entity_type,
shm_free(dlg->storage.s);
if (shm_str_dup(&dlg->storage, &st) < 0) {
LM_ERR("oom!\n");
return;
return -1;
}
}
}
Expand All @@ -585,18 +587,24 @@ void b2b_run_cb(b2b_dlg_t *dlg, unsigned int hash_index, int entity_type,
}
}

if (entity_type == B2B_SERVER)
lock_release(&server_htable[hash_index].lock);
else
lock_release(&client_htable[hash_index].lock);
lock_release(&table[hash_index].lock);

cb->cbf(entity_type, entity_type == B2B_SERVER ? &dlg->tag[1] : &dlg->callid,
&dlg->logic_key, dlg->param, event_type, storage, backend);

if (entity_type == B2B_SERVER)
lock_get(&server_htable[hash_index].lock);
else
lock_get(&client_htable[hash_index].lock);
lock_get(&table[hash_index].lock);

/* search the dialog */
for(aux_dlg = table[hash_index].first; aux_dlg; aux_dlg = aux_dlg->next)
{
if(aux_dlg == dlg)
break;
}
if(!aux_dlg)
{
LM_DBG("Record not found anymore\n");
return 1;
}

if (cbs_type == B2BCB_TRIGGER_EVENT && event_type != B2B_EVENT_DELETE &&
b2be_db_mode != NO_DB && bin_get_content_start(storage, &st) > 0) {
Expand All @@ -607,10 +615,12 @@ void b2b_run_cb(b2b_dlg_t *dlg, unsigned int hash_index, int entity_type,
shm_free(dlg->storage.s);
if (shm_str_dup(&dlg->storage, &st) < 0) {
LM_ERR("oom!\n");
return;
return -1;
}
}
}

return 0;
}

static void run_create_cb_all(struct b2b_callback *cb, int etype)
Expand Down Expand Up @@ -1038,7 +1048,7 @@ int b2b_prescript_f(struct sip_msg *msg, void *uparam)
if(req_routeid > 0)
run_top_route(sroutes->request[req_routeid], msg);

goto done;
return SCB_DROP_MSG;
}
}

Expand Down Expand Up @@ -1293,13 +1303,15 @@ int b2b_prescript_f(struct sip_msg *msg, void *uparam)
if (dlg_state == B2B_ESTABLISHED) {
b2b_ev = B2B_EVENT_ACK;

b2b_run_cb(dlg, hash_index, etype, B2BCB_TRIGGER_EVENT, b2b_ev,
&storage, serialize_backend);
if (b2b_run_cb(dlg, hash_index, etype, B2BCB_TRIGGER_EVENT, b2b_ev,
&storage, serialize_backend) != 0)
goto done;
} else if (dlg_state == B2B_TERMINATED) {
b2b_ev = B2B_EVENT_DELETE;

b2b_run_cb(dlg, hash_index, etype, B2BCB_TRIGGER_EVENT, b2b_ev,
&storage, serialize_backend);
if (b2b_run_cb(dlg, hash_index, etype, B2BCB_TRIGGER_EVENT, b2b_ev,
&storage, serialize_backend) != 0)
goto done;
}
}

Expand All @@ -1324,7 +1336,7 @@ int b2b_prescript_f(struct sip_msg *msg, void *uparam)
bin_free_packet(&storage);

done:

lock_release(&table[hash_index].lock);
return SCB_DROP_MSG;
}

Expand Down Expand Up @@ -1784,12 +1796,14 @@ int b2b_send_reply(b2b_rpl_data_t* rpl_data)
* callbacks is not neccesary unless we have replication */
b2be_cluster) {
b2b_ev = B2B_EVENT_CREATE;
b2b_run_cb(dlg, hash_index, et, B2BCB_TRIGGER_EVENT, b2b_ev, &storage,
serialize_backend);
if (b2b_run_cb(dlg, hash_index, et, B2BCB_TRIGGER_EVENT, b2b_ev,
&storage, serialize_backend) != 0)
goto error;
} else if (prev_state == B2B_MODIFIED && dlg->state == B2B_CONFIRMED) {
b2b_ev = B2B_EVENT_UPDATE;
b2b_run_cb(dlg, hash_index, et, B2BCB_TRIGGER_EVENT, b2b_ev, &storage,
serialize_backend);
if (b2b_run_cb(dlg, hash_index, et, B2BCB_TRIGGER_EVENT, b2b_ev,
&storage, serialize_backend) != 0)
goto error;
}
}

Expand Down Expand Up @@ -1979,8 +1993,11 @@ void b2b_entity_delete(enum b2b_entity_type et, str* b2b_key,

if (B2BE_SERIALIZE_STORAGE() && replicate) {
trig_ev = 1;
b2b_run_cb(dlg, hash_index, et, B2BCB_TRIGGER_EVENT, B2B_EVENT_DELETE,
&storage, serialize_backend);
if (b2b_run_cb(dlg, hash_index, et, B2BCB_TRIGGER_EVENT,
B2B_EVENT_DELETE, &storage, serialize_backend) != 0) {
lock_release(&table[hash_index].lock);
return;
}
}

if(db_del)
Expand Down Expand Up @@ -2380,13 +2397,15 @@ int b2b_send_request(b2b_req_data_t* req_data)
if (dlg->state == B2B_ESTABLISHED) {
if (b2be_db_mode != NO_DB || dlg->replicated) {
b2b_ev = B2B_EVENT_ACK;
b2b_run_cb(dlg, hash_index, et, B2BCB_TRIGGER_EVENT, b2b_ev, &storage,
serialize_backend);
if (b2b_run_cb(dlg, hash_index, et, B2BCB_TRIGGER_EVENT,
b2b_ev, &storage, serialize_backend) != 0)
goto error;
}
} else if (dlg->state == B2B_TERMINATED) {
b2b_ev = B2B_EVENT_DELETE;
b2b_run_cb(dlg, hash_index, et, B2BCB_TRIGGER_EVENT, b2b_ev, &storage,
serialize_backend);
if (b2b_run_cb(dlg, hash_index, et, B2BCB_TRIGGER_EVENT, b2b_ev,
&storage, serialize_backend) != 0)
goto error;
}
}

Expand Down Expand Up @@ -3532,16 +3551,22 @@ void b2b_tm_cback(struct cell *t, b2b_table htable, struct tmcb_params *ps)

if (dlg->state != B2B_TERMINATED) {
b2b_ev = B2B_EVENT_UPDATE;
b2b_run_cb(dlg, hash_index, etype, B2BCB_TRIGGER_EVENT, b2b_ev,
&storage, serialize_backend);
if (b2b_run_cb(dlg, hash_index, etype, B2BCB_TRIGGER_EVENT,
b2b_ev, &storage, serialize_backend) != 0) {
lock_release(&htable[hash_index].lock);
return;
}
} else {
b2b_ev = -1;
}
} else if (b2b_ev == B2B_EVENT_CREATE) {

if (dlg->state != B2B_TERMINATED) {
b2b_run_cb(dlg, hash_index, etype, B2BCB_TRIGGER_EVENT, b2b_ev,
&storage, serialize_backend);
if (b2b_run_cb(dlg, hash_index, etype, B2BCB_TRIGGER_EVENT,
b2b_ev, &storage, serialize_backend) != 0) {
lock_release(&htable[hash_index].lock);
return;
}

if (b2be_db_mode == WRITE_THROUGH)
b2be_db_insert(dlg, etype);
Expand Down
2 changes: 1 addition & 1 deletion modules/b2b_entities/dlg.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -195,7 +195,7 @@ int b2b_apply_lumps(struct sip_msg* msg);

int b2b_register_cb(b2b_cb_t cb, int cb_type, str *mod_name);

void b2b_run_cb(b2b_dlg_t *dlg, unsigned int hash_index, int entity_type,
int b2b_run_cb(b2b_dlg_t *dlg, unsigned int hash_index, int entity_type,
int cbs_type, int event_type, bin_packet_t *storage, int backend);

dlg_leg_t* b2b_dup_leg(dlg_leg_t* leg, int mem_type);
Expand Down

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