libmsc/sms_queue.c: fix memleak in smsq_take_next_sms()
A memleak has been noticed after executing some of TTCN-3 test
cases. For example, the following ones:
- MSC_Tests.TC_lu_and_mo_sms,
- MSC_Tests.TC_lu_and_mt_sms.
The key point is that MSC_Tests.TC_lu_and_mo_sms basically sends
a MO SMS to a non-attached subscriber with MSISDN 12345, so this
message is getting stored in the SMSC's database.
As soon as the SMSC's queue is triggered, sms_submit_pending() would
retrieve pending messages from the database by calling function
smsq_take_next_sms() in loop and attempt to deliver them.
This function in it's turn checks whether the subscriber is attached
or not. If not, the allocated 'gsm_sms' structure would not be
free()ed! Therefore, every time smsq_take_next_sms() is called,
one 'gsm_sms' structure for an unattached subscriber is leaked.
Furthermore, there is a unit test called 'sms_queue_test', that
actually does cover smsq_take_next_sms() and was designed to
catch some potential memory leaks, but...
In order to avoid emulating the low-level SQLite API, the unit
test by design overwrites some functions of libmsc, including
db_sms_get_next_unsent_rr_msisdn(), that is being called by
smsq_take_next_sms().
The problem is that the original function in libmsc does
allocate a 'gsm_sms' structure on heap (using talloc), while
the overwriting function did this statically, returning a
pointer to stack. This critical difference made it impossible
to spot the memleak in smsq_take_next_sms() during the
unit test execution.
Let's refactor 'sms_queue_test' to use dynamic memory allocation,
and finally fix the evil memleak in smsq_take_next_sms().
Change-Id: Iad5e4d84d8d410ea43d5907e9ddf6e5fdb55bc7a
Closes: OS#3860
diff --git a/tests/sms_queue/sms_queue_test.c b/tests/sms_queue/sms_queue_test.c
index e426377..f64f715 100644
--- a/tests/sms_queue/sms_queue_test.c
+++ b/tests/sms_queue/sms_queue_test.c
@@ -26,8 +26,10 @@
#include <osmocom/msc/debug.h>
#include <osmocom/msc/vlr.h>
#include <osmocom/msc/gsm_data.h>
+#include <osmocom/msc/gsm_04_11.h>
static void *talloc_ctx = NULL;
+extern void *tall_gsms_ctx;
struct gsm_sms *smsq_take_next_sms(struct gsm_network *net,
char *last_msisdn,
@@ -45,8 +47,6 @@
printf(" (last_msisdn='%s')\n", last_msisdn? last_msisdn : "NULL");
}
-static struct gsm_sms fake_sms = { 0 };
-
struct {
const char *msisdn;
int nr_of_sms;
@@ -91,11 +91,19 @@
const char *last_msisdn,
unsigned int max_failed)
{
- static struct vlr_subscr arbitrary_vsub = { .lu_complete = true };
+ static struct vlr_subscr arbitrary_vsub;
+ struct gsm_sms *sms;
int i;
printf(" hitting database: looking for MSISDN > '%s', failed_attempts <= %d\n",
last_msisdn, max_failed);
+ /* Every time we call sms_free(), the internal logic of libmsc
+ * may call vlr_subscr_put() on our arbitrary_vsub, what would
+ * lead to a segfault if its use_count <= 0. To prevent this,
+ * let's ensure a big enough initial value. */
+ arbitrary_vsub.use_count = 1000;
+ arbitrary_vsub.lu_complete = true;
+
for (i = 0; i < ARRAY_SIZE(fake_sms_db); i++) {
if (!fake_sms_db[i].nr_of_sms)
continue;
@@ -103,14 +111,19 @@
continue;
if (fake_sms_db[i].failed_attempts > max_failed)
continue;
- osmo_strlcpy(fake_sms.dst.addr, fake_sms_db[i].msisdn,
- sizeof(fake_sms.dst.addr));
- fake_sms.receiver = fake_sms_db[i].vsub_attached? &arbitrary_vsub : NULL;
- osmo_strlcpy(fake_sms.text, fake_sms_db[i].msisdn, sizeof(fake_sms.text));
+
+ sms = sms_alloc();
+ OSMO_ASSERT(sms);
+
+ osmo_strlcpy(sms->dst.addr, fake_sms_db[i].msisdn,
+ sizeof(sms->dst.addr));
+ sms->receiver = fake_sms_db[i].vsub_attached? &arbitrary_vsub : NULL;
+ osmo_strlcpy(sms->text, fake_sms_db[i].msisdn, sizeof(sms->text));
if (fake_sms_db[i].vsub_attached)
fake_sms_db[i].nr_of_sms--;
- return &fake_sms;
+ return sms;
}
+
return NULL;
}
@@ -127,6 +140,10 @@
printf("-->\n");
}
+/* sms_free() is not safe against NULL */
+#define sms_free_safe(sms) \
+ if (sms != NULL) sms_free(sms)
+
static void test_next_sms()
{
int i;
@@ -141,6 +158,7 @@
struct gsm_sms *sms = smsq_take_next_sms(NULL, last_msisdn, sizeof(last_msisdn));
_test_take_next_sms_print(i, sms, last_msisdn);
OSMO_ASSERT(i >= 4 || sms);
+ sms_free_safe(sms);
}
printf("\n- SMS are pending at various nr failed attempts (cutoff at >= 10)\n");
@@ -156,6 +174,7 @@
struct gsm_sms *sms = smsq_take_next_sms(NULL, last_msisdn, sizeof(last_msisdn));
_test_take_next_sms_print(i, sms, last_msisdn);
OSMO_ASSERT(i >= 2 || sms);
+ sms_free_safe(sms);
}
printf("\n- iterate the SMS DB at most once\n");
@@ -206,6 +225,10 @@
logging_ctx = talloc_named_const(talloc_ctx, 0, "logging");
osmo_init_logging2(logging_ctx, &info);
+ /* Share our talloc context with libmsc's GSM 04.11 code,
+ * so sms_alloc() would use it instead of NULL. */
+ tall_gsms_ctx = talloc_ctx;
+
OSMO_ASSERT(osmo_stderr_target);
log_set_use_color(osmo_stderr_target, 0);
log_set_print_timestamp(osmo_stderr_target, 0);