From 4b24731640abfdc9fe97dba193cf7abe590ab2fe Mon Sep 17 00:00:00 2001
From: Corey Farrell <git@cfware.com>
Date: Tue, 13 Nov 2018 11:51:00 -0500
Subject: [PATCH] test_res_pjsip_scheduler: Fix possible write after free in
scheduler_policy.
It's possible for a 4th task to be spawned before we cancel. This
results in a write to the already freed test_data1. Wait long enough to
verify success of the cancelation before freeing test_data1.
Change-Id: I057e2fcbe97f8a175e50890be89c28c20490a20f
---
tests/test_res_pjsip_scheduler.c | 39 ++++++++++++++++++++++++++++----
1 file changed, 34 insertions(+), 5 deletions(-)
diff --git a/tests/test_res_pjsip_scheduler.c b/tests/test_res_pjsip_scheduler.c
index d0c2d90b52..cecb742a77 100644
--- a/tests/test_res_pjsip_scheduler.c
+++ b/tests/test_res_pjsip_scheduler.c
@@ -53,6 +53,7 @@ struct test_data {
int interval;
int sleep;
int done;
+ int no_clear_done;
struct ast_test *test;
};
@@ -63,7 +64,9 @@ static int task_1(void *data)
{
struct test_data *test = data;
- test->done = 0;
+ if (!test->no_clear_done) {
+ test->done = 0;
+ }
test->task_start = ast_tvnow();
test->tid = pthread_self();
test->is_servant = ast_sip_thread_is_servant();
@@ -71,7 +74,7 @@ static int task_1(void *data)
test->task_end = ast_tvnow();
ast_mutex_lock(&test->lock);
- test->done = 1;
+ test->done++;
ast_mutex_unlock(&test->lock);
ast_cond_signal(&test->cond);
@@ -345,11 +348,12 @@ AST_TEST_DEFINE(scheduler_policy)
test_data1->test_start = ast_tvnow();
test_data1->interval = 1000;
test_data1->sleep = 500;
+ test_data1->no_clear_done = 1;
ast_mutex_init(&test_data1->lock);
ast_cond_init(&test_data1->cond, NULL);
ast_test_status_update(test, "This test will take about %3.1f seconds\n",
- ((test_data1->interval * 3) + test_data1->sleep) / 1000.0);
+ ((test_data1->interval * 4) + test_data1->sleep) / 1000.0);
task = ast_sip_schedule_task(NULL, test_data1->interval, task_1, "test_1", test_data1,
AST_SIP_SCHED_TASK_DATA_NO_CLEANUP | AST_SIP_SCHED_TASK_PERIODIC);
@@ -368,8 +372,33 @@ AST_TEST_DEFINE(scheduler_policy)
ast_test_validate(test, when > test_data1->interval * 3 * 0.9 && when < test_data1->interval * 3 * 1.1);
ast_sip_sched_task_cancel(task);
- ao2_ref(task, -1);
- task = NULL;
+
+ /* Wait a full interval in case a 4th call to test_1 happened before the cancel */
+ usleep(M2U(test_data1->interval));
+
+ ast_mutex_lock(&test_data1->lock);
+ if (test_data1->done) {
+ int done = test_data1->done;
+
+ test_data1->done = 0;
+ ast_mutex_unlock(&test_data1->lock);
+
+ ast_test_validate(test, done == 1);
+
+ /* Wait two full intervals to be certain no further calls to test_1. */
+ usleep(M2U(test_data1->interval * 2));
+
+ ast_mutex_lock(&test_data1->lock);
+ if (test_data1->done != 0) {
+ ast_mutex_unlock(&test_data1->lock);
+ /* The cancelation failed so we need to prevent cleanup of
+ * test_data1 to prevent a crash from write-after-free. */
+ test_data1 = NULL;
+ ast_test_status_update(test, "Failed to cancel task");
+ return AST_TEST_FAIL;
+ }
+ }
+ ast_mutex_unlock(&test_data1->lock);
return AST_TEST_PASS;
}
--
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