Adds a test to verify timer stack recording and print it
in KASAN report.
The KASAN report was as follows(cleaned up slightly):
BUG: KASAN: use-after-free in kasan_timer_uaf
Freed by task 0:
kasan_save_stack+0x24/0x50
kasan_set_track+0x24/0x38
kasan_set_free_info+0x20/0x40
__kasan_slab_free+0x10c/0x170
kasan_slab_free+0x10/0x18
kfree+0x98/0x270
kasan_timer_function+0x1c/0x28
Last potentially related work creation:
kasan_save_stack+0x24/0x50
kasan_record_tmr_stack+0xa8/0xb8
init_timer_key+0xf0/0x248
kasan_timer_uaf+0x5c/0xd8
Signed-off-by: Walter Wu <[email protected]>
Cc: Andrey Ryabinin <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Cc: Alexander Potapenko <[email protected]>
Cc: Matthias Brugger <[email protected]>
Cc: Andrey Konovalov <[email protected]>
---
lib/test_kasan.c | 25 +++++++++++++++++++++++++
1 file changed, 25 insertions(+)
diff --git a/lib/test_kasan.c b/lib/test_kasan.c
index 6e5fb05d42d8..2bd61674c7a3 100644
--- a/lib/test_kasan.c
+++ b/lib/test_kasan.c
@@ -821,6 +821,30 @@ static noinline void __init kasan_rcu_uaf(void)
call_rcu(&global_ptr->rcu, kasan_rcu_reclaim);
}
+static noinline void __init kasan_timer_function(struct timer_list *timer)
+{
+ del_timer(timer);
+ kfree(timer);
+}
+
+static noinline void __init kasan_timer_uaf(void)
+{
+ struct timer_list *timer;
+
+ timer = kmalloc(sizeof(struct timer_list), GFP_KERNEL);
+ if (!timer) {
+ pr_err("Allocation failed\n");
+ return;
+ }
+
+ timer_setup(timer, kasan_timer_function, 0);
+ add_timer(timer);
+ msleep(100);
+
+ pr_info("use-after-free on timer\n");
+ ((volatile struct timer_list *)timer)->expires;
+}
+
static int __init kmalloc_tests_init(void)
{
/*
@@ -869,6 +893,7 @@ static int __init kmalloc_tests_init(void)
kmalloc_double_kzfree();
vmalloc_oob();
kasan_rcu_uaf();
+ kasan_timer_uaf();
kasan_restore_multi_shot(multishot);
--
2.18.0