BACKPORT: FROMLIST: binder: fix freeze UAF in binder_release_work()
When a binder reference is cleaned up, any freeze work queued in the
associated process should also be removed. Otherwise, the reference is
freed while its ref->freeze.work is still queued in proc->work leading
to a use-after-free issue as shown by the following KASAN report:
==================================================================
BUG: KASAN: slab-use-after-free in binder_release_work+0x398/0x3d0
Read of size 8 at addr ffff31600ee91488 by task kworker/5:1/211
CPU: 5 UID: 0 PID: 211 Comm: kworker/5:1 Not tainted 6.11.0-rc7-00382-gfc6c92196396 #22
Hardware name: linux,dummy-virt (DT)
Workqueue: events binder_deferred_func
Call trace:
binder_release_work+0x398/0x3d0
binder_deferred_func+0xb60/0x109c
process_one_work+0x51c/0xbd4
worker_thread+0x608/0xee8
Allocated by task 703:
__kmalloc_cache_noprof+0x130/0x280
binder_thread_write+0xdb4/0x42a0
binder_ioctl+0x18f0/0x25ac
__arm64_sys_ioctl+0x124/0x190
invoke_syscall+0x6c/0x254
Freed by task 211:
kfree+0xc4/0x230
binder_deferred_func+0xae8/0x109c
process_one_work+0x51c/0xbd4
worker_thread+0x608/0xee8
==================================================================
This commit fixes the issue by ensuring any queued freeze work is removed
when cleaning up a binder reference.
Fixes: d579b04a52a1 ("binder: frozen notification")
Cc: stable@vger.kernel.org
Signed-off-by: Carlos Llamas <cmllamas@google.com>
Bug: 366003708
Link: https://lore.kernel.org/all/20240924184401.76043-4-cmllamas@google.com/
Change-Id: Icc40e7dd6157981f4adbea7243e55be118552321
[cmllamas: drop BINDER_STAT_FREEZE as it's not supported here]
Signed-off-by: Carlos Llamas <cmllamas@google.com>
diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index 91eec3d..b70cc8b 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -1421,6 +1421,10 @@ static void binder_cleanup_ref_olocked(struct binder_ref *ref)
binder_dequeue_work(ref->proc, &ref->death->work);
binder_stats_deleted(BINDER_STAT_DEATH);
}
+
+ if (ref->freeze)
+ binder_dequeue_work(ref->proc, &ref->freeze->work);
+
binder_stats_deleted(BINDER_STAT_REF);
}
