From 1668d19dbbf2515030b850a37eb34dc12fd3139b Mon Sep 17 00:00:00 2001 From: Zou Wei Date: Mon, 3 Jun 2024 11:47:53 +0800 Subject: [PATCH] watchdog: sc520_wdt: Fix possible use-after-free in wdt_turnoff() stable inclusion from stable-v4.19.198 commit 522e75ed63f67e815d4ec0deace67df22d9ce78e category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9S3H8 CVE: CVE-2021-47323 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=linux-4.19.y&id=522e75ed63f67e815d4ec0deace67df22d9ce78e -------------------------------- [ Upstream commit 90b7c141132244e8e49a34a4c1e445cce33e07f4 ] This module's remove path calls del_timer(). However, that function does not wait until the timer handler finishes. This means that the timer handler may still be running after the driver's remove function has finished, which would result in a use-after-free. Fix by calling del_timer_sync(), which makes sure the timer handler has finished, and unable to re-schedule itself. Reported-by: Hulk Robot Signed-off-by: Zou Wei Reviewed-by: Guenter Roeck Link: https://lore.kernel.org/r/1620716691-108460-1-git-send-email-zou_wei@huawei.com Signed-off-by: Guenter Roeck Signed-off-by: Wim Van Sebroeck Signed-off-by: Sasha Levin Signed-off-by: Yu Liao --- drivers/watchdog/sc520_wdt.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/watchdog/sc520_wdt.c b/drivers/watchdog/sc520_wdt.c index 6aadb56e7faa..809ebcaef51d 100644 --- a/drivers/watchdog/sc520_wdt.c +++ b/drivers/watchdog/sc520_wdt.c @@ -190,7 +190,7 @@ static int wdt_startup(void) static int wdt_turnoff(void) { /* Stop the timer */ - del_timer(&timer); + del_timer_sync(&timer); /* Stop the watchdog */ wdt_config(0); -- Gitee