From fdff0e351e62333a4eb6c646e9038ec680e78836 Mon Sep 17 00:00:00 2001 From: Zou Wei Date: Fri, 7 Jun 2024 17:16:07 +0800 Subject: [PATCH] watchdog: Fix possible use-after-free in wdt_startup() mainline inclusion from mainline-v5.14-rc1 commit c08a6b31e4917034f0ed0cb457c3bb209576f542 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9ROH3 CVE: CVE-2021-47324 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=c08a6b31e4917034f0ed0cb457c3bb209576f542 -------------------------------- 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/1620716495-108352-1-git-send-email-zou_wei@huawei.com Signed-off-by: Guenter Roeck Signed-off-by: Wim Van Sebroeck Signed-off-by: Zeng Heng --- drivers/watchdog/sbc60xxwdt.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/watchdog/sbc60xxwdt.c b/drivers/watchdog/sbc60xxwdt.c index 87333a41f753..1702df7f8c38 100644 --- a/drivers/watchdog/sbc60xxwdt.c +++ b/drivers/watchdog/sbc60xxwdt.c @@ -152,7 +152,7 @@ static void wdt_startup(void) static void wdt_turnoff(void) { /* Stop the timer */ - del_timer(&timer); + del_timer_sync(&timer); inb_p(wdt_stop); pr_info("Watchdog timer is now disabled...\n"); } -- Gitee