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From:   rentao.bupt@gmail.com
To:     Wim Van Sebroeck <wim@linux-watchdog.org>,
        Guenter Roeck <linux@roeck-us.net>,
        Joel Stanley <joel@jms.id.au>,
        Andrew Jeffery <andrew@aj.id.au>,
        linux-watchdog@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org,
        linux-aspeed@lists.ozlabs.org, linux-kernel@vger.kernel.org,
        openbmc@lists.ozlabs.org, Tao Ren <taoren@fb.com>,
        Amithash Prasad <amithash@fb.com>
Cc:     Tao Ren <rentao.bupt@gmail.com>
Subject: [PATCH] watchdog: aspeed: fix integer overflow in set_timeout handler
Date:   Thu, 15 Apr 2021 17:12:08 -0700
Message-Id: <20210416001208.16788-1-rentao.bupt@gmail.com>
Precedence: bulk

From: Tao Ren <rentao.bupt@gmail.com>

Fix the time comparison (timeout vs. max_hw_heartbeat_ms) in set_timeout
handler to avoid potential integer overflow when the supplied timeout is
greater than aspeed's maximum allowed timeout (4294 seconds).

Fixes: efa859f7d786 ("watchdog: Add Aspeed watchdog driver")
Reported-by: Amithash Prasad <amithash@fb.com>
Signed-off-by: Tao Ren <rentao.bupt@gmail.com>
---
 drivers/watchdog/aspeed_wdt.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/watchdog/aspeed_wdt.c b/drivers/watchdog/aspeed_wdt.c
index 7e00960651fa..9f77272dc906 100644
--- a/drivers/watchdog/aspeed_wdt.c
+++ b/drivers/watchdog/aspeed_wdt.c
@@ -145,9 +145,8 @@ static int aspeed_wdt_set_timeout(struct watchdog_device *wdd,
 	struct aspeed_wdt *wdt = to_aspeed_wdt(wdd);
 	u32 actual;
 
-	wdd->timeout = timeout;
-
-	actual = min(timeout, wdd->max_hw_heartbeat_ms * 1000);
+	actual = min(timeout, wdd->max_hw_heartbeat_ms / 1000);
+	wdd->timeout = actual;
 
 	writel(actual * WDT_RATE_1MHZ, wdt->base + WDT_RELOAD_VALUE);
 	writel(WDT_RESTART_MAGIC, wdt->base + WDT_RESTART);
-- 
2.17.1