linux-kernel - [PATCH] watchdog: dw_wdt: Fix buffer overflow when get timeout

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Date:   Tue, 28 Jun 2022 13:45:39 +0800
From:   Schspa Shi <schspa@...il.com>
To:     wim@...ux-watchdog.org, linux@...ck-us.net
Cc:     linux-watchdog@...r.kernel.org, linux-kernel@...r.kernel.org,
        zhaohui.shi@...izon.ai, Schspa Shi <schspa@...il.com>
Subject: [PATCH] watchdog: dw_wdt: Fix buffer overflow when get timeout

The top_val can be obtained from device-tree, if it is not configured
correctly, there will be buffer overflow.

Signed-off-by: Schspa Shi <schspa@...il.com>
---
 drivers/watchdog/dw_wdt.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/watchdog/dw_wdt.c b/drivers/watchdog/dw_wdt.c
index cd578843277e..1f8605c0d712 100644
--- a/drivers/watchdog/dw_wdt.c
+++ b/drivers/watchdog/dw_wdt.c
@@ -155,6 +155,9 @@ static unsigned int dw_wdt_get_min_timeout(struct dw_wdt *dw_wdt)
 			break;
 	}
 
+	if (WARN_ON_ONCE(idx == DW_WDT_NUM_TOPS))
+		idx = DW_WDT_NUM_TOPS - 1;
+
 	return dw_wdt->timeouts[idx].sec;
 }
 
@@ -178,6 +181,9 @@ static unsigned int dw_wdt_get_timeout(struct dw_wdt *dw_wdt)
 			break;
 	}
 
+	if (WARN_ON_ONCE(idx == DW_WDT_NUM_TOPS))
+		idx = DW_WDT_NUM_TOPS - 1;
+
 	/*
 	 * In IRQ mode due to the two stages counter, the actual timeout is
 	 * twice greater than the TOP setting.
-- 
2.29.0