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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Hyunwoo Kim <imv4bel@gmail.com>,
        Helge Deller <deller@gmx.de>, Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.19 17/58] video: fbdev: pxa3xx-gcu: Fix integer overflow in pxa3xx_gcu_write
Date:   Mon, 26 Sep 2022 12:11:36 +0200
Message-Id: <20220926100742.062048441@linuxfoundation.org>
In-Reply-To: <20220926100741.430882406@linuxfoundation.org>
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From: Hyunwoo Kim <imv4bel@gmail.com>

[ Upstream commit a09d2d00af53b43c6f11e6ab3cb58443c2cac8a7 ]

In pxa3xx_gcu_write, a count parameter of type size_t is passed to words of
type int.  Then, copy_from_user() may cause a heap overflow because it is used
as the third argument of copy_from_user().

Signed-off-by: Hyunwoo Kim <imv4bel@gmail.com>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/video/fbdev/pxa3xx-gcu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/video/fbdev/pxa3xx-gcu.c b/drivers/video/fbdev/pxa3xx-gcu.c
index 43695a33f062..aec0b85db5bf 100644
--- a/drivers/video/fbdev/pxa3xx-gcu.c
+++ b/drivers/video/fbdev/pxa3xx-gcu.c
@@ -394,7 +394,7 @@ pxa3xx_gcu_write(struct file *file, const char *buff,
 	struct pxa3xx_gcu_batch	*buffer;
 	struct pxa3xx_gcu_priv *priv = to_pxa3xx_gcu_priv(file);
 
-	int words = count / 4;
+	size_t words = count / 4;
 
 	/* Does not need to be atomic. There's a lock in user space,
 	 * but anyhow, this is just for statistics. */
-- 
2.35.1