From: Hyunwoo Kim <imv4bel@gmail.com>
Date: Mon, 20 Jun 2022 14:17:46 +0000 (-0700)
Subject: video: fbdev: pxa3xx-gcu: Fix integer overflow in pxa3xx_gcu_write
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=a09d2d00af53b43c6f11e6ab3cb58443c2cac8a7;p=linux.git

video: fbdev: pxa3xx-gcu: Fix integer overflow in pxa3xx_gcu_write

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>
---

diff --git a/drivers/video/fbdev/pxa3xx-gcu.c b/drivers/video/fbdev/pxa3xx-gcu.c
index 043cc8f9ef1c7..c3cd1e1cc01b4 100644
--- a/drivers/video/fbdev/pxa3xx-gcu.c
+++ b/drivers/video/fbdev/pxa3xx-gcu.c
@@ -381,7 +381,7 @@ 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. */