[PATCH AUTOSEL 5.4 13/27] video: fbdev: pxa3xx-gcu: Fix integer overflow in pxa3xx_gcu_write

Sasha Levin
2022-06-28T02:31:06Z

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 7c4694d70dac..15162b37f302 100644
--- a/drivers/video/fbdev/pxa3xx-gcu.c
+++ b/drivers/video/fbdev/pxa3xx-gcu.c
@@ -382,7 +382,7 @@ 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