[PATCH 5.15 41/45] video: fbdev: pxa3xx-gcu: Fix integer overflow in pxa3xx_gcu_write

From: Greg Kroah-Hartman
Date: Wed Sep 21 2022 - 11:55:05 EST


From: Hyunwoo Kim <imv4bel@xxxxxxxxx>

[ 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@xxxxxxxxx>
Signed-off-by: Helge Deller <deller@xxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
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 9421d14d0eb0..9e9888e40c57 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. */
--
2.35.1