Re: [PATCH] usb: typec: anx7411: Fix possible buffer overflow in anx7411_send_msg()

From: Christophe JAILLET
Date: Sun Mar 17 2024 - 03:53:55 EST


Le 16/03/2024 à 21:33, Grigory Bazilevich a écrit :
Passing a size argument greater than or equal to MAX_BUF_LEN causes
a buffer overflow when the checksum is written.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: fe6d8a9c8e64 ("usb: typec: anx7411: Add Analogix PD ANX7411 support")
Signed-off-by: Grigory Bazilevich <bazilevich-vHv2KSI2GGSHXe+LvDLADg@xxxxxxxxxxxxxxxx>
---
drivers/usb/typec/anx7411.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/typec/anx7411.c b/drivers/usb/typec/anx7411.c
index b12a07edc71b..70ba56dfb22b 100644
--- a/drivers/usb/typec/anx7411.c
+++ b/drivers/usb/typec/anx7411.c
@@ -733,7 +733,7 @@ static int anx7411_send_msg(struct anx7411_data *ctx, u8 type, u8 *buf, u8 size)
u8 crc;
int ret;
- size = min_t(u8, size, (u8)MAX_BUF_LEN);
+ size = min_t(u8, size, (u8)(MAX_BUF_LEN - 1));

Hi,

with "min_t(u8, ...", is the casting needed?

CJ

memcpy(msg->buf, buf, size);
msg->msg_type = type;
/* msg len equals buffer length + msg_type */