usb: typec: anx7411: Fix possible buffer overflow in anx7411_send_msg()

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

Posted by Grigory Bazilevich 2 years, 3 months ago

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@sicamp.ru>
---
 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));
 	memcpy(msg->buf, buf, size);
 	msg->msg_type = type;
 	/* msg len equals buffer length + msg_type */
-- 
2.39.2

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

Posted by Heikki Krogerus 2 years, 3 months ago

On Sat, Mar 16, 2024 at 11:33:53PM +0300, Grigory Bazilevich wrote:
> 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@sicamp.ru>

Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>

> ---
>  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));
>  	memcpy(msg->buf, buf, size);
>  	msg->msg_type = type;
>  	/* msg len equals buffer length + msg_type */
> -- 
> 2.39.2

-- 
heikki

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

Posted by Christophe JAILLET 2 years, 3 months ago

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@public.gmane.org>
> ---
>   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 */