On Tue, Dec 22, 2020 at 12:07:04PM +0000, James Reynolds wrote:

When processing a MCE_RSP_GETPORTSTATUS command, the bit index to set in ir->txports_cabled comes from response data, and isn't validated.

As ir->txports_cabled is a u8, nothing should be done if the bit index is greater than 7.

Cc: stable@vger.kernel.org Reported-by: syzbot+ec3b3128c576e109171d@syzkaller.appspotmail.com Signed-off-by: James Reynolds jr@memlen.com

---

drivers/media/rc/mceusb.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/media/rc/mceusb.c b/drivers/media/rc/mceusb.c index f1dbd059ed08..c8d63673e131 100644 --- a/drivers/media/rc/mceusb.c +++ b/drivers/media/rc/mceusb.c @@ -1169,7 +1169,7 @@ static void mceusb_handle_command(struct mceusb_dev *ir, u8 *buf_in) switch (subcmd) { /* the one and only 5-byte return value command */ case MCE_RSP_GETPORTSTATUS:

• 	if (buf_in[5] == 0)
  

• 	if (buf_in[5] == 0 && *hi < 8)
  	ir->txports_cabled |= 1 << *hi;
  

So *hi is a port number. I don't know of any devices that have more than 2 ports, so this is fine.

Reviewed-by: Sean Young sean@mess.org

Thanks

Sean