usb: gadget: rndis: prevent integer overflow in rndis_set_response()

If "BufOffset" is very large the "BufOffset + 8" operation can have an
integer overflow.

Cc: stable@kernel.org
Fixes: 38ea1eac7d88 ("usb: gadget: rndis: check size of RNDIS_MSG_SET command")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/20220301080424.GA17208@kili
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/gadget/function/rndis.c b/drivers/usb/gadget/function/rndis.c
index 00b3f6b..713efd9 100644 (file)
--- a/drivers/usb/gadget/function/rndis.c
+++ b/drivers/usb/gadget/function/rndis.c
@@ -640,6 +640,7 @@ static int rndis_set_response(struct rndis_params *params,
        BufLength = le32_to_cpu(buf->InformationBufferLength);
        BufOffset = le32_to_cpu(buf->InformationBufferOffset);
        if ((BufLength > RNDIS_MAX_TOTAL_SIZE) ||
+           (BufOffset > RNDIS_MAX_TOTAL_SIZE) ||
            (BufOffset + 8 >= RNDIS_MAX_TOTAL_SIZE))
                    return -EINVAL;