net: usb: sr9700: Handle negative len

Packet len computed as difference of length word extracted from
skb data and four may result in a negative value. In such case
processing of the buffer should be interrupted rather than
setting sr_skb->len to an unexpectedly large value (due to cast
from signed to unsigned integer) and passing sr_skb to
usbnet_skb_return.

Fixes: e9da0b56fe ("sr9700: sanity check for packet length")
Signed-off-by: Szymon Heidrich <szymon.heidrich@gmail.com>
Link: https://lore.kernel.org/r/20230114182326.30479-1-szymon.heidrich@gmail.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
This commit is contained in:
Szymon Heidrich 2023-01-14 19:23:26 +01:00 committed by Paolo Abeni
parent 87b93b678e
commit ecf7cf8efb

View file

@ -413,7 +413,7 @@ static int sr9700_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
/* ignore the CRC length */
len = (skb->data[1] | (skb->data[2] << 8)) - 4;
if (len > ETH_FRAME_LEN || len > skb->len)
if (len > ETH_FRAME_LEN || len > skb->len || len < 0)
return 0;
/* the last packet of current skb */