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: e9da0b56fe27 ("sr9700: sanity check for packet length")
Signed-off-by: Szymon Heidrich <szymon.heidrich@xxxxxxxxx>
---
drivers/net/usb/sr9700.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/usb/sr9700.c b/drivers/net/usb/sr9700.c
index 5a53e63d3..3164451e1 100644
--- a/drivers/net/usb/sr9700.c
+++ b/drivers/net/usb/sr9700.c
@@ -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 */
--
2.39.0
