From 73da3a86719d92f2d7b755816819016bb9a61027 Mon Sep 17 00:00:00 2001 From: Szymon Heidrich Date: Sat, 14 Jan 2023 19:23:26 +0100 Subject: [PATCH] net: usb: sr9700: Handle negative len [ Upstream commit ecf7cf8efb59789e2b21d2f9ab926142579092b2 ] 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: 250634397fa9 ("sr9700: sanity check for packet length") Signed-off-by: Szymon Heidrich Link: https://lore.kernel.org/r/20230114182326.30479-1-szymon.heidrich@gmail.com Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin --- 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 fce6713e970ba..811c8751308c6 100644 --- a/drivers/net/usb/sr9700.c +++ b/drivers/net/usb/sr9700.c @@ -410,7 +410,7 @@ 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 */ -- 2.39.5