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* [PATCH] sr9700: improve packet length sanity check
@ 2022-07-14 13:21 Thadeu Lima de Souza Cascardo
  2022-07-19  3:07 ` Jakub Kicinski
  0 siblings, 1 reply; 2+ messages in thread
From: Thadeu Lima de Souza Cascardo @ 2022-07-14 13:21 UTC (permalink / raw)
  To: netdev
  Cc: linux-usb, oneukum, grundler, pabeni, kuba, edumazet, davem,
	Thadeu Lima de Souza Cascardo

The packet format includes a 3 byte headers and a 4 byte CRC. Account for
that when checking the given length is not larger than the skb length.

Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Fixes: e9da0b56fe27 ("sr9700: sanity check for packet length")
---
 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 5a53e63d33a6..09bb40ac6e09 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 + SR_RX_OVERHEAD > skb->len)
 			return 0;
 
 		/* the last packet of current skb */
-- 
2.34.1


^ permalink raw reply related	[flat|nested] 2+ messages in thread

* Re: [PATCH] sr9700: improve packet length sanity check
  2022-07-14 13:21 [PATCH] sr9700: improve packet length sanity check Thadeu Lima de Souza Cascardo
@ 2022-07-19  3:07 ` Jakub Kicinski
  0 siblings, 0 replies; 2+ messages in thread
From: Jakub Kicinski @ 2022-07-19  3:07 UTC (permalink / raw)
  To: Thadeu Lima de Souza Cascardo
  Cc: netdev, linux-usb, oneukum, grundler, pabeni, edumazet, davem

On Thu, 14 Jul 2022 10:21:34 -0300 Thadeu Lima de Souza Cascardo wrote:
> The packet format includes a 3 byte headers and a 4 byte CRC. Account for
> that when checking the given length is not larger than the skb length.

Please describe in detail the issue you're fixing. What will happen if
we don't include SR_RX_OVERHEAD in the check.

> Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
> Fixes: e9da0b56fe27 ("sr9700: sanity check for packet length")

^ permalink raw reply	[flat|nested] 2+ messages in thread

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2022-07-14 13:21 [PATCH] sr9700: improve packet length sanity check Thadeu Lima de Souza Cascardo
2022-07-19  3:07 ` Jakub Kicinski

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