Commit 33e2b32b authored Feb 04, 2020 by Moritz Fischer Committed by David S. Miller Feb 05, 2020

net: ethernet: dec: tulip: Fix length mask in receive length calculation



The receive frame length calculation uses a wrong mask to calculate the
length of the received frames.

Per spec table 4-1 the length is contained in the FL (Frame Length)
field in bits 30:16.

This didn't show up as an issue so far since frames were limited to
1500 bytes which falls within the 11 bit window.

Signed-off-by: Moritz Fischer <mdf@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 7bb77d4b

drivers/net/ethernet/dec/tulip/de2104x.c

+4 −1

Original line number	Original line	Diff line number	Diff line
	@@ -417,7 +417,10 @@ static void de_rx (struct de_private *de)
	if (status & DescOwn)		if (status & DescOwn)
	break;		break;

	len = ((status >> 16) & 0x7ff) - 4;		/* the length is actually a 15 bit value here according
			* to Table 4-1 in the DE2104x spec so mask is 0x7fff
			*/
			len = ((status >> 16) & 0x7fff) - 4;
	mapping = de->rx_skb[rx_tail].mapping;		mapping = de->rx_skb[rx_tail].mapping;

	if (unlikely(drop)) {		if (unlikely(drop)) {