summary refs log tree commit diff
path: root/drivers/net
diff options
context:
space:
mode:
authorMoritz Fischer <mdf@kernel.org>2020-02-04 15:01:18 -0800
committerDavid S. Miller <davem@davemloft.net>2020-02-05 14:21:31 +0100
commit33e2b32b5df2b544ac5d43c4de2194bcc822b1b5 (patch)
treed6a1cb4363e7c15cf6ad8772ee9aaeeffbe2f94e /drivers/net
parent7bb77d4b8567b35aadd57f3154a08d873572ae20 (diff)
downloadlinux-33e2b32b5df2b544ac5d43c4de2194bcc822b1b5.tar.gz
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>
Diffstat (limited to 'drivers/net')
-rw-r--r--drivers/net/ethernet/dec/tulip/de2104x.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/drivers/net/ethernet/dec/tulip/de2104x.c b/drivers/net/ethernet/dec/tulip/de2104x.c
index d305d1b24b0a..42b798a3fad4 100644
--- a/drivers/net/ethernet/dec/tulip/de2104x.c
+++ b/drivers/net/ethernet/dec/tulip/de2104x.c
@@ -417,7 +417,10 @@ static void de_rx (struct de_private *de)
 		if (status & DescOwn)
 			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;
 
 		if (unlikely(drop)) {