From 1bc5b60197d01f5ebb4043ade11de540b2652024 Mon Sep 17 00:00:00 2001 From: Jukka Rissanen <jukka.rissanen@linux.intel.com> Date: Wed, 13 Nov 2013 11:03:39 +0200 Subject: [PATCH] 6lowpan: Uncompression of traffic class field was incorrect [ Upstream commit 1188f05497e7bd2f2614b99c54adfbe7413d5749 ] If priority/traffic class field in IPv6 header is set (seen when using ssh), the uncompression sets the TC and Flow fields incorrectly. Example: This is IPv6 header of a sent packet. Note the priority/TC (=1) in the first byte. 00000000: 61 00 00 00 00 2c 06 40 fe 80 00 00 00 00 00 00 00000010: 02 02 72 ff fe c6 42 10 fe 80 00 00 00 00 00 00 00000020: 02 1e ab ff fe 4c 52 57 This gets compressed like this in the sending side 00000000: 72 31 04 06 02 1e ab ff fe 4c 52 57 ec c2 00 16 00000010: aa 2d fe 92 86 4e be c6 .... In the receiving end, the packet gets uncompressed to this IPv6 header 00000000: 60 06 06 02 00 2a 1e 40 fe 80 00 00 00 00 00 00 00000010: 02 02 72 ff fe c6 42 10 fe 80 00 00 00 00 00 00 00000020: ab ff fe 4c 52 57 ec c2 First four bytes are set incorrectly and we have also lost two bytes from destination address. The fix is to switch the case values in switch statement when checking the TC field. Signed-off-by: Jukka Rissanen <jukka.rissanen@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> --- net/ieee802154/6lowpan.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/ieee802154/6lowpan.c b/net/ieee802154/6lowpan.c index 19d6aefe97d4..5d42df22c3c5 100644 --- a/net/ieee802154/6lowpan.c +++ b/net/ieee802154/6lowpan.c @@ -563,7 +563,7 @@ lowpan_process_data(struct sk_buff *skb) * Traffic class carried in-line * ECN + DSCP (1 byte), Flow Label is elided */ - case 1: /* 10b */ + case 2: /* 10b */ if (!skb->len) goto drop; tmp = lowpan_fetch_skb_u8(skb); @@ -576,7 +576,7 @@ lowpan_process_data(struct sk_buff *skb) * Flow Label carried in-line * ECN + 2-bit Pad + Flow Label (3 bytes), DSCP is elided */ - case 2: /* 01b */ + case 1: /* 01b */ if (!skb->len) goto drop; tmp = lowpan_fetch_skb_u8(skb); -- 2.30.9