netdev - [PATCH net v3 1/2] act_ife: Fix external mac header on encode

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1474886726-56363-2-git-send-email-yotamg@mellanox.com>
Date:   Mon, 26 Sep 2016 13:45:25 +0300
From:   Yotam Gigi <yotam.gi@...il.com>
To:     jhs@...atatu.com, davem@...emloft.net, netdev@...r.kernel.org,
        mlxsw@...lanox.com
Cc:     Yotam Gigi <yotamg@...lanox.com>
Subject: [PATCH net v3 1/2] act_ife: Fix external mac header on encode

On ife encode side, external mac header is copied from the original packet
and may be overridden if the user requests. Before, the mac header copy
was done from memory region that might not be accessible anymore, as
skb_cow_head might free it and copy the packet. This led to random values
in the external mac header once the values were not set by user.

This fix takes the internal mac header from the packet, after the call to
skb_cow_head.

Fixes: ef6980b6becb ("net sched: introduce IFE action")
Acked-by: Jamal Hadi Salim <jhs@...atatu.com>
Signed-off-by: Yotam Gigi <yotamg@...lanox.com>
---
 net/sched/act_ife.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/net/sched/act_ife.c b/net/sched/act_ife.c
index ccf7b4b..b949d97 100644
--- a/net/sched/act_ife.c
+++ b/net/sched/act_ife.c
@@ -766,8 +766,6 @@ static int tcf_ife_encode(struct sk_buff *skb, const struct tc_action *a,
 		return TC_ACT_SHOT;
 	}
 
-	iethh = eth_hdr(skb);
-
 	err = skb_cow_head(skb, hdrm);
 	if (unlikely(err)) {
 		ife->tcf_qstats.drops++;
@@ -778,6 +776,7 @@ static int tcf_ife_encode(struct sk_buff *skb, const struct tc_action *a,
 	if (!(at & AT_EGRESS))
 		skb_push(skb, skb->dev->hard_header_len);
 
+	iethh = (struct ethhdr *)skb->data;
 	__skb_push(skb, hdrm);
 	memcpy(skb->data, iethh, skb->mac_len);
 	skb_reset_mac_header(skb);
-- 
2.4.11