This is a note to let you know that I've just added the patch titled
netfilter: nfnetlink_queue: fix OOB when mac header was cleared
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
netfilter-nfnetlink_queue-fix-oob-when-mac-header-wa.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 390d036c03e13fe5def702b95998b76c5728a0e2
Author: Florian Westphal <fw@xxxxxxxxx>
Date: Wed Oct 20 18:08:10 2021 +0200
netfilter: nfnetlink_queue: fix OOB when mac header was cleared
[ Upstream commit 5648b5e1169ff1d6d6a46c35c0b5fbebd2a5cbb2 ]
On 64bit platforms the MAC header is set to 0xffff on allocation and
also when a helper like skb_unset_mac_header() is called.
dev_parse_header may call skb_mac_header() which assumes valid mac offset:
BUG: KASAN: use-after-free in eth_header_parse+0x75/0x90
Read of size 6 at addr ffff8881075a5c05 by task nf-queue/1364
Call Trace:
memcpy+0x20/0x60
eth_header_parse+0x75/0x90
__nfqnl_enqueue_packet+0x1a61/0x3380
__nf_queue+0x597/0x1300
nf_queue+0xf/0x40
nf_hook_slow+0xed/0x190
nf_hook+0x184/0x440
ip_output+0x1c0/0x2a0
nf_reinject+0x26f/0x700
nfqnl_recv_verdict+0xa16/0x18b0
nfnetlink_rcv_msg+0x506/0xe70
The existing code only works if the skb has a mac header.
Fixes: 2c38de4c1f8da7 ("netfilter: fix looped (broad|multi)cast's MAC handling")
Signed-off-by: Florian Westphal <fw@xxxxxxxxx>
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c
index 54cde78c27183..ebce25080f7ff 100644
--- a/net/netfilter/nfnetlink_queue.c
+++ b/net/netfilter/nfnetlink_queue.c
@@ -486,7 +486,7 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue,
goto nla_put_failure;
if (indev && entskb->dev &&
- entskb->mac_header != entskb->network_header) {
+ skb_mac_header_was_set(entskb)) {
struct nfqnl_msg_packet_hw phw;
int len;
