iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

bpf: Set mac_len in bpf_skb_change_head

Browse Source 
[ Upstream commit 84316ca4e100d8cbfccd9f774e23817cb2059868 ]

The skb_change_head() helper did not set "skb->mac_len", which is
problematic when it's used in combination with skb_redirect_peer().
Without it, redirecting a packet from a L3 device such as wireguard to
the veth peer device will cause skb->data to point to the middle of the
IP header on entry to tcp_v4_rcv() since the L2 header is not pulled
correctly due to mac_len=0.

Fixes: 3a0af8fd61f9 ("bpf: BPF for lightweight tunnel infrastructure")
Signed-off-by: Jussi Maki <joamaki@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20210519154743.2554771-2-joamaki@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Jussi Maki 2021-05-19 15:47:42 +00:00 committed by Greg Kroah-Hartman
parent 272729d56b
commit 7a143b92d1
1 changed files with 1 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
net/core/filter.c
View File

@ -3331,6 +3331,7 @@ static inline int __bpf_skb_change_head(struct sk_buff *skb, u32 head_room,
__skb_push(skb, head_room);
memset(skb->data, 0, head_room);
skb_reset_mac_header(skb);
skb_reset_mac_len(skb);
}
return ret;