From: Jussi Maki <joamaki@gmail.com>
To: bpf@vger.kernel.org
Cc: daniel@iogearbox.net, Jussi Maki <joamaki@gmail.com>
Subject: [PATCH bpf 1/2] bpf: Set mac_len in bpf_skb_change_head
Date: Tue, 27 Apr 2021 13:55:49 +0000 [thread overview]
Message-ID: <20210427135550.807355-1-joamaki@gmail.com> (raw)
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.
Signed-off-by: Jussi Maki <joamaki@gmail.com>
---
net/core/filter.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/net/core/filter.c b/net/core/filter.c
index cae56d08a670..65ab4e21c087 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -3784,6 +3784,7 @@ 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;
--
2.30.2
next reply other threads:[~2021-04-27 13:56 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-27 13:55 Jussi Maki [this message]
2021-04-27 13:55 ` [PATCH bpf 2/2] selftests/bpf: Add test for bpf_skb_change_head Jussi Maki
2021-04-27 21:41 ` Andrii Nakryiko
2021-04-28 10:39 ` Jussi Maki
2021-04-28 10:49 ` Daniel Borkmann
2021-04-28 13:39 ` Jussi Maki
2021-05-17 10:11 ` [PATCH bpf v2 0/2] bpf: Fix l3 to l2 use of bpf_skb_change_head Jussi Maki
2021-05-17 10:11 ` [PATCH bpf v2 1/2] selftests/bpf: Add test for l3 use of bpf_redirect_peer Jussi Maki
2021-05-17 10:11 ` [PATCH bpf v2 2/2] bpf: Set mac_len in bpf_skb_change_head Jussi Maki
2021-05-18 14:23 ` [PATCH bpf v3 0/2] bpf: Fix l3 to l2 use of bpf_skb_change_head Jussi Maki
2021-05-18 14:23 ` [PATCH bpf v3 1/2] bpf: Set mac_len in bpf_skb_change_head Jussi Maki
2021-05-18 14:23 ` [PATCH bpf v3 2/2] selftests/bpf: Add test for l3 use of bpf_redirect_peer Jussi Maki
2021-05-19 15:33 ` Daniel Borkmann
2021-05-19 15:47 ` [PATCH bpf v4 0/2] bpf: Fix l3 to l2 use of bpf_skb_change_head Jussi Maki
2021-05-19 15:47 ` [PATCH bpf v4 1/2] bpf: Set mac_len in bpf_skb_change_head Jussi Maki
2021-05-20 22:07 ` Daniel Borkmann
2021-05-25 10:22 ` [PATCH bpf v5] selftests/bpf: Add test for l3 use of bpf_redirect_peer Jussi Maki
2021-05-19 15:47 ` [PATCH bpf v4 2/2] " Jussi Maki
2021-05-25 10:29 ` [PATCH bpf v5] " Jussi Maki
2021-05-25 16:03 ` Daniel Borkmann
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