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| author | Jussi Maki <joamaki@gmail.com> | 2021-05-19 17:47:42 +0200 |
|---|---|---|
| committer | Daniel Borkmann <daniel@iogearbox.net> | 2021-05-21 00:03:51 +0200 |
| commit | 84316ca4e100d8cbfccd9f774e23817cb2059868 (patch) | |
| tree | 62e7d5b25ec67270ff834530363db0c89d542114 /net | |
| parent | bpf, offload: Reorder offload callback 'prepare' in verifier (diff) | |
| download | linux-84316ca4e100d8cbfccd9f774e23817cb2059868.tar.xz linux-84316ca4e100d8cbfccd9f774e23817cb2059868.zip | |
bpf: Set mac_len in bpf_skb_change_head
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
Diffstat (limited to 'net')
| -rw-r--r-- | net/core/filter.c | 1 |
1 files changed, 1 insertions, 0 deletions
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; |