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| author | Jussi Maki <joamaki@gmail.com> | 2021-05-19 18:47:42 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-06-03 09:59:15 +0300 |
| commit | 7a143b92d1dc0dfba1c310c9212a30dd272f037a (patch) | |
| tree | dc5dd03d8e0616dabe9f34496d36a4dc8699cb5e | |
| parent | 272729d56b2d308de38dab5760515c1653a09e60 (diff) | |
| download | linux-7a143b92d1dc0dfba1c310c9212a30dd272f037a.tar.xz | |
bpf: Set mac_len in bpf_skb_change_head
[ 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>
| -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 7fbb274b7fe3..108bcf600052 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -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; |