From c0e760c9c66ebd8a5a1ede81868677f4df993dfb Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Wed, 30 Mar 2016 00:02:00 +0200 Subject: [PATCH] bpf: make padding in bpf_tunnel_key explicit Make the 2 byte padding in struct bpf_tunnel_key between tunnel_ttl and tunnel_label members explicit. No issue has been observed, and gcc/llvm does padding for the old struct already, where tunnel_label was not yet present, so the current code works, but since it's part of uapi, make sure we don't introduce holes in structs. Therefore, add tunnel_ext that we can use generically in future (f.e. to flag OAM messages for backends, etc). Also add the offset to the compat tests to be sure should some compilers not padd the tail of the old version of bpf_tunnel_key. Fixes: 4018ab1875e0 ("bpf: support flow label for bpf_skb_{set, get}_tunnel_key") Signed-off-by: Daniel Borkmann Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller --- include/uapi/linux/bpf.h | 1 + net/core/filter.c | 5 ++++- 2 files changed, 5 insertions(+), 1 deletion(-) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 924f537183fd..23917bb47bf3 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -375,6 +375,7 @@ struct bpf_tunnel_key { }; __u8 tunnel_tos; __u8 tunnel_ttl; + __u16 tunnel_ext; __u32 tunnel_label; }; diff --git a/net/core/filter.c b/net/core/filter.c index b7177d01ecb0..4b81b71171b4 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -1764,6 +1764,7 @@ static u64 bpf_skb_get_tunnel_key(u64 r1, u64 r2, u64 size, u64 flags, u64 r5) if (unlikely(size != sizeof(struct bpf_tunnel_key))) { switch (size) { case offsetof(struct bpf_tunnel_key, tunnel_label): + case offsetof(struct bpf_tunnel_key, tunnel_ext): goto set_compat; case offsetof(struct bpf_tunnel_key, remote_ipv6[1]): /* Fixup deprecated structure layouts here, so we have @@ -1849,6 +1850,7 @@ static u64 bpf_skb_set_tunnel_key(u64 r1, u64 r2, u64 size, u64 flags, u64 r5) if (unlikely(size != sizeof(struct bpf_tunnel_key))) { switch (size) { case offsetof(struct bpf_tunnel_key, tunnel_label): + case offsetof(struct bpf_tunnel_key, tunnel_ext): case offsetof(struct bpf_tunnel_key, remote_ipv6[1]): /* Fixup deprecated structure layouts here, so we have * a common path later on. @@ -1861,7 +1863,8 @@ static u64 bpf_skb_set_tunnel_key(u64 r1, u64 r2, u64 size, u64 flags, u64 r5) return -EINVAL; } } - if (unlikely(!(flags & BPF_F_TUNINFO_IPV6) && from->tunnel_label)) + if (unlikely((!(flags & BPF_F_TUNINFO_IPV6) && from->tunnel_label) || + from->tunnel_ext)) return -EINVAL; skb_dst_drop(skb); -- 2.20.1