From b90efd2258749e04e1b3f71ef0d716f2ac2337e0 Mon Sep 17 00:00:00 2001 From: Willem de Bruijn Date: Thu, 7 Feb 2019 14:54:16 -0500 Subject: bpf: only adjust gso_size on bytestream protocols bpf_skb_change_proto and bpf_skb_adjust_room change skb header length. For GSO packets they adjust gso_size to maintain the same MTU. The gso size can only be safely adjusted on bytestream protocols. Commit d02f51cbcf12 ("bpf: fix bpf_skb_adjust_net/bpf_skb_proto_xlat to deal with gso sctp skbs") excluded SKB_GSO_SCTP. Since then type SKB_GSO_UDP_L4 has been added, whose contents are one gso_size unit per datagram. Also exclude these. Move from a blacklist to a whitelist check to future proof against additional such new GSO types, e.g., for fraglist based GRO. Fixes: bec1f6f69736 ("udp: generate gso with UDP_SEGMENT") Signed-off-by: Willem de Bruijn Signed-off-by: Alexei Starovoitov --- net/core/filter.c | 12 ++++-------- 1 file changed, 4 insertions(+), 8 deletions(-) (limited to 'net/core') diff --git a/net/core/filter.c b/net/core/filter.c index 7a54dc11ac2d..f7d0004fc160 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -2789,8 +2789,7 @@ static int bpf_skb_proto_4_to_6(struct sk_buff *skb) u32 off = skb_mac_header_len(skb); int ret; - /* SCTP uses GSO_BY_FRAGS, thus cannot adjust it. */ - if (skb_is_gso(skb) && unlikely(skb_is_gso_sctp(skb))) + if (!skb_is_gso_tcp(skb)) return -ENOTSUPP; ret = skb_cow(skb, len_diff); @@ -2831,8 +2830,7 @@ static int bpf_skb_proto_6_to_4(struct sk_buff *skb) u32 off = skb_mac_header_len(skb); int ret; - /* SCTP uses GSO_BY_FRAGS, thus cannot adjust it. */ - if (skb_is_gso(skb) && unlikely(skb_is_gso_sctp(skb))) + if (!skb_is_gso_tcp(skb)) return -ENOTSUPP; ret = skb_unclone(skb, GFP_ATOMIC); @@ -2957,8 +2955,7 @@ static int bpf_skb_net_grow(struct sk_buff *skb, u32 len_diff) u32 off = skb_mac_header_len(skb) + bpf_skb_net_base_len(skb); int ret; - /* SCTP uses GSO_BY_FRAGS, thus cannot adjust it. */ - if (skb_is_gso(skb) && unlikely(skb_is_gso_sctp(skb))) + if (!skb_is_gso_tcp(skb)) return -ENOTSUPP; ret = skb_cow(skb, len_diff); @@ -2987,8 +2984,7 @@ static int bpf_skb_net_shrink(struct sk_buff *skb, u32 len_diff) u32 off = skb_mac_header_len(skb) + bpf_skb_net_base_len(skb); int ret; - /* SCTP uses GSO_BY_FRAGS, thus cannot adjust it. */ - if (skb_is_gso(skb) && unlikely(skb_is_gso_sctp(skb))) + if (!skb_is_gso_tcp(skb)) return -ENOTSUPP; ret = skb_unclone(skb, GFP_ATOMIC); -- cgit v1.2.3