From: Willem de Bruijn willemb@google.com
[ Upstream commit b90efd2258749e04e1b3f71ef0d716f2ac2337e0 ]
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 willemb@google.com Signed-off-by: Alexei Starovoitov ast@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- include/linux/skbuff.h | 6 ++++++ net/core/filter.c | 12 ++++-------- 2 files changed, 10 insertions(+), 8 deletions(-)
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 8e63c166765e..875f56cbb756 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -4118,6 +4118,12 @@ static inline bool skb_is_gso_sctp(const struct sk_buff *skb) return skb_shinfo(skb)->gso_type & SKB_GSO_SCTP; }
+static inline bool skb_is_gso_tcp(const struct sk_buff *skb) +{ + return skb_is_gso(skb) && + skb_shinfo(skb)->gso_type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6); +} + static inline void skb_gso_reset(struct sk_buff *skb) { skb_shinfo(skb)->gso_size = 0; diff --git a/net/core/filter.c b/net/core/filter.c index 16350f8c8815..6e37c639519e 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -2624,8 +2624,7 @@ 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); @@ -2666,8 +2665,7 @@ 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); @@ -2792,8 +2790,7 @@ 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); @@ -2822,8 +2819,7 @@ 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);