[PATCH AUTOSEL 4.19 06/48] bpf: only adjust gso_size on bytestream protocols
From: Sasha Levin <sashal@kernel.org>
Date: 2019-03-13 19:13:17
Also in:
bpf, lkml, stable
Subsystem:
bpf [general] (safe dynamic programs and tools), bpf [networking] (tcx & tc bpf, sock_addr), networking [general], the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
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 a404d475acee..3b0a25bb7c6f 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h@@ -4086,6 +4086,12 @@ 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 fb0080e84bd4..cb792b344b5e 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c@@ -2614,8 +2614,7 @@ 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);
@@ -2656,8 +2655,7 @@ 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);
@@ -2782,8 +2780,7 @@ 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);
@@ -2812,8 +2809,7 @@ 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);
--
2.19.1