[PATCH AUTOSEL 4.19 17/60] bpf: udp: Avoid calling reuseport's bpf_prog from udp_gro

Sasha Levin
2019-06-27T00:37:16Z

From: Martin KaFai Lau <kafai@fb.com>

[ Upstream commit 257a525fe2e49584842c504a92c27097407f778f ]

When the commit a6024562ffd7 ("udp: Add GRO functions to UDP socket")
added udp[46]_lib_lookup_skb to the udp_gro code path, it broke
the reuseport_select_sock() assumption that skb->data is pointing
to the transport header.

This patch follows an earlier __udp6_lib_err() fix by
passing a NULL skb to avoid calling the reuseport's bpf_prog.

Fixes: a6024562ffd7 ("udp: Add GRO functions to UDP socket")
Cc: Tom Herbert <tom@herbertland.com>
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/ipv4/udp.c | 6 +++++-
net/ipv6/udp.c | 2 +-
2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index e45a5e19e509..e6dbe3912b93 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -542,7 +542,11 @@ static inline struct sock *__udp4_lib_lookup_skb(struct sk_buff *skb,
struct sock *udp4_lib_lookup_skb(struct sk_buff *skb,
__be16 sport, __be16 dport)
{
- return __udp4_lib_lookup_skb(skb, sport, dport, &udp_table);
+ const struct iphdr *iph = ip_hdr(skb);
+
+ return __udp4_lib_lookup(dev_net(skb->dev), iph->saddr, sport,
+ iph->daddr, dport, inet_iif(skb),
+ inet_sdif(skb), &udp_table, NULL);
}
EXPORT_SYMBOL_GPL(udp4_lib_lookup_skb);

diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index cab8b2b647f9..7c3ea06f86a9 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -282,7 +282,7 @@ struct sock *udp6_lib_lookup_skb(struct sk_buff *skb,

return __udp6_lib_lookup(dev_net(skb->dev), &iph->saddr, sport,
&iph->daddr, dport, inet6_iif(skb),
- inet6_sdif(skb), &udp_table, skb);
+ inet6_sdif(skb), &udp_table, NULL);
}
EXPORT_SYMBOL_GPL(udp6_lib_lookup_skb);

--
2.20.1