Commit cac6cc2f authored Nov 09, 2018 by Andrey Ignatov Committed by Alexei Starovoitov Nov 16, 2018

bpf: Fix IPv6 dport byte order in bpf_sk_lookup_udp



Lookup functions in sk_lookup have different expectations about byte
order of provided arguments.

Specifically __inet_lookup, __udp4_lib_lookup and __udp6_lib_lookup
expect dport to be in network byte order and do ntohs(dport) internally.

At the same time __inet6_lookup expects dport to be in host byte order
and correspondingly name the argument hnum.

sk_lookup works correctly with __inet_lookup, __udp4_lib_lookup and
__inet6_lookup with regard to dport. But in __udp6_lib_lookup case it
uses host instead of expected network byte order. It makes result
returned by bpf_sk_lookup_udp for IPv6 incorrect.

The patch fixes byte order of dport passed to __udp6_lib_lookup.

Originally sk_lookup properly handled UDPv6, but not TCPv6. 5ef0ae84
fixes TCPv6 but breaks UDPv6.

Fixes: 5ef0ae84 ("bpf: Fix IPv6 dport byte-order in bpf_sk_lookup")
Signed-off-by: Andrey Ignatov <rdna@fb.com>
Acked-by: Joe Stringer <joe@wand.net.nz>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

parent ac8acec9

net/core/filter.c

+2 −3

Original line number	Diff line number	Diff line
		@@ -4867,17 +4867,16 @@ static struct sock sk_lookup(struct net net, struct bpf_sock_tuple *tuple,
		} else {
		struct in6_addr src6 = (struct in6_addr )&tuple->ipv6.saddr;
		struct in6_addr dst6 = (struct in6_addr )&tuple->ipv6.daddr;
		u16 hnum = ntohs(tuple->ipv6.dport);

		if (proto == IPPROTO_TCP)
		sk = __inet6_lookup(net, &tcp_hashinfo, NULL, 0,
		src6, tuple->ipv6.sport,
		dst6, hnum,
		dst6, ntohs(tuple->ipv6.dport),
		dif, sdif, &refcounted);
		else if (likely(ipv6_bpf_stub))
		sk = ipv6_bpf_stub->udp6_lib_lookup(net,
		src6, tuple->ipv6.sport,
		dst6, hnum,
		dst6, tuple->ipv6.dport,
		dif, sdif,
		&udp_table, NULL);
		#endif