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. 5ef0ae84f02a
fixes TCPv6 but breaks UDPv6.
Fixes: 5ef0ae84f02a ("bpf: Fix IPv6 dport byte-order in bpf_sk_lookup")
Signed-off-by: Andrey Ignatov <r...@fb.com>
---
net/core/filter.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/net/core/filter.c b/net/core/filter.c
index e521c5ebc7d1..9a1327eb25fa 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -4852,18 +4852,17 @@ 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);
int sdif = inet6_sdif(skb);
if (proto == IPPROTO_TCP)
sk = __inet6_lookup(net, &tcp_hashinfo, skb, 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, skb);
#endif
--
2.17.1
