diff options
| author | Martin KaFai Lau <kafai@fb.com> | 2018-01-24 23:15:27 -0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2018-01-29 11:37:40 -0500 |
| commit | 7ece54a60ee2ba7a386308cae73c790bd580589c (patch) | |
| tree | 571463d777eabe1dfdf2295e2a9240d513481aea /net | |
| parent | 2479c2c9f4c4db24afc8be1a0ff507343ff000f8 (diff) | |
ipv6: Fix SO_REUSEPORT UDP socket with implicit sk_ipv6only
If a sk_v6_rcv_saddr is !IPV6_ADDR_ANY and !IPV6_ADDR_MAPPED, it
implicitly implies it is an ipv6only socket. However, in inet6_bind(),
this addr_type checking and setting sk->sk_ipv6only to 1 are only done
after sk->sk_prot->get_port(sk, snum) has been completed successfully.
This inconsistency between sk_v6_rcv_saddr and sk_ipv6only confuses
the 'get_port()'.
In particular, when binding SO_REUSEPORT UDP sockets,
udp_reuseport_add_sock(sk,...) is called. udp_reuseport_add_sock()
checks "ipv6_only_sock(sk2) == ipv6_only_sock(sk)" before adding sk to
sk2->sk_reuseport_cb. In this case, ipv6_only_sock(sk2) could be
1 while ipv6_only_sock(sk) is still 0 here. The end result is,
reuseport_alloc(sk) is called instead of adding sk to the existing
sk2->sk_reuseport_cb.
It can be reproduced by binding two SO_REUSEPORT UDP sockets on an
IPv6 address (!ANY and !MAPPED). Only one of the socket will
receive packet.
The fix is to set the implicit sk_ipv6only before calling get_port().
The original sk_ipv6only has to be saved such that it can be restored
in case get_port() failed. The situation is similar to the
inet_reset_saddr(sk) after get_port() has failed.
Thanks to Calvin Owens <calvinowens@fb.com> who created an easy
reproduction which leads to a fix.
Fixes: e32ea7e74727 ("soreuseport: fast reuseport UDP socket selection")
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
| -rw-r--r-- | net/ipv6/af_inet6.c | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c index c9441ca45399..416917719a6f 100644 --- a/net/ipv6/af_inet6.c +++ b/net/ipv6/af_inet6.c @@ -284,6 +284,7 @@ int inet6_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len) struct net *net = sock_net(sk); __be32 v4addr = 0; unsigned short snum; + bool saved_ipv6only; int addr_type = 0; int err = 0; @@ -389,19 +390,21 @@ int inet6_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len) if (!(addr_type & IPV6_ADDR_MULTICAST)) np->saddr = addr->sin6_addr; + saved_ipv6only = sk->sk_ipv6only; + if (addr_type != IPV6_ADDR_ANY && addr_type != IPV6_ADDR_MAPPED) + sk->sk_ipv6only = 1; + /* Make sure we are allowed to bind here. */ if ((snum || !inet->bind_address_no_port) && sk->sk_prot->get_port(sk, snum)) { + sk->sk_ipv6only = saved_ipv6only; inet_reset_saddr(sk); err = -EADDRINUSE; goto out; } - if (addr_type != IPV6_ADDR_ANY) { + if (addr_type != IPV6_ADDR_ANY) sk->sk_userlocks |= SOCK_BINDADDR_LOCK; - if (addr_type != IPV6_ADDR_MAPPED) - sk->sk_ipv6only = 1; - } if (snum) sk->sk_userlocks |= SOCK_BINDPORT_LOCK; inet->inet_sport = htons(inet->inet_num); |