From 0bd84065b19bca12f07f288c8ea470e2c1b2de7a Mon Sep 17 00:00:00 2001 From: "subashab@codeaurora.org" Date: Tue, 18 Apr 2017 11:39:41 -0600 Subject: [PATCH] net: ipv6: Fix UDP early demux lookup with udp_l3mdev_accept=0 David Ahern reported that 5425077d73e0c ("net: ipv6: Add early demux handler for UDP unicast") breaks udp_l3mdev_accept=0 since early demux for IPv6 UDP was doing a generic socket lookup which does not require an exact match. Fix this by making UDPv6 early demux match connected sockets only. v1->v2: Take reference to socket after match as suggested by Eric v2->v3: Add comment before break Fixes: 5425077d73e0c ("net: ipv6: Add early demux handler for UDP unicast") Reported-by: David Ahern Signed-off-by: Subash Abhinov Kasiviswanathan Cc: Eric Dumazet Acked-by: David Ahern Tested-by: David Ahern Signed-off-by: David S. Miller --- net/ipv6/udp.c | 24 +++++++++++++++--------- 1 file changed, 15 insertions(+), 9 deletions(-) diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c index fd4b1c98a472..04862abfe4ec 100644 --- a/net/ipv6/udp.c +++ b/net/ipv6/udp.c @@ -46,6 +46,7 @@ #include #include #include +#include #include #include #include @@ -864,21 +865,26 @@ discard: return 0; } + static struct sock *__udp6_lib_demux_lookup(struct net *net, __be16 loc_port, const struct in6_addr *loc_addr, __be16 rmt_port, const struct in6_addr *rmt_addr, int dif) { + unsigned short hnum = ntohs(loc_port); + unsigned int hash2 = udp6_portaddr_hash(net, loc_addr, hnum); + unsigned int slot2 = hash2 & udp_table.mask; + struct udp_hslot *hslot2 = &udp_table.hash2[slot2]; + const __portpair ports = INET_COMBINED_PORTS(rmt_port, hnum); struct sock *sk; - rcu_read_lock(); - sk = __udp6_lib_lookup(net, rmt_addr, rmt_port, loc_addr, loc_port, - dif, &udp_table, NULL); - if (sk && !atomic_inc_not_zero(&sk->sk_refcnt)) - sk = NULL; - rcu_read_unlock(); - - return sk; + udp_portaddr_for_each_entry_rcu(sk, &hslot2->head) { + if (INET6_MATCH(sk, net, rmt_addr, loc_addr, ports, dif)) + return sk; + /* Only check first socket in chain */ + break; + } + return NULL; } static void udp_v6_early_demux(struct sk_buff *skb) @@ -903,7 +909,7 @@ static void udp_v6_early_demux(struct sk_buff *skb) else return; - if (!sk) + if (!sk || !atomic_inc_not_zero_hint(&sk->sk_refcnt, 2)) return; skb->sk = sk; -- 2.20.1