From 0bd84065b19bca12f07f288c8ea470e2c1b2de7a Mon Sep 17 00:00:00 2001
From: "subashab@codeaurora.org" <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 <dsa@cumulusnetworks.com>
Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
Cc: Eric Dumazet <edumazet@google.com>
Acked-by: David Ahern <dsa@cumulusnetworks.com>
Tested-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
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 <net/tcp_states.h>
#include <net/ip6_checksum.h>
#include <net/xfrm.h>
+#include <net/inet_hashtables.h>
#include <net/inet6_hashtables.h>
#include <net/busy_poll.h>
#include <net/sock_reuseport.h>
@@ -864,21 +865,26 @@ int __udp6_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
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;
--
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