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Subject[PATCH 4.9 036/109] l2tp: take remote address into account in l2tp_ip and l2tp_ip6 socket lookups
Date
4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Guillaume Nault <g.nault@alphalink.fr>


[ Upstream commit a9b2dff80be979432484afaf7f8d8e73f9e8838a ]

For connected sockets, __l2tp_ip{,6}_bind_lookup() needs to check the
remote IP when looking for a matching socket. Otherwise a connected
socket can receive traffic not originating from its peer.

Drop l2tp_ip_bind_lookup() and l2tp_ip6_bind_lookup() instead of
updating their prototype, as these functions aren't used.

Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/l2tp/l2tp_ip.c | 19 ++++++-------------
net/l2tp/l2tp_ip6.c | 20 ++++++--------------
2 files changed, 12 insertions(+), 27 deletions(-)

--- a/net/l2tp/l2tp_ip.c
+++ b/net/l2tp/l2tp_ip.c
@@ -48,7 +48,8 @@ static inline struct l2tp_ip_sock *l2tp_
return (struct l2tp_ip_sock *)sk;
}

-static struct sock *__l2tp_ip_bind_lookup(struct net *net, __be32 laddr, int dif, u32 tunnel_id)
+static struct sock *__l2tp_ip_bind_lookup(const struct net *net, __be32 laddr,
+ __be32 raddr, int dif, u32 tunnel_id)
{
struct sock *sk;

@@ -62,6 +63,7 @@ static struct sock *__l2tp_ip_bind_looku
if ((l2tp->conn_id == tunnel_id) &&
net_eq(sock_net(sk), net) &&
!(inet->inet_rcv_saddr && inet->inet_rcv_saddr != laddr) &&
+ (!inet->inet_daddr || !raddr || inet->inet_daddr == raddr) &&
(!sk->sk_bound_dev_if || !dif ||
sk->sk_bound_dev_if == dif))
goto found;
@@ -72,15 +74,6 @@ found:
return sk;
}

-static inline struct sock *l2tp_ip_bind_lookup(struct net *net, __be32 laddr, int dif, u32 tunnel_id)
-{
- struct sock *sk = __l2tp_ip_bind_lookup(net, laddr, dif, tunnel_id);
- if (sk)
- sock_hold(sk);
-
- return sk;
-}
-
/* When processing receive frames, there are two cases to
* consider. Data frames consist of a non-zero session-id and an
* optional cookie. Control frames consist of a regular L2TP header
@@ -186,8 +179,8 @@ pass_up:
struct iphdr *iph = (struct iphdr *) skb_network_header(skb);

read_lock_bh(&l2tp_ip_lock);
- sk = __l2tp_ip_bind_lookup(net, iph->daddr, inet_iif(skb),
- tunnel_id);
+ sk = __l2tp_ip_bind_lookup(net, iph->daddr, iph->saddr,
+ inet_iif(skb), tunnel_id);
if (!sk) {
read_unlock_bh(&l2tp_ip_lock);
goto discard;
@@ -289,7 +282,7 @@ static int l2tp_ip_bind(struct sock *sk,
inet->inet_saddr = 0; /* Use device */

write_lock_bh(&l2tp_ip_lock);
- if (__l2tp_ip_bind_lookup(net, addr->l2tp_addr.s_addr,
+ if (__l2tp_ip_bind_lookup(net, addr->l2tp_addr.s_addr, 0,
sk->sk_bound_dev_if, addr->l2tp_conn_id)) {
write_unlock_bh(&l2tp_ip_lock);
ret = -EADDRINUSE;
--- a/net/l2tp/l2tp_ip6.c
+++ b/net/l2tp/l2tp_ip6.c
@@ -59,12 +59,14 @@ static inline struct l2tp_ip6_sock *l2tp

static struct sock *__l2tp_ip6_bind_lookup(struct net *net,
struct in6_addr *laddr,
+ const struct in6_addr *raddr,
int dif, u32 tunnel_id)
{
struct sock *sk;

sk_for_each_bound(sk, &l2tp_ip6_bind_table) {
const struct in6_addr *sk_laddr = inet6_rcv_saddr(sk);
+ const struct in6_addr *sk_raddr = &sk->sk_v6_daddr;
struct l2tp_ip6_sock *l2tp = l2tp_ip6_sk(sk);

if (l2tp == NULL)
@@ -73,6 +75,7 @@ static struct sock *__l2tp_ip6_bind_look
if ((l2tp->conn_id == tunnel_id) &&
net_eq(sock_net(sk), net) &&
(!sk_laddr || ipv6_addr_any(sk_laddr) || ipv6_addr_equal(sk_laddr, laddr)) &&
+ (!raddr || ipv6_addr_any(sk_raddr) || ipv6_addr_equal(sk_raddr, raddr)) &&
(!sk->sk_bound_dev_if || !dif ||
sk->sk_bound_dev_if == dif))
goto found;
@@ -83,17 +86,6 @@ found:
return sk;
}

-static inline struct sock *l2tp_ip6_bind_lookup(struct net *net,
- struct in6_addr *laddr,
- int dif, u32 tunnel_id)
-{
- struct sock *sk = __l2tp_ip6_bind_lookup(net, laddr, dif, tunnel_id);
- if (sk)
- sock_hold(sk);
-
- return sk;
-}
-
/* When processing receive frames, there are two cases to
* consider. Data frames consist of a non-zero session-id and an
* optional cookie. Control frames consist of a regular L2TP header
@@ -200,8 +192,8 @@ pass_up:
struct ipv6hdr *iph = ipv6_hdr(skb);

read_lock_bh(&l2tp_ip6_lock);
- sk = __l2tp_ip6_bind_lookup(net, &iph->daddr, inet6_iif(skb),
- tunnel_id);
+ sk = __l2tp_ip6_bind_lookup(net, &iph->daddr, &iph->saddr,
+ inet6_iif(skb), tunnel_id);
if (!sk) {
read_unlock_bh(&l2tp_ip6_lock);
goto discard;
@@ -339,7 +331,7 @@ static int l2tp_ip6_bind(struct sock *sk
rcu_read_unlock();

write_lock_bh(&l2tp_ip6_lock);
- if (__l2tp_ip6_bind_lookup(net, &addr->l2tp_addr, bound_dev_if,
+ if (__l2tp_ip6_bind_lookup(net, &addr->l2tp_addr, NULL, bound_dev_if,
addr->l2tp_conn_id)) {
write_unlock_bh(&l2tp_ip6_lock);
err = -EADDRINUSE;

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