[PATCH 4.1 133/159] ipv6: lock socket in ip6_datagram_connect()

Greg Kroah-Hartman
2015-09-26T21:18:16Z

From: Eric Dumazet <edumazet@google.com>

[ Upstream commit 03645a11a570d52e70631838cb786eb4253eb463 ]

ip6_datagram_connect() is doing a lot of socket changes without
socket being locked.

This looks wrong, at least for udp_lib_rehash() which could corrupt
lists because of concurrent udp_sk(sk)->udp_portaddr_hash accesses.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
include/net/ip.h | 1 +
net/ipv4/datagram.c | 16 ++++++++++++----
net/ipv6/datagram.c | 20 +++++++++++++++-----
3 files changed, 28 insertions(+), 9 deletions(-)

--- a/include/net/ip.h
+++ b/include/net/ip.h
@@ -161,6 +161,7 @@ static inline __u8 get_rtconn_flags(stru
}

/* datagram.c */
+int __ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);
int ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);

void ip4_datagram_release_cb(struct sock *sk);
--- a/net/ipv4/datagram.c
+++ b/net/ipv4/datagram.c
@@ -20,7 +20,7 @@
#include <net/route.h>
#include <net/tcp_states.h>

-int ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
+int __ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
{
struct inet_sock *inet = inet_sk(sk);
struct sockaddr_in *usin = (struct sockaddr_in *) uaddr;
@@ -39,8 +39,6 @@ int ip4_datagram_connect(struct sock *sk

sk_dst_reset(sk);

- lock_sock(sk);
-
oif = sk->sk_bound_dev_if;
saddr = inet->inet_saddr;
if (ipv4_is_multicast(usin->sin_addr.s_addr)) {
@@ -82,9 +80,19 @@ int ip4_datagram_connect(struct sock *sk
sk_dst_set(sk, &rt->dst);
err = 0;
out:
- release_sock(sk);
return err;
}
+EXPORT_SYMBOL(__ip4_datagram_connect);
+
+int ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
+{
+ int res;
+
+ lock_sock(sk);
+ res = __ip4_datagram_connect(sk, uaddr, addr_len);
+ release_sock(sk);
+ return res;
+}
EXPORT_SYMBOL(ip4_datagram_connect);

/* Because UDP xmit path can manipulate sk_dst_cache without holding
--- a/net/ipv6/datagram.c
+++ b/net/ipv6/datagram.c
@@ -40,7 +40,7 @@ static bool ipv6_mapped_addr_any(const s
return ipv6_addr_v4mapped(a) && (a->s6_addr32[3] == 0);
}

-int ip6_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
+static int __ip6_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
{
struct sockaddr_in6 *usin = (struct sockaddr_in6 *) uaddr;
struct inet_sock *inet = inet_sk(sk);
@@ -56,7 +56,7 @@ int ip6_datagram_connect(struct sock *sk
if (usin->sin6_family == AF_INET) {
if (__ipv6_only_sock(sk))
return -EAFNOSUPPORT;
- err = ip4_datagram_connect(sk, uaddr, addr_len);
+ err = __ip4_datagram_connect(sk, uaddr, addr_len);
goto ipv4_connected;
}

@@ -98,9 +98,9 @@ int ip6_datagram_connect(struct sock *sk
sin.sin_addr.s_addr = daddr->s6_addr32[3];
sin.sin_port = usin->sin6_port;

- err = ip4_datagram_connect(sk,
- (struct sockaddr *) &sin,
- sizeof(sin));
+ err = __ip4_datagram_connect(sk,
+ (struct sockaddr *) &sin,
+ sizeof(sin));

ipv4_connected:
if (err)
@@ -204,6 +204,16 @@ out:
fl6_sock_release(flowlabel);
return err;
}
+
+int ip6_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
+{
+ int res;
+
+ lock_sock(sk);
+ res = __ip6_datagram_connect(sk, uaddr, addr_len);
+ release_sock(sk);
+ return res;
+}
EXPORT_SYMBOL_GPL(ip6_datagram_connect);

int ip6_datagram_connect_v6_only(struct sock *sk, struct sockaddr *uaddr,