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| author | Eric Dumazet <eric.dumazet@gmail.com> | 2009-10-19 06:41:58 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2009-10-19 21:34:20 -0700 |
| commit | 55b8050353c4a212c94d7156e2bd5885225b869b (patch) | |
| tree | 013778c4d48b946b2c565f8b55f40e505ec255ce | |
| parent | 45054dc1bf2367ccb0e7c0486037907cd9395f8b (diff) | |
| download | lwn-55b8050353c4a212c94d7156e2bd5885225b869b.tar.gz lwn-55b8050353c4a212c94d7156e2bd5885225b869b.zip | |
net: Fix IP_MULTICAST_IF
ipv4/ipv6 setsockopt(IP_MULTICAST_IF) have dubious __dev_get_by_index() calls.
This function should be called only with RTNL or dev_base_lock held, or reader
could see a corrupt hash chain and eventually enter an endless loop.
Fix is to call dev_get_by_index()/dev_put().
If this happens to be performance critical, we could define a new dev_exist_by_index()
function to avoid touching dev refcount.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/ipv4/ip_sockglue.c | 7 | ||||
| -rw-r--r-- | net/ipv6/ipv6_sockglue.c | 6 |
2 files changed, 8 insertions, 5 deletions
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c index 0c0b6e363a20..e982b5c1ee17 100644 --- a/net/ipv4/ip_sockglue.c +++ b/net/ipv4/ip_sockglue.c @@ -634,17 +634,16 @@ static int do_ip_setsockopt(struct sock *sk, int level, break; } dev = ip_dev_find(sock_net(sk), mreq.imr_address.s_addr); - if (dev) { + if (dev) mreq.imr_ifindex = dev->ifindex; - dev_put(dev); - } } else - dev = __dev_get_by_index(sock_net(sk), mreq.imr_ifindex); + dev = dev_get_by_index(sock_net(sk), mreq.imr_ifindex); err = -EADDRNOTAVAIL; if (!dev) break; + dev_put(dev); err = -EINVAL; if (sk->sk_bound_dev_if && diff --git a/net/ipv6/ipv6_sockglue.c b/net/ipv6/ipv6_sockglue.c index 14f54eb5a7fc..4f7aaf6996a3 100644 --- a/net/ipv6/ipv6_sockglue.c +++ b/net/ipv6/ipv6_sockglue.c @@ -496,13 +496,17 @@ done: goto e_inval; if (val) { + struct net_device *dev; + if (sk->sk_bound_dev_if && sk->sk_bound_dev_if != val) goto e_inval; - if (__dev_get_by_index(net, val) == NULL) { + dev = dev_get_by_index(net, val); + if (!dev) { retv = -ENODEV; break; } + dev_put(dev); } np->mcast_oif = val; retv = 0; |