summaryrefslogtreecommitdiff
path: root/net
diff options
context:
space:
mode:
authorWANG Cong <xiyou.wangcong@gmail.com>2017-04-12 12:32:13 -0700
committerDavid S. Miller <davem@davemloft.net>2017-04-17 12:46:50 -0400
commit1215e51edad1272e669172b26aa12aac94810c7f (patch)
tree273156966c9fb351ee4181712ebbcfc576495258 /net
parent271a8b428f8361f3ad4c599835ccd34dd458b212 (diff)
ipv4: fix a deadlock in ip_ra_control
Similar to commit 87e9f0315952 ("ipv4: fix a potential deadlock in mcast getsockopt() path"), there is a deadlock scenario for IP_ROUTER_ALERT too: CPU0 CPU1 ---- ---- lock(rtnl_mutex); lock(sk_lock-AF_INET); lock(rtnl_mutex); lock(sk_lock-AF_INET); Fix this by always locking RTNL first on all setsockopt() paths. Note, after this patch ip_ra_lock is no longer needed either. Reported-by: Dmitry Vyukov <dvyukov@google.com> Tested-by: Andrey Konovalov <andreyknvl@google.com> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/ipv4/ip_sockglue.c1
-rw-r--r--net/ipv4/ipmr.c11
-rw-r--r--net/ipv4/raw.c2
3 files changed, 5 insertions, 9 deletions
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index ebd953bc5607..bda318ae9876 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -591,6 +591,7 @@ static bool setsockopt_needs_rtnl(int optname)
case MCAST_LEAVE_GROUP:
case MCAST_LEAVE_SOURCE_GROUP:
case MCAST_UNBLOCK_SOURCE:
+ case IP_ROUTER_ALERT:
return true;
}
return false;
diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index c0317c940bcd..b036e85e093b 100644
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -1278,7 +1278,7 @@ static void mrtsock_destruct(struct sock *sk)
struct net *net = sock_net(sk);
struct mr_table *mrt;
- rtnl_lock();
+ ASSERT_RTNL();
ipmr_for_each_table(mrt, net) {
if (sk == rtnl_dereference(mrt->mroute_sk)) {
IPV4_DEVCONF_ALL(net, MC_FORWARDING)--;
@@ -1289,7 +1289,6 @@ static void mrtsock_destruct(struct sock *sk)
mroute_clean_tables(mrt, false);
}
}
- rtnl_unlock();
}
/* Socket options and virtual interface manipulation. The whole
@@ -1353,13 +1352,8 @@ int ip_mroute_setsockopt(struct sock *sk, int optname, char __user *optval,
if (sk != rcu_access_pointer(mrt->mroute_sk)) {
ret = -EACCES;
} else {
- /* We need to unlock here because mrtsock_destruct takes
- * care of rtnl itself and we can't change that due to
- * the IP_ROUTER_ALERT setsockopt which runs without it.
- */
- rtnl_unlock();
ret = ip_ra_control(sk, 0, NULL);
- goto out;
+ goto out_unlock;
}
break;
case MRT_ADD_VIF:
@@ -1470,7 +1464,6 @@ int ip_mroute_setsockopt(struct sock *sk, int optname, char __user *optval,
}
out_unlock:
rtnl_unlock();
-out:
return ret;
}
diff --git a/net/ipv4/raw.c b/net/ipv4/raw.c
index 8119e1f66e03..9d943974de2b 100644
--- a/net/ipv4/raw.c
+++ b/net/ipv4/raw.c
@@ -682,7 +682,9 @@ static void raw_close(struct sock *sk, long timeout)
/*
* Raw sockets may have direct kernel references. Kill them.
*/
+ rtnl_lock();
ip_ra_control(sk, 0, NULL);
+ rtnl_unlock();
sk_common_release(sk);
}