[PATCH 3.10 223/319] ipv6: fix rtnl locking in setsockopt for anycast and multicast

Willy Tarreau
2017-02-05T19:52:09Z

From: Sabrina Dubroca <sd@queasysnail.net>

commit a9ed4a2986e13011fcf4ed2d1a1647c53112f55b upstream.

Calling setsockopt with IPV6_JOIN_ANYCAST or IPV6_LEAVE_ANYCAST
triggers the assertion in addrconf_join_solict()/addrconf_leave_solict()

ipv6_sock_ac_join(), ipv6_sock_ac_drop(), ipv6_sock_ac_close() need to
take RTNL before calling ipv6_dev_ac_inc/dec. Same thing with
ipv6_sock_mc_join(), ipv6_sock_mc_drop(), ipv6_sock_mc_close() before
calling ipv6_dev_mc_inc/dec.

This patch moves ASSERT_RTNL() up a level in the call stack.

Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Reported-by: Tommi Rantala <tt.rantala@gmail.com>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Cc: <stable@vger.kernel.org>
Cc: <stable@vger.kernel.org>
Cc: <stable@vger.kernel.org>
[Mike Manning <mmanning@brocade.com>: resolved minor conflicts in addrconf.c]
Signed-off-by: Mike Manning <mmanning@brocade.com>
Signed-off-by: Willy Tarreau <w@1wt.eu>
---
net/ipv6/addrconf.c | 15 +++++----------
net/ipv6/anycast.c | 12 ++++++++++++
net/ipv6/mcast.c | 14 ++++++++++++++
3 files changed, 31 insertions(+), 10 deletions(-)

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 0f18d858..3bfd8a5 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -1697,14 +1697,12 @@ void addrconf_dad_failure(struct inet6_ifaddr *ifp)
in6_ifa_put(ifp);
}

-/* Join to solicited addr multicast group. */
-
+/* Join to solicited addr multicast group.
+ * caller must hold RTNL */
void addrconf_join_solict(struct net_device *dev, const struct in6_addr *addr)
{
struct in6_addr maddr;

- ASSERT_RTNL();
-
if (dev->flags&(IFF_LOOPBACK|IFF_NOARP))
return;

@@ -1712,12 +1710,11 @@ void addrconf_join_solict(struct net_device *dev, const struct in6_addr *addr)
ipv6_dev_mc_inc(dev, &maddr);
}

+/* caller must hold RTNL */
void addrconf_leave_solict(struct inet6_dev *idev, const struct in6_addr *addr)
{
struct in6_addr maddr;

- ASSERT_RTNL();
-
if (idev->dev->flags&(IFF_LOOPBACK|IFF_NOARP))
return;

@@ -1725,12 +1722,11 @@ void addrconf_leave_solict(struct inet6_dev *idev, const struct in6_addr *addr)
__ipv6_dev_mc_dec(idev, &maddr);
}

+/* caller must hold RTNL */
static void addrconf_join_anycast(struct inet6_ifaddr *ifp)
{
struct in6_addr addr;

- ASSERT_RTNL();
-
if (ifp->prefix_len == 127) /* RFC 6164 */
return;
ipv6_addr_prefix(&addr, &ifp->addr, ifp->prefix_len);
@@ -1739,12 +1735,11 @@ static void addrconf_join_anycast(struct inet6_ifaddr *ifp)
ipv6_dev_ac_inc(ifp->idev->dev, &addr);
}

+/* caller must hold RTNL */
static void addrconf_leave_anycast(struct inet6_ifaddr *ifp)
{
struct in6_addr addr;

- ASSERT_RTNL();
-
if (ifp->prefix_len == 127) /* RFC 6164 */
return;
ipv6_addr_prefix(&addr, &ifp->addr, ifp->prefix_len);
diff --git a/net/ipv6/anycast.c b/net/ipv6/anycast.c
index 5a80f15..c59083c 100644
--- a/net/ipv6/anycast.c
+++ b/net/ipv6/anycast.c
@@ -77,6 +77,7 @@ int ipv6_sock_ac_join(struct sock *sk, int ifindex, const struct in6_addr *addr)
pac->acl_next = NULL;
pac->acl_addr = *addr;

+ rtnl_lock();
rcu_read_lock();
if (ifindex == 0) {
struct rt6_info *rt;
@@ -137,6 +138,7 @@ int ipv6_sock_ac_join(struct sock *sk, int ifindex, const struct in6_addr *addr)

error:
rcu_read_unlock();
+ rtnl_unlock();
if (pac)
sock_kfree_s(sk, pac, sizeof(*pac));
return err;
@@ -171,13 +173,17 @@ int ipv6_sock_ac_drop(struct sock *sk, int ifindex, const struct in6_addr *addr)

spin_unlock_bh(&ipv6_sk_ac_lock);

+ rtnl_lock();
rcu_read_lock();
dev = dev_get_by_index_rcu(net, pac->acl_ifindex);
if (dev)
ipv6_dev_ac_dec(dev, &pac->acl_addr);
rcu_read_unlock();
+ rtnl_unlock();

sock_kfree_s(sk, pac, sizeof(*pac));
+ if (!dev)
+ return -ENODEV;
return 0;
}

@@ -198,6 +204,7 @@ void ipv6_sock_ac_close(struct sock *sk)
spin_unlock_bh(&ipv6_sk_ac_lock);

prev_index = 0;
+ rtnl_lock();
rcu_read_lock();
while (pac) {
struct ipv6_ac_socklist *next = pac->acl_next;
@@ -212,6 +219,7 @@ void ipv6_sock_ac_close(struct sock *sk)
pac = next;
}
rcu_read_unlock();
+ rtnl_unlock();
}

static void aca_put(struct ifacaddr6 *ac)
@@ -233,6 +241,8 @@ int ipv6_dev_ac_inc(struct net_device *dev, const struct in6_addr *addr)
struct rt6_info *rt;
int err;

+ ASSERT_RTNL();
+
idev = in6_dev_get(dev);

if (idev == NULL)
@@ -302,6 +312,8 @@ int __ipv6_dev_ac_dec(struct inet6_dev *idev, const struct in6_addr *addr)
{
struct ifacaddr6 *aca, *prev_aca;

+ ASSERT_RTNL();
+
write_lock_bh(&idev->lock);
prev_aca = NULL;
for (aca = idev->ac_list; aca; aca = aca->aca_next) {
diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c
index 7ba6180..cf16eb4 100644
--- a/net/ipv6/mcast.c
+++ b/net/ipv6/mcast.c
@@ -157,6 +157,7 @@ int ipv6_sock_mc_join(struct sock *sk, int ifindex, const struct in6_addr *addr)
mc_lst->next = NULL;
mc_lst->addr = *addr;

+ rtnl_lock();
rcu_read_lock();
if (ifindex == 0) {
struct rt6_info *rt;
@@ -170,6 +171,7 @@ int ipv6_sock_mc_join(struct sock *sk, int ifindex, const struct in6_addr *addr)

if (dev == NULL) {
rcu_read_unlock();
+ rtnl_unlock();
sock_kfree_s(sk, mc_lst, sizeof(*mc_lst));
return -ENODEV;
}
@@ -187,6 +189,7 @@ int ipv6_sock_mc_join(struct sock *sk, int ifindex, const struct in6_addr *addr)

if (err) {
rcu_read_unlock();
+ rtnl_unlock();
sock_kfree_s(sk, mc_lst, sizeof(*mc_lst));
return err;
}
@@ -197,6 +200,7 @@ int ipv6_sock_mc_join(struct sock *sk, int ifindex, const struct in6_addr *addr)
spin_unlock(&ipv6_sk_mc_lock);

rcu_read_unlock();
+ rtnl_unlock();

return 0;
}
@@ -214,6 +218,7 @@ int ipv6_sock_mc_drop(struct sock *sk, int ifindex, const struct in6_addr *addr)
if (!ipv6_addr_is_multicast(addr))
return -EINVAL;

+ rtnl_lock();
spin_lock(&ipv6_sk_mc_lock);
for (lnk = &np->ipv6_mc_list;
(mc_lst = rcu_dereference_protected(*lnk,
@@ -237,12 +242,15 @@ int ipv6_sock_mc_drop(struct sock *sk, int ifindex, const struct in6_addr *addr)
} else
(void) ip6_mc_leave_src(sk, mc_lst, NULL);
rcu_read_unlock();
+ rtnl_unlock();
+
atomic_sub(sizeof(*mc_lst), &sk->sk_omem_alloc);
kfree_rcu(mc_lst, rcu);
return 0;
}
}
spin_unlock(&ipv6_sk_mc_lock);
+ rtnl_unlock();

return -EADDRNOTAVAIL;
}
@@ -287,6 +295,7 @@ void ipv6_sock_mc_close(struct sock *sk)
if (!rcu_access_pointer(np->ipv6_mc_list))
return;

+ rtnl_lock();
spin_lock(&ipv6_sk_mc_lock);
while ((mc_lst = rcu_dereference_protected(np->ipv6_mc_list,
lockdep_is_held(&ipv6_sk_mc_lock))) != NULL) {
@@ -313,6 +322,7 @@ void ipv6_sock_mc_close(struct sock *sk)
spin_lock(&ipv6_sk_mc_lock);
}
spin_unlock(&ipv6_sk_mc_lock);
+ rtnl_unlock();
}

int ip6_mc_source(int add, int omode, struct sock *sk,
@@ -830,6 +840,8 @@ int ipv6_dev_mc_inc(struct net_device *dev, const struct in6_addr *addr)
struct ifmcaddr6 *mc;
struct inet6_dev *idev;

+ ASSERT_RTNL();
+
/* we need to take a reference on idev */
idev = in6_dev_get(dev);

@@ -901,6 +913,8 @@ int __ipv6_dev_mc_dec(struct inet6_dev *idev, const struct in6_addr *addr)
{
struct ifmcaddr6 *ma, **map;

+ ASSERT_RTNL();
+
write_lock_bh(&idev->lock);
for (map = &idev->mc_list; (ma=*map) != NULL; map = &ma->next) {
if (ipv6_addr_equal(&ma->mca_addr, addr)) {
--
2.8.0.rc2.1.gbe9624a