linux-stable.git/net/bridge, branch v3.4.112

bridge: multicast: restore router configuration on port link down/up

2015-10-22T01:20:06+00:00

commit 754bc547f0a79f7568b5b81c7fc0a8d044a6571a upstream.

When a port goes through a link down/up the multicast router configuration
is not restored.

Signed-off-by: Satish Ashok 
Signed-off-by: Nikolay Aleksandrov 
Fixes: 0909e11758bd ("bridge: Add multicast_router sysfs entries")
Acked-by: Herbert Xu 
Signed-off-by: David S. Miller 
[lizf: Backported to 3.4: adjust context]
Signed-off-by: Zefan Li

bridge: fix br_stp_set_bridge_priority race conditions

2015-10-22T01:20:05+00:00

commit 2dab80a8b486f02222a69daca6859519e05781d9 upstream.

After the ->set() spinlocks were removed br_stp_set_bridge_priority
was left running without any protection when used via sysfs. It can
race with port add/del and could result in use-after-free cases and
corrupted lists. Tested by running port add/del in a loop with stp
enabled while setting priority in a loop, crashes are easily
reproducible.
The spinlocks around sysfs ->set() were removed in commit:
14f98f258f19 ("bridge: range check STP parameters")
There's also a race condition in the netlink priority support that is
fixed by this change, but it was introduced recently and the fixes tag
covers it, just in case it's needed the commit is:
af615762e972 ("bridge: add ageing_time, stp_state, priority over netlink")

Signed-off-by: Nikolay Aleksandrov 
Fixes: 14f98f258f19 ("bridge: range check STP parameters")
Signed-off-by: David S. Miller 
Signed-off-by: Zefan Li

bridge: superfluous skb->nfct check in br_nf_dev_queue_xmit

2015-09-18T01:20:46+00:00

commit aff09ce303f83bd370772349238482ae422a2341 upstream.

Currently bridge can silently drop ipv4 fragments.
If node have loaded nf_defrag_ipv4 module but have no nf_conntrack_ipv4,
br_nf_pre_routing defragments incoming ipv4 fragments
but nfct check in br_nf_dev_queue_xmit does not allow re-fragment combined
packet back, and therefore it is dropped in br_dev_queue_push_xmit without
incrementing of any failcounters

It seems the only way to hit the ip_fragment code in the bridge xmit
path is to have a fragment list whose reassembled fragments go over
the mtu. This only happens if nf_defrag is enabled. Thanks to
Florian Westphal for providing feedback to clarify this.

Defragmentation ipv4 is required not only in conntracks but at least in
TPROXY target and socket match, therefore #ifdef is changed from
NF_CONNTRACK_IPV4 to NF_DEFRAG_IPV4

Signed-off-by: Vasily Averin 
Signed-off-by: Pablo Neira Ayuso 
Cc: Kirill Tkhai 
Signed-off-by: Zefan Li

bridge: fix multicast router rlist endless loop

2015-09-18T01:20:45+00:00

commit 1a040eaca1a22f8da8285ceda6b5e4a2cb704867 upstream.

Since the addition of sysfs multicast router support if one set
multicast_router to "2" more than once, then the port would be added to
the hlist every time and could end up linking to itself and thus causing an
endless loop for rlist walkers.
So to reproduce just do:
echo 2 > multicast_router; echo 2 > multicast_router;
in a bridge port and let some igmp traffic flow, for me it hangs up
in br_multicast_flood().
Fix this by adding a check in br_multicast_add_router() if the port is
already linked.
The reason this didn't happen before the addition of multicast_router
sysfs entries is because there's a !hlist_unhashed check that prevents
it.

Signed-off-by: Nikolay Aleksandrov 
Fixes: 0909e11758bd ("bridge: Add multicast_router sysfs entries")
Acked-by: Herbert Xu 
Signed-off-by: David S. Miller 
[lizf: Backported to 3.4: adjust context]
Signed-off-by: Zefan Li

bridge: disable softirqs around br_fdb_update to avoid lockup

2015-09-18T01:20:45+00:00

commit c4c832f89dc468cf11dc0dd17206bace44526651 upstream.

br_fdb_update() can be called in process context in the following way:
br_fdb_add() -> __br_fdb_add() -> br_fdb_update() (if NTF_USE flag is set)
so we need to disable softirqs because there are softirq users of the
hash_lock. One easy way to reproduce this is to modify the bridge utility
to set NTF_USE, enable stp and then set maxageing to a low value so
br_fdb_cleanup() is called frequently and then just add new entries in
a loop. This happens because br_fdb_cleanup() is called from timer/softirq
context. The spin locks in br_fdb_update were _bh before commit f8ae737deea1
("[BRIDGE]: forwarding remove unneeded preempt and bh diasables")
and at the time that commit was correct because br_fdb_update() couldn't be
called from process context, but that changed after commit:
292d1398983f ("bridge: add NTF_USE support")
Using local_bh_disable/enable around br_fdb_update() allows us to keep
using the spin_lock/unlock in br_fdb_update for the fast-path.

Signed-off-by: Nikolay Aleksandrov 
Fixes: 292d1398983f ("bridge: add NTF_USE support")
Signed-off-by: David S. Miller 
[lizf: Backported to 3.4: adjust context]
Signed-off-by: Zefan Li

bridge: use _bh spinlock variant for br_fdb_update to avoid lockup

2015-09-18T01:20:45+00:00

commit 1d7c49037b12016e7056b9f2c990380e2187e766 upstream.

br_fdb_update() can be called in process context in the following way:
br_fdb_add() -> __br_fdb_add() -> br_fdb_update() (if NTF_USE flag is set)
so we need to use spin_lock_bh because there are softirq users of the
hash_lock. One easy way to reproduce this is to modify the bridge utility
to set NTF_USE, enable stp and then set maxageing to a low value so
br_fdb_cleanup() is called frequently and then just add new entries in
a loop. This happens because br_fdb_cleanup() is called from timer/softirq
context. These locks were _bh before commit f8ae737deea1
("[BRIDGE]: forwarding remove unneeded preempt and bh diasables")
and at the time that commit was correct because br_fdb_update() couldn't be
called from process context, but that changed after commit:
292d1398983f ("bridge: add NTF_USE support")

Signed-off-by: Wilson Kok 
Signed-off-by: Nikolay Aleksandrov 
Fixes: 292d1398983f ("bridge: add NTF_USE support")
Signed-off-by: David S. Miller 
[lizf: Backported to 3.4: adjust context]
Signed-off-by: Zefan Li

bridge: fix parsing of MLDv2 reports

2015-09-18T01:20:42+00:00

commit 47cc84ce0c2fe75c99ea5963c4b5704dd78ead54 upstream.

When more than a multicast address is present in a MLDv2 report, all but
the first address is ignored, because the code breaks out of the loop if
there has not been an error adding that address.

This has caused failures when two guests connected through the bridge
tried to communicate using IPv6. Neighbor discoveries would not be
transmitted to the other guest when both used a link-local address and a
static address.

This only happens when there is a MLDv2 querier in the network.

The fix will only break out of the loop when there is a failure adding a
multicast address.

The mdb before the patch:

dev ovirtmgmt port vnet0 grp ff02::1:ff7d:6603 temp
dev ovirtmgmt port vnet1 grp ff02::1:ff7d:6604 temp
dev ovirtmgmt port bond0.86 grp ff02::2 temp

After the patch:

dev ovirtmgmt port vnet0 grp ff02::1:ff7d:6603 temp
dev ovirtmgmt port vnet1 grp ff02::1:ff7d:6604 temp
dev ovirtmgmt port bond0.86 grp ff02::fb temp
dev ovirtmgmt port bond0.86 grp ff02::2 temp
dev ovirtmgmt port bond0.86 grp ff02::d temp
dev ovirtmgmt port vnet0 grp ff02::1:ff00:76 temp
dev ovirtmgmt port bond0.86 grp ff02::16 temp
dev ovirtmgmt port vnet1 grp ff02::1:ff00:77 temp
dev ovirtmgmt port bond0.86 grp ff02::1:ff00:def temp
dev ovirtmgmt port bond0.86 grp ff02::1:ffa1:40bf temp

Fixes: 08b202b67264 ("bridge br_multicast: IPv6 MLD support.")
Reported-by: Rik Theys 
Signed-off-by: Thadeu Lima de Souza Cascardo 
Tested-by: Rik Theys 
Signed-off-by: David S. Miller 
Signed-off-by: Zefan Li

netfilter: Can't fail and free after table replacement

2014-05-18T12:25:56+00:00

commit c58dd2dd443c26d856a168db108a0cd11c285bf3 upstream.

All xtables variants suffer from the defect that the copy_to_user()
to copy the counters to user memory may fail after the table has
already been exchanged and thus exposed. Return an error at this
point will result in freeing the already exposed table. Any
subsequent packet processing will result in a kernel panic.

We can't copy the counters before exposing the new tables as we
want provide the counter state after the old table has been
unhooked. Therefore convert this into a silent error.

Cc: Florian Westphal 
Signed-off-by: Thomas Graf 
Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: Greg Kroah-Hartman

bridge: multicast: add sanity check for query source addresses

2014-04-27T00:13:16+00:00

[ Upstream commit 6565b9eeef194afbb3beec80d6dd2447f4091f8c ]

MLD queries are supposed to have an IPv6 link-local source address
according to RFC2710, section 4 and RFC3810, section 5.1.14. This patch
adds a sanity check to ignore such broken MLD queries.

Without this check, such malformed MLD queries can result in a
denial of service: The queries are ignored by any MLD listener
therefore they will not respond with an MLD report. However,
without this patch these malformed MLD queries would enable the
snooping part in the bridge code, potentially shutting down the
according ports towards these hosts for multicast traffic as the
bridge did not learn about these listeners.

Reported-by: Jan Stancek 
Signed-off-by: Linus Lüssing 
Reviewed-by: Hannes Frederic Sowa 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

bridge: use spin_lock_bh() in br_multicast_set_hash_max

2014-01-15T23:27:11+00:00

[ Upstream commit fe0d692bbc645786bce1a98439e548ae619269f5 ]

br_multicast_set_hash_max() is called from process context in
net/bridge/br_sysfs_br.c by the sysfs store_hash_max() function.

br_multicast_set_hash_max() calls spin_lock(&br->multicast_lock),
which can deadlock the CPU if a softirq that also tries to take the
same lock interrupts br_multicast_set_hash_max() while the lock is
held .  This can happen quite easily when any of the bridge multicast
timers expire, which try to take the same lock.

The fix here is to use spin_lock_bh(), preventing other softirqs from
executing on this CPU.

Steps to reproduce:

1. Create a bridge with several interfaces (I used 4).
2. Set the "multicast query interval" to a low number, like 2.
3. Enable the bridge as a multicast querier.
4. Repeatedly set the bridge hash_max parameter via sysfs.

  # brctl addbr br0
  # brctl addif br0 eth1 eth2 eth3 eth4
  # brctl setmcqi br0 2
  # brctl setmcquerier br0 1

  # while true ; do echo 4096 > /sys/class/net/br0/bridge/hash_max; done

Signed-off-by: Curt Brune 
Signed-off-by: Scott Feldman 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman