linux-toradex.git/net/bridge, branch v3.12.20

bridge: multicast: enable snooping on general queries only

2014-04-18T09:07:03+00:00

[ Upstream commit 20a599bec95a52fa72432b2376a2ce47c5bb68fb ]

Without this check someone could easily create a denial of service
by injecting multicast-specific queries to enable the bridge
snooping part if no real querier issuing periodic general queries
is present on the link which would result in the bridge wrongly
shutting down ports for multicast traffic as the bridge did not learn
about these listeners.

With this patch the snooping code is enabled upon receiving valid,
general queries only.

Signed-off-by: Linus Lüssing 
Signed-off-by: David S. Miller 
Signed-off-by: Jiri Slaby

bridge: multicast: add sanity check for general query destination

2014-04-18T09:07:02+00:00

[ Upstream commit 9ed973cc40c588abeaa58aea0683ea665132d11d ]

General IGMP and MLD queries are supposed to have the multicast
link-local all-nodes address as their destination according to RFC2236
section 9, RFC3376 section 4.1.12/9.1, RFC2710 section 8 and RFC3810
section 5.1.15.

Without this check, such malformed IGMP/MLD queries can result in a
denial of service: The queries are ignored by most IGMP/MLD listeners
therefore they will not respond with an IGMP/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 
Signed-off-by: David S. Miller 
Signed-off-by: Jiri Slaby

bridge: multicast: add sanity check for query source addresses

2014-04-18T09:06:54+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: Jiri Slaby

bridge: fix netconsole setup over bridge

2014-02-26T09:22:51+00:00

[ Upstream commit dbe173079ab58a444e12dbebe96f5aec1e0bed1a ]

Commit 93d8bf9fb8f3 ("bridge: cleanup netpoll code") introduced
a check in br_netpoll_enable(), but this check is incorrect for
br_netpoll_setup(). This patch moves the code after the check
into __br_netpoll_enable() and calls it in br_netpoll_setup().
For br_add_if(), the check is still needed.

Fixes: 93d8bf9fb8f3 ("bridge: cleanup netpoll code")
Cc: Toshiaki Makita 
Cc: Stephen Hemminger 
Cc: David S. Miller 
Signed-off-by: Cong Wang 
Signed-off-by: Cong Wang 
Acked-by: Toshiaki Makita 
Tested-by: Toshiaki Makita 
Signed-off-by: David S. Miller 
Signed-off-by: Jiri Slaby

bridge: use spin_lock_bh() in br_multicast_set_hash_max

2014-01-15T23:31:38+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

br: fix use of ->rx_handler_data in code executed on non-rx_handler path

2014-01-15T23:31:33+00:00

[ Upstream commit 859828c0ea476b42f3a93d69d117aaba90994b6f ]

br_stp_rcv() is reached by non-rx_handler path. That means there is no
guarantee that dev is bridge port and therefore simple NULL check of
->rx_handler_data is not enough. There is need to check if dev is really
bridge port and since only rcu read lock is held here, do it by checking
->rx_handler pointer.

Note that synchronize_net() in netdev_rx_handler_unregister() ensures
this approach as valid.

Introduced originally by:
commit f350a0a87374418635689471606454abc7beaa3a
  "bridge: use rx_handler_data pointer to store net_bridge_port pointer"

Fixed but not in the best way by:
commit b5ed54e94d324f17c97852296d61a143f01b227a
  "bridge: fix RCU races with bridge port"

Reintroduced by:
commit 716ec052d2280d511e10e90ad54a86f5b5d4dcc2
  "bridge: fix NULL pointer deref of br_port_get_rcu"

Please apply to stable trees as well. Thanks.

RH bugzilla reference: https://bugzilla.redhat.com/show_bug.cgi?id=1025770

Reported-by: Laine Stump 
Debugged-by: Michael S. Tsirkin 
Signed-off-by: Michael S. Tsirkin 
Signed-off-by: Jiri Pirko 
Acked-by: Michael S. Tsirkin 
Acked-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

bridge: flush br's address entry in fdb when remove the bridge dev

2013-12-08T15:29:14+00:00

[ Upstream commit f873042093c0b418d2351fe142222b625c740149 ]

When the following commands are executed:

brctl addbr br0
ifconfig br0 hw ether 
rmmod bridge

The calltrace will occur:

[  563.312114] device eth1 left promiscuous mode
[  563.312188] br0: port 1(eth1) entered disabled state
[  563.468190] kmem_cache_destroy bridge_fdb_cache: Slab cache still has objects
[  563.468197] CPU: 6 PID: 6982 Comm: rmmod Tainted: G           O 3.12.0-0.7-default+ #9
[  563.468199] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2007
[  563.468200]  0000000000000880 ffff88010f111e98 ffffffff814d1c92 ffff88010f111eb8
[  563.468204]  ffffffff81148efd ffff88010f111eb8 0000000000000000 ffff88010f111ec8
[  563.468206]  ffffffffa062a270 ffff88010f111ed8 ffffffffa063ac76 ffff88010f111f78
[  563.468209] Call Trace:
[  563.468218]  [] dump_stack+0x6a/0x78
[  563.468234]  [] kmem_cache_destroy+0xfd/0x100
[  563.468242]  [] br_fdb_fini+0x10/0x20 [bridge]
[  563.468247]  [] br_deinit+0x4e/0x50 [bridge]
[  563.468254]  [] SyS_delete_module+0x199/0x2b0
[  563.468259]  [] system_call_fastpath+0x16/0x1b
[  570.377958] Bridge firewalling registered

--------------------------- cut here -------------------------------

The reason is that when the bridge dev's address is changed, the
br_fdb_change_mac_address() will add new address in fdb, but when
the bridge was removed, the address entry in the fdb did not free,
the bridge_fdb_cache still has objects when destroy the cache, Fix
this by flushing the bridge address entry when removing the bridge.

v2: according to the Toshiaki Makita and Vlad's suggestion, I only
    delete the vlan0 entry, it still have a leak here if the vlan id
    is other number, so I need to call fdb_delete_by_port(br, NULL, 1)
    to flush all entries whose dst is NULL for the bridge.

Suggested-by: Toshiaki Makita 
Suggested-by: Vlad Yasevich 
Signed-off-by: Ding Tianhong 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

Revert "bridge: only expire the mdb entry when query is received"

2013-10-22T18:41:02+00:00

While this commit was a good attempt to fix issues occuring when no
multicast querier is present, this commit still has two more issues:

1) There are cases where mdb entries do not expire even if there is a
querier present. The bridge will unnecessarily continue flooding
multicast packets on the according ports.

2) Never removing an mdb entry could be exploited for a Denial of
Service by an attacker on the local link, slowly, but steadily eating up
all memory.

Actually, this commit became obsolete with
"bridge: disable snooping if there is no querier" (b00589af3b)
which included fixes for a few more cases.

Therefore reverting the following commits (the commit stated in the
commit message plus three of its follow up fixes):

====================
Revert "bridge: update mdb expiration timer upon reports."
This reverts commit f144febd93d5ee534fdf23505ab091b2b9088edc.
Revert "bridge: do not call setup_timer() multiple times"
This reverts commit 1faabf2aab1fdaa1ace4e8c829d1b9cf7bfec2f1.
Revert "bridge: fix some kernel warning in multicast timer"
This reverts commit c7e8e8a8f7a70b343ca1e0f90a31e35ab2d16de1.
Revert "bridge: only expire the mdb entry when query is received"
This reverts commit 9f00b2e7cf241fa389733d41b615efdaa2cb0f5b.
====================

CC: Cong Wang 
Signed-off-by: Linus Lüssing 
Reviewed-by: Vlad Yasevich 
Signed-off-by: David S. Miller

bridge: Fix updating FDB entries when the PVID is applied

2013-10-18T20:02:53+00:00

We currently set the value that variable vid is pointing, which will be
used in FDB later, to 0 at br_allowed_ingress() when we receive untagged
or priority-tagged frames, even though the PVID is valid.
This leads to FDB updates in such a wrong way that they are learned with
VID 0.
Update the value to that of PVID if the PVID is applied.

Signed-off-by: Toshiaki Makita 
Reviewed-by: Vlad Yasevich 
Signed-off-by: David S. Miller

bridge: Fix the way the PVID is referenced

2013-10-18T20:02:53+00:00

We are using the VLAN_TAG_PRESENT bit to detect whether the PVID is
set or not at br_get_pvid(), while we don't care about the bit in
adding/deleting the PVID, which makes it impossible to forward any
incomming untagged frame with vlan_filtering enabled.

Since vid 0 cannot be used for the PVID, we can use vid 0 to indicate
that the PVID is not set, which is slightly more efficient than using
the VLAN_TAG_PRESENT.

Fix the problem by getting rid of using the VLAN_TAG_PRESENT.

Signed-off-by: Toshiaki Makita 
Reviewed-by: Vlad Yasevich 
Signed-off-by: David S. Miller