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authorXin Long <lucien.xin@gmail.com>2017-04-25 17:58:37 +0300
committerDavid S. Miller <davem@davemloft.net>2017-04-25 21:02:39 +0300
commitb1b9d366028ff580e6dd80b48a69c473361456f1 (patch)
tree9a2a81e9f02ab8006492e8048ee785c37c605ada /net/bridge
parentec9c4215fef37da6668c4105f5ad3891aaa6527a (diff)
downloadlinux-b1b9d366028ff580e6dd80b48a69c473361456f1.tar.xz
bridge: move bridge multicast cleanup to ndo_uninit
During removing a bridge device, if the bridge is still up, a new mdb entry still can be added in br_multicast_add_group() after all mdb entries are removed in br_multicast_dev_del(). Like the path: mld_ifc_timer_expire -> mld_sendpack -> ... br_multicast_rcv -> br_multicast_add_group The new mp's timer will be set up. If the timer expires after the bridge is freed, it may cause use-after-free panic in br_multicast_group_expired. BUG: unable to handle kernel NULL pointer dereference at 0000000000000048 IP: [<ffffffffa07ed2c8>] br_multicast_group_expired+0x28/0xb0 [bridge] Call Trace: <IRQ> [<ffffffff81094536>] call_timer_fn+0x36/0x110 [<ffffffffa07ed2a0>] ? br_mdb_free+0x30/0x30 [bridge] [<ffffffff81096967>] run_timer_softirq+0x237/0x340 [<ffffffff8108dcbf>] __do_softirq+0xef/0x280 [<ffffffff8169889c>] call_softirq+0x1c/0x30 [<ffffffff8102c275>] do_softirq+0x65/0xa0 [<ffffffff8108e055>] irq_exit+0x115/0x120 [<ffffffff81699515>] smp_apic_timer_interrupt+0x45/0x60 [<ffffffff81697a5d>] apic_timer_interrupt+0x6d/0x80 Nikolay also found it would cause a memory leak - the mdb hash is reallocated and not freed due to the mdb rehash. unreferenced object 0xffff8800540ba800 (size 2048): backtrace: [<ffffffff816e2287>] kmemleak_alloc+0x67/0xc0 [<ffffffff81260bea>] __kmalloc+0x1ba/0x3e0 [<ffffffffa05c60ee>] br_mdb_rehash+0x5e/0x340 [bridge] [<ffffffffa05c74af>] br_multicast_new_group+0x43f/0x6e0 [bridge] [<ffffffffa05c7aa3>] br_multicast_add_group+0x203/0x260 [bridge] [<ffffffffa05ca4b5>] br_multicast_rcv+0x945/0x11d0 [bridge] [<ffffffffa05b6b10>] br_dev_xmit+0x180/0x470 [bridge] [<ffffffff815c781b>] dev_hard_start_xmit+0xbb/0x3d0 [<ffffffff815c8743>] __dev_queue_xmit+0xb13/0xc10 [<ffffffff815c8850>] dev_queue_xmit+0x10/0x20 [<ffffffffa02f8d7a>] ip6_finish_output2+0x5ca/0xac0 [ipv6] [<ffffffffa02fbfc6>] ip6_finish_output+0x126/0x2c0 [ipv6] [<ffffffffa02fc245>] ip6_output+0xe5/0x390 [ipv6] [<ffffffffa032b92c>] NF_HOOK.constprop.44+0x6c/0x240 [ipv6] [<ffffffffa032bd16>] mld_sendpack+0x216/0x3e0 [ipv6] [<ffffffffa032d5eb>] mld_ifc_timer_expire+0x18b/0x2b0 [ipv6] This could happen when ip link remove a bridge or destroy a netns with a bridge device inside. With Nikolay's suggestion, this patch is to clean up bridge multicast in ndo_uninit after bridge dev is shutdown, instead of br_dev_delete, so that netif_running check in br_multicast_add_group can avoid this issue. v1->v2: - fix this issue by moving br_multicast_dev_del to ndo_uninit, instead of calling dev_close in br_dev_delete. (NOTE: Depends upon b6fe0440c637 ("bridge: implement missing ndo_uninit()")) Fixes: e10177abf842 ("bridge: multicast: fix handling of temp and perm entries") Reported-by: Jianwen Ji <jiji@redhat.com> Signed-off-by: Xin Long <lucien.xin@gmail.com> Reviewed-by: Stephen Hemminger <stephen@networkplumber.org> Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/bridge')
-rw-r--r--net/bridge/br_device.c1
-rw-r--r--net/bridge/br_if.c1
2 files changed, 1 insertions, 1 deletions
diff --git a/net/bridge/br_device.c b/net/bridge/br_device.c
index 90f49a194249..430b53e7d941 100644
--- a/net/bridge/br_device.c
+++ b/net/bridge/br_device.c
@@ -123,6 +123,7 @@ static void br_dev_uninit(struct net_device *dev)
{
struct net_bridge *br = netdev_priv(dev);
+ br_multicast_dev_del(br);
br_multicast_uninit_stats(br);
br_vlan_flush(br);
free_percpu(br->stats);
diff --git a/net/bridge/br_if.c b/net/bridge/br_if.c
index 56a2a72e7738..a8d0ed282a10 100644
--- a/net/bridge/br_if.c
+++ b/net/bridge/br_if.c
@@ -311,7 +311,6 @@ void br_dev_delete(struct net_device *dev, struct list_head *head)
br_fdb_delete_by_port(br, NULL, 0, 1);
- br_multicast_dev_del(br);
cancel_delayed_work_sync(&br->gc_work);
br_sysfs_delbr(br->dev);