[PATCH 4.12 17/84] bridge: mdb: fix leak on complete_info ptr on fail path

From: Greg Kroah-Hartman
Date: Wed Jul 19 2017 - 06:05:28 EST


4.12-stable review patch. If anyone has any objections, please let me know.

------------------

From: Eduardo Valentin <eduval@xxxxxxxxxx>


[ Upstream commit 1bfb159673957644951ab0a8d2aec44b93ddb1ae ]

We currently get the following kmemleak report:
unreferenced object 0xffff8800039d9820 (size 32):
comm "softirq", pid 0, jiffies 4295212383 (age 792.416s)
hex dump (first 32 bytes):
00 0c e0 03 00 88 ff ff ff 02 00 00 00 00 00 00 ................
00 00 00 01 ff 11 00 02 86 dd 00 00 ff ff ff ff ................
backtrace:
[<ffffffff8152b4aa>] kmemleak_alloc+0x4a/0xa0
[<ffffffff811d8ec8>] kmem_cache_alloc_trace+0xb8/0x1c0
[<ffffffffa0389683>] __br_mdb_notify+0x2a3/0x300 [bridge]
[<ffffffffa038a0ce>] br_mdb_notify+0x6e/0x70 [bridge]
[<ffffffffa0386479>] br_multicast_add_group+0x109/0x150 [bridge]
[<ffffffffa0386518>] br_ip6_multicast_add_group+0x58/0x60 [bridge]
[<ffffffffa0387fb5>] br_multicast_rcv+0x1d5/0xdb0 [bridge]
[<ffffffffa037d7cf>] br_handle_frame_finish+0xcf/0x510 [bridge]
[<ffffffffa03a236b>] br_nf_hook_thresh.part.27+0xb/0x10 [br_netfilter]
[<ffffffffa03a3738>] br_nf_hook_thresh+0x48/0xb0 [br_netfilter]
[<ffffffffa03a3fb9>] br_nf_pre_routing_finish_ipv6+0x109/0x1d0 [br_netfilter]
[<ffffffffa03a4400>] br_nf_pre_routing_ipv6+0xd0/0x14c [br_netfilter]
[<ffffffffa03a3c27>] br_nf_pre_routing+0x197/0x3d0 [br_netfilter]
[<ffffffff814a2952>] nf_iterate+0x52/0x60
[<ffffffff814a29bc>] nf_hook_slow+0x5c/0xb0
[<ffffffffa037ddf4>] br_handle_frame+0x1a4/0x2c0 [bridge]

This happens when switchdev_port_obj_add() fails. This patch
frees complete_info object in the fail path.

Reviewed-by: Vallish Vaidyeshwara <vallish@xxxxxxxxxx>
Signed-off-by: Eduardo Valentin <eduval@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/bridge/br_mdb.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

--- a/net/bridge/br_mdb.c
+++ b/net/bridge/br_mdb.c
@@ -323,7 +323,8 @@ static void __br_mdb_notify(struct net_d
__mdb_entry_to_br_ip(entry, &complete_info->ip);
mdb.obj.complete_priv = complete_info;
mdb.obj.complete = br_mdb_complete;
- switchdev_port_obj_add(port_dev, &mdb.obj);
+ if (switchdev_port_obj_add(port_dev, &mdb.obj))
+ kfree(complete_info);
}
} else if (port_dev && type == RTM_DELMDB) {
switchdev_port_obj_del(port_dev, &mdb.obj);