[PATCH 5.4 09/19] rtnetlink: Fix memory(net_device) leak when ->newlink fails

Greg Kroah-Hartman
2020-07-30T08:06:23Z

From: Weilong Chen <chenweilong@huawei.com>

[ Upstream commit cebb69754f37d68e1355a5e726fdac317bcda302 ]

When vlan_newlink call register_vlan_dev fails, it might return error
with dev->reg_state = NETREG_UNREGISTERED. The rtnl_newlink should
free the memory. But currently rtnl_newlink only free the memory which
state is NETREG_UNINITIALIZED.

BUG: memory leak
unreferenced object 0xffff8881051de000 (size 4096):
comm "syz-executor139", pid 560, jiffies 4294745346 (age 32.445s)
hex dump (first 32 bytes):
76 6c 61 6e 32 00 00 00 00 00 00 00 00 00 00 00 vlan2...........
00 45 28 03 81 88 ff ff 00 00 00 00 00 00 00 00 .E(.............
backtrace:
[<0000000047527e31>] kmalloc_node include/linux/slab.h:578 [inline]
[<0000000047527e31>] kvmalloc_node+0x33/0xd0 mm/util.c:574
[<000000002b59e3bc>] kvmalloc include/linux/mm.h:753 [inline]
[<000000002b59e3bc>] kvzalloc include/linux/mm.h:761 [inline]
[<000000002b59e3bc>] alloc_netdev_mqs+0x83/0xd90 net/core/dev.c:9929
[<000000006076752a>] rtnl_create_link+0x2c0/0xa20 net/core/rtnetlink.c:3067
[<00000000572b3be5>] __rtnl_newlink+0xc9c/0x1330 net/core/rtnetlink.c:3329
[<00000000e84ea553>] rtnl_newlink+0x66/0x90 net/core/rtnetlink.c:3397
[<0000000052c7c0a9>] rtnetlink_rcv_msg+0x540/0x990 net/core/rtnetlink.c:5460
[<000000004b5cb379>] netlink_rcv_skb+0x12b/0x3a0 net/netlink/af_netlink.c:2469
[<00000000c71c20d3>] netlink_unicast_kernel net/netlink/af_netlink.c:1303 [inline]
[<00000000c71c20d3>] netlink_unicast+0x4c6/0x690 net/netlink/af_netlink.c:1329
[<00000000cca72fa9>] netlink_sendmsg+0x735/0xcc0 net/netlink/af_netlink.c:1918
[<000000009221ebf7>] sock_sendmsg_nosec net/socket.c:652 [inline]
[<000000009221ebf7>] sock_sendmsg+0x109/0x140 net/socket.c:672
[<000000001c30ffe4>] ____sys_sendmsg+0x5f5/0x780 net/socket.c:2352
[<00000000b71ca6f3>] ___sys_sendmsg+0x11d/0x1a0 net/socket.c:2406
[<0000000007297384>] __sys_sendmsg+0xeb/0x1b0 net/socket.c:2439
[<000000000eb29b11>] do_syscall_64+0x56/0xa0 arch/x86/entry/common.c:359
[<000000006839b4d0>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

Fixes: cb626bf566eb ("net-sysfs: Fix reference count leak")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Weilong Chen <chenweilong@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/core/rtnetlink.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -3231,7 +3231,8 @@ replay:
*/
if (err < 0) {
/* If device is not registered at all, free it now */
- if (dev->reg_state == NETREG_UNINITIALIZED)
+ if (dev->reg_state == NETREG_UNINITIALIZED ||
+ dev->reg_state == NETREG_UNREGISTERED)
free_netdev(dev);
goto out;
}