[PATCH 4.20 42/76] net: sit: fix memory leak in sit_init_net()

Greg Kroah-Hartman
2019-03-08T12:55:23Z

From: Mao Wenan <maowenan@huawei.com>

[ Upstream commit 07f12b26e21ab359261bf75cfcb424fdc7daeb6d ]

If register_netdev() is failed to register sitn->fb_tunnel_dev,
it will go to err_reg_dev and forget to free netdev(sitn->fb_tunnel_dev).

BUG: memory leak
unreferenced object 0xffff888378daad00 (size 512):
comm "syz-executor.1", pid 4006, jiffies 4295121142 (age 16.115s)
hex dump (first 32 bytes):
00 e6 ed c0 83 88 ff ff 00 00 00 00 00 00 00 00 ................
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<00000000d6dcb63e>] kvmalloc include/linux/mm.h:577 [inline]
[<00000000d6dcb63e>] kvzalloc include/linux/mm.h:585 [inline]
[<00000000d6dcb63e>] netif_alloc_netdev_queues net/core/dev.c:8380 [inline]
[<00000000d6dcb63e>] alloc_netdev_mqs+0x600/0xcc0 net/core/dev.c:8970
[<00000000867e172f>] sit_init_net+0x295/0xa40 net/ipv6/sit.c:1848
[<00000000871019fa>] ops_init+0xad/0x3e0 net/core/net_namespace.c:129
[<00000000319507f6>] setup_net+0x2ba/0x690 net/core/net_namespace.c:314
[<0000000087db4f96>] copy_net_ns+0x1dc/0x330 net/core/net_namespace.c:437
[<0000000057efc651>] create_new_namespaces+0x382/0x730 kernel/nsproxy.c:107
[<00000000676f83de>] copy_namespaces+0x2ed/0x3d0 kernel/nsproxy.c:165
[<0000000030b74bac>] copy_process.part.27+0x231e/0x6db0 kernel/fork.c:1919
[<00000000fff78746>] copy_process kernel/fork.c:1713 [inline]
[<00000000fff78746>] _do_fork+0x1bc/0xe90 kernel/fork.c:2224
[<000000001c2e0d1c>] do_syscall_64+0xc8/0x580 arch/x86/entry/common.c:290
[<00000000ec48bd44>] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[<0000000039acff8a>] 0xffffffffffffffff

Signed-off-by: Mao Wenan <maowenan@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/ipv6/sit.c | 1 +
1 file changed, 1 insertion(+)

--- a/net/ipv6/sit.c
+++ b/net/ipv6/sit.c
@@ -1873,6 +1873,7 @@ static int __net_init sit_init_net(struc

err_reg_dev:
ipip6_dev_free(sitn->fb_tunnel_dev);
+ free_netdev(sitn->fb_tunnel_dev);
err_alloc_dev:
return err;
}