[PATCH 5.4 153/165] vlan: fix memory leak in vlan_dev_set_egress_priority

Greg Kroah-Hartman
2020-01-11T10:33:50Z

From: Eric Dumazet <edumazet@google.com>

[ Upstream commit 9bbd917e0bec9aebdbd0c8dbc966caec15eb33e9 ]

There are few cases where the ndo_uninit() handler might be not
called if an error happens while device is initialized.

Since vlan_newlink() calls vlan_changelink() before
trying to register the netdevice, we need to make sure
vlan_dev_uninit() has been called at least once,
or we might leak allocated memory.

BUG: memory leak
unreferenced object 0xffff888122a206c0 (size 32):
comm "syz-executor511", pid 7124, jiffies 4294950399 (age 32.240s)
hex dump (first 32 bytes):
00 00 00 00 00 00 61 73 00 00 00 00 00 00 00 00 ......as........
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<000000000eb3bb85>] kmemleak_alloc_recursive include/linux/kmemleak.h:43 [inline]
[<000000000eb3bb85>] slab_post_alloc_hook mm/slab.h:586 [inline]
[<000000000eb3bb85>] slab_alloc mm/slab.c:3320 [inline]
[<000000000eb3bb85>] kmem_cache_alloc_trace+0x145/0x2c0 mm/slab.c:3549
[<000000007b99f620>] kmalloc include/linux/slab.h:556 [inline]
[<000000007b99f620>] vlan_dev_set_egress_priority+0xcc/0x150 net/8021q/vlan_dev.c:194
[<000000007b0cb745>] vlan_changelink+0xd6/0x140 net/8021q/vlan_netlink.c:126
[<0000000065aba83a>] vlan_newlink+0x135/0x200 net/8021q/vlan_netlink.c:181
[<00000000fb5dd7a2>] __rtnl_newlink+0x89a/0xb80 net/core/rtnetlink.c:3305
[<00000000ae4273a1>] rtnl_newlink+0x4e/0x80 net/core/rtnetlink.c:3363
[<00000000decab39f>] rtnetlink_rcv_msg+0x178/0x4b0 net/core/rtnetlink.c:5424
[<00000000accba4ee>] netlink_rcv_skb+0x61/0x170 net/netlink/af_netlink.c:2477
[<00000000319fe20f>] rtnetlink_rcv+0x1d/0x30 net/core/rtnetlink.c:5442
[<00000000d51938dc>] netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline]
[<00000000d51938dc>] netlink_unicast+0x223/0x310 net/netlink/af_netlink.c:1328
[<00000000e539ac79>] netlink_sendmsg+0x2c0/0x570 net/netlink/af_netlink.c:1917
[<000000006250c27e>] sock_sendmsg_nosec net/socket.c:639 [inline]
[<000000006250c27e>] sock_sendmsg+0x54/0x70 net/socket.c:659
[<00000000e2a156d1>] ____sys_sendmsg+0x2d0/0x300 net/socket.c:2330
[<000000008c87466e>] ___sys_sendmsg+0x8a/0xd0 net/socket.c:2384
[<00000000110e3054>] __sys_sendmsg+0x80/0xf0 net/socket.c:2417
[<00000000d71077c8>] __do_sys_sendmsg net/socket.c:2426 [inline]
[<00000000d71077c8>] __se_sys_sendmsg net/socket.c:2424 [inline]
[<00000000d71077c8>] __x64_sys_sendmsg+0x23/0x30 net/socket.c:2424

Fixe: 07b5b17e157b ("[VLAN]: Use rtnl_link API")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/8021q/vlan.h | 1 +
net/8021q/vlan_dev.c | 3 ++-
net/8021q/vlan_netlink.c | 9 +++++----
3 files changed, 8 insertions(+), 5 deletions(-)

--- a/net/8021q/vlan.h
+++ b/net/8021q/vlan.h
@@ -126,6 +126,7 @@ int vlan_check_real_dev(struct net_devic
void vlan_setup(struct net_device *dev);
int register_vlan_dev(struct net_device *dev, struct netlink_ext_ack *extack);
void unregister_vlan_dev(struct net_device *dev, struct list_head *head);
+void vlan_dev_uninit(struct net_device *dev);
bool vlan_dev_inherit_address(struct net_device *dev,
struct net_device *real_dev);

--- a/net/8021q/vlan_dev.c
+++ b/net/8021q/vlan_dev.c
@@ -586,7 +586,8 @@ static int vlan_dev_init(struct net_devi
return 0;
}

-static void vlan_dev_uninit(struct net_device *dev)
+/* Note: this function might be called multiple times for the same device. */
+void vlan_dev_uninit(struct net_device *dev)
{
struct vlan_priority_tci_mapping *pm;
struct vlan_dev_priv *vlan = vlan_dev_priv(dev);
--- a/net/8021q/vlan_netlink.c
+++ b/net/8021q/vlan_netlink.c
@@ -179,10 +179,11 @@ static int vlan_newlink(struct net *src_
return -EINVAL;

err = vlan_changelink(dev, tb, data, extack);
- if (err < 0)
- return err;
-
- return register_vlan_dev(dev, extack);
+ if (!err)
+ err = register_vlan_dev(dev, extack);
+ if (err)
+ vlan_dev_uninit(dev);
+ return err;
}

static inline size_t vlan_qos_map_size(unsigned int n)