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net-sysfs: Fix reference count leak in rx|netdev_queue_add_kobject

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kobject_init_and_add takes reference even when it fails. This has
to be given up by the caller in error handling. Otherwise memory
allocated by kobject_init_and_add is never freed. Originally found
by Syzkaller:

BUG: memory leak
unreferenced object 0xffff8880679f8b08 (size 8):
  comm "netdev_register", pid 269, jiffies 4294693094 (age 12.132s)
  hex dump (first 8 bytes):
    72 78 2d 30 00 36 20 d4                          rx-0.6 .
  backtrace:
    [<000000008c93818e>] __kmalloc_track_caller+0x16e/0x290
    [<000000001f2e4e49>] kvasprintf+0xb1/0x140
    [<000000007f313394>] kvasprintf_const+0x56/0x160
    [<00000000aeca11c8>] kobject_set_name_vargs+0x5b/0x140
    [<0000000073a0367c>] kobject_init_and_add+0xd8/0x170
    [<0000000088838e4b>] net_rx_queue_update_kobjects+0x152/0x560
    [<000000006be5f104>] netdev_register_kobject+0x210/0x380
    [<00000000e31dab9d>] register_netdevice+0xa1b/0xf00
    [<00000000f68b2465>] __tun_chr_ioctl+0x20d5/0x3dd0
    [<000000004c50599f>] tun_chr_ioctl+0x2f/0x40
    [<00000000bbd4c317>] do_vfs_ioctl+0x1c7/0x1510
    [<00000000d4c59e8f>] ksys_ioctl+0x99/0xb0
    [<00000000946aea81>] __x64_sys_ioctl+0x78/0xb0
    [<0000000038d946e5>] do_syscall_64+0x16f/0x580
    [<00000000e0aa5d8f>] entry_SYSCALL_64_after_hwframe+0x44/0xa9
    [<00000000285b3d1a>] 0xffffffffffffffff

Cc: David Miller <davem@davemloft.net>
Cc: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Jouni Hogander <jouni.hogander@unikie.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Jouni Hogander 2019-11-20 09:08:16 +02:00 committed by David S. Miller
parent 6e4ff1c94a
commit b8eb718348
1 changed files with 13 additions and 11 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

24
net/core/net-sysfs.c
View file

@ -923,21 +923,23 @@ static int rx_queue_add_kobject(struct net_device *dev, int index)
error = kobject_init_and_add(kobj, &rx_queue_ktype, NULL,
"rx-%u", index);
if (error)
return error;
goto err;
dev_hold(queue->dev);
if (dev->sysfs_rx_queue_group) {
error = sysfs_create_group(kobj, dev->sysfs_rx_queue_group);
if (error) {
kobject_put(kobj);
return error;
}
if (error)
goto err;
}
kobject_uevent(kobj, KOBJ_ADD);
return error;
err:
kobject_put(kobj);
return error;
}
#endif /* CONFIG_SYSFS */
@ -1461,21 +1463,21 @@ static int netdev_queue_add_kobject(struct net_device *dev, int index)
error = kobject_init_and_add(kobj, &netdev_queue_ktype, NULL,
"tx-%u", index);
if (error)
return error;
goto err;
dev_hold(queue->dev);
#ifdef CONFIG_BQL
error = sysfs_create_group(kobj, &dql_group);
if (error) {
kobject_put(kobj);
return error;
}
if (error)
goto err;
#endif
kobject_uevent(kobj, KOBJ_ADD);
return 0;
err:
kobject_put(kobj);
return error;
}
#endif /* CONFIG_SYSFS */