Hi,
On Wed, Nov 27, 2019 at 09:32:12PM +0100, Greg Kroah-Hartman wrote:
> From: Jouni Hogander <jouni.hogander@xxxxxxxxxx>
>
> commit b8eb718348b8fb30b5a7d0a8fce26fb3f4ac741b upstream.
>
> 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@xxxxxxxxxxxxx>
> Cc: Lukas Bulwahn <lukas.bulwahn@xxxxxxxxx>
> Signed-off-by: Jouni Hogander <jouni.hogander@xxxxxxxxxx>
> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
>
We also need the following commits to fix this issue:
commit 48a322b6f9965b2f1e4ce81af972f0e287b07ed0
Author: Eric Dumazet <edumazet@xxxxxxxxxx>
Date: Wed Nov 20 19:19:07 2019 -0800
net-sysfs: fix netdev_queue_add_kobject() breakage
kobject_put() should only be called in error path.
Fixes: b8eb718348b8 ("net-sysfs: Fix reference count leak in rx|netdev_queue_add_kobject")
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Cc: Jouni Hogander <jouni.hogander@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
And this should also apply to 4.14.y and 5.3.y.
Please apply this commnit to 4.14.y, 4.19.y and 5.3.y
Best regards,
Nobuhiro
> ---
> net/core/net-sysfs.c | 24 +++++++++++++-----------
> 1 file changed, 13 insertions(+), 11 deletions(-)
>
> --- a/net/core/net-sysfs.c
> +++ b/net/core/net-sysfs.c
> @@ -932,21 +932,23 @@ static int rx_queue_add_kobject(struct n
> 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 */
>
> @@ -1471,21 +1473,21 @@ static int netdev_queue_add_kobject(stru
> 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 */
>
>
>
>
