Hi,
On Wed, Nov 27, 2019 at 09:32:12PM +0100, Greg Kroah-Hartman wrote:
From: Jouni Hogander jouni.hogander@unikie.com
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@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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
We also need the following commits to fix this issue:
commit 48a322b6f9965b2f1e4ce81af972f0e287b07ed0 Author: Eric Dumazet edumazet@google.com 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@google.com Cc: Jouni Hogander jouni.hogander@unikie.com Signed-off-by: David S. Miller davem@davemloft.net
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 */