* [PATCH] net-sysfs: Fix memory leak in register_queue_kobjects
@ 2019-11-14 11:13 jouni.hogander
2019-11-15 20:21 ` David Miller
2019-11-19 9:23 ` Jouni Högander
0 siblings, 2 replies; 3+ messages in thread
From: jouni.hogander @ 2019-11-14 11:13 UTC (permalink / raw)
To: netdev; +Cc: Jouni Hogander, David Miller, Lukas Bulwahn
From: Jouni Hogander <jouni.hogander@unikie.com>
net_rx_queue_update_kobjects and netdev_queue_update_kobjects are
leaking memory in their error paths. Leak was originally reported
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>
---
net/core/net-sysfs.c | 34 ++++++++++++++++++++++++----------
1 file changed, 24 insertions(+), 10 deletions(-)
diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index 865ba6ca16eb..2f44c6a3bcae 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -923,20 +923,25 @@ 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_init_and_add;
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_sysfs_create;
}
kobject_uevent(kobj, KOBJ_ADD);
+ return error;
+
+err_sysfs_create:
+ kobject_put(kobj);
+err_init_and_add:
+ kfree_const(kobj->name);
+
return error;
}
#endif /* CONFIG_SYSFS */
@@ -968,6 +973,7 @@ net_rx_queue_update_kobjects(struct net_device *dev, int old_num, int new_num)
if (dev->sysfs_rx_queue_group)
sysfs_remove_group(kobj, dev->sysfs_rx_queue_group);
kobject_put(kobj);
+ kfree_const(kobj->name);
}
return error;
@@ -1461,21 +1467,28 @@ 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_init_and_add;
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_sysfs_create;
#endif
kobject_uevent(kobj, KOBJ_ADD);
return 0;
+
+#ifdef CONFIG_BQL
+err_sysfs_create:
+ kobject_put(kobj);
+#endif
+err_init_and_add:
+ kfree_const(kobj->name);
+
+ return error;
}
#endif /* CONFIG_SYSFS */
@@ -1503,6 +1516,7 @@ netdev_queue_update_kobjects(struct net_device *dev, int old_num, int new_num)
sysfs_remove_group(&queue->kobj, &dql_group);
#endif
kobject_put(&queue->kobj);
+ kfree_const(queue->kobj.name);
}
return error;
--
2.17.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] net-sysfs: Fix memory leak in register_queue_kobjects
2019-11-14 11:13 [PATCH] net-sysfs: Fix memory leak in register_queue_kobjects jouni.hogander
@ 2019-11-15 20:21 ` David Miller
2019-11-19 9:23 ` Jouni Högander
1 sibling, 0 replies; 3+ messages in thread
From: David Miller @ 2019-11-15 20:21 UTC (permalink / raw)
To: jouni.hogander; +Cc: netdev, lukas.bulwahn
From: jouni.hogander@unikie.com
Date: Thu, 14 Nov 2019 13:13:25 +0200
> +err_sysfs_create:
> + kobject_put(kobj);
> +err_init_and_add:
> + kfree_const(kobj->name);
If you put the object, then you cannot access kobj->name afterwards as kobj
may be released at this point.
Both of your fixes add this bug.
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] net-sysfs: Fix memory leak in register_queue_kobjects
2019-11-14 11:13 [PATCH] net-sysfs: Fix memory leak in register_queue_kobjects jouni.hogander
2019-11-15 20:21 ` David Miller
@ 2019-11-19 9:23 ` Jouni Högander
1 sibling, 0 replies; 3+ messages in thread
From: Jouni Högander @ 2019-11-19 9:23 UTC (permalink / raw)
To: netdev; +Cc: David Miller, Lukas Bulwahn
jouni.hogander@unikie.com writes:
> From: Jouni Hogander <jouni.hogander@unikie.com>
>
> net_rx_queue_update_kobjects and netdev_queue_update_kobjects are
> leaking memory in their error paths. Leak was originally reported
> 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>
> ---
> net/core/net-sysfs.c | 34 ++++++++++++++++++++++++----------
> 1 file changed, 24 insertions(+), 10 deletions(-)
>
> diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
> index 865ba6ca16eb..2f44c6a3bcae 100644
> --- a/net/core/net-sysfs.c
> +++ b/net/core/net-sysfs.c
> @@ -923,20 +923,25 @@ 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_init_and_add;
>
> 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_sysfs_create;
> }
>
> kobject_uevent(kobj, KOBJ_ADD);
>
> + return error;
> +
> +err_sysfs_create:
> + kobject_put(kobj);
> +err_init_and_add:
> + kfree_const(kobj->name);
> +
> return error;
> }
> #endif /* CONFIG_SYSFS */
> @@ -968,6 +973,7 @@ net_rx_queue_update_kobjects(struct net_device *dev, int old_num, int new_num)
> if (dev->sysfs_rx_queue_group)
> sysfs_remove_group(kobj, dev->sysfs_rx_queue_group);
> kobject_put(kobj);
> + kfree_const(kobj->name);
> }
>
> return error;
> @@ -1461,21 +1467,28 @@ 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_init_and_add;
>
> 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_sysfs_create;
> #endif
>
> kobject_uevent(kobj, KOBJ_ADD);
>
> return 0;
> +
> +#ifdef CONFIG_BQL
> +err_sysfs_create:
> + kobject_put(kobj);
> +#endif
> +err_init_and_add:
> + kfree_const(kobj->name);
> +
> + return error;
> }
> #endif /* CONFIG_SYSFS */
>
> @@ -1503,6 +1516,7 @@ netdev_queue_update_kobjects(struct net_device *dev, int old_num, int new_num)
> sysfs_remove_group(&queue->kobj, &dql_group);
> #endif
> kobject_put(&queue->kobj);
> + kfree_const(queue->kobj.name);
> }
>
> return error;
This patch should be ignored. Rootcause for this memory leak is
reference count leak. I will upload another patch.
BR,
Jouni Högander
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2019-11-19 9:23 UTC | newest]
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2019-11-14 11:13 [PATCH] net-sysfs: Fix memory leak in register_queue_kobjects jouni.hogander
2019-11-15 20:21 ` David Miller
2019-11-19 9:23 ` Jouni Högander
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