* [PATCH] UBI: fix use after free in ubi_remove_volume()
@ 2019-11-30 9:33 Wen Yang
2019-12-03 13:13 ` Hou Tao
0 siblings, 1 reply; 3+ messages in thread
From: Wen Yang @ 2019-11-30 9:33 UTC (permalink / raw)
To: Richard Weinberger, Miquel Raynal, Vignesh Raghavendra
Cc: linux-kernel, linux-mtd, xlpang, Wen Yang
We can't use "vol" after it has been freed.
Fixes: 493cfaeaa0c9 ("mtd: utilize new cdev_device_add helper function")
Signed-off-by: Wen Yang <wenyang@linux.alibaba.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: Vignesh Raghavendra <vigneshr@ti.com>
Cc: linux-mtd@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
---
drivers/mtd/ubi/vmt.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/mtd/ubi/vmt.c b/drivers/mtd/ubi/vmt.c
index 139ee13..8ff1478 100644
--- a/drivers/mtd/ubi/vmt.c
+++ b/drivers/mtd/ubi/vmt.c
@@ -375,7 +375,6 @@ int ubi_remove_volume(struct ubi_volume_desc *desc, int no_vtbl)
}
cdev_device_del(&vol->cdev, &vol->dev);
- put_device(&vol->dev);
spin_lock(&ubi->volumes_lock);
ubi->rsvd_pebs -= reserved_pebs;
@@ -388,6 +387,8 @@ int ubi_remove_volume(struct ubi_volume_desc *desc, int no_vtbl)
if (!no_vtbl)
self_check_volumes(ubi);
+ put_device(&vol->dev);
+
return 0;
out_err:
--
1.8.3.1
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^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] UBI: fix use after free in ubi_remove_volume()
2019-11-30 9:33 [PATCH] UBI: fix use after free in ubi_remove_volume() Wen Yang
@ 2019-12-03 13:13 ` Hou Tao
2019-12-05 1:33 ` Hou Tao
0 siblings, 1 reply; 3+ messages in thread
From: Hou Tao @ 2019-12-03 13:13 UTC (permalink / raw)
To: Wen Yang, Richard Weinberger, Miquel Raynal, Vignesh Raghavendra
Cc: linux-mtd, linux-kernel, xlpang
Reviewed-by: Hou Tao <houtao1@huawei.com>
On 2019/11/30 17:33, Wen Yang wrote:
> We can't use "vol" after it has been freed.
>
> Fixes: 493cfaeaa0c9 ("mtd: utilize new cdev_device_add helper function")
> Signed-off-by: Wen Yang <wenyang@linux.alibaba.com>
> Cc: Richard Weinberger <richard@nod.at>
> Cc: Miquel Raynal <miquel.raynal@bootlin.com>
> Cc: Vignesh Raghavendra <vigneshr@ti.com>
> Cc: linux-mtd@lists.infradead.org
> Cc: linux-kernel@vger.kernel.org
> ---
> drivers/mtd/ubi/vmt.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mtd/ubi/vmt.c b/drivers/mtd/ubi/vmt.c
> index 139ee13..8ff1478 100644
> --- a/drivers/mtd/ubi/vmt.c
> +++ b/drivers/mtd/ubi/vmt.c
> @@ -375,7 +375,6 @@ int ubi_remove_volume(struct ubi_volume_desc *desc, int no_vtbl)
> }
>
> cdev_device_del(&vol->cdev, &vol->dev);
> - put_device(&vol->dev);
>
> spin_lock(&ubi->volumes_lock);
> ubi->rsvd_pebs -= reserved_pebs;
> @@ -388,6 +387,8 @@ int ubi_remove_volume(struct ubi_volume_desc *desc, int no_vtbl)
> if (!no_vtbl)
> self_check_volumes(ubi);
>
> + put_device(&vol->dev);
> +
> return 0;
>
> out_err:
>
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^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] UBI: fix use after free in ubi_remove_volume()
2019-12-03 13:13 ` Hou Tao
@ 2019-12-05 1:33 ` Hou Tao
0 siblings, 0 replies; 3+ messages in thread
From: Hou Tao @ 2019-12-05 1:33 UTC (permalink / raw)
To: Wen Yang, Richard Weinberger, Miquel Raynal, Vignesh Raghavendra
Cc: linux-mtd, linux-kernel, xlpang
Hi,
On 2019/12/3 21:13, Hou Tao wrote:
> Reviewed-by: Hou Tao <houtao1@huawei.com>
>
Sorry for my early conclusion.
The reference of ubi_volume had already been increased in ubi_open_volume()
in ubi_cdev_ioctl(), so this reference dropped in ubi_remove_volume() will not
be the last one, and there will no use-after-free problem.
Regards,
Tao
> On 2019/11/30 17:33, Wen Yang wrote:
>> We can't use "vol" after it has been freed.
>>
>> Fixes: 493cfaeaa0c9 ("mtd: utilize new cdev_device_add helper function")
>> Signed-off-by: Wen Yang <wenyang@linux.alibaba.com>
>> Cc: Richard Weinberger <richard@nod.at>
>> Cc: Miquel Raynal <miquel.raynal@bootlin.com>
>> Cc: Vignesh Raghavendra <vigneshr@ti.com>
>> Cc: linux-mtd@lists.infradead.org
>> Cc: linux-kernel@vger.kernel.org
>> ---
>> drivers/mtd/ubi/vmt.c | 3 ++-
>> 1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/mtd/ubi/vmt.c b/drivers/mtd/ubi/vmt.c
>> index 139ee13..8ff1478 100644
>> --- a/drivers/mtd/ubi/vmt.c
>> +++ b/drivers/mtd/ubi/vmt.c
>> @@ -375,7 +375,6 @@ int ubi_remove_volume(struct ubi_volume_desc *desc, int no_vtbl)
>> }
>>
>> cdev_device_del(&vol->cdev, &vol->dev);
>> - put_device(&vol->dev);
>>
>> spin_lock(&ubi->volumes_lock);
>> ubi->rsvd_pebs -= reserved_pebs;
>> @@ -388,6 +387,8 @@ int ubi_remove_volume(struct ubi_volume_desc *desc, int no_vtbl)
>> if (!no_vtbl)
>> self_check_volumes(ubi);
>>
>> + put_device(&vol->dev);
>> +
>> return 0;
>>
>> out_err:
>>
>
>
> ______________________________________________________
> Linux MTD discussion mailing list
> http://lists.infradead.org/mailman/listinfo/linux-mtd/
>
>
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2019-12-03 13:13 ` Hou Tao
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