* [PATCH] block: xen-blkfront: Fix possible NULL ptr dereference
@ 2013-11-09 15:36 Felipe Pena
2013-11-11 9:48 ` [Xen-devel] " Roger Pau Monné
2013-11-11 9:48 ` Roger Pau Monné
0 siblings, 2 replies; 3+ messages in thread
From: Felipe Pena @ 2013-11-09 15:36 UTC (permalink / raw)
To: Konrad Rzeszutek Wilk, Boris Ostrovsky, David Vrabel
Cc: xen-devel, linux-kernel, Felipe Pena
In the blkif_release function the bdget_disk() call might returns
a NULL ptr which might be dereferenced on bdev->bd_openers checking
Signed-off-by: Felipe Pena <felipensp@gmail.com>
---
drivers/block/xen-blkfront.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index a4660bb..7bb1552 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -1959,6 +1959,9 @@ static void blkif_release(struct gendisk *disk, fmode_t mode)
bdev = bdget_disk(disk, 0);
+ if (!bdev)
+ goto out_mutex;
+
if (bdev->bd_openers)
goto out;
@@ -1989,6 +1992,7 @@ static void blkif_release(struct gendisk *disk, fmode_t mode)
out:
bdput(bdev);
+out_mutex:
mutex_unlock(&blkfront_mutex);
}
--
1.7.10.4
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [Xen-devel] [PATCH] block: xen-blkfront: Fix possible NULL ptr dereference
2013-11-09 15:36 [PATCH] block: xen-blkfront: Fix possible NULL ptr dereference Felipe Pena
@ 2013-11-11 9:48 ` Roger Pau Monné
2013-11-11 9:48 ` Roger Pau Monné
1 sibling, 0 replies; 3+ messages in thread
From: Roger Pau Monné @ 2013-11-11 9:48 UTC (permalink / raw)
To: Felipe Pena, Konrad Rzeszutek Wilk, Boris Ostrovsky, David Vrabel
Cc: xen-devel, linux-kernel
On 09/11/13 16:36, Felipe Pena wrote:
> In the blkif_release function the bdget_disk() call might returns
> a NULL ptr which might be dereferenced on bdev->bd_openers checking
>
> Signed-off-by: Felipe Pena <felipensp@gmail.com>
> ---
> drivers/block/xen-blkfront.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
> index a4660bb..7bb1552 100644
> --- a/drivers/block/xen-blkfront.c
> +++ b/drivers/block/xen-blkfront.c
> @@ -1959,6 +1959,9 @@ static void blkif_release(struct gendisk *disk, fmode_t mode)
>
> bdev = bdget_disk(disk, 0);
>
> + if (!bdev)
> + goto out_mutex;
Is this actually possible? By looking at blkfront code, it seems like we
don't remove the device if it is still open, so maybe this should be a
BUG_ON instead of failing silently.
Roger.
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] block: xen-blkfront: Fix possible NULL ptr dereference
2013-11-09 15:36 [PATCH] block: xen-blkfront: Fix possible NULL ptr dereference Felipe Pena
2013-11-11 9:48 ` [Xen-devel] " Roger Pau Monné
@ 2013-11-11 9:48 ` Roger Pau Monné
1 sibling, 0 replies; 3+ messages in thread
From: Roger Pau Monné @ 2013-11-11 9:48 UTC (permalink / raw)
To: Felipe Pena, Konrad Rzeszutek Wilk, Boris Ostrovsky, David Vrabel
Cc: xen-devel, linux-kernel
On 09/11/13 16:36, Felipe Pena wrote:
> In the blkif_release function the bdget_disk() call might returns
> a NULL ptr which might be dereferenced on bdev->bd_openers checking
>
> Signed-off-by: Felipe Pena <felipensp@gmail.com>
> ---
> drivers/block/xen-blkfront.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
> index a4660bb..7bb1552 100644
> --- a/drivers/block/xen-blkfront.c
> +++ b/drivers/block/xen-blkfront.c
> @@ -1959,6 +1959,9 @@ static void blkif_release(struct gendisk *disk, fmode_t mode)
>
> bdev = bdget_disk(disk, 0);
>
> + if (!bdev)
> + goto out_mutex;
Is this actually possible? By looking at blkfront code, it seems like we
don't remove the device if it is still open, so maybe this should be a
BUG_ON instead of failing silently.
Roger.
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2013-11-11 9:48 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
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2013-11-09 15:36 [PATCH] block: xen-blkfront: Fix possible NULL ptr dereference Felipe Pena
2013-11-11 9:48 ` [Xen-devel] " Roger Pau Monné
2013-11-11 9:48 ` Roger Pau Monné
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