* [PATCH] block: fix use-after-free in disk_part_iter_next
@ 2020-12-21 4:33 Ming Lei
2021-01-05 7:51 ` Christoph Hellwig
2021-01-05 18:35 ` Jens Axboe
0 siblings, 2 replies; 3+ messages in thread
From: Ming Lei @ 2020-12-21 4:33 UTC (permalink / raw)
To: Jens Axboe
Cc: linux-block, Christoph Hellwig, Ming Lei, stable,
syzbot+825f0f9657d4e528046e
Make sure that bdgrab() is done on the 'block_device' instance before
referring to it for avoiding use-after-free.
Cc: <stable@vger.kernel.org>
Reported-by: syzbot+825f0f9657d4e528046e@syzkaller.appspotmail.com
Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
block/genhd.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/block/genhd.c b/block/genhd.c
index b84b8671e627..2df3c5b1c9c8 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -244,15 +244,18 @@ struct block_device *disk_part_iter_next(struct disk_part_iter *piter)
part = rcu_dereference(ptbl->part[piter->idx]);
if (!part)
continue;
+ piter->part = bdgrab(part);
+ if (!piter->part)
+ continue;
if (!bdev_nr_sectors(part) &&
!(piter->flags & DISK_PITER_INCL_EMPTY) &&
!(piter->flags & DISK_PITER_INCL_EMPTY_PART0 &&
- piter->idx == 0))
+ piter->idx == 0)) {
+ bdput(piter->part);
+ piter->part = NULL;
continue;
+ }
- piter->part = bdgrab(part);
- if (!piter->part)
- continue;
piter->idx += inc;
break;
}
--
2.28.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] block: fix use-after-free in disk_part_iter_next
2020-12-21 4:33 [PATCH] block: fix use-after-free in disk_part_iter_next Ming Lei
@ 2021-01-05 7:51 ` Christoph Hellwig
2021-01-05 18:35 ` Jens Axboe
1 sibling, 0 replies; 3+ messages in thread
From: Christoph Hellwig @ 2021-01-05 7:51 UTC (permalink / raw)
To: Ming Lei
Cc: Jens Axboe, linux-block, Christoph Hellwig, stable,
syzbot+825f0f9657d4e528046e
On Mon, Dec 21, 2020 at 12:33:35PM +0800, Ming Lei wrote:
> Make sure that bdgrab() is done on the 'block_device' instance before
> referring to it for avoiding use-after-free.
>
> Cc: <stable@vger.kernel.org>
> Reported-by: syzbot+825f0f9657d4e528046e@syzkaller.appspotmail.com
> Signed-off-by: Ming Lei <ming.lei@redhat.com>
Looks good,
Reviewed-by: Christoph Hellwig <hch@lst.de>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] block: fix use-after-free in disk_part_iter_next
2020-12-21 4:33 [PATCH] block: fix use-after-free in disk_part_iter_next Ming Lei
2021-01-05 7:51 ` Christoph Hellwig
@ 2021-01-05 18:35 ` Jens Axboe
1 sibling, 0 replies; 3+ messages in thread
From: Jens Axboe @ 2021-01-05 18:35 UTC (permalink / raw)
To: Ming Lei
Cc: linux-block, Christoph Hellwig, stable, syzbot+825f0f9657d4e528046e
On 12/20/20 9:33 PM, Ming Lei wrote:
> Make sure that bdgrab() is done on the 'block_device' instance before
> referring to it for avoiding use-after-free.
Applied, thanks.
--
Jens Axboe
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2021-01-05 18:36 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2020-12-21 4:33 [PATCH] block: fix use-after-free in disk_part_iter_next Ming Lei
2021-01-05 7:51 ` Christoph Hellwig
2021-01-05 18:35 ` Jens Axboe
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