block: fix use-after-free in disk_part_iter_next
commit aebf5db917
upstream.
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>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
5.4-rM2-2.2.x-imx-squashed
parent
c5fe50e18f
commit
bd0051a5cb
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@ -222,14 +222,17 @@ struct hd_struct *disk_part_iter_next(struct disk_part_iter *piter)
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part = rcu_dereference(ptbl->part[piter->idx]);
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part = rcu_dereference(ptbl->part[piter->idx]);
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if (!part)
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if (!part)
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continue;
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continue;
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get_device(part_to_dev(part));
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piter->part = part;
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if (!part_nr_sects_read(part) &&
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if (!part_nr_sects_read(part) &&
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!(piter->flags & DISK_PITER_INCL_EMPTY) &&
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!(piter->flags & DISK_PITER_INCL_EMPTY) &&
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!(piter->flags & DISK_PITER_INCL_EMPTY_PART0 &&
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!(piter->flags & DISK_PITER_INCL_EMPTY_PART0 &&
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piter->idx == 0))
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piter->idx == 0)) {
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put_device(part_to_dev(part));
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piter->part = NULL;
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continue;
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continue;
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}
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get_device(part_to_dev(part));
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piter->part = part;
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piter->idx += inc;
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piter->idx += inc;
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break;
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break;
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}
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}
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