Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 5.10 099/103] block: fix use-after-free in disk_part_iter_next | Date | Fri, 15 Jan 2021 13:28:32 +0100 |
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From: Ming Lei <ming.lei@redhat.com>
commit aebf5db917055b38f4945ed6d621d9f07a44ff30 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>
--- block/genhd.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)
--- a/block/genhd.c +++ b/block/genhd.c @@ -256,14 +256,17 @@ struct hd_struct *disk_part_iter_next(st part = rcu_dereference(ptbl->part[piter->idx]); if (!part) continue; + get_device(part_to_dev(part)); + piter->part = part; if (!part_nr_sects_read(part) && !(piter->flags & DISK_PITER_INCL_EMPTY) && !(piter->flags & DISK_PITER_INCL_EMPTY_PART0 && - piter->idx == 0)) + piter->idx == 0)) { + put_device(part_to_dev(part)); + piter->part = NULL; continue; + } - get_device(part_to_dev(part)); - piter->part = part; piter->idx += inc; break; }
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