ublk: detach gendisk from ublk device if add_disk() fails
BugLink: https://bugs.launchpad.net/bugs/2103869
[ Upstream commit 75cd4005da5492129917a4a4ee45e81660556104 ]
Inside ublk_abort_requests(), gendisk is grabbed for aborting all
inflight requests. And ublk_abort_requests() is called when exiting
the uring context or handling timeout.
If add_disk() fails, the gendisk may have been freed when calling
ublk_abort_requests(), so use-after-free can be caused when getting
disk's reference in ublk_abort_requests().
Fixes the bug by detaching gendisk from ublk device if add_disk() fails.
Fixes: bd23f6c2c2 ("ublk: quiesce request queue when aborting queue")
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20241225110640.351531-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
CVE-2024-56764
Signed-off-by: Manuel Diewald <manuel.diewald@canonical.com>
Signed-off-by: Mehmet Basaran <mehmet.basaran@canonical.com>
This commit is contained in:
@@ -1645,6 +1645,21 @@ static void ublk_unquiesce_dev(struct ublk_device *ub)
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blk_mq_kick_requeue_list(ub->ub_disk->queue);
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}
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static struct gendisk *ublk_detach_disk(struct ublk_device *ub)
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{
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struct gendisk *disk;
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/* Sync with ublk_abort_queue() by holding the lock */
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spin_lock(&ub->lock);
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disk = ub->ub_disk;
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ub->dev_info.state = UBLK_S_DEV_DEAD;
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ub->dev_info.ublksrv_pid = -1;
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ub->ub_disk = NULL;
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spin_unlock(&ub->lock);
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return disk;
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}
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static void ublk_stop_dev(struct ublk_device *ub)
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{
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struct gendisk *disk;
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@@ -1658,14 +1673,7 @@ static void ublk_stop_dev(struct ublk_device *ub)
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ublk_unquiesce_dev(ub);
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}
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del_gendisk(ub->ub_disk);
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/* Sync with ublk_abort_queue() by holding the lock */
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spin_lock(&ub->lock);
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disk = ub->ub_disk;
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ub->dev_info.state = UBLK_S_DEV_DEAD;
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ub->dev_info.ublksrv_pid = -1;
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ub->ub_disk = NULL;
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spin_unlock(&ub->lock);
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disk = ublk_detach_disk(ub);
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put_disk(disk);
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unlock:
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mutex_unlock(&ub->mutex);
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@@ -2298,7 +2306,7 @@ static int ublk_ctrl_start_dev(struct ublk_device *ub, struct io_uring_cmd *cmd)
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out_put_cdev:
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if (ret) {
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ub->dev_info.state = UBLK_S_DEV_DEAD;
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ublk_detach_disk(ub);
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ublk_put_device(ub);
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}
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out_put_disk:
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