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ublk_drv: don't probe partitions if the ubq daemon isn't trusted

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[ Upstream commit 73a166d9749230d598320fdae3b687cdc0e2e205 ]

If any ubq daemon is unprivileged, the ublk char device is allowed
for unprivileged user actually, and we can't trust the current user,
so not probe partitions.

Fixes: 71f28f3136af ("ublk_drv: add io_uring based userspace block driver")
Reviewed-by: ZiyangZhang <ZiyangZhang@linux.alibaba.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20230106041711.914434-3-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Ming Lei 2023-01-06 12:17:07 +08:00 committed by Greg Kroah-Hartman
parent 23e79f75e6
commit e6829910b9
1 changed files with 9 additions and 0 deletions
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9
drivers/block/ublk_drv.c
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@ -159,6 +159,7 @@ struct ublk_device {
struct completion completion;
unsigned int nr_queues_ready;
unsigned int nr_privileged_daemon;
/*
* Our ubq->daemon may be killed without any notification, so
@ -1178,6 +1179,9 @@ static void ublk_mark_io_ready(struct ublk_device *ub, struct ublk_queue *ubq)
ubq->ubq_daemon = current;
get_task_struct(ubq->ubq_daemon);
ub->nr_queues_ready++;
if (capable(CAP_SYS_ADMIN))
ub->nr_privileged_daemon++;
}
if (ub->nr_queues_ready == ub->dev_info.nr_hw_queues)
complete_all(&ub->completion);
@ -1534,6 +1538,10 @@ static int ublk_ctrl_start_dev(struct io_uring_cmd *cmd)
if (ret)
goto out_put_disk;
/* don't probe partitions if any one ubq daemon is un-trusted */
if (ub->nr_privileged_daemon != ub->nr_queues_ready)
set_bit(GD_SUPPRESS_PART_SCAN, &disk->state);
get_device(&ub->cdev_dev);
ret = add_disk(disk);
if (ret) {
@ -1935,6 +1943,7 @@ static int ublk_ctrl_start_recovery(struct io_uring_cmd *cmd)
/* set to NULL, otherwise new ubq_daemon cannot mmap the io_cmd_buf */
ub->mm = NULL;
ub->nr_queues_ready = 0;
ub->nr_privileged_daemon = 0;
init_completion(&ub->completion);
ret = 0;
out_unlock: