block: ublk: make sure that block size is set correctly

block size is one very key setting for block layer, and bad block size
could panic kernel easily.

Make sure that block size is set correctly.

Meantime if ublk_validate_params() fails, clear ub->params so that disk
is prevented from being added.

Fixes: 71f28f3 ("ublk_drv: add io_uring based userspace block driver")
Reported-and-tested-by: Breno Leitao <[email protected]>
Signed-off-by: Ming Lei <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>

Author: Ming Lei

drivers/block/ublk_drv.c

@@ -246,7 +246,7 @@ static int ublk_validate_params(const struct ublk_device *ub)
 	if (ub->params.types & UBLK_PARAM_TYPE_BASIC) {
 		const struct ublk_param_basic *p = &ub->params.basic;
 
-		if (p->logical_bs_shift > PAGE_SHIFT)
+		if (p->logical_bs_shift > PAGE_SHIFT || p->logical_bs_shift < 9)
 			return -EINVAL;
 
 		if (p->logical_bs_shift > p->physical_bs_shift)
@@ -1970,6 +1970,8 @@ static int ublk_ctrl_set_params(struct ublk_device *ub,
 		/* clear all we don't support yet */
 		ub->params.types &= UBLK_PARAM_TYPE_ALL;
 		ret = ublk_validate_params(ub);
+		if (ret)
+			ub->params.types = 0;
 	}
 	mutex_unlock(&ub->mutex);