null_blk: fix validation of block size

Block size should be between 512 and PAGE_SIZE and be a power of 2. The current
check does not validate this, so update the check.

Without this patch, null_blk would Oops due to a null pointer deref when
loaded with bs=1536 [1].

Link: https://lore.kernel.org/all/87wmn8mocd.fsf@metaspace.dk/
Signed-off-by: Andreas Hindborg <a.hindborg@samsung.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20240603192645.977968-1-nmi@metaspace.dk
[axboe: remove unnecessary braces and != 0 check]
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/drivers/block/null_blk/main.c b/drivers/block/null_blk/main.c
index 631dca2..75f189e 100644 (file)
--- a/drivers/block/null_blk/main.c
+++ b/drivers/block/null_blk/main.c
@@ -1824,8 +1824,8 @@ static int null_validate_conf(struct nullb_device *dev)
                dev->queue_mode = NULL_Q_MQ;
        }
 
-       dev->blocksize = round_down(dev->blocksize, 512);
-       dev->blocksize = clamp_t(unsigned int, dev->blocksize, 512, 4096);
+       if (blk_validate_block_size(dev->blocksize))
+               return -EINVAL;
 
        if (dev->use_per_node_hctx) {
                if (dev->submit_queues != nr_online_nodes)