From 721c7fc701c71f693307d274d2b346a1ecd4a534 Mon Sep 17 00:00:00 2001 From: Ilya Dryomov Date: Thu, 11 Jan 2018 14:09:11 +0100 Subject: block: fail op_is_write() requests to read-only partitions Regular block device writes go through blkdev_write_iter(), which does bdev_read_only(), while zeroout/discard/etc requests are never checked, both userspace- and kernel-triggered. Add a generic catch-all check to generic_make_request_checks() to actually enforce ioctl(BLKROSET) and set_disk_ro(), which is used by quite a few drivers for things like snapshots, read-only backing files/images, etc. Reviewed-by: Sagi Grimberg Signed-off-by: Ilya Dryomov Signed-off-by: Jens Axboe --- block/blk-core.c | 56 ++++++++++++++++++++++++++++++++++++++------------------ 1 file changed, 38 insertions(+), 18 deletions(-) (limited to 'block/blk-core.c') diff --git a/block/blk-core.c b/block/blk-core.c index 55f338020254b..c21a16e9fdf96 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -2062,6 +2062,21 @@ static inline bool should_fail_request(struct hd_struct *part, #endif /* CONFIG_FAIL_MAKE_REQUEST */ +static inline bool bio_check_ro(struct bio *bio, struct hd_struct *part) +{ + if (part->policy && op_is_write(bio_op(bio))) { + char b[BDEVNAME_SIZE]; + + printk(KERN_ERR + "generic_make_request: Trying to write " + "to read-only block-device %s (partno %d)\n", + bio_devname(bio, b), part->partno); + return true; + } + + return false; +} + /* * Remap block n of partition p to block n+start(p) of the disk. */ @@ -2070,27 +2085,28 @@ static inline int blk_partition_remap(struct bio *bio) struct hd_struct *p; int ret = 0; + rcu_read_lock(); + p = __disk_get_part(bio->bi_disk, bio->bi_partno); + if (unlikely(!p || should_fail_request(p, bio->bi_iter.bi_size) || + bio_check_ro(bio, p))) { + ret = -EIO; + goto out; + } + /* * Zone reset does not include bi_size so bio_sectors() is always 0. * Include a test for the reset op code and perform the remap if needed. */ - if (!bio->bi_partno || - (!bio_sectors(bio) && bio_op(bio) != REQ_OP_ZONE_RESET)) - return 0; + if (!bio_sectors(bio) && bio_op(bio) != REQ_OP_ZONE_RESET) + goto out; - rcu_read_lock(); - p = __disk_get_part(bio->bi_disk, bio->bi_partno); - if (likely(p && !should_fail_request(p, bio->bi_iter.bi_size))) { - bio->bi_iter.bi_sector += p->start_sect; - bio->bi_partno = 0; - trace_block_bio_remap(bio->bi_disk->queue, bio, part_devt(p), - bio->bi_iter.bi_sector - p->start_sect); - } else { - printk("%s: fail for partition %d\n", __func__, bio->bi_partno); - ret = -EIO; - } - rcu_read_unlock(); + bio->bi_iter.bi_sector += p->start_sect; + bio->bi_partno = 0; + trace_block_bio_remap(bio->bi_disk->queue, bio, part_devt(p), + bio->bi_iter.bi_sector - p->start_sect); +out: + rcu_read_unlock(); return ret; } @@ -2149,15 +2165,19 @@ generic_make_request_checks(struct bio *bio) * For a REQ_NOWAIT based request, return -EOPNOTSUPP * if queue is not a request based queue. */ - if ((bio->bi_opf & REQ_NOWAIT) && !queue_is_rq_based(q)) goto not_supported; if (should_fail_request(&bio->bi_disk->part0, bio->bi_iter.bi_size)) goto end_io; - if (blk_partition_remap(bio)) - goto end_io; + if (!bio->bi_partno) { + if (unlikely(bio_check_ro(bio, &bio->bi_disk->part0))) + goto end_io; + } else { + if (blk_partition_remap(bio)) + goto end_io; + } if (bio_check_eod(bio, nr_sectors)) goto end_io; -- cgit v1.2.3