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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 <sagi@grimberg.me>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Ilya Dryomov 2018-01-11 14:09:11 +01:00 committed by Jens Axboe
parent 17534c6f2c
commit 721c7fc701
1 changed files with 38 additions and 18 deletions
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56
block/blk-core.c
View File

@ -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;
}
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;