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authorIlya Dryomov <idryomov@gmail.com>2018-01-11 14:09:11 +0100
committerJens Axboe <axboe@kernel.dk>2018-01-18 12:57:17 -0700
commit721c7fc701c71f693307d274d2b346a1ecd4a534 (patch)
tree02b8934cb55c6b00a533c536419e2d157d18917b /block
parent17534c6f2c065ad8e34ff6f013e5afaa90428512 (diff)
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>
Diffstat (limited to 'block')
-rw-r--r--block/blk-core.c56
1 files changed, 38 insertions, 18 deletions
diff --git a/block/blk-core.c b/block/blk-core.c
index 55f338020254..c21a16e9fdf9 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;

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