Commit 9fc06ff5 authored by Nikos Tsironis's avatar Nikos Tsironis Committed by Mike Snitzer
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dm clone: Add missing casts to prevent overflows and data corruption 



Add missing casts when converting from regions to sectors.

In case BITS_PER_LONG == 32, the lack of the appropriate casts can lead
to overflows and miscalculation of the device sector.

As a result, we could end up discarding and/or copying the wrong parts
of the device, thus corrupting the device's data.

Fixes: 7431b783 ("dm: add clone target")
Cc: stable@vger.kernel.org # v5.4+
Signed-off-by: default avatarNikos Tsironis <ntsironis@arrikto.com>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
parent cd481c12

drivers/md/dm-clone-target.c

+6 −3
Original line number Diff line number Diff line
@@ -282,7 +282,7 @@ static bool bio_triggers_commit(struct clone *clone, struct bio *bio) 
/* Get the address of the region in sectors */

static inline sector_t region_to_sector(struct clone *clone, unsigned long region_nr)

{

	return (region_nr << clone->region_shift);

	return ((sector_t)region_nr << clone->region_shift);

}



/* Get the region number of the bio */
@@ -471,7 +471,7 @@ static void complete_discard_bio(struct clone *clone, struct bio *bio, bool succ 
	if (test_bit(DM_CLONE_DISCARD_PASSDOWN, &clone->flags) && success) {

		remap_to_dest(clone, bio);

		bio_region_range(clone, bio, &rs, &nr_regions);

		trim_bio(bio, rs << clone->region_shift,

		trim_bio(bio, region_to_sector(clone, rs),

			 nr_regions << clone->region_shift);

		generic_make_request(bio);

	} else
@@ -804,11 +804,14 @@ static void hydration_copy(struct dm_clone_region_hydration *hd, unsigned int nr 
	struct dm_io_region from, to;

	struct clone *clone = hd->clone;



	if (WARN_ON(!nr_regions))

		return;



	region_size = clone->region_size;

	region_start = hd->region_nr;

	region_end = region_start + nr_regions - 1;



	total_size = (nr_regions - 1) << clone->region_shift;

	total_size = region_to_sector(clone, nr_regions - 1);



	if (region_end == clone->nr_regions - 1) {

		/*

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