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dm clone: Add missing casts to prevent overflows and data corruption

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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: 7431b7835f ("dm: add clone target")
Cc: stable@vger.kernel.org # v5.4+
Signed-off-by: Nikos Tsironis <ntsironis@arrikto.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
This commit is contained in:
Nikos Tsironis 2020-03-27 16:01:10 +02:00 committed by Mike Snitzer
parent cd481c1226
commit 9fc06ff568
1 changed files with 6 additions and 3 deletions
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9
drivers/md/dm-clone-target.c
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@ -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) {
/*