From: Damien Le Moal damien.lemoal@wdc.com
commit 0ebcdd702f49aeb0ad2e2d894f8c124a0acc6e23 upstream.
For a null_blk device with zoned mode enabled is currently initialized with a number of zones equal to the device capacity divided by the zone size, without considering if the device capacity is a multiple of the zone size. If the zone size is not a divisor of the capacity, the zones end up not covering the entire capacity, potentially resulting is out of bounds accesses to the zone array.
Fix this by adding one last smaller zone with a size equal to the remainder of the disk capacity divided by the zone size if the capacity is not a multiple of the zone size. For such smaller last zone, the zone capacity is also checked so that it does not exceed the smaller zone size.
Reported-by: Naohiro Aota naohiro.aota@wdc.com Fixes: ca4b2a011948 ("null_blk: add zone support") Cc: stable@vger.kernel.org Signed-off-by: Damien Le Moal damien.lemoal@wdc.com Reviewed-by: Christoph Hellwig hch@lst.de Reviewed-by: Johannes Thumshirn johannes.thumshirn@wdc.com Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/block/null_blk_zoned.c | 19 ++++++++++++------- 1 file changed, 12 insertions(+), 7 deletions(-)
--- a/drivers/block/null_blk_zoned.c +++ b/drivers/block/null_blk_zoned.c @@ -2,8 +2,7 @@ #include <linux/vmalloc.h> #include "null_blk.h"
-/* zone_size in MBs to sectors. */ -#define ZONE_SIZE_SHIFT 11 +#define MB_TO_SECTS(mb) (((sector_t)mb * SZ_1M) >> SECTOR_SHIFT)
static inline unsigned int null_zone_no(struct nullb_device *dev, sector_t sect) { @@ -12,7 +11,7 @@ static inline unsigned int null_zone_no(
int null_zone_init(struct nullb_device *dev) { - sector_t dev_size = (sector_t)dev->size * 1024 * 1024; + sector_t dev_capacity_sects; sector_t sector = 0; unsigned int i;
@@ -25,9 +24,12 @@ int null_zone_init(struct nullb_device * return -EINVAL; }
- dev->zone_size_sects = dev->zone_size << ZONE_SIZE_SHIFT; - dev->nr_zones = dev_size >> - (SECTOR_SHIFT + ilog2(dev->zone_size_sects)); + dev_capacity_sects = MB_TO_SECTS(dev->size); + dev->zone_size_sects = MB_TO_SECTS(dev->zone_size); + dev->nr_zones = dev_capacity_sects >> ilog2(dev->zone_size_sects); + if (dev_capacity_sects & (dev->zone_size_sects - 1)) + dev->nr_zones++; + dev->zones = kvmalloc_array(dev->nr_zones, sizeof(struct blk_zone), GFP_KERNEL | __GFP_ZERO); if (!dev->zones) @@ -55,7 +57,10 @@ int null_zone_init(struct nullb_device * struct blk_zone *zone = &dev->zones[i];
zone->start = zone->wp = sector; - zone->len = dev->zone_size_sects; + if (zone->start + dev->zone_size_sects > dev_capacity_sects) + zone->len = dev_capacity_sects - zone->start; + else + zone->len = dev->zone_size_sects; zone->type = BLK_ZONE_TYPE_SEQWRITE_REQ; zone->cond = BLK_ZONE_COND_EMPTY;