From: Damien Le Moal <damien.lemoal@wdc.com>
Date: Fri, 12 Oct 2018 19:08:44 +0900
Subject: [PATCH] block: Limit allocation of zone descriptors for report zones
Git-commit: 2e85fbaff3a71e46038ec736186c42ffa721c775
Patch-mainline: v4.20-rc1
References: bsc#1118139

There is no point in allocating more zone descriptors than the number of
zones a block device has for doing a zone report. Avoid doing that in
blkdev_report_zones_ioctl() by limiting the number of zone decriptors
allocated internally to process the user request.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Acked-by: Hannes Reinecke <hare@suse.com>
---
 block/blk-zoned.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/block/blk-zoned.c b/block/blk-zoned.c
index 32e377f755d8..bb4ed69f917f 100644
--- a/block/blk-zoned.c
+++ b/block/blk-zoned.c
@@ -355,8 +355,7 @@ int blkdev_report_zones_ioctl(struct block_device *bdev, fmode_t mode,
 	if (!rep.nr_zones)
 		return -EINVAL;
 
-	if (rep.nr_zones > INT_MAX / sizeof(struct blk_zone))
-		return -ERANGE;
+	rep.nr_zones = min(blkdev_nr_zones(bdev), rep.nr_zones);
 
 	zones = kvmalloc(rep.nr_zones * sizeof(struct blk_zone),
 			GFP_KERNEL | __GFP_ZERO);
-- 
2.16.4