From 43946b70494beefe40ec1b2ba4744c0f294d7736 Mon Sep 17 00:00:00 2001

From: Namjae Jeon <namjae.jeon@samsung.com>

Date: Fri, 3 Jul 2020 11:16:32 +0900

Subject: [Backport 43946b70494b] exfat: fix overflow issue in

 exfat_cluster_to_sector()

An overflow issue can occur while calculating sector in

exfat_cluster_to_sector(). It needs to cast clus's type to sector_t

before left shifting.

Fixes: 1acf1a564b60 ("exfat: add in-memory and on-disk structures and headers")

Cc: stable@vger.kernel.org # v5.7

Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>

Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>

---

 src/exfat_fs.h | 2 +-

 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/exfat_fs.h b/src/exfat_fs.h

index 7579cd3bbadba87a8bfd56c0699c8186902a6763..75c7bdbeba6d3e9316c7b795cd525d1323e47b83 100644

--- a/src/exfat_fs.h

+++ b/src/exfat_fs.h

@@ -371,7 +371,7 @@ static inline bool exfat_is_last_sector_in_cluster(struct exfat_sb_info *sbi,

 static inline sector_t exfat_cluster_to_sector(struct exfat_sb_info *sbi,

 		unsigned int clus)

 {

-	return ((clus - EXFAT_RESERVED_CLUSTERS) << sbi->sect_per_clus_bits) +

+	return ((sector_t)(clus - EXFAT_RESERVED_CLUSTERS) << sbi->sect_per_clus_bits) +

 		sbi->data_start_sector;

 }

-- 

2.31.1