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: 1acf1a5 ("exfat: add in-memory and on-disk structures and headers") Cc: [email protected] # v5.7 Reviewed-by: Sungjong Seo <[email protected]> Signed-off-by: Namjae Jeon <[email protected]>
ashr · Jul 21, 2020 · 43946b7 · 43946b7
1 parent ba47d84
commit 43946b7
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/fs/exfat/exfat_fs.h b/fs/exfat/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;
 }