[PATCH 1/1] fs: fat: avoid multiplication overflow

[Heinrich Schuchardt]

The product of two 32 bit integers is a 32 bit integer. Hence
clustcount * bytesperclust may overflow on > 4 GiB devices.

Change the type of clustcount.

Fixes: cb8af8af5ba0 ("fs: fat: support write with non-zero offset")
Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt at canonical.com>
---
 fs/fat/fat_write.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/fat/fat_write.c b/fs/fat/fat_write.c
index e2a9913f80..289e7aa641 100644
--- a/fs/fat/fat_write.c
+++ b/fs/fat/fat_write.c
@@ -690,8 +690,8 @@ get_set_cluster(fsdata *mydata, __u32 clustnum, loff_t pos, __u8 *buffer,
 	static u8 *tmpbuf_cluster;
 	unsigned int bytesperclust = mydata->clust_size * mydata->sect_size;
 	__u32 startsect;
-	loff_t wsize;
-	int clustcount, i, ret;
+	loff_t clustcount, wsize;
+	int i, ret;
 
 	*gotsize = 0;
 	if (!size)
-- 
2.40.1