[PATCH v4] mtd: diskonchip: Cast an operand to prevent potential overflow

[Gax-c]

From: Zichen Xie <zichenxie0106 at gmail.com>

There may be a potential integer overflow issue in inftl_partscan().
parts[0].size is defined as "uint64_t"  while mtd->erasesize and
ip->firstUnit are defined as 32-bit unsigned integer. The result of
the calculation will be limited to 32 bits without correct casting.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Zichen Xie <zichenxie0106 at gmail.com>
Cc: stable at vger.kernel.org
---
v2: Correct "Fixes" tag.
v3: Shorten subject and adjust commit log wrapping.
v4: Add Cc tag.
---
 drivers/mtd/nand/raw/diskonchip.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mtd/nand/raw/diskonchip.c b/drivers/mtd/nand/raw/diskonchip.c
index 8db7fc424571..70d6c2250f32 100644
--- a/drivers/mtd/nand/raw/diskonchip.c
+++ b/drivers/mtd/nand/raw/diskonchip.c
@@ -1098,7 +1098,7 @@ static inline int __init inftl_partscan(struct mtd_info *mtd, struct mtd_partiti
 		    (i == 0) && (ip->firstUnit > 0)) {
 			parts[0].name = " DiskOnChip IPL / Media Header partition";
 			parts[0].offset = 0;
-			parts[0].size = mtd->erasesize * ip->firstUnit;
+			parts[0].size = (uint64_t)mtd->erasesize * ip->firstUnit;
 			numparts = 1;
 		}
 
-- 
2.34.1