[PATCH mtd-utils] nand-utils: Fix integer overflow in nandflipbits.c

[Anton Moryakov]

Report of the static analyzer:
The value of an arithmetic expression 'page * (mtd.min_io_size + mtd.oob_size)' is a subject to overflow because its operands are not cast to a larger data type before performing arithmetic

Corrections explained:
Casting bit_to_flip->block to unsigned long long expands the range of values ​​and allows the result of the multiplication to be calculated in a wider data type.
The arithmetic is performed in a safe range, preventing overflow.
Sum + blkoffs is now also safe, since the result of the expression is already calculated in unsigned long long.

Triggers found by static analyzer Svace.

Signed-off-by: Anton Moryakov <ant.v.moryakov at gmail.com>

---
 nand-utils/nandflipbits.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/nand-utils/nandflipbits.c b/nand-utils/nandflipbits.c
index ef663c6..c4642fe 100644
--- a/nand-utils/nandflipbits.c
+++ b/nand-utils/nandflipbits.c
@@ -213,7 +213,7 @@ int main(int argc, char **argv)
 		bits_to_flip[i].block = bits_to_flip[i].offset / blklen;
 		bits_to_flip[i].offset %= blklen;
 		page = bits_to_flip[i].offset / pagelen;
-		bits_to_flip[i].offset = (page *
+		bits_to_flip[i].offset = ((unsigned long long)page *
 					  (mtd.min_io_size + mtd.oob_size)) +
 					 (bits_to_flip[i].offset % pagelen);
 	}
-- 
2.30.2