fs/ntfs3: Fix integer overflow in multiplication

The multiplication of the u32 data_size with a int is being performed
using 32 bit arithmetic however the results is being assigned to the
variable nbits that is a size_t (64 bit) value. Fix a potential
integer overflow by casting the u32 value to a size_t before the
multiply to use a size_t sized bit multiply operation.

Addresses-Coverity: ("Unintentional integer overflow")
Fixes: 82cae269cfa9 ("fs/ntfs3: Add initialization of super block")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>

diff --git a/fs/ntfs3/index.c b/fs/ntfs3/index.c
index 6aa9540..9386c55 100644 (file)
--- a/fs/ntfs3/index.c
+++ b/fs/ntfs3/index.c
@@ -2012,7 +2012,7 @@ static int indx_shrink(struct ntfs_index *indx, struct ntfs_inode *ni,
                unsigned long pos;
                const unsigned long *bm = resident_data(b);
 
-               nbits = le32_to_cpu(b->res.data_size) * 8;
+               nbits = (size_t)le32_to_cpu(b->res.data_size) * 8;
 
                if (bit >= nbits)
                        return 0;