fs/ufs: avoid potential u32 multiplication overflow

The 64 bit ino is being compared to the product of two u32 values,
however, the multiplication is being performed using a 32 bit multiply so
there is a potential of an overflow.  To be fully safe, cast uspi->s_ncg
to a u64 to ensure a 64 bit multiplication occurs to avoid any chance of
overflow.

Fixes: f3e2a520f5fb ("ufs: NFS support")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Evgeniy Dushistov <dushistov@mail.ru>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Link: http://lkml.kernel.org/r/20200715170355.1081713-1-colin.king@canonical.com
Addresses-Coverity: ("Unintentional integer overflow")
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/ufs/super.c b/fs/ufs/super.c
index 1da0be667409b2cdc302e2cb2b9291bad2842ba6..e3b69fb280e8ccc60162f8597d971ba83e0c1c10 100644 (file)
--- a/fs/ufs/super.c
+++ b/fs/ufs/super.c
@@ -101,7 +101,7 @@ static struct inode *ufs_nfs_get_inode(struct super_block *sb, u64 ino, u32 gene
        struct ufs_sb_private_info *uspi = UFS_SB(sb)->s_uspi;
        struct inode *inode;
 
-       if (ino < UFS_ROOTINO || ino > uspi->s_ncg * uspi->s_ipg)
+       if (ino < UFS_ROOTINO || ino > (u64)uspi->s_ncg * uspi->s_ipg)
                return ERR_PTR(-ESTALE);
 
        inode = ufs_iget(sb, ino);