fs/ntfs3: Fix an NULL dereference bug

BugLink: https://bugs.launchpad.net/bugs/2059991

[ Upstream commit b2dd7b9 ]

The issue here is when this is called from ntfs_load_attr_list().  The
"size" comes from le32_to_cpu(attr->res.data_size) so it can't overflow
on a 64bit systems but on 32bit systems the "+ 1023" can overflow and
the result is zero.  This means that the kmalloc will succeed by
returning the ZERO_SIZE_PTR and then the memcpy() will crash with an
Oops on the next line.

Fixes: be71b5c ("fs/ntfs3: Add attrib operations")
Signed-off-by: Dan Carpenter <[email protected]>
Signed-off-by: Konstantin Komarov <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
Signed-off-by: Portia Stephens <[email protected]>
Signed-off-by: Roxana Nicolescu <[email protected]>

Author: Dan Carpenter

fs/ntfs3/ntfs_fs.h

@@ -473,7 +473,7 @@ bool al_delete_le(struct ntfs_inode *ni, enum ATTR_TYPE type, CLST vcn,
 int al_update(struct ntfs_inode *ni, int sync);
 static inline size_t al_aligned(size_t size)
 {
-	return (size + 1023) & ~(size_t)1023;
+	return size_add(size, 1023) & ~(size_t)1023;
 }
 
 /* Globals from bitfunc.c */