fs: Fix uninitialized value issue in from_kuid and from_kgid

ocfs2_setattr() uses attr->ia_mode, attr->ia_uid and attr->ia_gid in
a trace point even though ATTR_MODE, ATTR_UID and ATTR_GID aren't set.

Initialize all fields of newattrs to avoid uninitialized variables, by
checking if ATTR_MODE, ATTR_UID, ATTR_GID are initialized, otherwise 0.

Reported-by: syzbot+6c55f725d1bdc8c52058@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=6c55f725d1bdc8c52058
Signed-off-by: Alessandro Zanni <alessandro.zanni87@gmail.com>
Link: https://lore.kernel.org/r/20241017120553.55331-1-alessandro.zanni87@gmail.com
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>

Author: echo-alez

fs/ocfs2/file.c

@@ -1129,9 +1129,12 @@ int ocfs2_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 	trace_ocfs2_setattr(inode, dentry,
 			    (unsigned long long)OCFS2_I(inode)->ip_blkno,
 			    dentry->d_name.len, dentry->d_name.name,
-			    attr->ia_valid, attr->ia_mode,
-			    from_kuid(&init_user_ns, attr->ia_uid),
-			    from_kgid(&init_user_ns, attr->ia_gid));
+			    attr->ia_valid,
+				attr->ia_valid & ATTR_MODE ? attr->ia_mode : 0,
+				attr->ia_valid & ATTR_UID ?
+					from_kuid(&init_user_ns, attr->ia_uid) : 0,
+				attr->ia_valid & ATTR_GID ?
+					from_kgid(&init_user_ns, attr->ia_gid) : 0);
 
 	/* ensuring we don't even attempt to truncate a symlink */
 	if (S_ISLNK(inode->i_mode))