[PATCH] utimes permission check

The utime and utimes should do exactly the smae permission check
according to SUSv3.
	"The effective user ID of the process shall match the owner of the file,
or has write access to the file or appropriate privileges to use this call
in this manner."

utimes when passed a NULL second argument would fail on a read only
file even if the file is owned by the caller.

fs/open.c

@@ -304,7 +304,8 @@ asmlinkage long sys_utimes(char * filename, struct timeval * utimes)
 		newattrs.ia_mtime = times[1].tv_sec;
 		newattrs.ia_valid |= ATTR_ATIME_SET | ATTR_MTIME_SET;
 	} else {
-		if ((error = permission(inode,MAY_WRITE)) != 0)
+		if (current->fsuid != inode->i_uid &&
+		    (error = permission(inode,MAY_WRITE)) != 0)
 			goto dput_and_out;
 	}
 	down(&inode->i_sem);