void auth_client(int fd, const char *user, const char *challenge)
{
	const char *pass;
	char pass2[MAX_DIGEST_LEN*2];

	if (!user || !*user)
		user = "nobody";

	if (!(pass = getpassf(password_file))
	 && !(pass = getenv("RSYNC_PASSWORD"))) {
		/* XXX: cyeoh says that getpass is deprecated, because
		 * it may return a truncated password on some systems,
		 * and it is not in the LSB.
                 *
                 * Andrew Klein says that getpassphrase() is present
                 * on Solaris and reads up to 256 characters.
                 *
                 * OpenBSD has a readpassphrase() that might be more suitable.
                 */
		pass = getpass("Password: ");
	}

	if (!pass)
		pass = "";

	generate_hash(pass, challenge, pass2);
	io_printf(fd, "%s %s\n", user, pass2);
}

The product does not validate or incorrectly validates the integrity check values or checksums of a message. This may prevent it from detecting if the data has been modified or corrupted in transmission.