Failed listen() on a tcp:// server reported as success with ext/openssl #24220

The quoted description below was written with an LLM (Claude). I reviewed it, and ran the checks it describes myself.

Description

With ext/openssl loaded, stream_socket_server() on a tcp:// address returns a stream even when listen() fails. The stream is not listening, so the error only shows later, when accepting.

php_openssl_sockop_set_option() handles STREAM_XPORT_OP_LISTEN since TLS session resumption was added (#20296):

case STREAM_XPORT_OP_LISTEN:
	/* Do normal listen first */
	xparam->outputs.returncode = php_stream_socket_ops.set_option(
		stream, option, value, ptrparam);

php_stream_socket_ops.set_option() stores the result of listen() in xparam->outputs.returncode, and returns PHP_STREAM_OPTION_RETURN_OK because it handled the option. Assigning that return value overwrites the -1 of a failed listen() with 0.

In practice, bind() usually fails first, for example on an address in use. So this needs listen() itself to fail. On Linux, strace can make it fail:

<?php
$server = @stream_socket_server("tcp://127.0.0.1:0", $errno, $errstr);
var_dump($server);

docker run --rm --security-opt seccomp=unconfined -v "$PWD":/app -w /app php:8.6.0RC3-cli sh -c '
  apt-get update -qq && apt-get install -y -qq strace >/dev/null
  strace -f -q -o /dev/null -e trace=listen -e inject=listen:error=EADDRINUSE php repro.php'

Resulted in this output:

resource(5) of type (stream)

But I expected this output instead:

bool(false)

PHP 8.5.11 (php:8.5-cli) prints bool(false) under the same injection. A build of PHP-8.6 without ext/openssl does too.

PHP Version

PHP 8.6.0RC3 (cli) (NTS)

Also present on the PHP-8.6 branch and master as of 2026-10-10.

Operating System

Debian (the php:8.6.0RC3-cli image). Not OS-specific.