| 1 |
<?php |
| 2 |
/** |
| 3 |
* Consent Endpoint. |
| 4 |
* |
| 5 |
* Handles POST /oauth/consent — the form submission from the consent screen |
| 6 |
* rendered by AuthorizeCallback. Verifies the WordPress nonce, looks up and |
| 7 |
* consumes the state transient, then either issues an auth code (Allow) or |
| 8 |
* redirects back to the client with error=access_denied (Deny). |
| 9 |
* |
| 10 |
* redirect_uri is always read from the server-side state transient, never from |
| 11 |
* $_POST, so it cannot be manipulated by the user or a third party. |
| 12 |
*/ |
| 13 |
|
| 14 |
declare(strict_types=1); |
| 15 |
|
| 16 |
namespace WPMedia\MCP\OAuth\Auth; |
| 17 |
|
| 18 |
use WPMedia\MCP\OAuth\Logging\McpLogger; |
| 19 |
|
| 20 |
class ConsentEndpoint { |
| 21 |
/** |
| 22 |
* Auth-code transient TTL (seconds). Codes are single-use; the transient |
| 23 |
* is deleted immediately on redemption at the token endpoint. |
| 24 |
*/ |
| 25 |
const CODE_TTL = 60; |
| 26 |
|
| 27 |
/** |
| 28 |
* Handle the consent form POST. |
| 29 |
* |
| 30 |
* @return void |
| 31 |
*/ |
| 32 |
public function handle_request(): void { |
| 33 |
$request_method = isset( $_SERVER['REQUEST_METHOD'] ) ? sanitize_text_field( wp_unslash( $_SERVER['REQUEST_METHOD'] ) ) : ''; |
| 34 |
|
| 35 |
if ( 'POST' !== $request_method ) { |
| 36 |
McpLogger::log( 'CONSENT', 'rejected: wrong method', [ 'method' => $request_method ] ); |
| 37 |
wp_die( esc_html__( 'Method not allowed.', 'mcp-oauth' ), esc_html__( 'OAuth Error', 'mcp-oauth' ), [ 'response' => 405 ] ); |
| 38 |
} |
| 39 |
|
| 40 |
if ( ! is_user_logged_in() ) { |
| 41 |
McpLogger::log( 'CONSENT', 'rejected: user not logged in' ); |
| 42 |
wp_die( esc_html__( 'You must be logged in to authorise an MCP session.', 'mcp-oauth' ), esc_html__( 'OAuth Error', 'mcp-oauth' ), [ 'response' => 401 ] ); |
| 43 |
} |
| 44 |
|
| 45 |
$state = sanitize_text_field( wp_unslash( $_POST['state'] ?? '' ) ); |
| 46 |
$action = sanitize_text_field( wp_unslash( $_POST['mcp_action'] ?? '' ) ); |
| 47 |
|
| 48 |
if ( '' === $state ) { |
| 49 |
McpLogger::log( 'CONSENT', 'rejected: missing state' ); |
| 50 |
wp_die( esc_html__( 'Missing state parameter.', 'mcp-oauth' ), esc_html__( 'OAuth Error', 'mcp-oauth' ), [ 'response' => 400 ] ); |
| 51 |
} |
| 52 |
|
| 53 |
// Nonce verification (CSRF protection) — must happen before consuming the transient. |
| 54 |
check_admin_referer( 'mcp_consent_' . $state, 'mcp_consent_nonce' ); |
| 55 |
|
| 56 |
$state_key = 'mcp_oauth_state_' . $state; |
| 57 |
$state_data = get_transient( $state_key ); |
| 58 |
|
| 59 |
if ( false === $state_data || ! is_array( $state_data ) ) { |
| 60 |
McpLogger::log( 'CONSENT', 'rejected: state transient not found or expired', [ 'state' => $state ] ); |
| 61 |
wp_die( esc_html__( 'Your session has expired. Please restart the authorization flow.', 'mcp-oauth' ), esc_html__( 'OAuth Error', 'mcp-oauth' ), [ 'response' => 400 ] ); |
| 62 |
} |
| 63 |
|
| 64 |
// Atomically consume the state — one-time use only. delete_transient() |
| 65 |
// returns true for a single caller when requests race, so a double |
| 66 |
// submission cannot mint two auth codes from one consent. |
| 67 |
if ( ! delete_transient( $state_key ) ) { |
| 68 |
McpLogger::log( 'CONSENT', 'rejected: state already consumed (concurrent submission)', [ 'state' => $state ] ); |
| 69 |
wp_die( esc_html__( 'Your session has expired. Please restart the authorization flow.', 'mcp-oauth' ), esc_html__( 'OAuth Error', 'mcp-oauth' ), [ 'response' => 400 ] ); |
| 70 |
} |
| 71 |
|
| 72 |
$redirect_uri = (string) ( $state_data['redirect_uri'] ?? '' ); |
| 73 |
$user_id = get_current_user_id(); |
| 74 |
|
| 75 |
if ( 'allow' !== $action ) { |
| 76 |
McpLogger::log( |
| 77 |
'CONSENT', |
| 78 |
'user denied access', |
| 79 |
[ |
| 80 |
'user_id' => $user_id, |
| 81 |
'client_id' => $state_data['client_id'] ?? '', |
| 82 |
'mcp_action' => $action, |
| 83 |
'redirect_uri' => $redirect_uri, |
| 84 |
] |
| 85 |
); |
| 86 |
|
| 87 |
wp_redirect( // phpcs:ignore WordPress.Security.SafeRedirect.wp_redirect_wp_redirect -- redirecting to the client's registered redirect_uri sourced from the server-side state transient, not user input. |
| 88 |
add_query_arg( |
| 89 |
[ |
| 90 |
'error' => 'access_denied', |
| 91 |
'state' => $state, |
| 92 |
], |
| 93 |
$redirect_uri |
| 94 |
) |
| 95 |
); |
| 96 |
exit; |
| 97 |
} |
| 98 |
|
| 99 |
// User allowed — issue a single-use auth code. |
| 100 |
$auth_code = bin2hex( random_bytes( 32 ) ); |
| 101 |
|
| 102 |
set_transient( |
| 103 |
'mcp_oauth_code_' . $auth_code, |
| 104 |
[ |
| 105 |
'user_id' => $user_id, |
| 106 |
'client_id' => $state_data['client_id'] ?? '', |
| 107 |
'client_name' => $state_data['client_name'] ?? '', |
| 108 |
'code_challenge' => $state_data['code_challenge'] ?? '', |
| 109 |
'redirect_uri' => $redirect_uri, |
| 110 |
], |
| 111 |
self::CODE_TTL |
| 112 |
); |
| 113 |
|
| 114 |
McpLogger::log( |
| 115 |
'CONSENT', |
| 116 |
'user granted access, auth code issued', |
| 117 |
[ |
| 118 |
'user_id' => $user_id, |
| 119 |
'client_id' => $state_data['client_id'] ?? '', |
| 120 |
'redirect_uri' => $redirect_uri, |
| 121 |
'code_ttl_s' => self::CODE_TTL, |
| 122 |
] |
| 123 |
); |
| 124 |
|
| 125 |
wp_redirect( // phpcs:ignore WordPress.Security.SafeRedirect.wp_redirect_wp_redirect -- redirecting to the client's registered redirect_uri sourced from the server-side state transient, not user input. |
| 126 |
add_query_arg( |
| 127 |
[ |
| 128 |
'code' => $auth_code, |
| 129 |
'state' => $state, |
| 130 |
], |
| 131 |
$redirect_uri |
| 132 |
) |
| 133 |
); |
| 134 |
exit; |
| 135 |
} |
| 136 |
} |
| 137 |
|
