implement a large chunk of the auth system itself :D

15 files changed, 393 insertions, 0 deletions

diff --git a/Psso/AuthFlow.php b/Psso/AuthFlow.php
new file mode 100644
index 0000000..c2a68ac
--- /dev/null
+++ b/Psso/AuthFlow.php
@@ -0,0 +1,9 @@
+<?php
+namespace Psso;
+
+abstract class AuthFlow {
+    public static function nextStep(Context $context) {
+        $last = array_last($context->results);
+        return eval(file_get_contents(__DIR__ . '/../auth-flow.conf.php'));
+    }
+}
diff --git a/Psso/AuthInterface/Password.php b/Psso/AuthInterface/Password.php
new file mode 100644
index 0000000..d20d759
--- /dev/null
+++ b/Psso/AuthInterface/Password.php
@@ -0,0 +1,9 @@
+<?php
+namespace Psso\AuthInterface;
+
+interface Password {
+    public function validatePassword(
+        string $username,
+        #[\SensitiveParameter] string $password
+    ): bool;
+}
diff --git a/Psso/AuthInterface/Totp.php b/Psso/AuthInterface/Totp.php
new file mode 100644
index 0000000..5e09117
--- /dev/null
+++ b/Psso/AuthInterface/Totp.php
@@ -0,0 +1,9 @@
+<?php
+namespace Psso\AuthInterface;
+
+interface Totp {
+    public function validateTotp(
+        string $user,
+        #[\SensitiveParameter] string $otp
+    ): bool;
+}
diff --git a/Psso/AuthProvider.php b/Psso/AuthProvider.php
new file mode 100644
index 0000000..c608084
--- /dev/null
+++ b/Psso/AuthProvider.php
@@ -0,0 +1,10 @@
+<?php
+namespace Psso;
+
+abstract class AuthProvider {
+    protected array $config;
+
+    public function __construct(array $config) {
+        $this->config = $config;
+    }
+}
diff --git a/Psso/AuthProvider/ConfigFile.php b/Psso/AuthProvider/ConfigFile.php
new file mode 100644
index 0000000..0d855d0
--- /dev/null
+++ b/Psso/AuthProvider/ConfigFile.php
@@ -0,0 +1,16 @@
+<?php
+namespace Psso\AuthProvider;
+use Psso\{AuthProvider, AuthInterface};
+
+class ConfigFile extends AuthProvider implements AuthInterface\Password {
+    public function validatePassword(
+        string $username,
+        #[\SensitiveParameter] string $password
+    ): bool {
+        $hash = $this->config['users']["$username.password-hash"] ?? null;
+        if (!isset($hash)) {
+            return false;
+        }
+        return password_verify($password, $hash);
+    }
+}
diff --git a/Psso/AuthProvider/Dummy.php b/Psso/AuthProvider/Dummy.php
new file mode 100644
index 0000000..15d44ee
--- /dev/null
+++ b/Psso/AuthProvider/Dummy.php
@@ -0,0 +1,20 @@
+<?php
+namespace Psso\AuthProvider;
+use Psso\{AuthProvider, AuthInterface};
+
+class Dummy extends AuthProvider
+implements AuthInterface\Password, AuthInterface\Totp {
+    public function validatePassword(
+        string $username,
+        #[\SensitiveParameter] string $password
+    ): bool {
+        return $password == 'dummy';
+    }
+
+    public function validateTotp(
+        string $username,
+        #[\SensitiveParameter] string $otp
+    ): bool {
+        return $otp == '123456';
+    }
+}
diff --git a/Psso/Challenge.php b/Psso/Challenge.php
new file mode 100644
index 0000000..72100ce
--- /dev/null
+++ b/Psso/Challenge.php
@@ -0,0 +1,59 @@
+<?php
+namespace Psso;
+
+abstract class Challenge {
+    public protected(set) Context $context;
+    protected array $inputs = [];
+    public protected(set) string $serial;
+    
+    protected function __construct(Context $context) {
+        $this->context = $context;
+        $this->serial = base64_encode(random_bytes(9));
+    }
+    
+    public static function create(Context $context): ?static {
+        return new static($context);
+    }
+    
+    public abstract function getInputs(): array;
+    
+    public abstract function validate(
+        AuthProvider $provider, array $inputData
+    ): ChallengeResult;
+
+    public function addAsHtml(\SimpleXMLElement $parent): void {
+        $form = $parent->addChild('form');
+        $form->addAttribute('method', 'post');
+        foreach ($this->getInputs() as $input) {
+            $input->addAsHtml($form);
+            $this->inputs[$input->serial] = $input;
+        }
+        $serial = $form->addChild('input');
+        $serial->addAttribute('type', 'hidden');
+        $serial->addAttribute('name', 'challenge');
+        $serial->addAttribute('value', $this->serial);
+        $submit = $form->addChild('button', L('challenge.continue'));
+    }
+
+    public function findInput(string $serial): ?Input {
+        return $this->inputs[$serial] ?? null;
+    }
+
+    protected static function requireInterface(
+        AuthProvider $provider, string $interface
+    ): void {
+        if (!($provider instanceof $interface)) {
+            throw new \InvalidArgumentException(
+                "Provider must implement $interface"
+            );
+        };
+    }
+
+    protected static function requireKnownUser(Context $context): void {
+        if (!isset($context->user)) {
+            throw new \RuntimeException(
+                'Unknown user, but known user required for ' . static::class
+            );
+        }
+    }
+}
diff --git a/Psso/Challenge/Password.php b/Psso/Challenge/Password.php
new file mode 100644
index 0000000..c20f5e2
--- /dev/null
+++ b/Psso/Challenge/Password.php
@@ -0,0 +1,32 @@
+<?php
+namespace Psso\Challenge;
+
+use Psso\{Challenge, ChallengeResult, Input, AuthProvider, AuthInterface};
+
+class Password extends Challenge {    
+    public function getInputs(): array {
+        if (isset($this->context->user)) {
+            return [
+                new Input('password', Input::SECRET, 'challenge.input.password')
+            ];
+        }
+        return [
+            new Input('username', Input::TEXT, 'challenge.input.username'),
+            new Input('password', Input::SECRET, 'challenge.input.password'),
+        ];
+    }
+
+    public function validate(
+        AuthProvider $provider, array $inputData
+    ): ChallengeResult {
+        self::requireInterface($provider, AuthInterface\Password::class);
+        $successful = $provider->validatePassword(
+            $inputData['username'] ?? $this->context->user,
+            $inputData['password']
+        );
+        return new ChallengeResult(
+            self::class, $successful, $inputData['username'] ?? null,
+            $successful ? null : 'challenge.message.wrong-password'
+        );
+    }
+}
diff --git a/Psso/Challenge/Totp.php b/Psso/Challenge/Totp.php
new file mode 100644
index 0000000..4fd47f4
--- /dev/null
+++ b/Psso/Challenge/Totp.php
@@ -0,0 +1,27 @@
+<?php
+namespace Psso\Challenge;
+use Psso\{Challenge, AuthProvider, ChallengeResult, Context, Input, AuthInterface};
+
+class Totp extends Challenge {
+    public static function create(Context $context): static {
+        self::requireKnownUser($context);
+        return new self($context);
+    }
+
+    public function getInputs(): array {
+        return [new Input('otp', Input::NUMERIC, 'challenge.input.otp')];
+    }
+
+    public function validate(
+        AuthProvider $provider, array $inputData
+    ): ChallengeResult {
+        self::requireInterface($provider, AuthInterface\Totp::class);
+        $success = $provider->validateTotp(
+            $this->context->user, $inputData['otp']
+        );
+        return new ChallengeResult(
+            self::class, $success, null,
+            $success ? null : 'challenge.message.wrong-otp'
+        );
+    }
+}
diff --git a/Psso/Challenge/Username.php b/Psso/Challenge/Username.php
new file mode 100644
index 0000000..43de085
--- /dev/null
+++ b/Psso/Challenge/Username.php
@@ -0,0 +1,16 @@
+<?php
+namespace Psso\Challenge;
+use Psso\{Challenge, AuthProvider, ChallengeResult, Input};
+
+/** Just asks for a username and sets it in the context. Always succeeds. */
+class Username extends Challenge {
+    public function getInputs(): array {
+        return [new Input('user', Input::TEXT, 'challenge.input.username')];
+    }
+
+    public function validate(
+        AuthProvider $provider, array $inputData
+    ): ChallengeResult {
+        return new ChallengeResult(self::class, true, $inputData['user'], null);
+    }
+}
diff --git a/Psso/ChallengeResult.php b/Psso/ChallengeResult.php
new file mode 100644
index 0000000..f8ced88
--- /dev/null
+++ b/Psso/ChallengeResult.php
@@ -0,0 +1,21 @@
+<?php
+namespace Psso;
+
+class ChallengeResult {
+    public protected(set) string $type;
+    public protected(set) bool $successful;
+    public protected(set) ?string $user;
+    public protected(set) ?string $message;
+
+    public function __construct(
+        string $type,
+        bool $successful,
+        ?string $user = null,
+        ?string $message = null
+    ) {
+        $this->type = $type;
+        $this->successful = $successful;
+        $this->user = $user;
+        $this->message = $message;
+    }
+}
diff --git a/Psso/Context.php b/Psso/Context.php
new file mode 100644
index 0000000..4a2cd82
--- /dev/null
+++ b/Psso/Context.php
@@ -0,0 +1,13 @@
+<?php
+namespace Psso;
+
+class Context {
+    public protected(set) array $results = [];
+    public ?string $user = null;
+    public protected(set) array $groups = [];
+    public protected(set) array $tags = [];
+
+    public function addResult(ChallengeResult $result): void {
+        $this->results[] = $result;
+    }
+}
diff --git a/Psso/Input.php b/Psso/Input.php
new file mode 100644
index 0000000..019d79f
--- /dev/null
+++ b/Psso/Input.php
@@ -0,0 +1,42 @@
+<?php
+namespace Psso;
+
+class Input {
+    // input-type constants that map to their HTML equivalents
+    /** Plain text. */
+    public const string TEXT = 'text';
+    /** Hidden/masked text. */
+    public const string SECRET = 'password';
+    /** Integer. */
+    public const string NUMERIC = 'number';
+
+    public protected(set) string $id;
+    public protected(set) string $type;
+    public protected(set) string $label;
+    public protected(set) bool $required;
+    public private(set) string $serial;
+    
+    public function __construct(
+        string $id, string $type, string $label, bool $required = true
+    ) {
+        $this->id = $id;
+        $this->type = $type;
+        $this->label = $label;
+        $this->required = $required;
+        $this->serial = base64_encode(random_bytes(9));
+    }
+
+    private function getUniqueName(): string {
+        return $this->id . '__' . $this->serial;
+    }
+
+    public function addAsHtml(\SimpleXMLElement $parent): void {
+        $label = $parent->addChild('label', L($this->label));
+        $label->addAttribute('for', 'input-' . $this->getUniqueName());
+        $input = $parent->addChild('input');
+        $input->addAttribute('type', $this->type);
+        $input->addAttribute('name', $this->getUniqueName());
+        $input->addAttribute('id', 'input-' . $this->getUniqueName());
+        if ($this->required) $input->addAttribute('required', '');
+    }
+}
diff --git a/Psso/Router.php b/Psso/Router.php
new file mode 100644
index 0000000..db1f851
--- /dev/null
+++ b/Psso/Router.php
@@ -0,0 +1,66 @@
+<?php
+namespace Psso;
+
+class Router {
+    private array $config;
+    private string $routesDir;
+    private array $statusHandlers = [];
+    private \Closure $exceptionHandler;
+
+    function __construct(string $routesDir, array $config) {
+        $this->routesDir = $routesDir;
+        $this->config = $config;
+    }
+
+    function registerStatusHandler(int $status, callable $handler) {
+        $this->statusHandlers[$status] = $handler;
+    }
+
+    function setExceptionHandler(callable $handler) {
+        $this->exceptionHandler = \Closure::fromCallable($handler);
+    }
+
+    private function dealWithError(int $status, string $path) {
+        http_response_code($status);
+        if (isset($this->statusHandlers[$status])) {
+            $this->statusHandlers[$status]($path);
+        } else {
+            echo '<p>' . $status . ' for ' . htmlspecialchars($path) . '</p>';
+        }
+    }
+
+    private function dealWithException(\Throwable $e) {
+        http_response_code(500);
+        if (isset($this->exceptionHandler)) {
+            ($this->exceptionHandler)($e);
+        } else {
+            echo '<p>Internal Server Error</p>';
+        }
+    }
+
+    function dispatch(string $path) {
+        if (str_contains($path, '..')) {
+            $this->dealWithError(404, $path);
+            return;
+        }
+
+        if (file_exists($this->routesDir . $path . '.php')) {
+            require_once $this->routesDir . $path . '.php';
+        } elseif (file_exists($this->routesDir . $path . 'index.php')) {
+            require_once $this->routesDir . $path . 'index.php';
+        } else {
+            $this->dealWithError(404, $path);
+            return;
+        }
+
+        if (function_exists($_SERVER['REQUEST_METHOD'])) {
+            try {
+                $_SERVER['REQUEST_METHOD']($this->config);
+            } catch (\Exception|\Error $e) {
+                $this->dealWithException($e);
+            }
+        } else {
+            $this->dealWithError(405, $path);
+        }
+    }
+}
diff --git a/Psso/XMLResponse.php b/Psso/XMLResponse.php
new file mode 100644
index 0000000..1b17660
--- /dev/null
+++ b/Psso/XMLResponse.php
@@ -0,0 +1,44 @@
+<?php
+namespace Psso;
+
+class XMLResponse {
+    public \SimpleXMLElement $doc;
+    private static array $stylesheets;
+    private static array $runFirst;
+
+    static function addStylesheet(string $path) {
+        $sheet = \Dom\XMLDocument::createFromFile($path);
+        self::$stylesheets[] = $sheet;
+    }
+
+    static function addPreamble(callable $preamble) {
+        self::$runFirst[] = $preamble;
+    }
+
+    function __construct(string $rootElement = 'page') {
+        $this->doc = new \SimpleXMLElement("<$rootElement/>");
+        foreach (self::$runFirst as $fn) {
+            $fn($this->doc);
+        }
+    }
+
+    function sendRaw() {
+        header('Content-Type: application/xml');
+        echo $this->doc->asXML();
+    }
+
+    function send() {
+        if (isset($_GET['RawXML'])) {
+            $this->sendRaw();
+            return;
+        }
+
+        //header('Content-Type: application/xhtml+xml');
+        $processor = new \XSLTProcessor;
+        foreach (self::$stylesheets as $sheet) {
+            $processor->importStylesheet($sheet);
+        }
+        $root = \Dom\import_simplexml($this->doc);
+        echo $processor->transformToXml($root);
+    }
+}