Update send_email_with_tor.php

1 files changed, 395 insertions, 180 deletions

diff --git a/send_email_with_tor.php b/send_email_with_tor.php
index c52de23..8bf6d2e 100644
--- a/send_email_with_tor.php
+++ b/send_email_with_tor.php
@@ -1,229 +1,444 @@
 <?php
-// Enable error display during development - comment out in production
-// ini_set('display_errors', 1);
-// ini_set('display_startup_errors', 1);
-// error_reporting(E_ALL);
+/**
+ * Secure YAMN Email Sender
+ * Implements all security requirements:
+ * - No metadata retention
+ * - Replay protection
+ * - Adaptive padding
+ * - Randomized delays
+ * - Secure file handling
+ * - Tor enforcement
+ */
 
-include 'download_remailers.php';
-include 'tor_extension.php';
+// Disable error display in production
+ini_set('display_errors', 0);
+ini_set('display_startup_errors', 0);
+error_reporting(0);
 
-if ($_SERVER['REQUEST_METHOD'] == 'POST') {
-    // Retrieve form data
-    $entryRemailer = isset($_POST['entry_remailer']) ? $_POST['entry_remailer'] : '';
-    $middleRemailer = isset($_POST['middle_remailer']) ? $_POST['middle_remailer'] : '';
-    $exitRemailer = isset($_POST['exit_remailer']) ? $_POST['exit_remailer'] : '';
-    $from = isset($_POST['from']) ? $_POST['from'] : '';
-    $replyTo = isset($_POST['reply_to']) ? $_POST['reply_to'] : '';
-    $to = isset($_POST['to']) ? $_POST['to'] : '';
-    $subject = isset($_POST['subject']) ? $_POST['subject'] : '';
-    $newsgroups = isset($_POST['newsgroups']) ? $_POST['newsgroups'] : '';
-    $references = isset($_POST['references']) ? $_POST['references'] : '';
-    $data = isset($_POST['data']) ? $_POST['data'] : '';
-    $copies = isset($_POST['copies']) ? intval($_POST['copies']) : 1;
-    
-    // Force Tor usage regardless of form input
-    $useTor = true;
-    
-    // Validation
-    $errors = [];
-    
-    // Required fields validation
-    if (empty($to)) {
-        $errors[] = "Recipient (To) field is required";
-    }
+require_once 'download_remailers_secure.php';
+require_once 'tor_extension_secure.php';
+
+class SecureYamnSender {
     
-    if (empty($from)) {
-        $errors[] = "Sender (From) field is required";
-    }
+    private $secureDir = '/opt/yamn-data/pool';
+    private $replayCache = '/opt/yamn-data/cache/replay_cache.db';
+    private $replayCacheTTL = 604800; // 7 days
     
-    if (empty($subject)) {
-        $errors[] = "Subject field is required";
-    }
+    // Padding sizes (in bytes)
+    private $paddingSizes = [512, 1024, 2048, 4096, 8192, 16384, 32768];
     
-    // Validate number of copies
-    if ($copies < 1 || $copies > 3) {
-        $errors[] = "Number of copies must be between 1 and 3";
-    }
+    // Delay ranges (seconds)
+    private $minDelay = 10;
+    private $maxDelay = 120;
     
-    // Check if Tor is available
-    if (!isTorAvailable()) {
-        $errors[] = "Tor is required but not available on the system. Please install and start Tor service.";
+    public function __construct() {
+        // Ensure secure directories exist
+        if (!file_exists($this->secureDir)) {
+            mkdir($this->secureDir, 0700, true);
+        }
+        
+        // Initialize replay cache DB
+        $this->initReplayCache();
     }
     
-    // If no errors, proceed with sending
-    if (empty($errors)) {
-        // Build the remailer chain
-        $chain = "$entryRemailer,$middleRemailer,$exitRemailer";
+    /**
+     * Main send function
+     */
+    public function sendEmail($postData) {
+        // Extract and validate input (no storage of raw data)
+        $validated = $this->validateInput($postData);
+        if ($validated['errors']) {
+            return ['success' => false, 'errors' => $validated['errors']];
+        }
         
-        // Build headers
-        $headers = "Content-Type: text/plain; charset=utf-8\n";
-        $headers .= "Content-Transfer-Encoding: 8bit\n";
-        $headers .= "MIME-Version: 1.0\n";
+        $data = $validated['data'];
+        
+        // Generate message-ID for replay protection
+        $messageId = $this->generateMessageId($data);
         
-        if (!empty($references)) {
-            $headers .= "References: $references\n";
+        // Check for replay attack
+        if ($this->isReplay($messageId)) {
+            return [
+                'success' => false,
+                'errors' => ['This message has already been sent recently']
+            ];
         }
         
         // Build message content
-        $messageContent = $headers . "From: $from\n";
+        $messageContent = $this->buildMessage($data);
         
-        if (!empty($replyTo)) {
-            $messageContent .= "Reply-To: $replyTo\n";
+        // Apply adaptive padding
+        $paddedMessage = $this->applyAdaptivePadding($messageContent);
+        
+        // Create secure temporary file
+        $messageFile = $this->createSecureMessageFile($paddedMessage);
+        
+        if (!$messageFile) {
+            return [
+                'success' => false,
+                'errors' => ['Failed to create secure message file']
+            ];
         }
         
-        $messageContent .= "To: $to\nSubject: $subject\n";
+        // Random delay to prevent timing correlation
+        $this->randomDelay();
         
-        if (!empty($newsgroups)) {
-            $messageContent .= "Newsgroups: $newsgroups\n";
+        // Build chain
+        $chain = implode(',', [
+            $data['entry_remailer'],
+            $data['middle_remailer'],
+            $data['exit_remailer']
+        ]);
+        
+        // Send via YAMN with Tor (always enforced)
+        try {
+            $result = sendYamnEmailSecure(
+                $chain,
+                $data['copies'],
+                $messageFile,
+                true // Force Tor
+            );
+            
+            // Store message-ID in replay cache only if successful
+            if ($result['success']) {
+                $this->storeMessageId($messageId);
+            }
+            
+            return $result;
+            
+        } catch (Exception $e) {
+            // No detailed error logging
+            return [
+                'success' => false,
+                'errors' => ['Failed to send message']
+            ];
+        } finally {
+            // ALWAYS secure delete the file
+            $this->secureDeleteFile($messageFile);
         }
+    }
+    
+    /**
+     * Validate input without storing sensitive data
+     */
+    private function validateInput($post) {
+        $errors = [];
+        $data = [];
         
-        $messageContent .= "\n$data";
+        // Required fields
+        $required = ['to', 'from', 'subject', 'entry_remailer', 'middle_remailer', 'exit_remailer'];
+        foreach ($required as $field) {
+            if (empty($post[$field])) {
+                $errors[] = ucfirst(str_replace('_', ' ', $field)) . " is required";
+            } else {
+                $data[$field] = $post[$field];
+            }
+        }
+        
+        // Optional fields
+        $optional = ['reply_to', 'newsgroups', 'references', 'data'];
+        foreach ($optional as $field) {
+            $data[$field] = isset($post[$field]) ? $post[$field] : '';
+        }
+        
+        // Validate copies
+        $copies = isset($post['copies']) ? intval($post['copies']) : 1;
+        if ($copies < 1 || $copies > 3) {
+            $errors[] = "Number of copies must be between 1 and 3";
+        }
+        $data['copies'] = $copies;
+        
+        // Check Tor availability
+        if (!isTorAvailable()) {
+            $errors[] = "Tor is required but not available";
+        }
         
-        // Create a unique filename for the message
-        $messageFile = '/var/www/yamnweb/message_' . time() . '_' . rand(1000, 9999) . '.txt';
+        // Email validation
+        if (!empty($data['to']) && !filter_var($data['to'], FILTER_VALIDATE_EMAIL)) {
+            $errors[] = "Invalid recipient email address";
+        }
         
-        $write_success = file_put_contents($messageFile, $messageContent);
-        if ($write_success === false) {
-            echo "Error: Unable to write to message file. Check permissions.";
-            exit;
+        if (!empty($data['from']) && !filter_var($data['from'], FILTER_VALIDATE_EMAIL)) {
+            $errors[] = "Invalid sender email address";
         }
         
-        // Log the operation
-        $log_entry = date('Y-m-d H:i:s') . " - Sending message: from $from to $to using Tor\n";
-        file_put_contents('/var/www/yamnweb/send_log.txt', $log_entry, FILE_APPEND);
+        return [
+            'errors' => $errors,
+            'data' => $data
+        ];
+    }
+    
+    /**
+     * Generate deterministic message-ID for replay detection
+     */
+    private function generateMessageId($data) {
+        // Use hash of critical fields (not entire message to allow minor variations)
+        $critical = $data['to'] . '|' . 
+                   $data['from'] . '|' . 
+                   $data['subject'] . '|' . 
+                   substr($data['data'], 0, 100); // First 100 chars of body
         
-        // Send the email with Tor (always enabled)
+        return hash('sha256', $critical);
+    }
+    
+    /**
+     * Initialize SQLite DB for replay protection
+     */
+    private function initReplayCache() {
         try {
-            $result = sendYamnEmail($chain, $copies, $messageFile, $useTor);
+            $db = new SQLite3($this->replayCache);
+            $db->exec('CREATE TABLE IF NOT EXISTS message_cache (
+                message_id TEXT PRIMARY KEY,
+                timestamp INTEGER NOT NULL
+            )');
+            
+            // Create index for faster lookups
+            $db->exec('CREATE INDEX IF NOT EXISTS idx_timestamp ON message_cache(timestamp)');
+            
+            $db->close();
         } catch (Exception $e) {
-            echo "Error sending email: " . $e->getMessage();
-            exit;
-        }
-        
-        // Clean up message file after sending
-        if (file_exists($messageFile)) {
-            unlink($messageFile);
-        }
-        
-        // Display result to user
-        if ($result['success']) {
-            echo "<!DOCTYPE html>
-            <html lang='en'>
-            <head>
-                <meta charset='UTF-8'>
-                <meta name='viewport' content='width=device-width, initial-scale=1.0'>
-                <title>Email Sent - YAMN Web Interface</title>
-                <link rel='stylesheet' href='styles.css'>
-            </head>
-            <body>
-                <div class='success-message'>
-                    <h2>Email sent successfully!</h2>
-                    <p>Your email has been added to the YAMN sending queue.</p>
-                    <p>As per system policy, Tor was used for enhanced anonymity.</p>
-                    <a href='index.php' class='button'>Return to Home</a>
-                </div>
-            </body>
-            </html>";
-        } else {
-            echo "<!DOCTYPE html>
-            <html lang='en'>
-            <head>
-                <meta charset='UTF-8'>
-                <meta name='viewport' content='width=device-width, initial-scale=1.0'>
-                <title>Email Error - YAMN Web Interface</title>
-                <link rel='stylesheet' href='styles.css'>
-                <style>
-                    pre {
-                        background-color: #f8f8f8;
-                        padding: 10px;
-                        border-radius: 4px;
-                        overflow-x: auto;
-                        font-size: 12px;
-                        text-align: left;
-                    }
-                </style>
-            </head>
-            <body>
-                <div class='error-message'>
-                    <h2>Error sending email</h2>
-                    <p>An error occurred while processing your request.</p>
-                    <p>Error details:</p>
-                    <pre>";
-            echo "===== ADD TO POOL COMMAND =====\n";
-            echo htmlspecialchars($result['add_to_pool']['command']) . "\n\n";
-            echo "===== ADD TO POOL OUTPUT =====\n";
-            echo htmlspecialchars(implode("\n", $result['add_to_pool']['output'])) . "\n\n";
-            echo "===== ADD TO POOL RETURN CODE =====\n";
-            echo $result['add_to_pool']['return_var'] . "\n\n";
+            // Fail silently - replay protection optional
+        }
+    }
+    
+    /**
+     * Check if message is a replay
+     */
+    private function isReplay($messageId) {
+        try {
+            $db = new SQLite3($this->replayCache);
             
-            if (isset($result['send']) && $result['add_to_pool']['return_var'] == 0) {
-                echo "===== SEND COMMAND =====\n";
-                echo htmlspecialchars($result['send']['command']) . "\n\n";
-                echo "===== SEND OUTPUT =====\n";
-                echo htmlspecialchars(implode("\n", $result['send']['output'])) . "\n\n";
-                echo "===== SEND RETURN CODE =====\n";
-                echo $result['send']['return_var'] . "\n";
-            }
-            echo "</pre>
-                    <p>Please check system logs for more details.</p>
-                    <a href='index.php' class='button'>Return to Home</a>
-                </div>
-            </body>
-            </html>";
+            // Clean old entries
+            $expiration = time() - $this->replayCacheTTL;
+            $db->exec("DELETE FROM message_cache WHERE timestamp < $expiration");
             
-            // Detailed error logging
-            $logEntry = "==== ERROR LOG ====\n";
-            $logEntry .= "Date: " . date('Y-m-d H:i:s') . "\n";
-            $logEntry .= "From: $from\n";
-            $logEntry .= "To: $to\n";
-            $logEntry .= "Subject: $subject\n";
-            if (!empty($newsgroups)) {
-                $logEntry .= "Newsgroups: $newsgroups\n";
-            }
-            $logEntry .= "Chain: $chain\n";
-            $logEntry .= "Copies: $copies\n";
-            $logEntry .= "Using Tor: Yes\n";
-            $logEntry .= "\n=== ADD TO POOL ===\n";
-            $logEntry .= "Command: " . $result['add_to_pool']['command'] . "\n";
-            $logEntry .= "Output: " . implode("\n", $result['add_to_pool']['output']) . "\n";
-            $logEntry .= "Return Code: " . $result['add_to_pool']['return_var'] . "\n";
+            // Check if message-ID exists
+            $stmt = $db->prepare('SELECT message_id FROM message_cache WHERE message_id = :id');
+            $stmt->bindValue(':id', $messageId, SQLITE3_TEXT);
+            $result = $stmt->execute();
             
-            if (isset($result['send'])) {
-                $logEntry .= "\n=== SEND ===\n";
-                $logEntry .= "Command: " . $result['send']['command'] . "\n";
-                $logEntry .= "Output: " . implode("\n", $result['send']['output']) . "\n";
-                $logEntry .= "Return Code: " . $result['send']['return_var'] . "\n";
-            }
+            $exists = $result->fetchArray() !== false;
             
-            $logEntry .= "----------------------------------------\n";
-            error_log($logEntry, 3, "/var/www/yamnweb/email_errors.log");
+            $db->close();
+            return $exists;
+            
+        } catch (Exception $e) {
+            // If cache fails, allow message (better than blocking legitimate use)
+            return false;
         }
-    } else {
-        // Display validation errors
-        echo "<!DOCTYPE html>
+    }
+    
+    /**
+     * Store message-ID in cache
+     */
+    private function storeMessageId($messageId) {
+        try {
+            $db = new SQLite3($this->replayCache);
+            
+            $stmt = $db->prepare('INSERT OR IGNORE INTO message_cache (message_id, timestamp) VALUES (:id, :ts)');
+            $stmt->bindValue(':id', $messageId, SQLITE3_TEXT);
+            $stmt->bindValue(':ts', time(), SQLITE3_INTEGER);
+            $stmt->execute();
+            
+            $db->close();
+        } catch (Exception $e) {
+            // Fail silently
+        }
+    }
+    
+    /**
+     * Build message with proper headers
+     */
+    private function buildMessage($data) {
+        $headers = "Content-Type: text/plain; charset=utf-8\n";
+        $headers .= "Content-Transfer-Encoding: 8bit\n";
+        $headers .= "MIME-Version: 1.0\n";
+        
+        if (!empty($data['references'])) {
+            $headers .= "References: {$data['references']}\n";
+        }
+        
+        $message = $headers . "From: {$data['from']}\n";
+        
+        if (!empty($data['reply_to'])) {
+            $message .= "Reply-To: {$data['reply_to']}\n";
+        }
+        
+        $message .= "To: {$data['to']}\n";
+        $message .= "Subject: {$data['subject']}\n";
+        
+        if (!empty($data['newsgroups'])) {
+            $message .= "Newsgroups: {$data['newsgroups']}\n";
+        }
+        
+        $message .= "\n{$data['data']}";
+        
+        return $message;
+    }
+    
+    /**
+     * Apply adaptive padding to prevent size correlation
+     */
+    private function applyAdaptivePadding($message) {
+        $currentSize = strlen($message);
+        
+        // Find next padding size
+        $targetSize = $currentSize;
+        foreach ($this->paddingSizes as $size) {
+            if ($size >= $currentSize) {
+                $targetSize = $size;
+                break;
+            }
+        }
+        
+        // If message is larger than max padding size, round up to next 32KB
+        if ($currentSize >= max($this->paddingSizes)) {
+            $targetSize = ceil($currentSize / 32768) * 32768;
+        }
+        
+        // Generate random padding
+        $paddingSize = $targetSize - $currentSize;
+        if ($paddingSize > 0) {
+            // Use printable random characters for padding
+            $padding = "\n\n--- Padding ---\n";
+            $padding .= base64_encode(random_bytes($paddingSize - strlen($padding)));
+            $message .= $padding;
+        }
+        
+        return $message;
+    }
+    
+    /**
+     * Create secure temporary file
+     */
+    private function createSecureMessageFile($content) {
+        // Generate cryptographically secure random filename
+        $filename = bin2hex(random_bytes(32)) . '.tmp';
+        $filepath = $this->secureDir . '/' . $filename;
+        
+        // Write with exclusive lock and restrictive permissions
+        $fp = fopen($filepath, 'w');
+        if (!$fp) {
+            return false;
+        }
+        
+        flock($fp, LOCK_EX);
+        fwrite($fp, $content);
+        flock($fp, LOCK_UN);
+        fclose($fp);
+        
+        // Set restrictive permissions
+        chmod($filepath, 0600);
+        
+        return $filepath;
+    }
+    
+    /**
+     * Random delay to prevent timing attacks
+     */
+    private function randomDelay() {
+        $delay = random_int($this->minDelay, $this->maxDelay);
+        sleep($delay);
+    }
+    
+    /**
+     * Secure file deletion (DoD 5220.22-M standard)
+     */
+    private function secureDeleteFile($filepath) {
+        if (!file_exists($filepath)) {
+            return;
+        }
+        
+        $filesize = filesize($filepath);
+        
+        // Overwrite with random data 3 times
+        for ($i = 0; $i < 3; $i++) {
+            $fp = fopen($filepath, 'w');
+            if ($fp) {
+                fwrite($fp, random_bytes($filesize));
+                fclose($fp);
+            }
+        }
+        
+        // Overwrite with zeros
+        $fp = fopen($filepath, 'w');
+        if ($fp) {
+            fwrite($fp, str_repeat("\0", $filesize));
+            fclose($fp);
+        }
+        
+        // Finally delete
+        unlink($filepath);
+    }
+    
+    /**
+     * Render success response (minimal info)
+     */
+    public function renderSuccess() {
+        return "<!DOCTYPE html>
         <html lang='en'>
         <head>
             <meta charset='UTF-8'>
             <meta name='viewport' content='width=device-width, initial-scale=1.0'>
-            <title>Form Error - YAMN Web Interface</title>
+            <title>Message Queued</title>
             <link rel='stylesheet' href='styles.css'>
         </head>
         <body>
-            <div class='error-message'>
-                <h2>Form Errors</h2>
-                <ul>";
+            <div class='success-message'>
+                <h2>Message queued successfully</h2>
+                <p>Your message has been added to the anonymous sending queue.</p>
+                <a href='index.php' class='button'>Return</a>
+            </div>
+        </body>
+        </html>";
+    }
+    
+    /**
+     * Render error response (minimal info)
+     */
+    public function renderError($errors) {
+        $errorList = '';
         foreach ($errors as $error) {
-            echo "<li>" . htmlspecialchars($error) . "</li>";
+            $errorList .= "<li>" . htmlspecialchars($error) . "</li>";
         }
-        echo "</ul>
-                <a href='javascript:history.back()' class='button'>Back to Form</a>
+        
+        return "<!DOCTYPE html>
+        <html lang='en'>
+        <head>
+            <meta charset='UTF-8'>
+            <meta name='viewport' content='width=device-width, initial-scale=1.0'>
+            <title>Error</title>
+            <link rel='stylesheet' href='styles.css'>
+        </head>
+        <body>
+            <div class='error-message'>
+                <h2>Unable to process request</h2>
+                <ul>$errorList</ul>
+                <a href='javascript:history.back()' class='button'>Back</a>
             </div>
         </body>
         </html>";
     }
-} else {
-    // If not a POST request, redirect to home
+}
+
+// Main execution
+if ($_SERVER['REQUEST_METHOD'] !== 'POST') {
     header("Location: index.php");
     exit;
 }
+
+try {
+    $sender = new SecureYamnSender();
+    $result = $sender->sendEmail($_POST);
+    
+    if ($result['success']) {
+        echo $sender->renderSuccess();
+    } else {
+        echo $sender->renderError($result['errors']);
+    }
+    
+} catch (Exception $e) {
+    // Generic error - no details leaked
+    echo (new SecureYamnSender())->renderError(['An error occurred. Please try again.']);
+}
 ?>