From 56e296e5875b10ed053cbdedbab08957fce2a461 Mon Sep 17 00:00:00 2001
From: Gab <24553253+gabrix73@users.noreply.github.com>
Date: Sun, 16 Aug 2026 19:24:16 +0200
Subject: Harden Usenet threading and ingress delivery

---
 index.php | 52 +++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 49 insertions(+), 3 deletions(-)

(limited to 'index.php')

diff --git a/index.php b/index.php
index af646a6..bbab642 100644
--- a/index.php
+++ b/index.php
@@ -85,6 +85,43 @@ if (empty($_SESSION['csrf_token'])) {
 // Store current token for validation BEFORE any regeneration
 $currentCsrfToken = $_SESSION['csrf_token'];
 
+/**
+ * Return remailer names whose public keys are valid today.
+ *
+ * @return array<string, bool> Name lookup table.
+ */
+function getUsableRemailerKeyNames(): array {
+    static $usableNames = null;
+    if (is_array($usableNames)) {
+        return $usableNames;
+    }
+
+    $usableNames = [];
+    $keyring = yamnConfig('YAMN_PUBRING', '/opt/yamn-master/pubring.mix');
+    if (!is_readable($keyring)) {
+        return $usableNames;
+    }
+
+    $today = gmdate('Y-m-d');
+    foreach (file($keyring, FILE_IGNORE_NEW_LINES | FILE_SKIP_EMPTY_LINES) ?: [] as $line) {
+        $parts = preg_split('/\s+/', trim($line));
+        if (count($parts) !== 7) {
+            continue;
+        }
+        [$name, , , , , $validFrom, $validUntil] = $parts;
+        if (!preg_match('/^[a-z0-9_-]+$/', $name)
+            || !preg_match('/^\d{4}-\d{2}-\d{2}$/', $validFrom)
+            || !preg_match('/^\d{4}-\d{2}-\d{2}$/', $validUntil)) {
+            continue;
+        }
+        if ($validFrom <= $today && $today <= $validUntil) {
+            $usableNames[$name] = true;
+        }
+    }
+
+    return $usableNames;
+}
+
 /**
  * Parse remailers from file and return array by type
  * Entry and Exit can use ANY remailer
@@ -95,6 +132,7 @@ $currentCsrfToken = $_SESSION['csrf_token'];
  */
 function getRemailers($type) {
     $remailers = ['*']; // Always include Random option
+    $usableKeyNames = getUsableRemailerKeyNames();
 
     // Try multiple file locations
     $files = [
@@ -140,6 +178,7 @@ function getRemailers($type) {
 
             // Validate name: lowercase letters, numbers, hyphens only
             if (!preg_match('/^[a-z0-9-]+$/', $remailerName)) continue;
+            if (!isset($usableKeyNames[$remailerName])) continue;
 
             // Check if last field is 'D' (middle capability flag)
             $lastField = end($parts);
@@ -185,6 +224,9 @@ function resolveRemailer($remailer, $availableRemailers) {
         $randomIndex = array_rand($candidates);
         return $candidates[$randomIndex];
     }
+    if (!in_array($remailer, $availableRemailers, true)) {
+        throw new Exception("Selected remailer is no longer available. Reload the page and choose again.");
+    }
     return $remailer;
 }
 
@@ -246,11 +288,15 @@ if ($_SERVER['REQUEST_METHOD'] === 'POST') {
             $middleRemailer = isset($_POST['middle_remailer']) ? filter_var($_POST['middle_remailer'], FILTER_SANITIZE_STRING) : '';
             $exitRemailer = isset($_POST['exit_remailer']) ? filter_var($_POST['exit_remailer'], FILTER_SANITIZE_STRING) : '';
             $from = isset($_POST['from']) ? filter_var($_POST['from'], FILTER_SANITIZE_STRING) : '';
-            $replyTo = isset($_POST['reply_to']) ? filter_var($_POST['reply_to'], FILTER_SANITIZE_STRING) : '';
+            $replyTo = isset($_POST['reply_to']) && is_string($_POST['reply_to'])
+                ? trim($_POST['reply_to'])
+                : '';
             $to = isset($_POST['to']) ? filter_var($_POST['to'], FILTER_SANITIZE_EMAIL) : '';
             $subject = isset($_POST['subject']) ? filter_var($_POST['subject'], FILTER_SANITIZE_STRING) : '';
             $newsgroups = isset($_POST['newsgroups']) ? filter_var($_POST['newsgroups'], FILTER_SANITIZE_STRING) : '';
-            $references = isset($_POST['references']) ? filter_var($_POST['references'], FILTER_SANITIZE_STRING) : '';
+            $references = isset($_POST['references']) && is_string($_POST['references'])
+                ? trim($_POST['references'])
+                : '';
             $data = isset($_POST['data']) ? $_POST['data'] : ''; // Keep original formatting
             $copies = isset($_POST['copies']) ? intval($_POST['copies']) : 1;
 
@@ -766,7 +812,7 @@ if ($_SERVER['REQUEST_METHOD'] === 'POST') {
             <div class="form-group"><label for="to">Email recipient</label><input type="email" name="to" id="to"><small>Required for email delivery. Leave empty when publishing to a newsgroup.</small></div>
             <div class="form-group"><label for="subject">Subject <span class="required">*</span></label><input type="text" name="subject" id="subject" required></div>
             <div class="form-group"><label for="newsgroups">Newsgroup</label><input type="text" name="newsgroups" id="newsgroups" placeholder="misc.test"><small>Optional. When set, the message is routed through the configured Mail-to-News gateway. Leave empty for email.</small></div>
-            <div class="form-group"><label for="references">References</label><input type="text" name="references" id="references" placeholder="&lt;message-id@example.org&gt;"><small>Optional. Links the article to an existing thread.</small></div>
+            <div class="form-group"><label for="references">References</label><input type="text" name="references" id="references" maxlength="900" placeholder="&lt;message-id@example.org&gt;"><small>Optional. Enter one or more space-separated Message-IDs, without the <code>References:</code> label. The last ID becomes <code>In-Reply-To</code>.</small></div>
             <div class="form-group"><label for="data">Message body <span class="required">*</span></label><textarea name="data" id="data" required></textarea>
                 <small>The server creates the encrypted YAMN envelope in memory and sends only that packet through Nym. Remailer queues may take several hours.</small>
             </div>
-- 
cgit v1.2.3