From 36c02fa3e959e212fabbc38363ccf2e1041b7f0e Mon Sep 17 00:00:00 2001
From: Pauljd <pauljd720@gmail.com>
Date: Fri, 11 Sep 2026 20:47:15 +0100
Subject: [PATCH] Davidson CI testing & AI refinement

---
 lib/ticket.php | 67 ++++++++++++++++++++++++++++++++++++++------------
 1 file changed, 51 insertions(+), 16 deletions(-)

diff --git a/lib/ticket.php b/lib/ticket.php
index 3ab7dfd..7d249cc 100644
--- a/lib/ticket.php
+++ b/lib/ticket.php
@@ -22,7 +22,13 @@ function getTicketSecret(): string
 function createTicket(int $userId, string $purpose = 'default', ?int $lifetimeSeconds = null): string
 {
     $expiresAt = time() + ($lifetimeSeconds ?? TICKET_LIFETIME_SECONDS);
-    $payload = $userId . '|' . $expiresAt . '|' . $purpose;
+    // The random nonce is what makes the payload (and therefore the resulting token and
+    // its hash) unique even when two tickets are minted for the same user/purpose within
+    // the same second — otherwise identical inputs produce an identical HMAC, and a second
+    // password-reset ticket in the same second collides with the first's UNIQUE token_hash
+    // row and throws instead of just minting a second, independently usable link.
+    $nonce = bin2hex(random_bytes(16));
+    $payload = $userId . '|' . $expiresAt . '|' . $purpose . '|' . $nonce;
     $signature = hash_hmac('sha256', $payload, getTicketSecret());
 
     return base64_encode($payload . '.' . $signature);
@@ -48,8 +54,8 @@ function decodeTicket(string $ticket, string $purpose = 'default'): ?int
         return null;
     }
 
-    $parts = explode('|', $payload, 3);
-    if (count($parts) !== 3 || !ctype_digit($parts[0]) || !ctype_digit($parts[1])) {
+    $parts = explode('|', $payload, 4);
+    if (count($parts) !== 4 || !ctype_digit($parts[0]) || !ctype_digit($parts[1])) {
         return null;
     }
 
@@ -82,22 +88,51 @@ function createPasswordResetTicket(PDO $pdo, int $userId): string
 {
     ensurePasswordResetTicketsTable($pdo);
 
-    // Opportunistic cleanup: every new ticket also sweeps out rows that are long past
-    // useful (expired for over a day), so this table doesn't grow unbounded without
-    // needing a separate cron job.
-    $pdo->prepare('DELETE FROM password_reset_tickets WHERE expires_at < :cutoff')
-        ->execute(['cutoff' => time() - 86400]);
-
     $token = createTicket($userId, 'password_reset');
+    $tokenHash = hash('sha256', $token);
+    $expiresAt = time() + TICKET_LIFETIME_SECONDS;
+    $cutoff = time() - 86400;
 
-    $stmt = $pdo->prepare('INSERT INTO password_reset_tickets (token_hash, user_id, expires_at) VALUES (:token_hash, :user_id, :expires_at)');
-    $stmt->execute([
-        'token_hash' => hash('sha256', $token),
-        'user_id' => $userId,
-        'expires_at' => time() + TICKET_LIFETIME_SECONDS,
-    ]);
+    // The cleanup delete and the insert run as one transaction so they can't be split by
+    // a concurrent writer. Retried on a transient SQLITE_BUSY: two password-reset requests
+    // landing at nearly the same instant can still surface "database is locked" here even
+    // with the connection's busy_timeout, so back off briefly and retry rather than let it
+    // bubble up as an uncaught 500.
+    $maxAttempts = 3;
+    for ($attempt = 1; $attempt <= $maxAttempts; $attempt++) {
+        try {
+            $pdo->exec('BEGIN IMMEDIATE');
 
-    return $token;
+            // Opportunistic cleanup: every new ticket also sweeps out rows that are long
+            // past useful (expired for over a day), so this table doesn't grow unbounded
+            // without needing a separate cron job.
+            $pdo->prepare('DELETE FROM password_reset_tickets WHERE expires_at < :cutoff')
+                ->execute(['cutoff' => $cutoff]);
+
+            $stmt = $pdo->prepare('INSERT INTO password_reset_tickets (token_hash, user_id, expires_at) VALUES (:token_hash, :user_id, :expires_at)');
+            $stmt->execute([
+                'token_hash' => $tokenHash,
+                'user_id' => $userId,
+                'expires_at' => $expiresAt,
+            ]);
+
+            $pdo->exec('COMMIT');
+
+            return $token;
+        } catch (PDOException $e) {
+            if ($pdo->inTransaction()) {
+                $pdo->exec('ROLLBACK');
+            }
+
+            if ($attempt === $maxAttempts || !str_contains($e->getMessage(), 'database is locked')) {
+                throw $e;
+            }
+
+            usleep(50000 * $attempt);
+        }
+    }
+
+    throw new RuntimeException('Unreachable');
 }
 
 // Validates signature/purpose/expiry only. Safe to call on GET to decide page