fix: harden proxy auth and SSRF defenses

app/api/auth/session/route.ts

@@ -4,6 +4,11 @@ import { logger } from '@/lib/logger';
 import { encryptSession, decryptSession } from '@/lib/auth/crypto';
 import { SESSION_COOKIE_MAX_AGE, sessionCookieName } from '@/lib/auth/session-cookie';
 import { getCookieOptions } from '@/lib/oauth/cookie-config';
+import { JmapAuthVerificationError, verifyJmapAuth } from '@/lib/auth/verify-jmap-auth';
+import {
+  clearStalwartAuthContextInStore,
+  setStalwartAuthContextInStore,
+} from '@/lib/stalwart/auth-context';
 
 const COOKIE_OPTIONS = {
   ...getCookieOptions(),
@@ -31,12 +36,23 @@ export async function POST(request: NextRequest) {
 
     const slot = typeof bodySlot === 'number' && bodySlot >= 0 && bodySlot <= 4 ? bodySlot : getSlot(request);
     const cookieName = sessionCookieName(slot);
-    const token = encryptSession(serverUrl, username, password);
+    const authHeader = `Basic ${Buffer.from(`${username}:${password}`).toString('base64')}`;
+    const normalizedServerUrl = await verifyJmapAuth(serverUrl, authHeader);
+    const token = encryptSession(normalizedServerUrl, username, password);
     const cookieStore = await cookies();
     cookieStore.set(cookieName, token, COOKIE_OPTIONS);
+    setStalwartAuthContextInStore(cookieStore, slot, {
+      serverUrl: normalizedServerUrl,
+      username,
+      authHeader,
+    });
 
     return NextResponse.json({ ok: true });
   } catch (error) {
+    if (error instanceof JmapAuthVerificationError) {
+      return NextResponse.json({ error: error.message }, { status: error.status });
+    }
+
     logger.error('Session store error', { error: error instanceof Error ? error.message : 'Unknown error' });
     return NextResponse.json({ error: 'Internal server error' }, { status: 500 });
   }
@@ -56,9 +72,16 @@ export async function GET(request: NextRequest) {
     const credentials = decryptSession(token);
     if (!credentials) {
       cookieStore.delete(cookieName);
+      clearStalwartAuthContextInStore(cookieStore, slot);
       return NextResponse.json({ error: 'Invalid session' }, { status: 401 });
     }
 
+    setStalwartAuthContextInStore(cookieStore, slot, {
+      serverUrl: credentials.serverUrl,
+      username: credentials.username,
+      authHeader: `Basic ${Buffer.from(`${credentials.username}:${credentials.password}`).toString('base64')}`,
+    });
+
     // Only return non-sensitive fields. Use PUT to retrieve full credentials.
     const { serverUrl, username } = credentials;
     return NextResponse.json(
@@ -99,9 +122,16 @@ export async function PUT(request: NextRequest) {
     const credentials = decryptSession(token);
     if (!credentials) {
       cookieStore.delete(cookieName);
+      clearStalwartAuthContextInStore(cookieStore, slot);
       return NextResponse.json({ error: 'Invalid session' }, { status: 401 });
     }
 
+    setStalwartAuthContextInStore(cookieStore, slot, {
+      serverUrl: credentials.serverUrl,
+      username: credentials.username,
+      authHeader: `Basic ${Buffer.from(`${credentials.username}:${credentials.password}`).toString('base64')}`,
+    });
+
     return NextResponse.json(credentials, {
       headers: { 'Cache-Control': 'no-store, no-cache, must-revalidate' },
     });
@@ -120,10 +150,12 @@ export async function DELETE(request: NextRequest) {
       // Delete all session cookies (slots 0-4)
       for (let i = 0; i <= 4; i++) {
         cookieStore.delete(sessionCookieName(i));
+        clearStalwartAuthContextInStore(cookieStore, i);
       }
     } else {
       const slot = getSlot(request);
       cookieStore.delete(sessionCookieName(slot));
+      clearStalwartAuthContextInStore(cookieStore, slot);
     }
 
     return NextResponse.json({ ok: true });

app/api/auth/stalwart-context/route.ts

@@ -0,0 +1,46 @@
+import { NextRequest, NextResponse } from 'next/server';
+import { logger } from '@/lib/logger';
+import { JmapAuthVerificationError, verifyJmapAuth } from '@/lib/auth/verify-jmap-auth';
+import { setStalwartAuthContext } from '@/lib/stalwart/auth-context';
+
+function getSlot(request: NextRequest, bodySlot: unknown): number {
+  if (typeof bodySlot === 'number' && bodySlot >= 0 && bodySlot <= 4) {
+    return bodySlot;
+  }
+
+  const raw = request.nextUrl.searchParams.get('slot');
+  if (raw === null) return 0;
+
+  const slot = parseInt(raw, 10);
+  return Number.isNaN(slot) || slot < 0 || slot > 4 ? 0 : slot;
+}
+
+export async function POST(request: NextRequest) {
+  try {
+    const { serverUrl, username, authHeader, slot: bodySlot } = await request.json();
+
+    if (!serverUrl || !username || !authHeader) {
+      return NextResponse.json({ error: 'Missing required fields' }, { status: 400 });
+    }
+
+    const slot = getSlot(request, bodySlot);
+    const normalizedServerUrl = await verifyJmapAuth(serverUrl, authHeader);
+
+    await setStalwartAuthContext(slot, {
+      serverUrl: normalizedServerUrl,
+      username,
+      authHeader,
+    });
+
+    return NextResponse.json({ ok: true });
+  } catch (error) {
+    if (error instanceof JmapAuthVerificationError) {
+      return NextResponse.json({ error: error.message }, { status: error.status });
+    }
+
+    logger.error('Failed to store Stalwart auth context', {
+      error: error instanceof Error ? error.message : 'Unknown error',
+    });
+    return NextResponse.json({ error: 'Internal server error' }, { status: 500 });
+  }
+}