fix(security): Phase 1 P0 hardening from cross-project audit

Close open uploads, image-proxy SSRF, fail-open AI quotas in production,
auth gaps on app routes, and MCP tenant isolation issues.

Co-authored-by: Cursor <cursoragent@cursor.com>

memento-note/app/api/ai/suggest-charts/route.ts

@@ -4,7 +4,7 @@ import { willUseByokForLane } from '@/lib/ai/provider-for-user'
 import { getSystemConfig } from '@/lib/config'
 import { prisma } from '@/lib/prisma'
 import { auth } from '@/auth'
-import { reserveUsageOrThrow, QuotaExceededError } from '@/lib/entitlements'
+import { reserveUsageOrThrow, QuotaExceededError, QuotaServiceUnavailableError } from '@/lib/entitlements'
 import { hasUserAiConsent } from '@/lib/consent/server-consent'
 
 export const maxDuration = 30
@@ -63,6 +63,9 @@ export async function POST(req: Request) {
     if (err instanceof QuotaExceededError) {
       return Response.json(err.toJSON(), { status: 402 })
     }
+    if (err instanceof QuotaServiceUnavailableError || process.env.NODE_ENV === 'production') {
+      return Response.json({ error: 'QUOTA_SERVICE_UNAVAILABLE' }, { status: 503 })
+    }
     console.error('[suggest-charts] Quota check error (fail-open):', err)
   }
 

memento-note/app/api/ai/tags/route.ts

@@ -4,7 +4,7 @@ import { contextualAutoTagService } from '@/lib/ai/services/contextual-auto-tag.
 import { runLaneWithBillingUser, willUseByokForLane } from '@/lib/ai/provider-for-user';
 import { getSystemConfig } from '@/lib/config';
 import { z } from 'zod';
-import { checkEntitlementOrThrow, QuotaExceededError } from '@/lib/entitlements';
+import { checkEntitlementOrThrow, QuotaExceededError, QuotaServiceUnavailableError } from '@/lib/entitlements';
 import { hasUserAiConsent } from '@/lib/consent/server-consent';
 
 import { getAISettings } from '@/app/actions/ai-settings';
@@ -42,6 +42,12 @@ export async function POST(req: NextRequest) {
       if (err instanceof QuotaExceededError) {
         return NextResponse.json(err.toJSON(), { status: 402 });
       }
+      if (err instanceof QuotaServiceUnavailableError || process.env.NODE_ENV === 'production') {
+        return NextResponse.json(
+          { error: 'QUOTA_SERVICE_UNAVAILABLE' },
+          { status: 503 },
+        );
+      }
       console.error('[/api/ai/tags] Quota check error (fail-open):', err);
     }
     const body = await req.json();

memento-note/app/api/ai/title-suggestions/route.ts

@@ -3,7 +3,7 @@ import { runLaneWithBillingUser, willUseByokForLane } from '@/lib/ai/provider-fo
 import { getSystemConfig } from '@/lib/config'
 import { auth } from '@/auth'
 import { getAISettings } from '@/app/actions/ai-settings'
-import { reserveUsageOrThrow, QuotaExceededError } from '@/lib/entitlements'
+import { reserveUsageOrThrow, QuotaExceededError, QuotaServiceUnavailableError } from '@/lib/entitlements'
 import { z } from 'zod'
 import { hasUserAiConsent } from '@/lib/consent/server-consent'
 
@@ -68,6 +68,9 @@ export async function POST(req: NextRequest) {
         if (err instanceof QuotaExceededError) {
           return NextResponse.json(err.toJSON(), { status: 402 })
         }
+        if (err instanceof QuotaServiceUnavailableError || process.env.NODE_ENV === 'production') {
+          return NextResponse.json({ error: 'QUOTA_SERVICE_UNAVAILABLE' }, { status: 503 })
+        }
         console.error('[/api/ai/title-suggestions] Quota check error (fail-open):', err)
       }
     }

memento-note/app/api/chat/route.ts

@@ -9,7 +9,7 @@ import { auth } from '@/auth'
 import { hasUserAiConsent } from '@/lib/consent/server-consent'
 import { loadTranslations, getTranslationValue, SupportedLanguage } from '@/lib/i18n'
 import { toolRegistry } from '@/lib/ai/tools'
-import { reserveUsageOrThrow, QuotaExceededError } from '@/lib/entitlements'
+import { reserveUsageOrThrow, QuotaExceededError, QuotaServiceUnavailableError } from '@/lib/entitlements'
 import { ByokUnavailableError } from '@/lib/byok'
 import { trackFeatureUsage } from '@/lib/usage-tracker'
 import { readFile } from 'fs/promises'
@@ -78,7 +78,15 @@ export async function POST(req: Request) {
         { status: 503 }
       )
     }
-    console.error('[chat] Quota check error (fail-open):', err)
+    if (err instanceof QuotaServiceUnavailableError) {
+      return Response.json({ error: err.code }, { status: 503 })
+    }
+    if (process.env.NODE_ENV !== 'production') {
+      console.error('[chat] Quota check error (fail-open):', err)
+    } else {
+      console.error('[chat] Quota check error:', err)
+      return Response.json({ error: 'QUOTA_SERVICE_UNAVAILABLE' }, { status: 503 })
+    }
   }
 
   // 2. Parse request body

memento-note/app/api/image-proxy/route.ts

@@ -1,6 +1,13 @@
 import { NextRequest, NextResponse } from 'next/server'
+import { auth } from '@/auth'
+import { isBlockedFetchHost } from '@/lib/ssrf-guard'
 
 export async function GET(req: NextRequest) {
+  const session = await auth()
+  if (!session?.user?.id) {
+    return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })
+  }
+
   const url = req.nextUrl.searchParams.get('url')
   if (!url) return NextResponse.json({ error: 'Missing url' }, { status: 400 })
 
@@ -9,6 +16,9 @@ export async function GET(req: NextRequest) {
     if (!['http:', 'https:'].includes(parsed.protocol)) {
       return NextResponse.json({ error: 'Invalid protocol' }, { status: 400 })
     }
+    if (isBlockedFetchHost(parsed.hostname)) {
+      return NextResponse.json({ error: 'Host not allowed' }, { status: 403 })
+    }
 
     const controller = new AbortController()
     const timeout = setTimeout(() => controller.abort(), 5000)

memento-note/app/api/uploads/[...path]/route.ts

@@ -2,6 +2,7 @@ import { NextRequest, NextResponse } from 'next/server'
 import { readFile, stat } from 'fs/promises'
 import path from 'path'
 import { auth } from '@/auth'
+import { canAccessUploadedNoteImage } from '@/lib/upload-access'
 
 const UPLOAD_DIR = path.join(process.cwd(), 'data', 'uploads')
 
@@ -17,6 +18,7 @@ export async function GET(
   _req: NextRequest,
   { params }: { params: Promise<{ path: string[] }> }
 ) {
+  const session = await auth()
   const { path: segments } = await params
 
   // Only serve from uploads/notes/ subdirectory
@@ -25,6 +27,13 @@ export async function GET(
   }
 
   const filename = segments[segments.length - 1]
+  const allowed = await canAccessUploadedNoteImage(filename, session?.user?.id)
+  if (!allowed) {
+    return new NextResponse(session?.user?.id ? 'Forbidden' : 'Unauthorized', {
+      status: session?.user?.id ? 403 : 401,
+    })
+  }
+
   const ext = path.extname(filename).toLowerCase()
   const contentType = MIME_MAP[ext]
   if (!contentType) {