security: configurable CORS origins, limit sentinel response body

- Add CORS_ALLOWED_ORIGINS config (comma-separated origins, default allow-all)
- CORS middleware now validates Origin header against allowlist
- Add io.LimitReader to sentinel.go (was unbounded, now 256KB)
- Include previous: agent chat auth middleware + frontend token header

agent/sentinel.go

@@ -115,7 +115,7 @@ func (s *Sentinel) check(symbol string) {
 	resp, err := s.http.Get(fmt.Sprintf("https://fapi.binance.com/fapi/v1/ticker/24hr?symbol=%s", symbol))
 	if err != nil { return }
 	defer resp.Body.Close()
-	body, err := io.ReadAll(resp.Body)
+	body, err := io.ReadAll(io.LimitReader(resp.Body, 256*1024)) // 256KB limit
 	if err != nil { return }
 	var t map[string]interface{}
 	if err := json.Unmarshal(body, &t); err != nil { return }

agent/stock.go

@@ -133,7 +133,7 @@ func searchStock(keyword string) ([]SearchResult, error) {
 	}
 	defer resp.Body.Close()
 
-	reader := transform.NewReader(resp.Body, simplifiedchinese.GBK.NewDecoder())
+	reader := transform.NewReader(io.LimitReader(resp.Body, 256*1024), simplifiedchinese.GBK.NewDecoder())
 	body, err := io.ReadAll(reader)
 	if err != nil {
 		return nil, err

api/agent_routes.go

@@ -7,8 +7,11 @@ import (
 )
 
 // RegisterAgentHandler registers NOFXi agent API routes on the main router.
+// Chat endpoint requires authentication; market data endpoints are public.
 func (s *Server) RegisterAgentHandler(h *agent.WebHandler) {
-	s.router.POST("/api/agent/chat", gin.WrapF(h.HandleChat))
+	// Chat requires auth — can trigger trades and access account data
+	s.router.POST("/api/agent/chat", s.authMiddleware(), gin.WrapF(h.HandleChat))
+	// Public endpoints — read-only market data
 	s.router.GET("/api/agent/health", gin.WrapF(h.HandleHealth))
 	s.router.GET("/api/agent/klines", gin.WrapF(h.HandleKlines))
 	s.router.GET("/api/agent/ticker", gin.WrapF(h.HandleTicker))

api/server.go

@@ -6,6 +6,7 @@ import (
 	"net"
 	"net/http"
 	"nofx/auth"
+	"nofx/config"
 	"nofx/crypto"
 	"nofx/logger"
 	"nofx/manager"
@@ -56,12 +57,44 @@ func NewServer(traderManager *manager.TraderManager, st *store.Store, cryptoServ
 	return s
 }
 
-// corsMiddleware CORS middleware
+// corsMiddleware CORS middleware with configurable allowed origins.
+// Set CORS_ALLOWED_ORIGINS env var to a comma-separated list of origins
+// (e.g. "http://localhost:5173,https://nofx.example.com").
+// If empty or "*", all origins are allowed (development mode).
 func corsMiddleware() gin.HandlerFunc {
+	cfg := config.Get()
+	raw := strings.TrimSpace(cfg.CORSAllowedOrigins)
+
+	// Build allowed origins set
+	allowAll := raw == "" || raw == "*"
+	var allowed map[string]bool
+	if !allowAll {
+		allowed = make(map[string]bool)
+		for _, o := range strings.Split(raw, ",") {
+			o = strings.TrimSpace(o)
+			if o != "" {
+				allowed[o] = true
+			}
+		}
+		if len(allowed) == 0 {
+			allowAll = true
+		}
+	}
+
 	return func(c *gin.Context) {
-		c.Writer.Header().Set("Access-Control-Allow-Origin", "*")
+		origin := c.Request.Header.Get("Origin")
+		if allowAll {
+			c.Writer.Header().Set("Access-Control-Allow-Origin", "*")
+		} else if origin != "" && allowed[origin] {
+			c.Writer.Header().Set("Access-Control-Allow-Origin", origin)
+			c.Writer.Header().Set("Vary", "Origin")
+		} else if origin != "" {
+			// Origin not in allow list — reject preflight, allow simple requests
+			// but without CORS headers the browser will block the response.
+		}
 		c.Writer.Header().Set("Access-Control-Allow-Methods", "GET, POST, PUT, DELETE, OPTIONS")
 		c.Writer.Header().Set("Access-Control-Allow-Headers", "Content-Type, Authorization")
+		c.Writer.Header().Set("Access-Control-Allow-Credentials", "true")
 
 		if c.Request.Method == "OPTIONS" {
 			c.AbortWithStatus(http.StatusOK)

config/config.go

@@ -38,6 +38,11 @@ type Config struct {
 	// Set EXPERIENCE_IMPROVEMENT=false to disable
 	ExperienceImprovement bool
 
+	// CORS configuration
+	// Comma-separated list of allowed origins. Empty or "*" means allow all.
+	// Example: "http://localhost:5173,https://nofx.example.com"
+	CORSAllowedOrigins string
+
 	// Market data provider API keys
 	AlpacaAPIKey    string // Alpaca API key for US stocks
 	AlpacaSecretKey string // Alpaca secret key
@@ -86,6 +91,9 @@ func Init() {
 		cfg.ExperienceImprovement = strings.ToLower(v) != "false"
 	}
 
+	// CORS allowed origins (comma-separated, empty = allow all)
+	cfg.CORSAllowedOrigins = os.Getenv("CORS_ALLOWED_ORIGINS")
+
 	// Market data provider API keys
 	cfg.AlpacaAPIKey = os.Getenv("ALPACA_API_KEY")
 	cfg.AlpacaSecretKey = os.Getenv("ALPACA_SECRET_KEY")

nofxi-tasks.md

@@ -0,0 +1,32 @@
+# NOFXi Self-Drive Tasks
+
+## Completed
+
+### 2026-03-23 09:37 — Security Hardening Batch
+- [DONE] Fix health endpoint returning `"time": null` → now returns proper RFC3339 timestamp
+- [DONE] Add login rate limiting (5 attempts / 15min, 5min block) to prevent brute-force
+- [DONE] Move `/api/reset-password` behind auth middleware (was unauthenticated — critical vuln)
+- [DONE] Add response body size limits on proxy/external API calls (prevent memory exhaustion)
+- [DONE] Sanitize error messages in agent chat endpoint (was leaking internal error details)
+- [DONE] Record login success/failure for rate limiter tracking
+- [DONE] Sanitize markdown link URLs in frontend (prevent javascript: XSS)
+
+## Pending
+
+### Security
+- [PENDING] Investigate GitHub Dependabot's 21 reported vulnerabilities (13 high, 7 moderate, 1 low)
+- [PENDING] Add CSRF protection or tighten CORS from wildcard `*` to specific origins
+- [PENDING] Agent chat endpoint (`/api/agent/chat`) is not behind auth middleware — should require authentication
+
+### Code Quality
+- [PENDING] The `resolveStockCodeDynamic` function at line 210 of `agent/stock.go` also has unlimited io.ReadAll (line 136)
+- [PENDING] `context.Background()` used in ~30+ exchange trader calls — should propagate request context for proper cancellation
+- [PENDING] `AgentChatPage.tsx` is 1001 lines — could be split into smaller components
+
+### Performance
+- [PENDING] `gatherContext` in agent.go iterates all traders and positions on every message — consider caching
+- [PENDING] News scan `seen` map grows unbounded, only reset at 1000 entries — use TTL-based expiry
+
+### Features
+- [PENDING] Agent chat has fake streaming (word-by-word setTimeout) — implement real SSE streaming
+- [PENDING] Add WebSocket support for real-time position/balance updates instead of polling

web/src/pages/AgentChatPage.tsx

@@ -15,6 +15,7 @@ import {
   Search,
 } from 'lucide-react'
 import { useLanguage } from '../contexts/LanguageContext'
+import { useAuth } from '../contexts/AuthContext'
 import { MarketTicker } from '../components/agent/MarketTicker'
 import { PositionsPanel } from '../components/agent/PositionsPanel'
 import { TraderStatusPanel } from '../components/agent/TraderStatusPanel'
@@ -227,6 +228,7 @@ interface SuggestionCard {
 
 export function AgentChatPage() {
   const { language } = useLanguage()
+  const { token } = useAuth()
   const [sidebarOpen, setSidebarOpen] = useState(() => window.innerWidth > 1024)
   const [messages, setMessages] = useState<Message[]>([])
   const [input, setInput] = useState('')
@@ -315,8 +317,11 @@ export function AgentChatPage() {
     try {
       const res = await fetch('/api/agent/chat', {
         method: 'POST',
-        headers: { 'Content-Type': 'application/json' },
-        body: JSON.stringify({ message: msg, user_id: 1, lang: language }),
+        headers: {
+          'Content-Type': 'application/json',
+          ...(token ? { Authorization: `Bearer ${token}` } : {}),
+        },
+        body: JSON.stringify({ message: msg, lang: language }),
       })
       const data = await res.json()
       const responseText = data.response || data.error || 'No response'