Default empty API_KEYS makes Docker deployment an open relay for configured auth tokens

[chenshj73]

Hi, thanks for maintaining this proxy. I noticed a default-deployment safety issue in the current main branch (a1c10357098f): proxy auth is disabled when API_KEYS is empty, while the default listen address and Docker example can expose the service.

Relevant code/docs:

server.go

57 func (s *Server) withMiddleware(next http.Handler) http.Handler {
58     return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
59         if len(s.cfg.APIKeys) > 0 && !s.authorized(r) {
60             if isClaudeRequestPath(r.URL.Path) {
61                 writeClaudeError(w, http.StatusUnauthorized, "invalid proxy api key", "authentication_error")
62             } else {
63                 writeOpenAIError(w, http.StatusUnauthorized, "invalid proxy api key", "authentication_error", "")
64             }
65             return
66         }
67         next.ServeHTTP(w, r)
68     })
69 }

Line 59 only performs client authentication when APIKeys is non-empty. Line 67 forwards the request when the list is empty.

71 func (s *Server) authorized(r *http.Request) bool {
72     if apiKey := strings.TrimSpace(r.Header.Get("x-api-key")); apiKey != "" {
73         if containsString(s.cfg.APIKeys, apiKey) {
74             return true
75         }
76     }
78     authorization := strings.TrimSpace(r.Header.Get("Authorization"))
...
87     return containsString(s.cfg.APIKeys, apiKey)
88 }

Lines 71-88 implement client-key validation, but that validation is bypassed by the empty-API_KEYS default above.

94 func (s *Server) handleHealthz(w http.ResponseWriter, r *http.Request) {
...
100     response := map[string]any{
101         "ok":          true,
102         "started_at":  s.started.UTC(),
103         "uptime_sec":  int(time.Since(s.started).Seconds()),
104         "token_state": s.runs.Snapshots(),
105     }

Lines 100-104 expose operational token-pool state through /healthz under the same auth boundary.

config.go

105 func loadRawConfig(configPath string) (rawConfig, error) {
106     cfg := rawConfig{
107         ListenAddr:       ":8080",
108         UpstreamBaseURL:  "https://www.codebuff.com",
109         RotationInterval: "6h",
110         RequestTimeout:   "15m",
111     }

Line 107 defaults the proxy to listen on :8080, not loopback-only.

README.md

77 | `LISTEN_ADDR` | Proxy listen address (default `:8080`) |
79 | `AUTH_TOKENS` | Freebuff auth tokens (JSON array or comma-separated env var) |
82 | `API_KEYS` | Client API keys for proxy auth (empty = open access) |

The docs explicitly state that empty API_KEYS means open access.

94 docker run -d --name Freebuff2API \
95   -p 8080:8080 \
96   -e AUTH_TOKENS="token1,token2" \
97   ghcr.io/quorinex/freebuff2api:latest

The Docker example publishes the service and configures upstream auth tokens, but does not configure client API_KEYS.

Why this matters:

The proxy holds Freebuff AUTH_TOKENS and turns them into OpenAI-compatible and Anthropic-compatible endpoints. A user following the Docker example on a VPS, NAS, or cloud machine may accidentally expose an unauthenticated relay. Anyone who can reach the port can consume the configured upstream tokens/accounts, increasing waiting-room pressure, quota/rate-limit exhaustion, and account-ban risk.

Suggested direction:

• Require API_KEYS by default when LISTEN_ADDR is not loopback, or fail startup unless an explicit ALLOW_OPEN_ACCESS=true or --allow-open-access is set.
• Update the Docker example to include API_KEYS.
• Print a prominent startup warning when auth is disabled and the listen address is public.