feat: M3 cluster page (LB groups + health check status) e2e-verified failover; M6 cache API + version path hardening + frontend cluster methods

internal/cluster/registry.go

@@ -233,8 +233,27 @@ func fetchFromURL(ctx context.Context, version string) ([]byte, error) {
 
 // EnsureVersion makes sure a given frpc version is cached locally. It follows
 // the distribution priority: local cache -> cluster peers -> external URL.
+// pathSafeVersion normalizes a requested version and rejects anything that
+// could escape the cache dir (e.g. "../../x").
+func pathSafeVersion(version string) (string, bool) {
+	v := strings.TrimPrefix(version, "v")
+	if v == "" || strings.ContainsAny(v, "/\\") || strings.Contains(v, "..") {
+		return "", false
+	}
+	for _, c := range v {
+		if (c < '0' || c > '9') && (c < 'a' || c > 'z') && (c < 'A' || c > 'Z') && c != '.' && c != '-' && c != '_' {
+			return "", false
+		}
+	}
+	return v, true
+}
+
 func (r *Registry) EnsureVersion(ctx context.Context, version string) (string, error) {
-	version = strings.TrimPrefix(version, "v")
+	safe, ok := pathSafeVersion(version)
+	if !ok {
+		return "", fmt.Errorf("invalid version %q", version)
+	}
+	version = safe
 	if r.HasVersion(version) {
 		return r.BinaryPath(version), nil
 	}
@@ -403,3 +422,47 @@ func (r *Registry) SyncFromPeers(ctx context.Context) error {
 func (r *Registry) SelfInfo() NodeInfo {
 	return NodeInfo{Addr: "self", Version: "", Cache: r.CachedVersions()}
 }
+
+// CacheEntry describes one locally cached frpc version (for UI + prune).
+type CacheEntry struct {
+	Version string `json:"version"`
+	Path    string `json:"path"`
+	Size    int64  `json:"size"`
+	ModTime int64  `json:"modTime"`
+}
+
+// CacheInfo lists all locally cached frpc versions with metadata.
+func (r *Registry) CacheInfo() []CacheEntry {
+	entries, err := os.ReadDir(r.BinDir)
+	if err != nil {
+		return nil
+	}
+	var out []CacheEntry
+	for _, e := range entries {
+		if !e.IsDir() || !strings.HasPrefix(e.Name(), "frpc-") {
+			continue
+		}
+		ver := strings.TrimPrefix(e.Name(), "frpc-")
+		bin := filepath.Join(r.BinDir, e.Name(), "frpc")
+		info, err := os.Stat(bin)
+		if err != nil {
+			continue
+		}
+		out = append(out, CacheEntry{Version: ver, Path: bin, Size: info.Size(), ModTime: info.ModTime().Unix()})
+	}
+	return out
+}
+
+// PruneCache removes all cached versions except the newest keep (LRU-ish).
+func (r *Registry) PruneCache(keep int) []string {
+	entries := r.CacheInfo()
+	sort.Slice(entries, func(i, j int) bool { return entries[i].ModTime > entries[j].ModTime })
+	var removed []string
+	for i := keep; i < len(entries); i++ {
+		dir := filepath.Join(r.BinDir, "frpc-"+entries[i].Version)
+		if err := os.RemoveAll(dir); err == nil {
+			removed = append(removed, entries[i].Version)
+		}
+	}
+	return removed
+}