fix(netpolicy): normalize allowlist CIDR inputs

docs/configuration.md

@@ -62,7 +62,7 @@ When `gateway.host` is a loopback address (`127.0.0.1`, `::1`, or `localhost`) a
 CIDR sources in fallback mode:
 
 - If `gateway.allowed_cidrs` is configured, that list is used.
-- If `gateway.allowed_cidrs` is empty, discovered private CIDRs are used (`10.0.0.0/8`, `172.16.0.0/12`, `192.168.0.0/16`, `100.64.0.0/10`, `fc00::/7`).
+- If `gateway.allowed_cidrs` is empty, PicoClaw discovers CIDR networks from local interfaces and uses only those that fall within private address ranges (for example, within `10.0.0.0/8`, `172.16.0.0/12`, `192.168.0.0/16`, `100.64.0.0/10`, `fc00::/7`).
 - If no private non-loopback CIDR can be discovered, gateway startup fails. On public-only hosts, configure `gateway.allowed_cidrs` explicitly.
 
 Loopback clients are always allowed for local administration.

pkg/netpolicy/allowlist.go

@@ -19,15 +19,31 @@ func NewIPAllowlist(allowedCIDRs []string) (*IPAllowlist, error) {
 		return &IPAllowlist{}, nil
 	}
 
+	seen := make(map[string]struct{}, len(allowedCIDRs))
 	nets := make([]*net.IPNet, 0, len(allowedCIDRs))
-	for _, cidr := range allowedCIDRs {
+	for _, rawCIDR := range allowedCIDRs {
+		cidr := strings.TrimSpace(rawCIDR)
+		if cidr == "" {
+			continue
+		}
+
 		_, ipNet, err := net.ParseCIDR(cidr)
 		if err != nil {
 			return nil, fmt.Errorf("invalid CIDR %q: %w", cidr, err)
 		}
+
+		canonical := ipNet.String()
+		if _, ok := seen[canonical]; ok {
+			continue
+		}
+		seen[canonical] = struct{}{}
 		nets = append(nets, ipNet)
 	}
 
+	if len(nets) == 0 {
+		return &IPAllowlist{}, nil
+	}
+
 	return &IPAllowlist{nets: nets}, nil
 }
 

pkg/netpolicy/allowlist_test.go

@@ -69,3 +69,42 @@ func TestIPAllowlistWithZoneAddressInCIDR(t *testing.T) {
 		t.Fatal("allowlist should accept IPv6 link-local with zone")
 	}
 }
+
+func TestNewIPAllowlistTrimsSkipsAndDedups(t *testing.T) {
+	allowlist, err := NewIPAllowlist([]string{
+		" 192.168.1.8/24 ",
+		"",
+		"192.168.1.0/24",
+		"   ",
+		"10.0.0.0/8",
+	})
+	if err != nil {
+		t.Fatalf("NewIPAllowlist() error = %v", err)
+	}
+	if allowlist.IsOpen() {
+		t.Fatal("allowlist should not be open")
+	}
+	if len(allowlist.nets) != 2 {
+		t.Fatalf("len(allowlist.nets) = %d, want 2", len(allowlist.nets))
+	}
+
+	if !allowlist.AllowsRemoteAddr("192.168.1.22:1234") {
+		t.Fatal("allowlist should allow deduplicated 192.168.1.0/24 CIDR")
+	}
+	if !allowlist.AllowsRemoteAddr("10.9.8.7:1234") {
+		t.Fatal("allowlist should allow 10.0.0.0/8 CIDR")
+	}
+	if allowlist.AllowsRemoteAddr("203.0.113.7:1234") {
+		t.Fatal("allowlist should reject outside CIDR")
+	}
+}
+
+func TestNewIPAllowlistAllEmptyEntries(t *testing.T) {
+	allowlist, err := NewIPAllowlist([]string{"", "   ", "\t"})
+	if err != nil {
+		t.Fatalf("NewIPAllowlist() error = %v", err)
+	}
+	if !allowlist.IsOpen() {
+		t.Fatal("allowlist should be open when all entries are empty")
+	}
+}