Additional IP range validations (#1152)

* [bugfix] Ensure requests happen over TCP

It's possible for the network to be udp4 or udp6. This is rather
unlikely to occur, but since we're given the network anyway as part of
the Sanitize function getting called we might as well check for it.

* [chore] Align reserved v6 blocks to IANA registry

* [chore] Add test for ValidateIP

The net and netip packages diverge in that net.ParseIP will consider an
IPv4-mapped address to be an IPv4 address and as such it would get
caught by the IPv4Reserved list. However, netip considers it an IPv6
address, so we need to ensure the mapped range is in IPv6Reserved.

* [chore] Align reserved v4 blocks to IANA registry

This includes a number of tests for /32's explicitly called out in the
registry to ensure we always consider those invalid.

internal/httpclient/client.go

@@ -36,6 +36,9 @@ import (
 // ErrInvalidRequest is returned if a given HTTP request is invalid and cannot be performed.
 var ErrInvalidRequest = errors.New("invalid http request")
 
+// ErrInvalidNetwork is returned if the request would not be performed over TCP
+var ErrInvalidNetwork = errors.New("invalid network type")
+
 // ErrReservedAddr is returned if a dialed address resolves to an IP within a blocked or reserved net.
 var ErrReservedAddr = errors.New("dial within blocked / reserved IP range")
 

internal/httpclient/sanitizer.go

@@ -38,6 +38,10 @@ func (s *sanitizer) Sanitize(ntwrk, addr string, _ syscall.RawConn) error {
 		return err
 	}
 
+	if !(ntwrk == "tcp4" || ntwrk == "tcp6") {
+		return ErrInvalidNetwork
+	}
+
 	// Seperate the IP
 	ip := ipport.Addr()
 

internal/netutil/validate.go

@@ -24,16 +24,34 @@ import (
 
 var (
 	// IPv6Reserved contains IPv6 reserved IP prefixes.
+	// https://www.iana.org/assignments/iana-ipv6-special-registry/iana-ipv6-special-registry.xhtml
 	IPv6Reserved = [...]netip.Prefix{
 		netip.MustParsePrefix("::1/128"),           // Loopback
-		netip.MustParsePrefix("fe80::/10"),     // Link-local
+		netip.MustParsePrefix("::/128"),            // Unspecified address
-		netip.MustParsePrefix("fc00::/7"),      // Unique Local
+		netip.MustParsePrefix("::ffff:0:0/96"),     // IPv4-mapped address
+		netip.MustParsePrefix("64:ff9b::/96"),      // IPv4/IPv6 translation, RFC 6052
+		netip.MustParsePrefix("64:ff9b:1::/48"),    // IPv4/IPv6 translation, RFC 8215
+		netip.MustParsePrefix("100::/64"),          // Discard prefix, RFC 6666
+		netip.MustParsePrefix("2001::/23"),         // IETF Protocol Assignments, RFC 2928
+		netip.MustParsePrefix("2001::/32"),         // Teredo
+		netip.MustParsePrefix("2001:1::1/128"),     // Port Control Protocol Anycast, RFC 7723
+		netip.MustParsePrefix("2001:1::2/128"),     // Traversal Using Relays around NAT Anycast, RFC 8155
+		netip.MustParsePrefix("2001:2::/48"),       // Benchmarking, RFC 5180
+		netip.MustParsePrefix("2001:3::/32"),       // AMT, RFC 7450
+		netip.MustParsePrefix("2001:4:112::/48"),   // AS112-v6, RFC 7535
+		netip.MustParsePrefix("2001:10::/28"),      // ORCHID, deprecated
+		netip.MustParsePrefix("2001:20::/28"),      // ORCHIDv2
 		netip.MustParsePrefix("2001:db8::/32"),     // Test, doc, examples
-		netip.MustParsePrefix("ff00::/8"),      // Multicast
+		netip.MustParsePrefix("2002::/16"),         // 6to4
+		netip.MustParsePrefix("2620:4f:8000::/48"), // Direct Delegation AS112 Service, RFC 7534
+		netip.MustParsePrefix("fc00::/7"),          // Unique Local
+		netip.MustParsePrefix("fe80::/10"),         // Link-local
 		netip.MustParsePrefix("fec0::/10"),         // Site-local, deprecated
+		netip.MustParsePrefix("ff00::/8"),          // Multicast
 	}
 
 	// IPv4Reserved contains IPv4 reserved IP prefixes.
+	// https://www.iana.org/assignments/iana-ipv4-special-registry/iana-ipv4-special-registry.xhtml
 	IPv4Reserved = [...]netip.Prefix{
 		netip.MustParsePrefix("0.0.0.0/8"),       // Current network
 		netip.MustParsePrefix("10.0.0.0/8"),      // Private
@@ -42,9 +60,13 @@ var (
 		netip.MustParsePrefix("169.254.0.0/16"),  // Link-local
 		netip.MustParsePrefix("172.16.0.0/12"),   // Private
 		netip.MustParsePrefix("192.0.0.0/24"),    // RFC6890
+		netip.MustParsePrefix("192.0.0.0/29"),    // IPv4 Service Continuity Prefix, RFC 7335
 		netip.MustParsePrefix("192.0.2.0/24"),    // Test, doc, examples
+		netip.MustParsePrefix("192.31.196.0/24"), // AS112-v4, RFC 7535
+		netip.MustParsePrefix("192.52.193.0/24"), // AMT, RFC 7450
 		netip.MustParsePrefix("192.88.99.0/24"),  // IPv6 to IPv4 relay
 		netip.MustParsePrefix("192.168.0.0/16"),  // Private
+		netip.MustParsePrefix("192.175.48.0/24"), // Direct Delegation AS112 Service, RFC 7534
 		netip.MustParsePrefix("198.18.0.0/15"),   // Benchmarking tests
 		netip.MustParsePrefix("198.51.100.0/24"), // Test, doc, examples
 		netip.MustParsePrefix("203.0.113.0/24"),  // Test, doc, examples

internal/netutil/validate_test.go

@@ -0,0 +1,54 @@
+package netutil
+
+import (
+	"net/netip"
+	"testing"
+)
+
+func TestValidateIP(t *testing.T) {
+	tests := []struct {
+		name string
+		ip   netip.Addr
+	}{
+		// IPv4 tests
+		{
+			name: "IPv4 this host on this network",
+			ip:   netip.MustParseAddr("0.0.0.0"),
+		},
+		{
+			name: "IPv4 dummy address",
+			ip:   netip.MustParseAddr("192.0.0.8"),
+		},
+		{
+			name: "IPv4 Port Control Protocol Anycast",
+			ip:   netip.MustParseAddr("192.0.0.9"),
+		},
+		{
+			name: "IPv4 Traversal Using Relays around NAT Anycast",
+			ip:   netip.MustParseAddr("192.0.0.10"),
+		},
+		{
+			name: "IPv4 NAT64/DNS64 Discovery 1",
+			ip:   netip.MustParseAddr("192.0.0.17"),
+		},
+		{
+			name: "IPv4 NAT64/DNS64 Discovery 2",
+			ip:   netip.MustParseAddr("192.0.0.171"),
+		},
+		// IPv6 tests
+		{
+			name: "IPv4-mapped address",
+			ip:   netip.MustParseAddr("::ffff:169.254.169.254"),
+		},
+	}
+
+	for _, tc := range tests {
+		tc := tc
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+			if valid := ValidateIP(tc.ip); valid != false {
+				t.Fatalf("Expected IP %s to be: %t, got: %t", tc.ip, false, valid)
+			}
+		})
+	}
+}