Add ShadowTLS protocol v3

transport/shadowtls/tls/boring.go

@@ -0,0 +1,98 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build boringcrypto
+
+package tls
+
+import (
+	"crypto/internal/boring/fipstls"
+)
+
+// needFIPS returns fipstls.Required(); it avoids a new import in common.go.
+func needFIPS() bool {
+	return fipstls.Required()
+}
+
+// fipsMinVersion replaces c.minVersion in FIPS-only mode.
+func fipsMinVersion(c *Config) uint16 {
+	// FIPS requires TLS 1.2.
+	return VersionTLS12
+}
+
+// fipsMaxVersion replaces c.maxVersion in FIPS-only mode.
+func fipsMaxVersion(c *Config) uint16 {
+	// FIPS requires TLS 1.2.
+	return VersionTLS12
+}
+
+// default defaultFIPSCurvePreferences is the FIPS-allowed curves,
+// in preference order (most preferable first).
+var defaultFIPSCurvePreferences = []CurveID{CurveP256, CurveP384, CurveP521}
+
+// fipsCurvePreferences replaces c.curvePreferences in FIPS-only mode.
+func fipsCurvePreferences(c *Config) []CurveID {
+	if c == nil || len(c.CurvePreferences) == 0 {
+		return defaultFIPSCurvePreferences
+	}
+	var list []CurveID
+	for _, id := range c.CurvePreferences {
+		for _, allowed := range defaultFIPSCurvePreferences {
+			if id == allowed {
+				list = append(list, id)
+				break
+			}
+		}
+	}
+	return list
+}
+
+// defaultCipherSuitesFIPS are the FIPS-allowed cipher suites.
+var defaultCipherSuitesFIPS = []uint16{
+	TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
+	TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,
+	TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,
+	TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,
+	TLS_RSA_WITH_AES_128_GCM_SHA256,
+	TLS_RSA_WITH_AES_256_GCM_SHA384,
+}
+
+// fipsCipherSuites replaces c.cipherSuites in FIPS-only mode.
+func fipsCipherSuites(c *Config) []uint16 {
+	if c == nil || c.CipherSuites == nil {
+		return defaultCipherSuitesFIPS
+	}
+	list := make([]uint16, 0, len(defaultCipherSuitesFIPS))
+	for _, id := range c.CipherSuites {
+		for _, allowed := range defaultCipherSuitesFIPS {
+			if id == allowed {
+				list = append(list, id)
+				break
+			}
+		}
+	}
+	return list
+}
+
+// fipsSupportedSignatureAlgorithms currently are a subset of
+// defaultSupportedSignatureAlgorithms without Ed25519 and SHA-1.
+var fipsSupportedSignatureAlgorithms = []SignatureScheme{
+	PSSWithSHA256,
+	PSSWithSHA384,
+	PSSWithSHA512,
+	PKCS1WithSHA256,
+	ECDSAWithP256AndSHA256,
+	PKCS1WithSHA384,
+	ECDSAWithP384AndSHA384,
+	PKCS1WithSHA512,
+	ECDSAWithP521AndSHA512,
+}
+
+// supportedSignatureAlgorithms returns the supported signature algorithms.
+func supportedSignatureAlgorithms() []SignatureScheme {
+	if !needFIPS() {
+		return defaultSupportedSignatureAlgorithms
+	}
+	return fipsSupportedSignatureAlgorithms
+}