package config import ( "crypto/tls" "fmt" "github.com/pkg/errors" ) var ( // DefaultTLSMinVersion default minimum version of TLS. DefaultTLSMinVersion = TLSVersion(1.2) // DefaultTLSMaxVersion default maximum version of TLS. DefaultTLSMaxVersion = TLSVersion(1.3) // DefaultTLSRenegotiation default TLS connection renegotiation policy. DefaultTLSRenegotiation = false // Never regnegotiate. // DefaultTLSCipherSuites specifies default step ciphersuite(s). // These are TLS 1.0 - 1.2 cipher suites. DefaultTLSCipherSuites = CipherSuites{ "TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256", "TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256", } // ApprovedTLSCipherSuites smallstep approved ciphersuites. ApprovedTLSCipherSuites = CipherSuites{ "TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA", "TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256", "TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256", "TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA", "TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384", "TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256", "TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA", "TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256", "TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256", "TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA", "TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384", "TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256", } // DefaultTLSOptions represents the default TLS version as well as the cipher // suites used in the TLS certificates. DefaultTLSOptions = TLSOptions{ CipherSuites: DefaultTLSCipherSuites, MinVersion: DefaultTLSMinVersion, MaxVersion: DefaultTLSMaxVersion, Renegotiation: DefaultTLSRenegotiation, } ) // TLSVersion represents a TLS version number. type TLSVersion float64 // Validate implements models.Validator and checks that a cipher suite is // valid. func (v TLSVersion) Validate() error { if _, ok := tlsVersions[v]; ok { return nil } return errors.Errorf("%f is not a valid tls version", v) } // Value returns the Go constant for the TLSVersion. func (v TLSVersion) Value() uint16 { return tlsVersions[v] } // String returns the Go constant for the TLSVersion. func (v TLSVersion) String() string { k := v.Value() switch k { case tls.VersionTLS10: return "1.0" case tls.VersionTLS11: return "1.1" case tls.VersionTLS12: return "1.2" case tls.VersionTLS13: return "1.3" default: return fmt.Sprintf("unexpected value: %f", v) } } // tlsVersions has the list of supported tls version. var tlsVersions = map[TLSVersion]uint16{ // Defaults to TLS 1.3 0: tls.VersionTLS13, // Options 1.0: tls.VersionTLS10, 1.1: tls.VersionTLS11, 1.2: tls.VersionTLS12, 1.3: tls.VersionTLS13, } // CipherSuites represents an array of string codes representing the cipher // suites. type CipherSuites []string // Validate implements models.Validator and checks that a cipher suite is // valid. func (c CipherSuites) Validate() error { for _, s := range c { if _, ok := cipherSuites[s]; !ok { return errors.Errorf("%s is not a valid cipher suite", s) } } return nil } // Value returns an []uint16 for the cipher suites. func (c CipherSuites) Value() []uint16 { values := make([]uint16, len(c)) for i, s := range c { values[i] = cipherSuites[s] } return values } // cipherSuites has the list of supported cipher suites. var cipherSuites = map[string]uint16{ // TLS 1.0 - 1.2 cipher suites. "TLS_RSA_WITH_RC4_128_SHA": tls.TLS_RSA_WITH_RC4_128_SHA, "TLS_RSA_WITH_3DES_EDE_CBC_SHA": tls.TLS_RSA_WITH_3DES_EDE_CBC_SHA, "TLS_RSA_WITH_AES_128_CBC_SHA": tls.TLS_RSA_WITH_AES_128_CBC_SHA, "TLS_RSA_WITH_AES_256_CBC_SHA": tls.TLS_RSA_WITH_AES_256_CBC_SHA, "TLS_RSA_WITH_AES_128_CBC_SHA256": tls.TLS_RSA_WITH_AES_128_CBC_SHA256, "TLS_RSA_WITH_AES_128_GCM_SHA256": tls.TLS_RSA_WITH_AES_128_GCM_SHA256, "TLS_RSA_WITH_AES_256_GCM_SHA384": tls.TLS_RSA_WITH_AES_256_GCM_SHA384, "TLS_ECDHE_ECDSA_WITH_RC4_128_SHA": tls.TLS_ECDHE_ECDSA_WITH_RC4_128_SHA, "TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA": tls.TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA, "TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA": tls.TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA, "TLS_ECDHE_RSA_WITH_RC4_128_SHA": tls.TLS_ECDHE_RSA_WITH_RC4_128_SHA, "TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA": tls.TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA, "TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA": tls.TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA, "TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA": tls.TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA, "TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256": tls.TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256, "TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256": tls.TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256, "TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256": tls.TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256, "TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256": tls.TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256, "TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384": tls.TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384, "TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384": tls.TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384, "TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256": tls.TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256, "TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256": tls.TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256, // TLS 1.3 cipher sutes. "TLS_AES_128_GCM_SHA256": tls.TLS_AES_128_GCM_SHA256, "TLS_AES_256_GCM_SHA384": tls.TLS_AES_256_GCM_SHA384, "TLS_CHACHA20_POLY1305_SHA256": tls.TLS_CHACHA20_POLY1305_SHA256, // Legacy names. "TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305": tls.TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305, "TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305": tls.TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305, } // TLSOptions represents the TLS options that can be specified on *tls.Config // types to configure HTTPS servers and clients. type TLSOptions struct { CipherSuites CipherSuites `json:"cipherSuites"` MinVersion TLSVersion `json:"minVersion"` MaxVersion TLSVersion `json:"maxVersion"` Renegotiation bool `json:"renegotiation"` } // TLSConfig returns the tls.Config equivalent of the TLSOptions. func (t *TLSOptions) TLSConfig() *tls.Config { var rs tls.RenegotiationSupport if t.Renegotiation { rs = tls.RenegotiateFreelyAsClient } else { rs = tls.RenegotiateNever } return &tls.Config{ CipherSuites: t.CipherSuites.Value(), MinVersion: t.MinVersion.Value(), MaxVersion: t.MaxVersion.Value(), Renegotiation: rs, } }