package tls
import (
+ "crypto"
"crypto/aes"
"crypto/cipher"
"crypto/des"
"crypto/hmac"
+ "crypto/internal/boring"
"crypto/rc4"
"crypto/sha1"
"crypto/sha256"
- "crypto/x509"
- "golang_org/x/crypto/chacha20poly1305"
+ "fmt"
"hash"
+ "internal/cpu"
+ "internal/godebug"
+ "runtime"
+
+ "golang.org/x/crypto/chacha20poly1305"
)
-// a keyAgreement implements the client and server side of a TLS key agreement
-// protocol by generating and processing key exchange messages.
-type keyAgreement interface {
- // On the server side, the first two methods are called in order.
+// CipherSuite is a TLS cipher suite. Note that most functions in this package
+// accept and expose cipher suite IDs instead of this type.
+type CipherSuite struct {
+ ID uint16
+ Name string
- // In the case that the key agreement protocol doesn't use a
- // ServerKeyExchange message, generateServerKeyExchange can return nil,
- // nil.
- generateServerKeyExchange(*Config, *Certificate, *clientHelloMsg, *serverHelloMsg) (*serverKeyExchangeMsg, error)
- processClientKeyExchange(*Config, *Certificate, *clientKeyExchangeMsg, uint16) ([]byte, error)
+ // Supported versions is the list of TLS protocol versions that can
+ // negotiate this cipher suite.
+ SupportedVersions []uint16
- // On the client side, the next two methods are called in order.
+ // Insecure is true if the cipher suite has known security issues
+ // due to its primitives, design, or implementation.
+ Insecure bool
+}
- // This method may not be called if the server doesn't send a
- // ServerKeyExchange message.
- processServerKeyExchange(*Config, *clientHelloMsg, *serverHelloMsg, *x509.Certificate, *serverKeyExchangeMsg) error
- generateClientKeyExchange(*Config, *clientHelloMsg, *x509.Certificate) ([]byte, *clientKeyExchangeMsg, error)
+var (
+ supportedUpToTLS12 = []uint16{VersionTLS10, VersionTLS11, VersionTLS12}
+ supportedOnlyTLS12 = []uint16{VersionTLS12}
+ supportedOnlyTLS13 = []uint16{VersionTLS13}
+)
+
+// CipherSuites returns a list of cipher suites currently implemented by this
+// package, excluding those with security issues, which are returned by
+// [InsecureCipherSuites].
+//
+// The list is sorted by ID. Note that the default cipher suites selected by
+// this package might depend on logic that can't be captured by a static list,
+// and might not match those returned by this function.
+func CipherSuites() []*CipherSuite {
+ return []*CipherSuite{
+ {TLS_RSA_WITH_AES_128_CBC_SHA, "TLS_RSA_WITH_AES_128_CBC_SHA", supportedUpToTLS12, false},
+ {TLS_RSA_WITH_AES_256_CBC_SHA, "TLS_RSA_WITH_AES_256_CBC_SHA", supportedUpToTLS12, false},
+ {TLS_RSA_WITH_AES_128_GCM_SHA256, "TLS_RSA_WITH_AES_128_GCM_SHA256", supportedOnlyTLS12, false},
+ {TLS_RSA_WITH_AES_256_GCM_SHA384, "TLS_RSA_WITH_AES_256_GCM_SHA384", supportedOnlyTLS12, false},
+
+ {TLS_AES_128_GCM_SHA256, "TLS_AES_128_GCM_SHA256", supportedOnlyTLS13, false},
+ {TLS_AES_256_GCM_SHA384, "TLS_AES_256_GCM_SHA384", supportedOnlyTLS13, false},
+ {TLS_CHACHA20_POLY1305_SHA256, "TLS_CHACHA20_POLY1305_SHA256", supportedOnlyTLS13, false},
+
+ {TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA, "TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA", supportedUpToTLS12, false},
+ {TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA, "TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA", supportedUpToTLS12, false},
+ {TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA, "TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA", supportedUpToTLS12, false},
+ {TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA, "TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA", supportedUpToTLS12, false},
+ {TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256, "TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256", supportedOnlyTLS12, false},
+ {TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384, "TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384", supportedOnlyTLS12, false},
+ {TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256, "TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256", supportedOnlyTLS12, false},
+ {TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384, "TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384", supportedOnlyTLS12, false},
+ {TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256, "TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256", supportedOnlyTLS12, false},
+ {TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256, "TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256", supportedOnlyTLS12, false},
+ }
+}
+
+// InsecureCipherSuites returns a list of cipher suites currently implemented by
+// this package and which have security issues.
+//
+// Most applications should not use the cipher suites in this list, and should
+// only use those returned by [CipherSuites].
+func InsecureCipherSuites() []*CipherSuite {
+ // This list includes RC4, CBC_SHA256, and 3DES cipher suites. See
+ // cipherSuitesPreferenceOrder for details.
+ return []*CipherSuite{
+ {TLS_RSA_WITH_RC4_128_SHA, "TLS_RSA_WITH_RC4_128_SHA", supportedUpToTLS12, true},
+ {TLS_RSA_WITH_3DES_EDE_CBC_SHA, "TLS_RSA_WITH_3DES_EDE_CBC_SHA", supportedUpToTLS12, true},
+ {TLS_RSA_WITH_AES_128_CBC_SHA256, "TLS_RSA_WITH_AES_128_CBC_SHA256", supportedOnlyTLS12, true},
+ {TLS_ECDHE_ECDSA_WITH_RC4_128_SHA, "TLS_ECDHE_ECDSA_WITH_RC4_128_SHA", supportedUpToTLS12, true},
+ {TLS_ECDHE_RSA_WITH_RC4_128_SHA, "TLS_ECDHE_RSA_WITH_RC4_128_SHA", supportedUpToTLS12, true},
+ {TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA, "TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA", supportedUpToTLS12, true},
+ {TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256, "TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256", supportedOnlyTLS12, true},
+ {TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256, "TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256", supportedOnlyTLS12, true},
+ }
+}
+
+// CipherSuiteName returns the standard name for the passed cipher suite ID
+// (e.g. "TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256"), or a fallback representation
+// of the ID value if the cipher suite is not implemented by this package.
+func CipherSuiteName(id uint16) string {
+ for _, c := range CipherSuites() {
+ if c.ID == id {
+ return c.Name
+ }
+ }
+ for _, c := range InsecureCipherSuites() {
+ if c.ID == id {
+ return c.Name
+ }
+ }
+ return fmt.Sprintf("0x%04X", id)
}
const (
- // suiteECDH indicates that the cipher suite involves elliptic curve
+ // suiteECDHE indicates that the cipher suite involves elliptic curve
// Diffie-Hellman. This means that it should only be selected when the
// client indicates that it supports ECC with a curve and point format
// that we're happy with.
suiteECDHE = 1 << iota
- // suiteECDSA indicates that the cipher suite involves an ECDSA
- // signature and therefore may only be selected when the server's
- // certificate is ECDSA. If this is not set then the cipher suite is
- // RSA based.
- suiteECDSA
+ // suiteECSign indicates that the cipher suite involves an ECDSA or
+ // EdDSA signature and therefore may only be selected when the server's
+ // certificate is ECDSA or EdDSA. If this is not set then the cipher suite
+ // is RSA based.
+ suiteECSign
// suiteTLS12 indicates that the cipher suite should only be advertised
// and accepted when using TLS 1.2.
suiteTLS12
// suiteSHA384 indicates that the cipher suite uses SHA384 as the
// handshake hash.
suiteSHA384
- // suiteDefaultOff indicates that this cipher suite is not included by
- // default.
- suiteDefaultOff
)
-// A cipherSuite is a specific combination of key agreement, cipher and MAC
-// function. All cipher suites currently assume RSA key agreement.
+// A cipherSuite is a TLS 1.0–1.2 cipher suite, and defines the key exchange
+// mechanism, as well as the cipher+MAC pair or the AEAD.
type cipherSuite struct {
id uint16
// the lengths, in bytes, of the key material needed for each component.
ka func(version uint16) keyAgreement
// flags is a bitmask of the suite* values, above.
flags int
- cipher func(key, iv []byte, isRead bool) interface{}
- mac func(version uint16, macKey []byte) macFunction
- aead func(key, fixedNonce []byte) cipher.AEAD
+ cipher func(key, iv []byte, isRead bool) any
+ mac func(key []byte) hash.Hash
+ aead func(key, fixedNonce []byte) aead
}
-var cipherSuites = []*cipherSuite{
- // Ciphersuite order is chosen so that ECDHE comes before plain RSA and
- // AEADs are the top preference.
+var cipherSuites = []*cipherSuite{ // TODO: replace with a map, since the order doesn't matter.
{TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305, 32, 0, 12, ecdheRSAKA, suiteECDHE | suiteTLS12, nil, nil, aeadChaCha20Poly1305},
- {TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305, 32, 0, 12, ecdheECDSAKA, suiteECDHE | suiteECDSA | suiteTLS12, nil, nil, aeadChaCha20Poly1305},
+ {TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305, 32, 0, 12, ecdheECDSAKA, suiteECDHE | suiteECSign | suiteTLS12, nil, nil, aeadChaCha20Poly1305},
{TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256, 16, 0, 4, ecdheRSAKA, suiteECDHE | suiteTLS12, nil, nil, aeadAESGCM},
- {TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256, 16, 0, 4, ecdheECDSAKA, suiteECDHE | suiteECDSA | suiteTLS12, nil, nil, aeadAESGCM},
+ {TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256, 16, 0, 4, ecdheECDSAKA, suiteECDHE | suiteECSign | suiteTLS12, nil, nil, aeadAESGCM},
{TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384, 32, 0, 4, ecdheRSAKA, suiteECDHE | suiteTLS12 | suiteSHA384, nil, nil, aeadAESGCM},
- {TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384, 32, 0, 4, ecdheECDSAKA, suiteECDHE | suiteECDSA | suiteTLS12 | suiteSHA384, nil, nil, aeadAESGCM},
- {TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256, 16, 32, 16, ecdheRSAKA, suiteECDHE | suiteTLS12 | suiteDefaultOff, cipherAES, macSHA256, nil},
+ {TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384, 32, 0, 4, ecdheECDSAKA, suiteECDHE | suiteECSign | suiteTLS12 | suiteSHA384, nil, nil, aeadAESGCM},
+ {TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256, 16, 32, 16, ecdheRSAKA, suiteECDHE | suiteTLS12, cipherAES, macSHA256, nil},
{TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA, 16, 20, 16, ecdheRSAKA, suiteECDHE, cipherAES, macSHA1, nil},
- {TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256, 16, 32, 16, ecdheECDSAKA, suiteECDHE | suiteECDSA | suiteTLS12 | suiteDefaultOff, cipherAES, macSHA256, nil},
- {TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA, 16, 20, 16, ecdheECDSAKA, suiteECDHE | suiteECDSA, cipherAES, macSHA1, nil},
+ {TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256, 16, 32, 16, ecdheECDSAKA, suiteECDHE | suiteECSign | suiteTLS12, cipherAES, macSHA256, nil},
+ {TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA, 16, 20, 16, ecdheECDSAKA, suiteECDHE | suiteECSign, cipherAES, macSHA1, nil},
{TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA, 32, 20, 16, ecdheRSAKA, suiteECDHE, cipherAES, macSHA1, nil},
- {TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA, 32, 20, 16, ecdheECDSAKA, suiteECDHE | suiteECDSA, cipherAES, macSHA1, nil},
+ {TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA, 32, 20, 16, ecdheECDSAKA, suiteECDHE | suiteECSign, cipherAES, macSHA1, nil},
{TLS_RSA_WITH_AES_128_GCM_SHA256, 16, 0, 4, rsaKA, suiteTLS12, nil, nil, aeadAESGCM},
{TLS_RSA_WITH_AES_256_GCM_SHA384, 32, 0, 4, rsaKA, suiteTLS12 | suiteSHA384, nil, nil, aeadAESGCM},
- {TLS_RSA_WITH_AES_128_CBC_SHA256, 16, 32, 16, rsaKA, suiteTLS12 | suiteDefaultOff, cipherAES, macSHA256, nil},
+ {TLS_RSA_WITH_AES_128_CBC_SHA256, 16, 32, 16, rsaKA, suiteTLS12, cipherAES, macSHA256, nil},
{TLS_RSA_WITH_AES_128_CBC_SHA, 16, 20, 16, rsaKA, 0, cipherAES, macSHA1, nil},
{TLS_RSA_WITH_AES_256_CBC_SHA, 32, 20, 16, rsaKA, 0, cipherAES, macSHA1, nil},
{TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA, 24, 20, 8, ecdheRSAKA, suiteECDHE, cipher3DES, macSHA1, nil},
{TLS_RSA_WITH_3DES_EDE_CBC_SHA, 24, 20, 8, rsaKA, 0, cipher3DES, macSHA1, nil},
+ {TLS_RSA_WITH_RC4_128_SHA, 16, 20, 0, rsaKA, 0, cipherRC4, macSHA1, nil},
+ {TLS_ECDHE_RSA_WITH_RC4_128_SHA, 16, 20, 0, ecdheRSAKA, suiteECDHE, cipherRC4, macSHA1, nil},
+ {TLS_ECDHE_ECDSA_WITH_RC4_128_SHA, 16, 20, 0, ecdheECDSAKA, suiteECDHE | suiteECSign, cipherRC4, macSHA1, nil},
+}
+
+// selectCipherSuite returns the first TLS 1.0–1.2 cipher suite from ids which
+// is also in supportedIDs and passes the ok filter.
+func selectCipherSuite(ids, supportedIDs []uint16, ok func(*cipherSuite) bool) *cipherSuite {
+ for _, id := range ids {
+ candidate := cipherSuiteByID(id)
+ if candidate == nil || !ok(candidate) {
+ continue
+ }
+
+ for _, suppID := range supportedIDs {
+ if id == suppID {
+ return candidate
+ }
+ }
+ }
+ return nil
+}
+
+// A cipherSuiteTLS13 defines only the pair of the AEAD algorithm and hash
+// algorithm to be used with HKDF. See RFC 8446, Appendix B.4.
+type cipherSuiteTLS13 struct {
+ id uint16
+ keyLen int
+ aead func(key, fixedNonce []byte) aead
+ hash crypto.Hash
+}
+
+var cipherSuitesTLS13 = []*cipherSuiteTLS13{ // TODO: replace with a map.
+ {TLS_AES_128_GCM_SHA256, 16, aeadAESGCMTLS13, crypto.SHA256},
+ {TLS_CHACHA20_POLY1305_SHA256, 32, aeadChaCha20Poly1305, crypto.SHA256},
+ {TLS_AES_256_GCM_SHA384, 32, aeadAESGCMTLS13, crypto.SHA384},
+}
+
+// cipherSuitesPreferenceOrder is the order in which we'll select (on the
+// server) or advertise (on the client) TLS 1.0–1.2 cipher suites.
+//
+// Cipher suites are filtered but not reordered based on the application and
+// peer's preferences, meaning we'll never select a suite lower in this list if
+// any higher one is available. This makes it more defensible to keep weaker
+// cipher suites enabled, especially on the server side where we get the last
+// word, since there are no known downgrade attacks on cipher suites selection.
+//
+// The list is sorted by applying the following priority rules, stopping at the
+// first (most important) applicable one:
+//
+// - Anything else comes before RC4
+//
+// RC4 has practically exploitable biases. See https://www.rc4nomore.com.
+//
+// - Anything else comes before CBC_SHA256
+//
+// SHA-256 variants of the CBC ciphersuites don't implement any Lucky13
+// countermeasures. See http://www.isg.rhul.ac.uk/tls/Lucky13.html and
+// https://www.imperialviolet.org/2013/02/04/luckythirteen.html.
+//
+// - Anything else comes before 3DES
+//
+// 3DES has 64-bit blocks, which makes it fundamentally susceptible to
+// birthday attacks. See https://sweet32.info.
+//
+// - ECDHE comes before anything else
+//
+// Once we got the broken stuff out of the way, the most important
+// property a cipher suite can have is forward secrecy. We don't
+// implement FFDHE, so that means ECDHE.
+//
+// - AEADs come before CBC ciphers
+//
+// Even with Lucky13 countermeasures, MAC-then-Encrypt CBC cipher suites
+// are fundamentally fragile, and suffered from an endless sequence of
+// padding oracle attacks. See https://eprint.iacr.org/2015/1129,
+// https://www.imperialviolet.org/2014/12/08/poodleagain.html, and
+// https://blog.cloudflare.com/yet-another-padding-oracle-in-openssl-cbc-ciphersuites/.
+//
+// - AES comes before ChaCha20
+//
+// When AES hardware is available, AES-128-GCM and AES-256-GCM are faster
+// than ChaCha20Poly1305.
+//
+// When AES hardware is not available, AES-128-GCM is one or more of: much
+// slower, way more complex, and less safe (because not constant time)
+// than ChaCha20Poly1305.
+//
+// We use this list if we think both peers have AES hardware, and
+// cipherSuitesPreferenceOrderNoAES otherwise.
+//
+// - AES-128 comes before AES-256
+//
+// The only potential advantages of AES-256 are better multi-target
+// margins, and hypothetical post-quantum properties. Neither apply to
+// TLS, and AES-256 is slower due to its four extra rounds (which don't
+// contribute to the advantages above).
+//
+// - ECDSA comes before RSA
+//
+// The relative order of ECDSA and RSA cipher suites doesn't matter,
+// as they depend on the certificate. Pick one to get a stable order.
+var cipherSuitesPreferenceOrder = []uint16{
+ // AEADs w/ ECDHE
+ TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256, TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
+ TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384, TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,
+ TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305, TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305,
+
+ // CBC w/ ECDHE
+ TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA, TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA,
+ TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA, TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA,
+
+ // AEADs w/o ECDHE
+ TLS_RSA_WITH_AES_128_GCM_SHA256,
+ TLS_RSA_WITH_AES_256_GCM_SHA384,
+
+ // CBC w/o ECDHE
+ TLS_RSA_WITH_AES_128_CBC_SHA,
+ TLS_RSA_WITH_AES_256_CBC_SHA,
+
+ // 3DES
+ TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA,
+ TLS_RSA_WITH_3DES_EDE_CBC_SHA,
+
+ // CBC_SHA256
+ TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256, TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256,
+ TLS_RSA_WITH_AES_128_CBC_SHA256,
+
+ // RC4
+ TLS_ECDHE_ECDSA_WITH_RC4_128_SHA, TLS_ECDHE_RSA_WITH_RC4_128_SHA,
+ TLS_RSA_WITH_RC4_128_SHA,
+}
+
+var cipherSuitesPreferenceOrderNoAES = []uint16{
+ // ChaCha20Poly1305
+ TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305, TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305,
+
+ // AES-GCM w/ ECDHE
+ TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256, TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
+ TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384, TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,
+
+ // The rest of cipherSuitesPreferenceOrder.
+ TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA, TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA,
+ TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA, TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA,
+ TLS_RSA_WITH_AES_128_GCM_SHA256,
+ TLS_RSA_WITH_AES_256_GCM_SHA384,
+ TLS_RSA_WITH_AES_128_CBC_SHA,
+ TLS_RSA_WITH_AES_256_CBC_SHA,
+ TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA,
+ TLS_RSA_WITH_3DES_EDE_CBC_SHA,
+ TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256, TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256,
+ TLS_RSA_WITH_AES_128_CBC_SHA256,
+ TLS_ECDHE_ECDSA_WITH_RC4_128_SHA, TLS_ECDHE_RSA_WITH_RC4_128_SHA,
+ TLS_RSA_WITH_RC4_128_SHA,
+}
+
+// disabledCipherSuites are not used unless explicitly listed in
+// Config.CipherSuites. They MUST be at the end of cipherSuitesPreferenceOrder.
+var disabledCipherSuites = []uint16{
+ // CBC_SHA256
+ TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256, TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256,
+ TLS_RSA_WITH_AES_128_CBC_SHA256,
+
+ // RC4
+ TLS_ECDHE_ECDSA_WITH_RC4_128_SHA, TLS_ECDHE_RSA_WITH_RC4_128_SHA,
+ TLS_RSA_WITH_RC4_128_SHA,
+}
+
+var (
+ defaultCipherSuitesLen int
+ defaultCipherSuites []uint16
+)
+
+// rsaKexCiphers contains the ciphers which use RSA based key exchange,
+// which we disable by default.
+var rsaKexCiphers = map[uint16]bool{
+ TLS_RSA_WITH_RC4_128_SHA: true,
+ TLS_RSA_WITH_3DES_EDE_CBC_SHA: true,
+ TLS_RSA_WITH_AES_128_CBC_SHA: true,
+ TLS_RSA_WITH_AES_256_CBC_SHA: true,
+ TLS_RSA_WITH_AES_128_CBC_SHA256: true,
+ TLS_RSA_WITH_AES_128_GCM_SHA256: true,
+ TLS_RSA_WITH_AES_256_GCM_SHA384: true,
+}
+
+var rsaKEXgodebug = godebug.New("tlsrsakex")
+
+func init() {
+ rsaKexEnabled := rsaKEXgodebug.Value() == "1"
+ for _, c := range cipherSuitesPreferenceOrder[:len(cipherSuitesPreferenceOrder)-len(disabledCipherSuites)] {
+ if !rsaKexEnabled && rsaKexCiphers[c] {
+ continue
+ }
+ defaultCipherSuites = append(defaultCipherSuites, c)
+ }
+ defaultCipherSuitesLen = len(defaultCipherSuites)
+}
+
+// defaultCipherSuitesTLS13 is also the preference order, since there are no
+// disabled by default TLS 1.3 cipher suites. The same AES vs ChaCha20 logic as
+// cipherSuitesPreferenceOrder applies.
+var defaultCipherSuitesTLS13 = []uint16{
+ TLS_AES_128_GCM_SHA256,
+ TLS_AES_256_GCM_SHA384,
+ TLS_CHACHA20_POLY1305_SHA256,
+}
- // RC4-based cipher suites are disabled by default.
- {TLS_RSA_WITH_RC4_128_SHA, 16, 20, 0, rsaKA, suiteDefaultOff, cipherRC4, macSHA1, nil},
- {TLS_ECDHE_RSA_WITH_RC4_128_SHA, 16, 20, 0, ecdheRSAKA, suiteECDHE | suiteDefaultOff, cipherRC4, macSHA1, nil},
- {TLS_ECDHE_ECDSA_WITH_RC4_128_SHA, 16, 20, 0, ecdheECDSAKA, suiteECDHE | suiteECDSA | suiteDefaultOff, cipherRC4, macSHA1, nil},
+var defaultCipherSuitesTLS13NoAES = []uint16{
+ TLS_CHACHA20_POLY1305_SHA256,
+ TLS_AES_128_GCM_SHA256,
+ TLS_AES_256_GCM_SHA384,
}
-func cipherRC4(key, iv []byte, isRead bool) interface{} {
+var (
+ hasGCMAsmAMD64 = cpu.X86.HasAES && cpu.X86.HasPCLMULQDQ
+ hasGCMAsmARM64 = cpu.ARM64.HasAES && cpu.ARM64.HasPMULL
+ // Keep in sync with crypto/aes/cipher_s390x.go.
+ hasGCMAsmS390X = cpu.S390X.HasAES && cpu.S390X.HasAESCBC && cpu.S390X.HasAESCTR &&
+ (cpu.S390X.HasGHASH || cpu.S390X.HasAESGCM)
+
+ hasAESGCMHardwareSupport = runtime.GOARCH == "amd64" && hasGCMAsmAMD64 ||
+ runtime.GOARCH == "arm64" && hasGCMAsmARM64 ||
+ runtime.GOARCH == "s390x" && hasGCMAsmS390X
+)
+
+var aesgcmCiphers = map[uint16]bool{
+ // TLS 1.2
+ TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256: true,
+ TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384: true,
+ TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256: true,
+ TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384: true,
+ // TLS 1.3
+ TLS_AES_128_GCM_SHA256: true,
+ TLS_AES_256_GCM_SHA384: true,
+}
+
+// aesgcmPreferred returns whether the first known cipher in the preference list
+// is an AES-GCM cipher, implying the peer has hardware support for it.
+func aesgcmPreferred(ciphers []uint16) bool {
+ for _, cID := range ciphers {
+ if c := cipherSuiteByID(cID); c != nil {
+ return aesgcmCiphers[cID]
+ }
+ if c := cipherSuiteTLS13ByID(cID); c != nil {
+ return aesgcmCiphers[cID]
+ }
+ }
+ return false
+}
+
+func cipherRC4(key, iv []byte, isRead bool) any {
cipher, _ := rc4.NewCipher(key)
return cipher
}
-func cipher3DES(key, iv []byte, isRead bool) interface{} {
+func cipher3DES(key, iv []byte, isRead bool) any {
block, _ := des.NewTripleDESCipher(key)
if isRead {
return cipher.NewCBCDecrypter(block, iv)
return cipher.NewCBCEncrypter(block, iv)
}
-func cipherAES(key, iv []byte, isRead bool) interface{} {
+func cipherAES(key, iv []byte, isRead bool) any {
block, _ := aes.NewCipher(key)
if isRead {
return cipher.NewCBCDecrypter(block, iv)
return cipher.NewCBCEncrypter(block, iv)
}
-// macSHA1 returns a macFunction for the given protocol version.
-func macSHA1(version uint16, key []byte) macFunction {
- if version == VersionSSL30 {
- mac := ssl30MAC{
- h: sha1.New(),
- key: make([]byte, len(key)),
- }
- copy(mac.key, key)
- return mac
+// macSHA1 returns a SHA-1 based constant time MAC.
+func macSHA1(key []byte) hash.Hash {
+ h := sha1.New
+ // The BoringCrypto SHA1 does not have a constant-time
+ // checksum function, so don't try to use it.
+ if !boring.Enabled {
+ h = newConstantTimeHash(h)
}
- return tls10MAC{h: hmac.New(newConstantTimeHash(sha1.New), key)}
-}
-
-// macSHA256 returns a SHA-256 based MAC. These are only supported in TLS 1.2
-// so the given version is ignored.
-func macSHA256(version uint16, key []byte) macFunction {
- return tls10MAC{h: hmac.New(sha256.New, key)}
+ return hmac.New(h, key)
}
-type macFunction interface {
- // Size returns the length of the MAC.
- Size() int
- // MAC appends the MAC of (seq, header, data) to out. The extra data is fed
- // into the MAC after obtaining the result to normalize timing. The result
- // is only valid until the next invocation of MAC as the buffer is reused.
- MAC(seq, header, data, extra []byte) []byte
+// macSHA256 returns a SHA-256 based MAC. This is only supported in TLS 1.2 and
+// is currently only used in disabled-by-default cipher suites.
+func macSHA256(key []byte) hash.Hash {
+ return hmac.New(sha256.New, key)
}
type aead interface {
explicitNonceLen() int
}
-// fixedNonceAEAD wraps an AEAD and prefixes a fixed portion of the nonce to
+const (
+ aeadNonceLength = 12
+ noncePrefixLength = 4
+)
+
+// prefixNonceAEAD wraps an AEAD and prefixes a fixed portion of the nonce to
// each call.
-type fixedNonceAEAD struct {
+type prefixNonceAEAD struct {
// nonce contains the fixed part of the nonce in the first four bytes.
- nonce [12]byte
+ nonce [aeadNonceLength]byte
aead cipher.AEAD
}
-func (f *fixedNonceAEAD) NonceSize() int { return 8 }
-func (f *fixedNonceAEAD) Overhead() int { return f.aead.Overhead() }
-func (f *fixedNonceAEAD) explicitNonceLen() int { return 8 }
+func (f *prefixNonceAEAD) NonceSize() int { return aeadNonceLength - noncePrefixLength }
+func (f *prefixNonceAEAD) Overhead() int { return f.aead.Overhead() }
+func (f *prefixNonceAEAD) explicitNonceLen() int { return f.NonceSize() }
-func (f *fixedNonceAEAD) Seal(out, nonce, plaintext, additionalData []byte) []byte {
+func (f *prefixNonceAEAD) Seal(out, nonce, plaintext, additionalData []byte) []byte {
copy(f.nonce[4:], nonce)
return f.aead.Seal(out, f.nonce[:], plaintext, additionalData)
}
-func (f *fixedNonceAEAD) Open(out, nonce, plaintext, additionalData []byte) ([]byte, error) {
+func (f *prefixNonceAEAD) Open(out, nonce, ciphertext, additionalData []byte) ([]byte, error) {
copy(f.nonce[4:], nonce)
- return f.aead.Open(out, f.nonce[:], plaintext, additionalData)
+ return f.aead.Open(out, f.nonce[:], ciphertext, additionalData)
}
-// xoredNonceAEAD wraps an AEAD by XORing in a fixed pattern to the nonce
+// xorNonceAEAD wraps an AEAD by XORing in a fixed pattern to the nonce
// before each call.
type xorNonceAEAD struct {
- nonceMask [12]byte
+ nonceMask [aeadNonceLength]byte
aead cipher.AEAD
}
-func (f *xorNonceAEAD) NonceSize() int { return 8 }
+func (f *xorNonceAEAD) NonceSize() int { return 8 } // 64-bit sequence number
func (f *xorNonceAEAD) Overhead() int { return f.aead.Overhead() }
func (f *xorNonceAEAD) explicitNonceLen() int { return 0 }
return result
}
-func (f *xorNonceAEAD) Open(out, nonce, plaintext, additionalData []byte) ([]byte, error) {
+func (f *xorNonceAEAD) Open(out, nonce, ciphertext, additionalData []byte) ([]byte, error) {
for i, b := range nonce {
f.nonceMask[4+i] ^= b
}
- result, err := f.aead.Open(out, f.nonceMask[:], plaintext, additionalData)
+ result, err := f.aead.Open(out, f.nonceMask[:], ciphertext, additionalData)
for i, b := range nonce {
f.nonceMask[4+i] ^= b
}
return result, err
}
-func aeadAESGCM(key, fixedNonce []byte) cipher.AEAD {
+func aeadAESGCM(key, noncePrefix []byte) aead {
+ if len(noncePrefix) != noncePrefixLength {
+ panic("tls: internal error: wrong nonce length")
+ }
aes, err := aes.NewCipher(key)
if err != nil {
panic(err)
}
- aead, err := cipher.NewGCM(aes)
+ var aead cipher.AEAD
+ if boring.Enabled {
+ aead, err = boring.NewGCMTLS(aes)
+ } else {
+ boring.Unreachable()
+ aead, err = cipher.NewGCM(aes)
+ }
if err != nil {
panic(err)
}
- ret := &fixedNonceAEAD{aead: aead}
- copy(ret.nonce[:], fixedNonce)
+ ret := &prefixNonceAEAD{aead: aead}
+ copy(ret.nonce[:], noncePrefix)
return ret
}
-func aeadChaCha20Poly1305(key, fixedNonce []byte) cipher.AEAD {
- aead, err := chacha20poly1305.New(key)
+func aeadAESGCMTLS13(key, nonceMask []byte) aead {
+ if len(nonceMask) != aeadNonceLength {
+ panic("tls: internal error: wrong nonce length")
+ }
+ aes, err := aes.NewCipher(key)
+ if err != nil {
+ panic(err)
+ }
+ aead, err := cipher.NewGCM(aes)
if err != nil {
panic(err)
}
ret := &xorNonceAEAD{aead: aead}
- copy(ret.nonceMask[:], fixedNonce)
+ copy(ret.nonceMask[:], nonceMask)
return ret
}
-// ssl30MAC implements the SSLv3 MAC function, as defined in
-// www.mozilla.org/projects/security/pki/nss/ssl/draft302.txt section 5.2.3.1
-type ssl30MAC struct {
- h hash.Hash
- key []byte
- buf []byte
-}
-
-func (s ssl30MAC) Size() int {
- return s.h.Size()
-}
-
-var ssl30Pad1 = [48]byte{0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36}
-
-var ssl30Pad2 = [48]byte{0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c}
-
-// MAC does not offer constant timing guarantees for SSL v3.0, since it's deemed
-// useless considering the similar, protocol-level POODLE vulnerability.
-func (s ssl30MAC) MAC(seq, header, data, extra []byte) []byte {
- padLength := 48
- if s.h.Size() == 20 {
- padLength = 40
+func aeadChaCha20Poly1305(key, nonceMask []byte) aead {
+ if len(nonceMask) != aeadNonceLength {
+ panic("tls: internal error: wrong nonce length")
+ }
+ aead, err := chacha20poly1305.New(key)
+ if err != nil {
+ panic(err)
}
- s.h.Reset()
- s.h.Write(s.key)
- s.h.Write(ssl30Pad1[:padLength])
- s.h.Write(seq)
- s.h.Write(header[:1])
- s.h.Write(header[3:5])
- s.h.Write(data)
- s.buf = s.h.Sum(s.buf[:0])
-
- s.h.Reset()
- s.h.Write(s.key)
- s.h.Write(ssl30Pad2[:padLength])
- s.h.Write(s.buf)
- return s.h.Sum(s.buf[:0])
+ ret := &xorNonceAEAD{aead: aead}
+ copy(ret.nonceMask[:], nonceMask)
+ return ret
}
type constantTimeHash interface {
func (c *cthWrapper) Sum(b []byte) []byte { return c.h.ConstantTimeSum(b) }
func newConstantTimeHash(h func() hash.Hash) func() hash.Hash {
+ boring.Unreachable()
return func() hash.Hash {
return &cthWrapper{h().(constantTimeHash)}
}
}
// tls10MAC implements the TLS 1.0 MAC function. RFC 2246, Section 6.2.3.
-type tls10MAC struct {
- h hash.Hash
- buf []byte
-}
-
-func (s tls10MAC) Size() int {
- return s.h.Size()
-}
-
-// MAC is guaranteed to take constant time, as long as
-// len(seq)+len(header)+len(data)+len(extra) is constant. extra is not fed into
-// the MAC, but is only provided to make the timing profile constant.
-func (s tls10MAC) MAC(seq, header, data, extra []byte) []byte {
- s.h.Reset()
- s.h.Write(seq)
- s.h.Write(header)
- s.h.Write(data)
- res := s.h.Sum(s.buf[:0])
+func tls10MAC(h hash.Hash, out, seq, header, data, extra []byte) []byte {
+ h.Reset()
+ h.Write(seq)
+ h.Write(header)
+ h.Write(data)
+ res := h.Sum(out)
if extra != nil {
- s.h.Write(extra)
+ h.Write(extra)
}
return res
}
func mutualCipherSuite(have []uint16, want uint16) *cipherSuite {
for _, id := range have {
if id == want {
- for _, suite := range cipherSuites {
- if suite.id == want {
- return suite
- }
- }
- return nil
+ return cipherSuiteByID(id)
+ }
+ }
+ return nil
+}
+
+func cipherSuiteByID(id uint16) *cipherSuite {
+ for _, cipherSuite := range cipherSuites {
+ if cipherSuite.id == id {
+ return cipherSuite
+ }
+ }
+ return nil
+}
+
+func mutualCipherSuiteTLS13(have []uint16, want uint16) *cipherSuiteTLS13 {
+ for _, id := range have {
+ if id == want {
+ return cipherSuiteTLS13ByID(id)
+ }
+ }
+ return nil
+}
+
+func cipherSuiteTLS13ByID(id uint16) *cipherSuiteTLS13 {
+ for _, cipherSuite := range cipherSuitesTLS13 {
+ if cipherSuite.id == id {
+ return cipherSuite
}
}
return nil
// A list of cipher suite IDs that are, or have been, implemented by this
// package.
//
-// Taken from https://www.iana.org/assignments/tls-parameters/tls-parameters.xml
+// See https://www.iana.org/assignments/tls-parameters/tls-parameters.xml
const (
- TLS_RSA_WITH_RC4_128_SHA uint16 = 0x0005
- TLS_RSA_WITH_3DES_EDE_CBC_SHA uint16 = 0x000a
- TLS_RSA_WITH_AES_128_CBC_SHA uint16 = 0x002f
- TLS_RSA_WITH_AES_256_CBC_SHA uint16 = 0x0035
- TLS_RSA_WITH_AES_128_CBC_SHA256 uint16 = 0x003c
- TLS_RSA_WITH_AES_128_GCM_SHA256 uint16 = 0x009c
- TLS_RSA_WITH_AES_256_GCM_SHA384 uint16 = 0x009d
- TLS_ECDHE_ECDSA_WITH_RC4_128_SHA uint16 = 0xc007
- TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA uint16 = 0xc009
- TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA uint16 = 0xc00a
- TLS_ECDHE_RSA_WITH_RC4_128_SHA uint16 = 0xc011
- TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA uint16 = 0xc012
- TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA uint16 = 0xc013
- TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA uint16 = 0xc014
- TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256 uint16 = 0xc023
- TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256 uint16 = 0xc027
- TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 uint16 = 0xc02f
- TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256 uint16 = 0xc02b
- TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 uint16 = 0xc030
- TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384 uint16 = 0xc02c
- TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305 uint16 = 0xcca8
- TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305 uint16 = 0xcca9
+ // TLS 1.0 - 1.2 cipher suites.
+ TLS_RSA_WITH_RC4_128_SHA uint16 = 0x0005
+ TLS_RSA_WITH_3DES_EDE_CBC_SHA uint16 = 0x000a
+ TLS_RSA_WITH_AES_128_CBC_SHA uint16 = 0x002f
+ TLS_RSA_WITH_AES_256_CBC_SHA uint16 = 0x0035
+ TLS_RSA_WITH_AES_128_CBC_SHA256 uint16 = 0x003c
+ TLS_RSA_WITH_AES_128_GCM_SHA256 uint16 = 0x009c
+ TLS_RSA_WITH_AES_256_GCM_SHA384 uint16 = 0x009d
+ TLS_ECDHE_ECDSA_WITH_RC4_128_SHA uint16 = 0xc007
+ TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA uint16 = 0xc009
+ TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA uint16 = 0xc00a
+ TLS_ECDHE_RSA_WITH_RC4_128_SHA uint16 = 0xc011
+ TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA uint16 = 0xc012
+ TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA uint16 = 0xc013
+ TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA uint16 = 0xc014
+ TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256 uint16 = 0xc023
+ TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256 uint16 = 0xc027
+ TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 uint16 = 0xc02f
+ TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256 uint16 = 0xc02b
+ TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 uint16 = 0xc030
+ TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384 uint16 = 0xc02c
+ TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256 uint16 = 0xcca8
+ TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256 uint16 = 0xcca9
+
+ // TLS 1.3 cipher suites.
+ TLS_AES_128_GCM_SHA256 uint16 = 0x1301
+ TLS_AES_256_GCM_SHA384 uint16 = 0x1302
+ TLS_CHACHA20_POLY1305_SHA256 uint16 = 0x1303
// TLS_FALLBACK_SCSV isn't a standard cipher suite but an indicator
// that the client is doing version fallback. See RFC 7507.
TLS_FALLBACK_SCSV uint16 = 0x5600
+
+ // Legacy names for the corresponding cipher suites with the correct _SHA256
+ // suffix, retained for backward compatibility.
+ TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305 = TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256
+ TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305 = TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256
)