diff options
Diffstat (limited to 'vendor/golang.org/x/crypto/ssh/common.go')
| -rw-r--r-- | vendor/golang.org/x/crypto/ssh/common.go | 476 |
1 files changed, 0 insertions, 476 deletions
diff --git a/vendor/golang.org/x/crypto/ssh/common.go b/vendor/golang.org/x/crypto/ssh/common.go deleted file mode 100644 index 7e9c2cbc6..000000000 --- a/vendor/golang.org/x/crypto/ssh/common.go +++ /dev/null @@ -1,476 +0,0 @@ -// Copyright 2011 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. - -package ssh - -import ( - "crypto" - "crypto/rand" - "fmt" - "io" - "math" - "sync" - - _ "crypto/sha1" - _ "crypto/sha256" - _ "crypto/sha512" -) - -// These are string constants in the SSH protocol. -const ( - compressionNone = "none" - serviceUserAuth = "ssh-userauth" - serviceSSH = "ssh-connection" -) - -// supportedCiphers lists ciphers we support but might not recommend. -var supportedCiphers = []string{ - "aes128-ctr", "aes192-ctr", "aes256-ctr", - "aes128-gcm@openssh.com", gcm256CipherID, - chacha20Poly1305ID, - "arcfour256", "arcfour128", "arcfour", - aes128cbcID, - tripledescbcID, -} - -// preferredCiphers specifies the default preference for ciphers. -var preferredCiphers = []string{ - "aes128-gcm@openssh.com", gcm256CipherID, - chacha20Poly1305ID, - "aes128-ctr", "aes192-ctr", "aes256-ctr", -} - -// supportedKexAlgos specifies the supported key-exchange algorithms in -// preference order. -var supportedKexAlgos = []string{ - kexAlgoCurve25519SHA256, kexAlgoCurve25519SHA256LibSSH, - // P384 and P521 are not constant-time yet, but since we don't - // reuse ephemeral keys, using them for ECDH should be OK. - kexAlgoECDH256, kexAlgoECDH384, kexAlgoECDH521, - kexAlgoDH14SHA256, kexAlgoDH16SHA512, kexAlgoDH14SHA1, - kexAlgoDH1SHA1, -} - -// serverForbiddenKexAlgos contains key exchange algorithms, that are forbidden -// for the server half. -var serverForbiddenKexAlgos = map[string]struct{}{ - kexAlgoDHGEXSHA1: {}, // server half implementation is only minimal to satisfy the automated tests - kexAlgoDHGEXSHA256: {}, // server half implementation is only minimal to satisfy the automated tests -} - -// preferredKexAlgos specifies the default preference for key-exchange -// algorithms in preference order. The diffie-hellman-group16-sha512 algorithm -// is disabled by default because it is a bit slower than the others. -var preferredKexAlgos = []string{ - kexAlgoCurve25519SHA256, kexAlgoCurve25519SHA256LibSSH, - kexAlgoECDH256, kexAlgoECDH384, kexAlgoECDH521, - kexAlgoDH14SHA256, kexAlgoDH14SHA1, -} - -// supportedHostKeyAlgos specifies the supported host-key algorithms (i.e. methods -// of authenticating servers) in preference order. -var supportedHostKeyAlgos = []string{ - CertAlgoRSASHA256v01, CertAlgoRSASHA512v01, - CertAlgoRSAv01, CertAlgoDSAv01, CertAlgoECDSA256v01, - CertAlgoECDSA384v01, CertAlgoECDSA521v01, CertAlgoED25519v01, - - KeyAlgoECDSA256, KeyAlgoECDSA384, KeyAlgoECDSA521, - KeyAlgoRSASHA256, KeyAlgoRSASHA512, - KeyAlgoRSA, KeyAlgoDSA, - - KeyAlgoED25519, -} - -// supportedMACs specifies a default set of MAC algorithms in preference order. -// This is based on RFC 4253, section 6.4, but with hmac-md5 variants removed -// because they have reached the end of their useful life. -var supportedMACs = []string{ - "hmac-sha2-256-etm@openssh.com", "hmac-sha2-512-etm@openssh.com", "hmac-sha2-256", "hmac-sha2-512", "hmac-sha1", "hmac-sha1-96", -} - -var supportedCompressions = []string{compressionNone} - -// hashFuncs keeps the mapping of supported signature algorithms to their -// respective hashes needed for signing and verification. -var hashFuncs = map[string]crypto.Hash{ - KeyAlgoRSA: crypto.SHA1, - KeyAlgoRSASHA256: crypto.SHA256, - KeyAlgoRSASHA512: crypto.SHA512, - KeyAlgoDSA: crypto.SHA1, - KeyAlgoECDSA256: crypto.SHA256, - KeyAlgoECDSA384: crypto.SHA384, - KeyAlgoECDSA521: crypto.SHA512, - // KeyAlgoED25519 doesn't pre-hash. - KeyAlgoSKECDSA256: crypto.SHA256, - KeyAlgoSKED25519: crypto.SHA256, -} - -// algorithmsForKeyFormat returns the supported signature algorithms for a given -// public key format (PublicKey.Type), in order of preference. See RFC 8332, -// Section 2. See also the note in sendKexInit on backwards compatibility. -func algorithmsForKeyFormat(keyFormat string) []string { - switch keyFormat { - case KeyAlgoRSA: - return []string{KeyAlgoRSASHA256, KeyAlgoRSASHA512, KeyAlgoRSA} - case CertAlgoRSAv01: - return []string{CertAlgoRSASHA256v01, CertAlgoRSASHA512v01, CertAlgoRSAv01} - default: - return []string{keyFormat} - } -} - -// isRSA returns whether algo is a supported RSA algorithm, including certificate -// algorithms. -func isRSA(algo string) bool { - algos := algorithmsForKeyFormat(KeyAlgoRSA) - return contains(algos, underlyingAlgo(algo)) -} - -func isRSACert(algo string) bool { - _, ok := certKeyAlgoNames[algo] - if !ok { - return false - } - return isRSA(algo) -} - -// supportedPubKeyAuthAlgos specifies the supported client public key -// authentication algorithms. Note that this doesn't include certificate types -// since those use the underlying algorithm. This list is sent to the client if -// it supports the server-sig-algs extension. Order is irrelevant. -var supportedPubKeyAuthAlgos = []string{ - KeyAlgoED25519, - KeyAlgoSKED25519, KeyAlgoSKECDSA256, - KeyAlgoECDSA256, KeyAlgoECDSA384, KeyAlgoECDSA521, - KeyAlgoRSASHA256, KeyAlgoRSASHA512, KeyAlgoRSA, - KeyAlgoDSA, -} - -// unexpectedMessageError results when the SSH message that we received didn't -// match what we wanted. -func unexpectedMessageError(expected, got uint8) error { - return fmt.Errorf("ssh: unexpected message type %d (expected %d)", got, expected) -} - -// parseError results from a malformed SSH message. -func parseError(tag uint8) error { - return fmt.Errorf("ssh: parse error in message type %d", tag) -} - -func findCommon(what string, client []string, server []string) (common string, err error) { - for _, c := range client { - for _, s := range server { - if c == s { - return c, nil - } - } - } - return "", fmt.Errorf("ssh: no common algorithm for %s; client offered: %v, server offered: %v", what, client, server) -} - -// directionAlgorithms records algorithm choices in one direction (either read or write) -type directionAlgorithms struct { - Cipher string - MAC string - Compression string -} - -// rekeyBytes returns a rekeying intervals in bytes. -func (a *directionAlgorithms) rekeyBytes() int64 { - // According to RFC 4344 block ciphers should rekey after - // 2^(BLOCKSIZE/4) blocks. For all AES flavors BLOCKSIZE is - // 128. - switch a.Cipher { - case "aes128-ctr", "aes192-ctr", "aes256-ctr", gcm128CipherID, gcm256CipherID, aes128cbcID: - return 16 * (1 << 32) - - } - - // For others, stick with RFC 4253 recommendation to rekey after 1 Gb of data. - return 1 << 30 -} - -var aeadCiphers = map[string]bool{ - gcm128CipherID: true, - gcm256CipherID: true, - chacha20Poly1305ID: true, -} - -type algorithms struct { - kex string - hostKey string - w directionAlgorithms - r directionAlgorithms -} - -func findAgreedAlgorithms(isClient bool, clientKexInit, serverKexInit *kexInitMsg) (algs *algorithms, err error) { - result := &algorithms{} - - result.kex, err = findCommon("key exchange", clientKexInit.KexAlgos, serverKexInit.KexAlgos) - if err != nil { - return - } - - result.hostKey, err = findCommon("host key", clientKexInit.ServerHostKeyAlgos, serverKexInit.ServerHostKeyAlgos) - if err != nil { - return - } - - stoc, ctos := &result.w, &result.r - if isClient { - ctos, stoc = stoc, ctos - } - - ctos.Cipher, err = findCommon("client to server cipher", clientKexInit.CiphersClientServer, serverKexInit.CiphersClientServer) - if err != nil { - return - } - - stoc.Cipher, err = findCommon("server to client cipher", clientKexInit.CiphersServerClient, serverKexInit.CiphersServerClient) - if err != nil { - return - } - - if !aeadCiphers[ctos.Cipher] { - ctos.MAC, err = findCommon("client to server MAC", clientKexInit.MACsClientServer, serverKexInit.MACsClientServer) - if err != nil { - return - } - } - - if !aeadCiphers[stoc.Cipher] { - stoc.MAC, err = findCommon("server to client MAC", clientKexInit.MACsServerClient, serverKexInit.MACsServerClient) - if err != nil { - return - } - } - - ctos.Compression, err = findCommon("client to server compression", clientKexInit.CompressionClientServer, serverKexInit.CompressionClientServer) - if err != nil { - return - } - - stoc.Compression, err = findCommon("server to client compression", clientKexInit.CompressionServerClient, serverKexInit.CompressionServerClient) - if err != nil { - return - } - - return result, nil -} - -// If rekeythreshold is too small, we can't make any progress sending -// stuff. -const minRekeyThreshold uint64 = 256 - -// Config contains configuration data common to both ServerConfig and -// ClientConfig. -type Config struct { - // Rand provides the source of entropy for cryptographic - // primitives. If Rand is nil, the cryptographic random reader - // in package crypto/rand will be used. - Rand io.Reader - - // The maximum number of bytes sent or received after which a - // new key is negotiated. It must be at least 256. If - // unspecified, a size suitable for the chosen cipher is used. - RekeyThreshold uint64 - - // The allowed key exchanges algorithms. If unspecified then a default set - // of algorithms is used. Unsupported values are silently ignored. - KeyExchanges []string - - // The allowed cipher algorithms. If unspecified then a sensible default is - // used. Unsupported values are silently ignored. - Ciphers []string - - // The allowed MAC algorithms. If unspecified then a sensible default is - // used. Unsupported values are silently ignored. - MACs []string -} - -// SetDefaults sets sensible values for unset fields in config. This is -// exported for testing: Configs passed to SSH functions are copied and have -// default values set automatically. -func (c *Config) SetDefaults() { - if c.Rand == nil { - c.Rand = rand.Reader - } - if c.Ciphers == nil { - c.Ciphers = preferredCiphers - } - var ciphers []string - for _, c := range c.Ciphers { - if cipherModes[c] != nil { - // Ignore the cipher if we have no cipherModes definition. - ciphers = append(ciphers, c) - } - } - c.Ciphers = ciphers - - if c.KeyExchanges == nil { - c.KeyExchanges = preferredKexAlgos - } - var kexs []string - for _, k := range c.KeyExchanges { - if kexAlgoMap[k] != nil { - // Ignore the KEX if we have no kexAlgoMap definition. - kexs = append(kexs, k) - } - } - c.KeyExchanges = kexs - - if c.MACs == nil { - c.MACs = supportedMACs - } - var macs []string - for _, m := range c.MACs { - if macModes[m] != nil { - // Ignore the MAC if we have no macModes definition. - macs = append(macs, m) - } - } - c.MACs = macs - - if c.RekeyThreshold == 0 { - // cipher specific default - } else if c.RekeyThreshold < minRekeyThreshold { - c.RekeyThreshold = minRekeyThreshold - } else if c.RekeyThreshold >= math.MaxInt64 { - // Avoid weirdness if somebody uses -1 as a threshold. - c.RekeyThreshold = math.MaxInt64 - } -} - -// buildDataSignedForAuth returns the data that is signed in order to prove -// possession of a private key. See RFC 4252, section 7. algo is the advertised -// algorithm, and may be a certificate type. -func buildDataSignedForAuth(sessionID []byte, req userAuthRequestMsg, algo string, pubKey []byte) []byte { - data := struct { - Session []byte - Type byte - User string - Service string - Method string - Sign bool - Algo string - PubKey []byte - }{ - sessionID, - msgUserAuthRequest, - req.User, - req.Service, - req.Method, - true, - algo, - pubKey, - } - return Marshal(data) -} - -func appendU16(buf []byte, n uint16) []byte { - return append(buf, byte(n>>8), byte(n)) -} - -func appendU32(buf []byte, n uint32) []byte { - return append(buf, byte(n>>24), byte(n>>16), byte(n>>8), byte(n)) -} - -func appendU64(buf []byte, n uint64) []byte { - return append(buf, - byte(n>>56), byte(n>>48), byte(n>>40), byte(n>>32), - byte(n>>24), byte(n>>16), byte(n>>8), byte(n)) -} - -func appendInt(buf []byte, n int) []byte { - return appendU32(buf, uint32(n)) -} - -func appendString(buf []byte, s string) []byte { - buf = appendU32(buf, uint32(len(s))) - buf = append(buf, s...) - return buf -} - -func appendBool(buf []byte, b bool) []byte { - if b { - return append(buf, 1) - } - return append(buf, 0) -} - -// newCond is a helper to hide the fact that there is no usable zero -// value for sync.Cond. -func newCond() *sync.Cond { return sync.NewCond(new(sync.Mutex)) } - -// window represents the buffer available to clients -// wishing to write to a channel. -type window struct { - *sync.Cond - win uint32 // RFC 4254 5.2 says the window size can grow to 2^32-1 - writeWaiters int - closed bool -} - -// add adds win to the amount of window available -// for consumers. -func (w *window) add(win uint32) bool { - // a zero sized window adjust is a noop. - if win == 0 { - return true - } - w.L.Lock() - if w.win+win < win { - w.L.Unlock() - return false - } - w.win += win - // It is unusual that multiple goroutines would be attempting to reserve - // window space, but not guaranteed. Use broadcast to notify all waiters - // that additional window is available. - w.Broadcast() - w.L.Unlock() - return true -} - -// close sets the window to closed, so all reservations fail -// immediately. -func (w *window) close() { - w.L.Lock() - w.closed = true - w.Broadcast() - w.L.Unlock() -} - -// reserve reserves win from the available window capacity. -// If no capacity remains, reserve will block. reserve may -// return less than requested. -func (w *window) reserve(win uint32) (uint32, error) { - var err error - w.L.Lock() - w.writeWaiters++ - w.Broadcast() - for w.win == 0 && !w.closed { - w.Wait() - } - w.writeWaiters-- - if w.win < win { - win = w.win - } - w.win -= win - if w.closed { - err = io.EOF - } - w.L.Unlock() - return win, err -} - -// waitWriterBlocked waits until some goroutine is blocked for further -// writes. It is used in tests only. -func (w *window) waitWriterBlocked() { - w.Cond.L.Lock() - for w.writeWaiters == 0 { - w.Cond.Wait() - } - w.Cond.L.Unlock() -} |