fix subrepo break change

modules/crypto/ssh/keys.go

@@ -0,0 +1,628 @@
+// Copyright 2012 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 (
+	"bytes"
+	"crypto"
+	"crypto/dsa"
+	"crypto/ecdsa"
+	"crypto/elliptic"
+	"crypto/rsa"
+	"crypto/x509"
+	"encoding/asn1"
+	"encoding/base64"
+	"encoding/pem"
+	"errors"
+	"fmt"
+	"io"
+	"math/big"
+)
+
+// These constants represent the algorithm names for key types supported by this
+// package.
+const (
+	KeyAlgoRSA      = "ssh-rsa"
+	KeyAlgoDSA      = "ssh-dss"
+	KeyAlgoECDSA256 = "ecdsa-sha2-nistp256"
+	KeyAlgoECDSA384 = "ecdsa-sha2-nistp384"
+	KeyAlgoECDSA521 = "ecdsa-sha2-nistp521"
+)
+
+// parsePubKey parses a public key of the given algorithm.
+// Use ParsePublicKey for keys with prepended algorithm.
+func parsePubKey(in []byte, algo string) (pubKey PublicKey, rest []byte, err error) {
+	switch algo {
+	case KeyAlgoRSA:
+		return parseRSA(in)
+	case KeyAlgoDSA:
+		return parseDSA(in)
+	case KeyAlgoECDSA256, KeyAlgoECDSA384, KeyAlgoECDSA521:
+		return parseECDSA(in)
+	case CertAlgoRSAv01, CertAlgoDSAv01, CertAlgoECDSA256v01, CertAlgoECDSA384v01, CertAlgoECDSA521v01:
+		cert, err := parseCert(in, certToPrivAlgo(algo))
+		if err != nil {
+			return nil, nil, err
+		}
+		return cert, nil, nil
+	}
+	return nil, nil, fmt.Errorf("ssh: unknown key algorithm: %v", err)
+}
+
+// parseAuthorizedKey parses a public key in OpenSSH authorized_keys format
+// (see sshd(8) manual page) once the options and key type fields have been
+// removed.
+func parseAuthorizedKey(in []byte) (out PublicKey, comment string, err error) {
+	in = bytes.TrimSpace(in)
+
+	i := bytes.IndexAny(in, " \t")
+	if i == -1 {
+		i = len(in)
+	}
+	base64Key := in[:i]
+
+	key := make([]byte, base64.StdEncoding.DecodedLen(len(base64Key)))
+	n, err := base64.StdEncoding.Decode(key, base64Key)
+	if err != nil {
+		return nil, "", err
+	}
+	key = key[:n]
+	out, err = ParsePublicKey(key)
+	if err != nil {
+		return nil, "", err
+	}
+	comment = string(bytes.TrimSpace(in[i:]))
+	return out, comment, nil
+}
+
+// ParseAuthorizedKeys parses a public key from an authorized_keys
+// file used in OpenSSH according to the sshd(8) manual page.
+func ParseAuthorizedKey(in []byte) (out PublicKey, comment string, options []string, rest []byte, err error) {
+	for len(in) > 0 {
+		end := bytes.IndexByte(in, '\n')
+		if end != -1 {
+			rest = in[end+1:]
+			in = in[:end]
+		} else {
+			rest = nil
+		}
+
+		end = bytes.IndexByte(in, '\r')
+		if end != -1 {
+			in = in[:end]
+		}
+
+		in = bytes.TrimSpace(in)
+		if len(in) == 0 || in[0] == '#' {
+			in = rest
+			continue
+		}
+
+		i := bytes.IndexAny(in, " \t")
+		if i == -1 {
+			in = rest
+			continue
+		}
+
+		if out, comment, err = parseAuthorizedKey(in[i:]); err == nil {
+			return out, comment, options, rest, nil
+		}
+
+		// No key type recognised. Maybe there's an options field at
+		// the beginning.
+		var b byte
+		inQuote := false
+		var candidateOptions []string
+		optionStart := 0
+		for i, b = range in {
+			isEnd := !inQuote && (b == ' ' || b == '\t')
+			if (b == ',' && !inQuote) || isEnd {
+				if i-optionStart > 0 {
+					candidateOptions = append(candidateOptions, string(in[optionStart:i]))
+				}
+				optionStart = i + 1
+			}
+			if isEnd {
+				break
+			}
+			if b == '"' && (i == 0 || (i > 0 && in[i-1] != '\\')) {
+				inQuote = !inQuote
+			}
+		}
+		for i < len(in) && (in[i] == ' ' || in[i] == '\t') {
+			i++
+		}
+		if i == len(in) {
+			// Invalid line: unmatched quote
+			in = rest
+			continue
+		}
+
+		in = in[i:]
+		i = bytes.IndexAny(in, " \t")
+		if i == -1 {
+			in = rest
+			continue
+		}
+
+		if out, comment, err = parseAuthorizedKey(in[i:]); err == nil {
+			options = candidateOptions
+			return out, comment, options, rest, nil
+		}
+
+		in = rest
+		continue
+	}
+
+	return nil, "", nil, nil, errors.New("ssh: no key found")
+}
+
+// ParsePublicKey parses an SSH public key formatted for use in
+// the SSH wire protocol according to RFC 4253, section 6.6.
+func ParsePublicKey(in []byte) (out PublicKey, err error) {
+	algo, in, ok := parseString(in)
+	if !ok {
+		return nil, errShortRead
+	}
+	var rest []byte
+	out, rest, err = parsePubKey(in, string(algo))
+	if len(rest) > 0 {
+		return nil, errors.New("ssh: trailing junk in public key")
+	}
+
+	return out, err
+}
+
+// MarshalAuthorizedKey serializes key for inclusion in an OpenSSH
+// authorized_keys file. The return value ends with newline.
+func MarshalAuthorizedKey(key PublicKey) []byte {
+	b := &bytes.Buffer{}
+	b.WriteString(key.Type())
+	b.WriteByte(' ')
+	e := base64.NewEncoder(base64.StdEncoding, b)
+	e.Write(key.Marshal())
+	e.Close()
+	b.WriteByte('\n')
+	return b.Bytes()
+}
+
+// PublicKey is an abstraction of different types of public keys.
+type PublicKey interface {
+	// Type returns the key's type, e.g. "ssh-rsa".
+	Type() string
+
+	// Marshal returns the serialized key data in SSH wire format,
+	// with the name prefix.
+	Marshal() []byte
+
+	// Verify that sig is a signature on the given data using this
+	// key. This function will hash the data appropriately first.
+	Verify(data []byte, sig *Signature) error
+}
+
+// A Signer can create signatures that verify against a public key.
+type Signer interface {
+	// PublicKey returns an associated PublicKey instance.
+	PublicKey() PublicKey
+
+	// Sign returns raw signature for the given data. This method
+	// will apply the hash specified for the keytype to the data.
+	Sign(rand io.Reader, data []byte) (*Signature, error)
+}
+
+type rsaPublicKey rsa.PublicKey
+
+func (r *rsaPublicKey) Type() string {
+	return "ssh-rsa"
+}
+
+// parseRSA parses an RSA key according to RFC 4253, section 6.6.
+func parseRSA(in []byte) (out PublicKey, rest []byte, err error) {
+	var w struct {
+		E    *big.Int
+		N    *big.Int
+		Rest []byte `ssh:"rest"`
+	}
+	if err := Unmarshal(in, &w); err != nil {
+		return nil, nil, err
+	}
+
+	if w.E.BitLen() > 24 {
+		return nil, nil, errors.New("ssh: exponent too large")
+	}
+	e := w.E.Int64()
+	if e < 3 || e&1 == 0 {
+		return nil, nil, errors.New("ssh: incorrect exponent")
+	}
+
+	var key rsa.PublicKey
+	key.E = int(e)
+	key.N = w.N
+	return (*rsaPublicKey)(&key), w.Rest, nil
+}
+
+func (r *rsaPublicKey) Marshal() []byte {
+	e := new(big.Int).SetInt64(int64(r.E))
+	wirekey := struct {
+		Name string
+		E    *big.Int
+		N    *big.Int
+	}{
+		KeyAlgoRSA,
+		e,
+		r.N,
+	}
+	return Marshal(&wirekey)
+}
+
+func (r *rsaPublicKey) Verify(data []byte, sig *Signature) error {
+	if sig.Format != r.Type() {
+		return fmt.Errorf("ssh: signature type %s for key type %s", sig.Format, r.Type())
+	}
+	h := crypto.SHA1.New()
+	h.Write(data)
+	digest := h.Sum(nil)
+	return rsa.VerifyPKCS1v15((*rsa.PublicKey)(r), crypto.SHA1, digest, sig.Blob)
+}
+
+type rsaPrivateKey struct {
+	*rsa.PrivateKey
+}
+
+func (r *rsaPrivateKey) PublicKey() PublicKey {
+	return (*rsaPublicKey)(&r.PrivateKey.PublicKey)
+}
+
+func (r *rsaPrivateKey) Sign(rand io.Reader, data []byte) (*Signature, error) {
+	h := crypto.SHA1.New()
+	h.Write(data)
+	digest := h.Sum(nil)
+	blob, err := rsa.SignPKCS1v15(rand, r.PrivateKey, crypto.SHA1, digest)
+	if err != nil {
+		return nil, err
+	}
+	return &Signature{
+		Format: r.PublicKey().Type(),
+		Blob:   blob,
+	}, nil
+}
+
+type dsaPublicKey dsa.PublicKey
+
+func (r *dsaPublicKey) Type() string {
+	return "ssh-dss"
+}
+
+// parseDSA parses an DSA key according to RFC 4253, section 6.6.
+func parseDSA(in []byte) (out PublicKey, rest []byte, err error) {
+	var w struct {
+		P, Q, G, Y *big.Int
+		Rest       []byte `ssh:"rest"`
+	}
+	if err := Unmarshal(in, &w); err != nil {
+		return nil, nil, err
+	}
+
+	key := &dsaPublicKey{
+		Parameters: dsa.Parameters{
+			P: w.P,
+			Q: w.Q,
+			G: w.G,
+		},
+		Y: w.Y,
+	}
+	return key, w.Rest, nil
+}
+
+func (k *dsaPublicKey) Marshal() []byte {
+	w := struct {
+		Name       string
+		P, Q, G, Y *big.Int
+	}{
+		k.Type(),
+		k.P,
+		k.Q,
+		k.G,
+		k.Y,
+	}
+
+	return Marshal(&w)
+}
+
+func (k *dsaPublicKey) Verify(data []byte, sig *Signature) error {
+	if sig.Format != k.Type() {
+		return fmt.Errorf("ssh: signature type %s for key type %s", sig.Format, k.Type())
+	}
+	h := crypto.SHA1.New()
+	h.Write(data)
+	digest := h.Sum(nil)
+
+	// Per RFC 4253, section 6.6,
+	// The value for 'dss_signature_blob' is encoded as a string containing
+	// r, followed by s (which are 160-bit integers, without lengths or
+	// padding, unsigned, and in network byte order).
+	// For DSS purposes, sig.Blob should be exactly 40 bytes in length.
+	if len(sig.Blob) != 40 {
+		return errors.New("ssh: DSA signature parse error")
+	}
+	r := new(big.Int).SetBytes(sig.Blob[:20])
+	s := new(big.Int).SetBytes(sig.Blob[20:])
+	if dsa.Verify((*dsa.PublicKey)(k), digest, r, s) {
+		return nil
+	}
+	return errors.New("ssh: signature did not verify")
+}
+
+type dsaPrivateKey struct {
+	*dsa.PrivateKey
+}
+
+func (k *dsaPrivateKey) PublicKey() PublicKey {
+	return (*dsaPublicKey)(&k.PrivateKey.PublicKey)
+}
+
+func (k *dsaPrivateKey) Sign(rand io.Reader, data []byte) (*Signature, error) {
+	h := crypto.SHA1.New()
+	h.Write(data)
+	digest := h.Sum(nil)
+	r, s, err := dsa.Sign(rand, k.PrivateKey, digest)
+	if err != nil {
+		return nil, err
+	}
+
+	sig := make([]byte, 40)
+	rb := r.Bytes()
+	sb := s.Bytes()
+
+	copy(sig[20-len(rb):20], rb)
+	copy(sig[40-len(sb):], sb)
+
+	return &Signature{
+		Format: k.PublicKey().Type(),
+		Blob:   sig,
+	}, nil
+}
+
+type ecdsaPublicKey ecdsa.PublicKey
+
+func (key *ecdsaPublicKey) Type() string {
+	return "ecdsa-sha2-" + key.nistID()
+}
+
+func (key *ecdsaPublicKey) nistID() string {
+	switch key.Params().BitSize {
+	case 256:
+		return "nistp256"
+	case 384:
+		return "nistp384"
+	case 521:
+		return "nistp521"
+	}
+	panic("ssh: unsupported ecdsa key size")
+}
+
+func supportedEllipticCurve(curve elliptic.Curve) bool {
+	return curve == elliptic.P256() || curve == elliptic.P384() || curve == elliptic.P521()
+}
+
+// ecHash returns the hash to match the given elliptic curve, see RFC
+// 5656, section 6.2.1
+func ecHash(curve elliptic.Curve) crypto.Hash {
+	bitSize := curve.Params().BitSize
+	switch {
+	case bitSize <= 256:
+		return crypto.SHA256
+	case bitSize <= 384:
+		return crypto.SHA384
+	}
+	return crypto.SHA512
+}
+
+// parseECDSA parses an ECDSA key according to RFC 5656, section 3.1.
+func parseECDSA(in []byte) (out PublicKey, rest []byte, err error) {
+	var w struct {
+		Curve    string
+		KeyBytes []byte
+		Rest     []byte `ssh:"rest"`
+	}
+
+	if err := Unmarshal(in, &w); err != nil {
+		return nil, nil, err
+	}
+
+	key := new(ecdsa.PublicKey)
+
+	switch w.Curve {
+	case "nistp256":
+		key.Curve = elliptic.P256()
+	case "nistp384":
+		key.Curve = elliptic.P384()
+	case "nistp521":
+		key.Curve = elliptic.P521()
+	default:
+		return nil, nil, errors.New("ssh: unsupported curve")
+	}
+
+	key.X, key.Y = elliptic.Unmarshal(key.Curve, w.KeyBytes)
+	if key.X == nil || key.Y == nil {
+		return nil, nil, errors.New("ssh: invalid curve point")
+	}
+	return (*ecdsaPublicKey)(key), w.Rest, nil
+}
+
+func (key *ecdsaPublicKey) Marshal() []byte {
+	// See RFC 5656, section 3.1.
+	keyBytes := elliptic.Marshal(key.Curve, key.X, key.Y)
+	w := struct {
+		Name string
+		ID   string
+		Key  []byte
+	}{
+		key.Type(),
+		key.nistID(),
+		keyBytes,
+	}
+
+	return Marshal(&w)
+}
+
+func (key *ecdsaPublicKey) Verify(data []byte, sig *Signature) error {
+	if sig.Format != key.Type() {
+		return fmt.Errorf("ssh: signature type %s for key type %s", sig.Format, key.Type())
+	}
+
+	h := ecHash(key.Curve).New()
+	h.Write(data)
+	digest := h.Sum(nil)
+
+	// Per RFC 5656, section 3.1.2,
+	// The ecdsa_signature_blob value has the following specific encoding:
+	//    mpint    r
+	//    mpint    s
+	var ecSig struct {
+		R *big.Int
+		S *big.Int
+	}
+
+	if err := Unmarshal(sig.Blob, &ecSig); err != nil {
+		return err
+	}
+
+	if ecdsa.Verify((*ecdsa.PublicKey)(key), digest, ecSig.R, ecSig.S) {
+		return nil
+	}
+	return errors.New("ssh: signature did not verify")
+}
+
+type ecdsaPrivateKey struct {
+	*ecdsa.PrivateKey
+}
+
+func (k *ecdsaPrivateKey) PublicKey() PublicKey {
+	return (*ecdsaPublicKey)(&k.PrivateKey.PublicKey)
+}
+
+func (k *ecdsaPrivateKey) Sign(rand io.Reader, data []byte) (*Signature, error) {
+	h := ecHash(k.PrivateKey.PublicKey.Curve).New()
+	h.Write(data)
+	digest := h.Sum(nil)
+	r, s, err := ecdsa.Sign(rand, k.PrivateKey, digest)
+	if err != nil {
+		return nil, err
+	}
+
+	sig := make([]byte, intLength(r)+intLength(s))
+	rest := marshalInt(sig, r)
+	marshalInt(rest, s)
+	return &Signature{
+		Format: k.PublicKey().Type(),
+		Blob:   sig,
+	}, nil
+}
+
+// NewSignerFromKey takes a pointer to rsa, dsa or ecdsa PrivateKey
+// returns a corresponding Signer instance. EC keys should use P256,
+// P384 or P521.
+func NewSignerFromKey(k interface{}) (Signer, error) {
+	var sshKey Signer
+	switch t := k.(type) {
+	case *rsa.PrivateKey:
+		sshKey = &rsaPrivateKey{t}
+	case *dsa.PrivateKey:
+		sshKey = &dsaPrivateKey{t}
+	case *ecdsa.PrivateKey:
+		if !supportedEllipticCurve(t.Curve) {
+			return nil, errors.New("ssh: only P256, P384 and P521 EC keys are supported.")
+		}
+
+		sshKey = &ecdsaPrivateKey{t}
+	default:
+		return nil, fmt.Errorf("ssh: unsupported key type %T", k)
+	}
+	return sshKey, nil
+}
+
+// NewPublicKey takes a pointer to rsa, dsa or ecdsa PublicKey
+// and returns a corresponding ssh PublicKey instance. EC keys should use P256, P384 or P521.
+func NewPublicKey(k interface{}) (PublicKey, error) {
+	var sshKey PublicKey
+	switch t := k.(type) {
+	case *rsa.PublicKey:
+		sshKey = (*rsaPublicKey)(t)
+	case *ecdsa.PublicKey:
+		if !supportedEllipticCurve(t.Curve) {
+			return nil, errors.New("ssh: only P256, P384 and P521 EC keys are supported.")
+		}
+		sshKey = (*ecdsaPublicKey)(t)
+	case *dsa.PublicKey:
+		sshKey = (*dsaPublicKey)(t)
+	default:
+		return nil, fmt.Errorf("ssh: unsupported key type %T", k)
+	}
+	return sshKey, nil
+}
+
+// ParsePrivateKey returns a Signer from a PEM encoded private key. It supports
+// the same keys as ParseRawPrivateKey.
+func ParsePrivateKey(pemBytes []byte) (Signer, error) {
+	key, err := ParseRawPrivateKey(pemBytes)
+	if err != nil {
+		return nil, err
+	}
+
+	return NewSignerFromKey(key)
+}
+
+// ParseRawPrivateKey returns a private key from a PEM encoded private key. It
+// supports RSA (PKCS#1), DSA (OpenSSL), and ECDSA private keys.
+func ParseRawPrivateKey(pemBytes []byte) (interface{}, error) {
+	block, _ := pem.Decode(pemBytes)
+	if block == nil {
+		return nil, errors.New("ssh: no key found")
+	}
+
+	switch block.Type {
+	case "RSA PRIVATE KEY":
+		return x509.ParsePKCS1PrivateKey(block.Bytes)
+	case "EC PRIVATE KEY":
+		return x509.ParseECPrivateKey(block.Bytes)
+	case "DSA PRIVATE KEY":
+		return ParseDSAPrivateKey(block.Bytes)
+	default:
+		return nil, fmt.Errorf("ssh: unsupported key type %q", block.Type)
+	}
+}
+
+// ParseDSAPrivateKey returns a DSA private key from its ASN.1 DER encoding, as
+// specified by the OpenSSL DSA man page.
+func ParseDSAPrivateKey(der []byte) (*dsa.PrivateKey, error) {
+	var k struct {
+		Version int
+		P       *big.Int
+		Q       *big.Int
+		G       *big.Int
+		Priv    *big.Int
+		Pub     *big.Int
+	}
+	rest, err := asn1.Unmarshal(der, &k)
+	if err != nil {
+		return nil, errors.New("ssh: failed to parse DSA key: " + err.Error())
+	}
+	if len(rest) > 0 {
+		return nil, errors.New("ssh: garbage after DSA key")
+	}
+
+	return &dsa.PrivateKey{
+		PublicKey: dsa.PublicKey{
+			Parameters: dsa.Parameters{
+				P: k.P,
+				Q: k.Q,
+				G: k.G,
+			},
+			Y: k.Priv,
+		},
+		X: k.Pub,
+	}, nil
+}