From 68c313911e8a3aed605a12398442212b99f41619 Mon Sep 17 00:00:00 2001 From: Daniel J Walsh Date: Sat, 22 Feb 2020 05:28:21 -0500 Subject: Update vendor of buildah and containers/common Signed-off-by: Daniel J Walsh --- vendor/golang.org/x/crypto/ssh/keys.go | 474 +++++++++++++++++++++++++++++---- 1 file changed, 420 insertions(+), 54 deletions(-) (limited to 'vendor/golang.org/x/crypto/ssh/keys.go') diff --git a/vendor/golang.org/x/crypto/ssh/keys.go b/vendor/golang.org/x/crypto/ssh/keys.go index 969804794..06f537c13 100644 --- a/vendor/golang.org/x/crypto/ssh/keys.go +++ b/vendor/golang.org/x/crypto/ssh/keys.go @@ -7,6 +7,8 @@ package ssh import ( "bytes" "crypto" + "crypto/aes" + "crypto/cipher" "crypto/dsa" "crypto/ecdsa" "crypto/elliptic" @@ -25,17 +27,20 @@ import ( "strings" "golang.org/x/crypto/ed25519" + "golang.org/x/crypto/ssh/internal/bcrypt_pbkdf" ) // 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" - KeyAlgoED25519 = "ssh-ed25519" + KeyAlgoRSA = "ssh-rsa" + KeyAlgoDSA = "ssh-dss" + KeyAlgoECDSA256 = "ecdsa-sha2-nistp256" + KeyAlgoSKECDSA256 = "sk-ecdsa-sha2-nistp256@openssh.com" + KeyAlgoECDSA384 = "ecdsa-sha2-nistp384" + KeyAlgoECDSA521 = "ecdsa-sha2-nistp521" + KeyAlgoED25519 = "ssh-ed25519" + KeyAlgoSKED25519 = "sk-ssh-ed25519@openssh.com" ) // These constants represent non-default signature algorithms that are supported @@ -58,9 +63,13 @@ func parsePubKey(in []byte, algo string) (pubKey PublicKey, rest []byte, err err return parseDSA(in) case KeyAlgoECDSA256, KeyAlgoECDSA384, KeyAlgoECDSA521: return parseECDSA(in) + case KeyAlgoSKECDSA256: + return parseSKECDSA(in) case KeyAlgoED25519: return parseED25519(in) - case CertAlgoRSAv01, CertAlgoDSAv01, CertAlgoECDSA256v01, CertAlgoECDSA384v01, CertAlgoECDSA521v01, CertAlgoED25519v01: + case KeyAlgoSKED25519: + return parseSKEd25519(in) + case CertAlgoRSAv01, CertAlgoDSAv01, CertAlgoECDSA256v01, CertAlgoECDSA384v01, CertAlgoECDSA521v01, CertAlgoSKECDSA256v01, CertAlgoED25519v01, CertAlgoSKED25519v01: cert, err := parseCert(in, certToPrivAlgo(algo)) if err != nil { return nil, nil, err @@ -553,9 +562,11 @@ func parseED25519(in []byte) (out PublicKey, rest []byte, err error) { return nil, nil, err } - key := ed25519.PublicKey(w.KeyBytes) + if l := len(w.KeyBytes); l != ed25519.PublicKeySize { + return nil, nil, fmt.Errorf("invalid size %d for Ed25519 public key", l) + } - return (ed25519PublicKey)(key), w.Rest, nil + return ed25519PublicKey(w.KeyBytes), w.Rest, nil } func (k ed25519PublicKey) Marshal() []byte { @@ -573,9 +584,11 @@ func (k ed25519PublicKey) Verify(b []byte, sig *Signature) error { if sig.Format != k.Type() { return fmt.Errorf("ssh: signature type %s for key type %s", sig.Format, k.Type()) } + if l := len(k); l != ed25519.PublicKeySize { + return fmt.Errorf("ssh: invalid size %d for Ed25519 public key", l) + } - edKey := (ed25519.PublicKey)(k) - if ok := ed25519.Verify(edKey, b, sig.Blob); !ok { + if ok := ed25519.Verify(ed25519.PublicKey(k), b, sig.Blob); !ok { return errors.New("ssh: signature did not verify") } @@ -685,6 +698,224 @@ func (k *ecdsaPublicKey) CryptoPublicKey() crypto.PublicKey { return (*ecdsa.PublicKey)(k) } +// skFields holds the additional fields present in U2F/FIDO2 signatures. +// See openssh/PROTOCOL.u2f 'SSH U2F Signatures' for details. +type skFields struct { + // Flags contains U2F/FIDO2 flags such as 'user present' + Flags byte + // Counter is a monotonic signature counter which can be + // used to detect concurrent use of a private key, should + // it be extracted from hardware. + Counter uint32 +} + +type skECDSAPublicKey struct { + // application is a URL-like string, typically "ssh:" for SSH. + // see openssh/PROTOCOL.u2f for details. + application string + ecdsa.PublicKey +} + +func (k *skECDSAPublicKey) Type() string { + return KeyAlgoSKECDSA256 +} + +func (k *skECDSAPublicKey) nistID() string { + return "nistp256" +} + +func parseSKECDSA(in []byte) (out PublicKey, rest []byte, err error) { + var w struct { + Curve string + KeyBytes []byte + Application string + Rest []byte `ssh:"rest"` + } + + if err := Unmarshal(in, &w); err != nil { + return nil, nil, err + } + + key := new(skECDSAPublicKey) + key.application = w.Application + + if w.Curve != "nistp256" { + return nil, nil, errors.New("ssh: unsupported curve") + } + key.Curve = elliptic.P256() + + 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 key, w.Rest, nil +} + +func (k *skECDSAPublicKey) Marshal() []byte { + // See RFC 5656, section 3.1. + keyBytes := elliptic.Marshal(k.Curve, k.X, k.Y) + w := struct { + Name string + ID string + Key []byte + Application string + }{ + k.Type(), + k.nistID(), + keyBytes, + k.application, + } + + return Marshal(&w) +} + +func (k *skECDSAPublicKey) 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 := ecHash(k.Curve).New() + h.Write([]byte(k.application)) + appDigest := h.Sum(nil) + + h.Reset() + h.Write(data) + dataDigest := h.Sum(nil) + + var ecSig struct { + R *big.Int + S *big.Int + } + if err := Unmarshal(sig.Blob, &ecSig); err != nil { + return err + } + + var skf skFields + if err := Unmarshal(sig.Rest, &skf); err != nil { + return err + } + + blob := struct { + ApplicationDigest []byte `ssh:"rest"` + Flags byte + Counter uint32 + MessageDigest []byte `ssh:"rest"` + }{ + appDigest, + skf.Flags, + skf.Counter, + dataDigest, + } + + original := Marshal(blob) + + h.Reset() + h.Write(original) + digest := h.Sum(nil) + + if ecdsa.Verify((*ecdsa.PublicKey)(&k.PublicKey), digest, ecSig.R, ecSig.S) { + return nil + } + return errors.New("ssh: signature did not verify") +} + +type skEd25519PublicKey struct { + // application is a URL-like string, typically "ssh:" for SSH. + // see openssh/PROTOCOL.u2f for details. + application string + ed25519.PublicKey +} + +func (k *skEd25519PublicKey) Type() string { + return KeyAlgoSKED25519 +} + +func parseSKEd25519(in []byte) (out PublicKey, rest []byte, err error) { + var w struct { + KeyBytes []byte + Application string + Rest []byte `ssh:"rest"` + } + + if err := Unmarshal(in, &w); err != nil { + return nil, nil, err + } + + if l := len(w.KeyBytes); l != ed25519.PublicKeySize { + return nil, nil, fmt.Errorf("invalid size %d for Ed25519 public key", l) + } + + key := new(skEd25519PublicKey) + key.application = w.Application + key.PublicKey = ed25519.PublicKey(w.KeyBytes) + + return key, w.Rest, nil +} + +func (k *skEd25519PublicKey) Marshal() []byte { + w := struct { + Name string + KeyBytes []byte + Application string + }{ + KeyAlgoSKED25519, + []byte(k.PublicKey), + k.application, + } + return Marshal(&w) +} + +func (k *skEd25519PublicKey) 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()) + } + if l := len(k.PublicKey); l != ed25519.PublicKeySize { + return fmt.Errorf("invalid size %d for Ed25519 public key", l) + } + + h := sha256.New() + h.Write([]byte(k.application)) + appDigest := h.Sum(nil) + + h.Reset() + h.Write(data) + dataDigest := h.Sum(nil) + + var edSig struct { + Signature []byte `ssh:"rest"` + } + + if err := Unmarshal(sig.Blob, &edSig); err != nil { + return err + } + + var skf skFields + if err := Unmarshal(sig.Rest, &skf); err != nil { + return err + } + + blob := struct { + ApplicationDigest []byte `ssh:"rest"` + Flags byte + Counter uint32 + MessageDigest []byte `ssh:"rest"` + }{ + appDigest, + skf.Flags, + skf.Counter, + dataDigest, + } + + original := Marshal(blob) + + if ok := ed25519.Verify(k.PublicKey, original, edSig.Signature); !ok { + return errors.New("ssh: signature did not verify") + } + + return nil +} + // NewSignerFromKey takes an *rsa.PrivateKey, *dsa.PrivateKey, // *ecdsa.PrivateKey or any other crypto.Signer and returns a // corresponding Signer instance. ECDSA keys must use P-256, P-384 or @@ -830,14 +1061,18 @@ func NewPublicKey(key interface{}) (PublicKey, error) { case *dsa.PublicKey: return (*dsaPublicKey)(key), nil case ed25519.PublicKey: - return (ed25519PublicKey)(key), nil + if l := len(key); l != ed25519.PublicKeySize { + return nil, fmt.Errorf("ssh: invalid size %d for Ed25519 public key", l) + } + return ed25519PublicKey(key), nil default: return nil, fmt.Errorf("ssh: unsupported key type %T", key) } } // ParsePrivateKey returns a Signer from a PEM encoded private key. It supports -// the same keys as ParseRawPrivateKey. +// the same keys as ParseRawPrivateKey. If the private key is encrypted, it +// will return a PassphraseMissingError. func ParsePrivateKey(pemBytes []byte) (Signer, error) { key, err := ParseRawPrivateKey(pemBytes) if err != nil { @@ -850,8 +1085,8 @@ func ParsePrivateKey(pemBytes []byte) (Signer, error) { // ParsePrivateKeyWithPassphrase returns a Signer from a PEM encoded private // key and passphrase. It supports the same keys as // ParseRawPrivateKeyWithPassphrase. -func ParsePrivateKeyWithPassphrase(pemBytes, passPhrase []byte) (Signer, error) { - key, err := ParseRawPrivateKeyWithPassphrase(pemBytes, passPhrase) +func ParsePrivateKeyWithPassphrase(pemBytes, passphrase []byte) (Signer, error) { + key, err := ParseRawPrivateKeyWithPassphrase(pemBytes, passphrase) if err != nil { return nil, err } @@ -867,8 +1102,21 @@ func encryptedBlock(block *pem.Block) bool { return strings.Contains(block.Headers["Proc-Type"], "ENCRYPTED") } +// A PassphraseMissingError indicates that parsing this private key requires a +// passphrase. Use ParsePrivateKeyWithPassphrase. +type PassphraseMissingError struct { + // PublicKey will be set if the private key format includes an unencrypted + // public key along with the encrypted private key. + PublicKey PublicKey +} + +func (*PassphraseMissingError) Error() string { + return "ssh: this private key is passphrase protected" +} + // ParseRawPrivateKey returns a private key from a PEM encoded private key. It -// supports RSA (PKCS#1), PKCS#8, DSA (OpenSSL), and ECDSA private keys. +// supports RSA (PKCS#1), PKCS#8, DSA (OpenSSL), and ECDSA private keys. If the +// private key is encrypted, it will return a PassphraseMissingError. func ParseRawPrivateKey(pemBytes []byte) (interface{}, error) { block, _ := pem.Decode(pemBytes) if block == nil { @@ -876,7 +1124,7 @@ func ParseRawPrivateKey(pemBytes []byte) (interface{}, error) { } if encryptedBlock(block) { - return nil, errors.New("ssh: cannot decode encrypted private keys") + return nil, &PassphraseMissingError{} } switch block.Type { @@ -890,33 +1138,35 @@ func ParseRawPrivateKey(pemBytes []byte) (interface{}, error) { case "DSA PRIVATE KEY": return ParseDSAPrivateKey(block.Bytes) case "OPENSSH PRIVATE KEY": - return parseOpenSSHPrivateKey(block.Bytes) + return parseOpenSSHPrivateKey(block.Bytes, unencryptedOpenSSHKey) default: return nil, fmt.Errorf("ssh: unsupported key type %q", block.Type) } } // ParseRawPrivateKeyWithPassphrase returns a private key decrypted with -// passphrase from a PEM encoded private key. If wrong passphrase, return -// x509.IncorrectPasswordError. -func ParseRawPrivateKeyWithPassphrase(pemBytes, passPhrase []byte) (interface{}, error) { +// passphrase from a PEM encoded private key. If the passphrase is wrong, it +// will return x509.IncorrectPasswordError. +func ParseRawPrivateKeyWithPassphrase(pemBytes, passphrase []byte) (interface{}, error) { block, _ := pem.Decode(pemBytes) if block == nil { return nil, errors.New("ssh: no key found") } - buf := block.Bytes - if encryptedBlock(block) { - if x509.IsEncryptedPEMBlock(block) { - var err error - buf, err = x509.DecryptPEMBlock(block, passPhrase) - if err != nil { - if err == x509.IncorrectPasswordError { - return nil, err - } - return nil, fmt.Errorf("ssh: cannot decode encrypted private keys: %v", err) - } + if block.Type == "OPENSSH PRIVATE KEY" { + return parseOpenSSHPrivateKey(block.Bytes, passphraseProtectedOpenSSHKey(passphrase)) + } + + if !encryptedBlock(block) || !x509.IsEncryptedPEMBlock(block) { + return nil, errors.New("ssh: not an encrypted key") + } + + buf, err := x509.DecryptPEMBlock(block, passphrase) + if err != nil { + if err == x509.IncorrectPasswordError { + return nil, err } + return nil, fmt.Errorf("ssh: cannot decode encrypted private keys: %v", err) } switch block.Type { @@ -926,8 +1176,6 @@ func ParseRawPrivateKeyWithPassphrase(pemBytes, passPhrase []byte) (interface{}, return x509.ParseECPrivateKey(buf) case "DSA PRIVATE KEY": return ParseDSAPrivateKey(buf) - case "OPENSSH PRIVATE KEY": - return parseOpenSSHPrivateKey(buf) default: return nil, fmt.Errorf("ssh: unsupported key type %q", block.Type) } @@ -965,9 +1213,60 @@ func ParseDSAPrivateKey(der []byte) (*dsa.PrivateKey, error) { }, nil } -// Implemented based on the documentation at -// https://github.com/openssh/openssh-portable/blob/master/PROTOCOL.key -func parseOpenSSHPrivateKey(key []byte) (crypto.PrivateKey, error) { +func unencryptedOpenSSHKey(cipherName, kdfName, kdfOpts string, privKeyBlock []byte) ([]byte, error) { + if kdfName != "none" || cipherName != "none" { + return nil, &PassphraseMissingError{} + } + if kdfOpts != "" { + return nil, errors.New("ssh: invalid openssh private key") + } + return privKeyBlock, nil +} + +func passphraseProtectedOpenSSHKey(passphrase []byte) openSSHDecryptFunc { + return func(cipherName, kdfName, kdfOpts string, privKeyBlock []byte) ([]byte, error) { + if kdfName == "none" || cipherName == "none" { + return nil, errors.New("ssh: key is not password protected") + } + if kdfName != "bcrypt" { + return nil, fmt.Errorf("ssh: unknown KDF %q, only supports %q", kdfName, "bcrypt") + } + + var opts struct { + Salt string + Rounds uint32 + } + if err := Unmarshal([]byte(kdfOpts), &opts); err != nil { + return nil, err + } + + k, err := bcrypt_pbkdf.Key(passphrase, []byte(opts.Salt), int(opts.Rounds), 32+16) + if err != nil { + return nil, err + } + key, iv := k[:32], k[32:] + + if cipherName != "aes256-ctr" { + return nil, fmt.Errorf("ssh: unknown cipher %q, only supports %q", cipherName, "aes256-ctr") + } + c, err := aes.NewCipher(key) + if err != nil { + return nil, err + } + ctr := cipher.NewCTR(c, iv) + ctr.XORKeyStream(privKeyBlock, privKeyBlock) + + return privKeyBlock, nil + } +} + +type openSSHDecryptFunc func(CipherName, KdfName, KdfOpts string, PrivKeyBlock []byte) ([]byte, error) + +// parseOpenSSHPrivateKey parses an OpenSSH private key, using the decrypt +// function to unwrap the encrypted portion. unencryptedOpenSSHKey can be used +// as the decrypt function to parse an unencrypted private key. See +// https://github.com/openssh/openssh-portable/blob/master/PROTOCOL.key. +func parseOpenSSHPrivateKey(key []byte, decrypt openSSHDecryptFunc) (crypto.PrivateKey, error) { const magic = "openssh-key-v1\x00" if len(key) < len(magic) || string(key[:len(magic)]) != magic { return nil, errors.New("ssh: invalid openssh private key format") @@ -986,9 +1285,22 @@ func parseOpenSSHPrivateKey(key []byte) (crypto.PrivateKey, error) { if err := Unmarshal(remaining, &w); err != nil { return nil, err } + if w.NumKeys != 1 { + // We only support single key files, and so does OpenSSH. + // https://github.com/openssh/openssh-portable/blob/4103a3ec7/sshkey.c#L4171 + return nil, errors.New("ssh: multi-key files are not supported") + } - if w.KdfName != "none" || w.CipherName != "none" { - return nil, errors.New("ssh: cannot decode encrypted private keys") + privKeyBlock, err := decrypt(w.CipherName, w.KdfName, w.KdfOpts, w.PrivKeyBlock) + if err != nil { + if err, ok := err.(*PassphraseMissingError); ok { + pub, errPub := ParsePublicKey(w.PubKey) + if errPub != nil { + return nil, fmt.Errorf("ssh: failed to parse embedded public key: %v", errPub) + } + err.PublicKey = pub + } + return nil, err } pk1 := struct { @@ -998,15 +1310,13 @@ func parseOpenSSHPrivateKey(key []byte) (crypto.PrivateKey, error) { Rest []byte `ssh:"rest"` }{} - if err := Unmarshal(w.PrivKeyBlock, &pk1); err != nil { - return nil, err - } - - if pk1.Check1 != pk1.Check2 { - return nil, errors.New("ssh: checkint mismatch") + if err := Unmarshal(privKeyBlock, &pk1); err != nil || pk1.Check1 != pk1.Check2 { + if w.CipherName != "none" { + return nil, x509.IncorrectPasswordError + } + return nil, errors.New("ssh: malformed OpenSSH key") } - // we only handle ed25519 and rsa keys currently switch pk1.Keytype { case KeyAlgoRSA: // https://github.com/openssh/openssh-portable/blob/master/sshkey.c#L2760-L2773 @@ -1025,10 +1335,8 @@ func parseOpenSSHPrivateKey(key []byte) (crypto.PrivateKey, error) { return nil, err } - for i, b := range key.Pad { - if int(b) != i+1 { - return nil, errors.New("ssh: padding not as expected") - } + if err := checkOpenSSHKeyPadding(key.Pad); err != nil { + return nil, err } pk := &rsa.PrivateKey{ @@ -1063,20 +1371,78 @@ func parseOpenSSHPrivateKey(key []byte) (crypto.PrivateKey, error) { return nil, errors.New("ssh: private key unexpected length") } - for i, b := range key.Pad { - if int(b) != i+1 { - return nil, errors.New("ssh: padding not as expected") - } + if err := checkOpenSSHKeyPadding(key.Pad); err != nil { + return nil, err } pk := ed25519.PrivateKey(make([]byte, ed25519.PrivateKeySize)) copy(pk, key.Priv) return &pk, nil + case KeyAlgoECDSA256, KeyAlgoECDSA384, KeyAlgoECDSA521: + key := struct { + Curve string + Pub []byte + D *big.Int + Comment string + Pad []byte `ssh:"rest"` + }{} + + if err := Unmarshal(pk1.Rest, &key); err != nil { + return nil, err + } + + if err := checkOpenSSHKeyPadding(key.Pad); err != nil { + return nil, err + } + + var curve elliptic.Curve + switch key.Curve { + case "nistp256": + curve = elliptic.P256() + case "nistp384": + curve = elliptic.P384() + case "nistp521": + curve = elliptic.P521() + default: + return nil, errors.New("ssh: unhandled elliptic curve: " + key.Curve) + } + + X, Y := elliptic.Unmarshal(curve, key.Pub) + if X == nil || Y == nil { + return nil, errors.New("ssh: failed to unmarshal public key") + } + + if key.D.Cmp(curve.Params().N) >= 0 { + return nil, errors.New("ssh: scalar is out of range") + } + + x, y := curve.ScalarBaseMult(key.D.Bytes()) + if x.Cmp(X) != 0 || y.Cmp(Y) != 0 { + return nil, errors.New("ssh: public key does not match private key") + } + + return &ecdsa.PrivateKey{ + PublicKey: ecdsa.PublicKey{ + Curve: curve, + X: X, + Y: Y, + }, + D: key.D, + }, nil default: return nil, errors.New("ssh: unhandled key type") } } +func checkOpenSSHKeyPadding(pad []byte) error { + for i, b := range pad { + if int(b) != i+1 { + return errors.New("ssh: padding not as expected") + } + } + return nil +} + // FingerprintLegacyMD5 returns the user presentation of the key's // fingerprint as described by RFC 4716 section 4. func FingerprintLegacyMD5(pubKey PublicKey) string { -- cgit v1.2.3-54-g00ecf