From 8c12c6939aab9106db14ec2d11d983bc5b29fb2c Mon Sep 17 00:00:00 2001 From: Niall Sheridan Date: Sun, 7 Jul 2019 21:33:44 +0100 Subject: Switch to modules --- vendor/golang.org/x/crypto/ssh/kex.go | 540 ---------------------------------- 1 file changed, 540 deletions(-) delete mode 100644 vendor/golang.org/x/crypto/ssh/kex.go (limited to 'vendor/golang.org/x/crypto/ssh/kex.go') diff --git a/vendor/golang.org/x/crypto/ssh/kex.go b/vendor/golang.org/x/crypto/ssh/kex.go deleted file mode 100644 index f34bcc0..0000000 --- a/vendor/golang.org/x/crypto/ssh/kex.go +++ /dev/null @@ -1,540 +0,0 @@ -// Copyright 2013 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/ecdsa" - "crypto/elliptic" - "crypto/rand" - "crypto/subtle" - "errors" - "io" - "math/big" - - "golang.org/x/crypto/curve25519" -) - -const ( - kexAlgoDH1SHA1 = "diffie-hellman-group1-sha1" - kexAlgoDH14SHA1 = "diffie-hellman-group14-sha1" - kexAlgoECDH256 = "ecdh-sha2-nistp256" - kexAlgoECDH384 = "ecdh-sha2-nistp384" - kexAlgoECDH521 = "ecdh-sha2-nistp521" - kexAlgoCurve25519SHA256 = "curve25519-sha256@libssh.org" -) - -// kexResult captures the outcome of a key exchange. -type kexResult struct { - // Session hash. See also RFC 4253, section 8. - H []byte - - // Shared secret. See also RFC 4253, section 8. - K []byte - - // Host key as hashed into H. - HostKey []byte - - // Signature of H. - Signature []byte - - // A cryptographic hash function that matches the security - // level of the key exchange algorithm. It is used for - // calculating H, and for deriving keys from H and K. - Hash crypto.Hash - - // The session ID, which is the first H computed. This is used - // to derive key material inside the transport. - SessionID []byte -} - -// handshakeMagics contains data that is always included in the -// session hash. -type handshakeMagics struct { - clientVersion, serverVersion []byte - clientKexInit, serverKexInit []byte -} - -func (m *handshakeMagics) write(w io.Writer) { - writeString(w, m.clientVersion) - writeString(w, m.serverVersion) - writeString(w, m.clientKexInit) - writeString(w, m.serverKexInit) -} - -// kexAlgorithm abstracts different key exchange algorithms. -type kexAlgorithm interface { - // Server runs server-side key agreement, signing the result - // with a hostkey. - Server(p packetConn, rand io.Reader, magics *handshakeMagics, s Signer) (*kexResult, error) - - // Client runs the client-side key agreement. Caller is - // responsible for verifying the host key signature. - Client(p packetConn, rand io.Reader, magics *handshakeMagics) (*kexResult, error) -} - -// dhGroup is a multiplicative group suitable for implementing Diffie-Hellman key agreement. -type dhGroup struct { - g, p, pMinus1 *big.Int -} - -func (group *dhGroup) diffieHellman(theirPublic, myPrivate *big.Int) (*big.Int, error) { - if theirPublic.Cmp(bigOne) <= 0 || theirPublic.Cmp(group.pMinus1) >= 0 { - return nil, errors.New("ssh: DH parameter out of bounds") - } - return new(big.Int).Exp(theirPublic, myPrivate, group.p), nil -} - -func (group *dhGroup) Client(c packetConn, randSource io.Reader, magics *handshakeMagics) (*kexResult, error) { - hashFunc := crypto.SHA1 - - var x *big.Int - for { - var err error - if x, err = rand.Int(randSource, group.pMinus1); err != nil { - return nil, err - } - if x.Sign() > 0 { - break - } - } - - X := new(big.Int).Exp(group.g, x, group.p) - kexDHInit := kexDHInitMsg{ - X: X, - } - if err := c.writePacket(Marshal(&kexDHInit)); err != nil { - return nil, err - } - - packet, err := c.readPacket() - if err != nil { - return nil, err - } - - var kexDHReply kexDHReplyMsg - if err = Unmarshal(packet, &kexDHReply); err != nil { - return nil, err - } - - ki, err := group.diffieHellman(kexDHReply.Y, x) - if err != nil { - return nil, err - } - - h := hashFunc.New() - magics.write(h) - writeString(h, kexDHReply.HostKey) - writeInt(h, X) - writeInt(h, kexDHReply.Y) - K := make([]byte, intLength(ki)) - marshalInt(K, ki) - h.Write(K) - - return &kexResult{ - H: h.Sum(nil), - K: K, - HostKey: kexDHReply.HostKey, - Signature: kexDHReply.Signature, - Hash: crypto.SHA1, - }, nil -} - -func (group *dhGroup) Server(c packetConn, randSource io.Reader, magics *handshakeMagics, priv Signer) (result *kexResult, err error) { - hashFunc := crypto.SHA1 - packet, err := c.readPacket() - if err != nil { - return - } - var kexDHInit kexDHInitMsg - if err = Unmarshal(packet, &kexDHInit); err != nil { - return - } - - var y *big.Int - for { - if y, err = rand.Int(randSource, group.pMinus1); err != nil { - return - } - if y.Sign() > 0 { - break - } - } - - Y := new(big.Int).Exp(group.g, y, group.p) - ki, err := group.diffieHellman(kexDHInit.X, y) - if err != nil { - return nil, err - } - - hostKeyBytes := priv.PublicKey().Marshal() - - h := hashFunc.New() - magics.write(h) - writeString(h, hostKeyBytes) - writeInt(h, kexDHInit.X) - writeInt(h, Y) - - K := make([]byte, intLength(ki)) - marshalInt(K, ki) - h.Write(K) - - H := h.Sum(nil) - - // H is already a hash, but the hostkey signing will apply its - // own key-specific hash algorithm. - sig, err := signAndMarshal(priv, randSource, H) - if err != nil { - return nil, err - } - - kexDHReply := kexDHReplyMsg{ - HostKey: hostKeyBytes, - Y: Y, - Signature: sig, - } - packet = Marshal(&kexDHReply) - - err = c.writePacket(packet) - return &kexResult{ - H: H, - K: K, - HostKey: hostKeyBytes, - Signature: sig, - Hash: crypto.SHA1, - }, nil -} - -// ecdh performs Elliptic Curve Diffie-Hellman key exchange as -// described in RFC 5656, section 4. -type ecdh struct { - curve elliptic.Curve -} - -func (kex *ecdh) Client(c packetConn, rand io.Reader, magics *handshakeMagics) (*kexResult, error) { - ephKey, err := ecdsa.GenerateKey(kex.curve, rand) - if err != nil { - return nil, err - } - - kexInit := kexECDHInitMsg{ - ClientPubKey: elliptic.Marshal(kex.curve, ephKey.PublicKey.X, ephKey.PublicKey.Y), - } - - serialized := Marshal(&kexInit) - if err := c.writePacket(serialized); err != nil { - return nil, err - } - - packet, err := c.readPacket() - if err != nil { - return nil, err - } - - var reply kexECDHReplyMsg - if err = Unmarshal(packet, &reply); err != nil { - return nil, err - } - - x, y, err := unmarshalECKey(kex.curve, reply.EphemeralPubKey) - if err != nil { - return nil, err - } - - // generate shared secret - secret, _ := kex.curve.ScalarMult(x, y, ephKey.D.Bytes()) - - h := ecHash(kex.curve).New() - magics.write(h) - writeString(h, reply.HostKey) - writeString(h, kexInit.ClientPubKey) - writeString(h, reply.EphemeralPubKey) - K := make([]byte, intLength(secret)) - marshalInt(K, secret) - h.Write(K) - - return &kexResult{ - H: h.Sum(nil), - K: K, - HostKey: reply.HostKey, - Signature: reply.Signature, - Hash: ecHash(kex.curve), - }, nil -} - -// unmarshalECKey parses and checks an EC key. -func unmarshalECKey(curve elliptic.Curve, pubkey []byte) (x, y *big.Int, err error) { - x, y = elliptic.Unmarshal(curve, pubkey) - if x == nil { - return nil, nil, errors.New("ssh: elliptic.Unmarshal failure") - } - if !validateECPublicKey(curve, x, y) { - return nil, nil, errors.New("ssh: public key not on curve") - } - return x, y, nil -} - -// validateECPublicKey checks that the point is a valid public key for -// the given curve. See [SEC1], 3.2.2 -func validateECPublicKey(curve elliptic.Curve, x, y *big.Int) bool { - if x.Sign() == 0 && y.Sign() == 0 { - return false - } - - if x.Cmp(curve.Params().P) >= 0 { - return false - } - - if y.Cmp(curve.Params().P) >= 0 { - return false - } - - if !curve.IsOnCurve(x, y) { - return false - } - - // We don't check if N * PubKey == 0, since - // - // - the NIST curves have cofactor = 1, so this is implicit. - // (We don't foresee an implementation that supports non NIST - // curves) - // - // - for ephemeral keys, we don't need to worry about small - // subgroup attacks. - return true -} - -func (kex *ecdh) Server(c packetConn, rand io.Reader, magics *handshakeMagics, priv Signer) (result *kexResult, err error) { - packet, err := c.readPacket() - if err != nil { - return nil, err - } - - var kexECDHInit kexECDHInitMsg - if err = Unmarshal(packet, &kexECDHInit); err != nil { - return nil, err - } - - clientX, clientY, err := unmarshalECKey(kex.curve, kexECDHInit.ClientPubKey) - if err != nil { - return nil, err - } - - // We could cache this key across multiple users/multiple - // connection attempts, but the benefit is small. OpenSSH - // generates a new key for each incoming connection. - ephKey, err := ecdsa.GenerateKey(kex.curve, rand) - if err != nil { - return nil, err - } - - hostKeyBytes := priv.PublicKey().Marshal() - - serializedEphKey := elliptic.Marshal(kex.curve, ephKey.PublicKey.X, ephKey.PublicKey.Y) - - // generate shared secret - secret, _ := kex.curve.ScalarMult(clientX, clientY, ephKey.D.Bytes()) - - h := ecHash(kex.curve).New() - magics.write(h) - writeString(h, hostKeyBytes) - writeString(h, kexECDHInit.ClientPubKey) - writeString(h, serializedEphKey) - - K := make([]byte, intLength(secret)) - marshalInt(K, secret) - h.Write(K) - - H := h.Sum(nil) - - // H is already a hash, but the hostkey signing will apply its - // own key-specific hash algorithm. - sig, err := signAndMarshal(priv, rand, H) - if err != nil { - return nil, err - } - - reply := kexECDHReplyMsg{ - EphemeralPubKey: serializedEphKey, - HostKey: hostKeyBytes, - Signature: sig, - } - - serialized := Marshal(&reply) - if err := c.writePacket(serialized); err != nil { - return nil, err - } - - return &kexResult{ - H: H, - K: K, - HostKey: reply.HostKey, - Signature: sig, - Hash: ecHash(kex.curve), - }, nil -} - -var kexAlgoMap = map[string]kexAlgorithm{} - -func init() { - // This is the group called diffie-hellman-group1-sha1 in RFC - // 4253 and Oakley Group 2 in RFC 2409. - p, _ := new(big.Int).SetString("FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD129024E088A67CC74020BBEA63B139B22514A08798E3404DDEF9519B3CD3A431B302B0A6DF25F14374FE1356D6D51C245E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7EDEE386BFB5A899FA5AE9F24117C4B1FE649286651ECE65381FFFFFFFFFFFFFFFF", 16) - kexAlgoMap[kexAlgoDH1SHA1] = &dhGroup{ - g: new(big.Int).SetInt64(2), - p: p, - pMinus1: new(big.Int).Sub(p, bigOne), - } - - // This is the group called diffie-hellman-group14-sha1 in RFC - // 4253 and Oakley Group 14 in RFC 3526. - p, _ = new(big.Int).SetString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kexAlgoMap[kexAlgoDH14SHA1] = &dhGroup{ - g: new(big.Int).SetInt64(2), - p: p, - pMinus1: new(big.Int).Sub(p, bigOne), - } - - kexAlgoMap[kexAlgoECDH521] = &ecdh{elliptic.P521()} - kexAlgoMap[kexAlgoECDH384] = &ecdh{elliptic.P384()} - kexAlgoMap[kexAlgoECDH256] = &ecdh{elliptic.P256()} - kexAlgoMap[kexAlgoCurve25519SHA256] = &curve25519sha256{} -} - -// curve25519sha256 implements the curve25519-sha256@libssh.org key -// agreement protocol, as described in -// https://git.libssh.org/projects/libssh.git/tree/doc/curve25519-sha256@libssh.org.txt -type curve25519sha256 struct{} - -type curve25519KeyPair struct { - priv [32]byte - pub [32]byte -} - -func (kp *curve25519KeyPair) generate(rand io.Reader) error { - if _, err := io.ReadFull(rand, kp.priv[:]); err != nil { - return err - } - curve25519.ScalarBaseMult(&kp.pub, &kp.priv) - return nil -} - -// curve25519Zeros is just an array of 32 zero bytes so that we have something -// convenient to compare against in order to reject curve25519 points with the -// wrong order. -var curve25519Zeros [32]byte - -func (kex *curve25519sha256) Client(c packetConn, rand io.Reader, magics *handshakeMagics) (*kexResult, error) { - var kp curve25519KeyPair - if err := kp.generate(rand); err != nil { - return nil, err - } - if err := c.writePacket(Marshal(&kexECDHInitMsg{kp.pub[:]})); err != nil { - return nil, err - } - - packet, err := c.readPacket() - if err != nil { - return nil, err - } - - var reply kexECDHReplyMsg - if err = Unmarshal(packet, &reply); err != nil { - return nil, err - } - if len(reply.EphemeralPubKey) != 32 { - return nil, errors.New("ssh: peer's curve25519 public value has wrong length") - } - - var servPub, secret [32]byte - copy(servPub[:], reply.EphemeralPubKey) - curve25519.ScalarMult(&secret, &kp.priv, &servPub) - if subtle.ConstantTimeCompare(secret[:], curve25519Zeros[:]) == 1 { - return nil, errors.New("ssh: peer's curve25519 public value has wrong order") - } - - h := crypto.SHA256.New() - magics.write(h) - writeString(h, reply.HostKey) - writeString(h, kp.pub[:]) - writeString(h, reply.EphemeralPubKey) - - ki := new(big.Int).SetBytes(secret[:]) - K := make([]byte, intLength(ki)) - marshalInt(K, ki) - h.Write(K) - - return &kexResult{ - H: h.Sum(nil), - K: K, - HostKey: reply.HostKey, - Signature: reply.Signature, - Hash: crypto.SHA256, - }, nil -} - -func (kex *curve25519sha256) Server(c packetConn, rand io.Reader, magics *handshakeMagics, priv Signer) (result *kexResult, err error) { - packet, err := c.readPacket() - if err != nil { - return - } - var kexInit kexECDHInitMsg - if err = Unmarshal(packet, &kexInit); err != nil { - return - } - - if len(kexInit.ClientPubKey) != 32 { - return nil, errors.New("ssh: peer's curve25519 public value has wrong length") - } - - var kp curve25519KeyPair - if err := kp.generate(rand); err != nil { - return nil, err - } - - var clientPub, secret [32]byte - copy(clientPub[:], kexInit.ClientPubKey) - curve25519.ScalarMult(&secret, &kp.priv, &clientPub) - if subtle.ConstantTimeCompare(secret[:], curve25519Zeros[:]) == 1 { - return nil, errors.New("ssh: peer's curve25519 public value has wrong order") - } - - hostKeyBytes := priv.PublicKey().Marshal() - - h := crypto.SHA256.New() - magics.write(h) - writeString(h, hostKeyBytes) - writeString(h, kexInit.ClientPubKey) - writeString(h, kp.pub[:]) - - ki := new(big.Int).SetBytes(secret[:]) - K := make([]byte, intLength(ki)) - marshalInt(K, ki) - h.Write(K) - - H := h.Sum(nil) - - sig, err := signAndMarshal(priv, rand, H) - if err != nil { - return nil, err - } - - reply := kexECDHReplyMsg{ - EphemeralPubKey: kp.pub[:], - HostKey: hostKeyBytes, - Signature: sig, - } - if err := c.writePacket(Marshal(&reply)); err != nil { - return nil, err - } - return &kexResult{ - H: H, - K: K, - HostKey: hostKeyBytes, - Signature: sig, - Hash: crypto.SHA256, - }, nil -} -- cgit v1.2.3