communicator/ssh: Add SimpleKeychain

communicator/ssh/keychain.go

+package ssh
+
+import (
+	"crypto"
+	"crypto/dsa"
+	"crypto/rsa"
+	"crypto/x509"
+	"encoding/pem"
+	"errors"
+	"io"
+)
+
+type SimpleKeychain struct {
+	keys []interface{}
+}
+
+// AddPEMKey adds a simple PEM encoded private key to the keychain.
+func (k *SimpleKeychain) AddPEMKey(key string) (err error) {
+	block, _ := pem.Decode([]byte(key))
+	rsakey, err := x509.ParsePKCS1PrivateKey(block.Bytes)
+	if err != nil {
+		return
+	}
+
+	k.keys = append(k.keys, rsakey)
+	return
+}
+
+// Key method for ssh.ClientKeyring interface
+func (k *SimpleKeychain) Key(i int) (interface{}, error) {
+	if i < 0 || i >= len(k.keys) {
+		return nil, nil
+	}
+	switch key := k.keys[i].(type) {
+	case *rsa.PrivateKey:
+		return &key.PublicKey, nil
+	case *dsa.PrivateKey:
+		return &key.PublicKey, nil
+	}
+	panic("unknown key type")
+}
+
+// Sign method for ssh.ClientKeyring interface
+func (k *SimpleKeychain) Sign(i int, rand io.Reader, data []byte) (sig []byte, err error) {
+	hashFunc := crypto.SHA1
+	h := hashFunc.New()
+	h.Write(data)
+	digest := h.Sum(nil)
+	switch key := k.keys[i].(type) {
+	case *rsa.PrivateKey:
+		return rsa.SignPKCS1v15(rand, key, hashFunc, digest)
+	}
+	return nil, errors.New("ssh: unknown key type")
+}

communicator/ssh/keychain_test.go

+package ssh
+
+import "testing"
+
+const testPrivateKey = `-----BEGIN RSA PRIVATE KEY-----
+MIIBOwIBAAJBALdGZxkXDAjsYk10ihwU6Id2KeILz1TAJuoq4tOgDWxEEGeTrcld
+r/ZwVaFzjWzxaf6zQIJbfaSEAhqD5yo72+sCAwEAAQJBAK8PEVU23Wj8mV0QjwcJ
+tZ4GcTUYQL7cF4+ezTCE9a1NrGnCP2RuQkHEKxuTVrxXt+6OF15/1/fuXnxKjmJC
+nxkCIQDaXvPPBi0c7vAxGwNY9726x01/dNbHCE0CBtcotobxpwIhANbbQbh3JHVW
+2haQh4fAG5mhesZKAGcxTyv4mQ7uMSQdAiAj+4dzMpJWdSzQ+qGHlHMIBvVHLkqB
+y2VdEyF7DPCZewIhAI7GOI/6LDIFOvtPo6Bj2nNmyQ1HU6k/LRtNIXi4c9NJAiAr
+rrxx26itVhJmcvoUhOjwuzSlP2bE5VHAvkGB352YBg==
+-----END RSA PRIVATE KEY-----`
+
+func TestAddPEMKey(t *testing.T) {
+	k := &SimpleKeychain{}
+	err := k.AddPEMKey(testPrivateKey)
+	if err != nil {
+		t.Fatalf("error while adding key: %s", err)
+	}
+}