Unit testing for def/ module.

Added unit tests to test code in def/ module.

vendor/golang.org/x/crypto/ssh/ssh_gss.go

@@ -0,0 +1,139 @@
+// 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 (
+	"encoding/asn1"
+	"errors"
+)
+
+var krb5OID []byte
+
+func init() {
+	krb5OID, _ = asn1.Marshal(krb5Mesh)
+}
+
+// GSSAPIClient provides the API to plug-in GSSAPI authentication for client logins.
+type GSSAPIClient interface {
+	// InitSecContext initiates the establishment of a security context for GSS-API between the
+	// ssh client and ssh server. Initially the token parameter should be specified as nil.
+	// The routine may return a outputToken which should be transferred to
+	// the ssh server, where the ssh server will present it to
+	// AcceptSecContext. If no token need be sent, InitSecContext will indicate this by setting
+	// needContinue to false. To complete the context
+	// establishment, one or more reply tokens may be required from the ssh
+	// server;if so, InitSecContext will return a needContinue which is true.
+	// In this case, InitSecContext should be called again when the
+	// reply token is received from the ssh server, passing the reply
+	// token to InitSecContext via the token parameters.
+	// See RFC 2743 section 2.2.1 and RFC 4462 section 3.4.
+	InitSecContext(target string, token []byte, isGSSDelegCreds bool) (outputToken []byte, needContinue bool, err error)
+	// GetMIC generates a cryptographic MIC for the SSH2 message, and places
+	// the MIC in a token for transfer to the ssh server.
+	// The contents of the MIC field are obtained by calling GSS_GetMIC()
+	// over the following, using the GSS-API context that was just
+	// established:
+	//  string    session identifier
+	//  byte      SSH_MSG_USERAUTH_REQUEST
+	//  string    user name
+	//  string    service
+	//  string    "gssapi-with-mic"
+	// See RFC 2743 section 2.3.1 and RFC 4462 3.5.
+	GetMIC(micFiled []byte) ([]byte, error)
+	// Whenever possible, it should be possible for
+	// DeleteSecContext() calls to be successfully processed even
+	// if other calls cannot succeed, thereby enabling context-related
+	// resources to be released.
+	// In addition to deleting established security contexts,
+	// gss_delete_sec_context must also be able to delete "half-built"
+	// security contexts resulting from an incomplete sequence of
+	// InitSecContext()/AcceptSecContext() calls.
+	// See RFC 2743 section 2.2.3.
+	DeleteSecContext() error
+}
+
+// GSSAPIServer provides the API to plug in GSSAPI authentication for server logins.
+type GSSAPIServer interface {
+	// AcceptSecContext allows a remotely initiated security context between the application
+	// and a remote peer to be established by the ssh client. The routine may return a
+	// outputToken which should be transferred to the ssh client,
+	// where the ssh client will present it to InitSecContext.
+	// If no token need be sent, AcceptSecContext will indicate this
+	// by setting the needContinue to false. To
+	// complete the context establishment, one or more reply tokens may be
+	// required from the ssh client. if so, AcceptSecContext
+	// will return a needContinue which is true, in which case it
+	// should be called again when the reply token is received from the ssh
+	// client, passing the token to AcceptSecContext via the
+	// token parameters.
+	// The srcName return value is the authenticated username.
+	// See RFC 2743 section 2.2.2 and RFC 4462 section 3.4.
+	AcceptSecContext(token []byte) (outputToken []byte, srcName string, needContinue bool, err error)
+	// VerifyMIC verifies that a cryptographic MIC, contained in the token parameter,
+	// fits the supplied message is received from the ssh client.
+	// See RFC 2743 section 2.3.2.
+	VerifyMIC(micField []byte, micToken []byte) error
+	// Whenever possible, it should be possible for
+	// DeleteSecContext() calls to be successfully processed even
+	// if other calls cannot succeed, thereby enabling context-related
+	// resources to be released.
+	// In addition to deleting established security contexts,
+	// gss_delete_sec_context must also be able to delete "half-built"
+	// security contexts resulting from an incomplete sequence of
+	// InitSecContext()/AcceptSecContext() calls.
+	// See RFC 2743 section 2.2.3.
+	DeleteSecContext() error
+}
+
+var (
+	// OpenSSH supports Kerberos V5 mechanism only for GSS-API authentication,
+	// so we also support the krb5 mechanism only.
+	// See RFC 1964 section 1.
+	krb5Mesh = asn1.ObjectIdentifier{1, 2, 840, 113554, 1, 2, 2}
+)
+
+// The GSS-API authentication method is initiated when the client sends an SSH_MSG_USERAUTH_REQUEST
+// See RFC 4462 section 3.2.
+type userAuthRequestGSSAPI struct {
+	N    uint32
+	OIDS []asn1.ObjectIdentifier
+}
+
+func parseGSSAPIPayload(payload []byte) (*userAuthRequestGSSAPI, error) {
+	n, rest, ok := parseUint32(payload)
+	if !ok {
+		return nil, errors.New("parse uint32 failed")
+	}
+	s := &userAuthRequestGSSAPI{
+		N:    n,
+		OIDS: make([]asn1.ObjectIdentifier, n),
+	}
+	for i := 0; i < int(n); i++ {
+		var (
+			desiredMech []byte
+			err         error
+		)
+		desiredMech, rest, ok = parseString(rest)
+		if !ok {
+			return nil, errors.New("parse string failed")
+		}
+		if rest, err = asn1.Unmarshal(desiredMech, &s.OIDS[i]); err != nil {
+			return nil, err
+		}
+
+	}
+	return s, nil
+}
+
+// See RFC 4462 section 3.6.
+func buildMIC(sessionID string, username string, service string, authMethod string) []byte {
+	out := make([]byte, 0, 0)
+	out = appendString(out, sessionID)
+	out = append(out, msgUserAuthRequest)
+	out = appendString(out, username)
+	out = appendString(out, service)
+	out = appendString(out, authMethod)
+	return out
+}