smallstep-certificates/authority/ssh_test.go

package authority

import (
	"crypto"
	"crypto/ecdsa"
	"crypto/elliptic"
	"crypto/rand"
	"fmt"
	"testing"
	"time"

	"github.com/smallstep/assert"
	"github.com/smallstep/certificates/authority/provisioner"
	"golang.org/x/crypto/ssh"
)

type sshTestModifier ssh.Certificate

func (m sshTestModifier) Modify(cert *ssh.Certificate) error {
	if m.CertType != 0 {
		cert.CertType = m.CertType
	}
	if m.KeyId != "" {
		cert.KeyId = m.KeyId
	}
	if m.ValidAfter != 0 {
		cert.ValidAfter = m.ValidAfter
	}
	if m.ValidBefore != 0 {
		cert.ValidBefore = m.ValidBefore
	}
	if len(m.ValidPrincipals) != 0 {
		cert.ValidPrincipals = m.ValidPrincipals
	}
	if m.Permissions.CriticalOptions != nil {
		cert.Permissions.CriticalOptions = m.Permissions.CriticalOptions
	}
	if m.Permissions.Extensions != nil {
		cert.Permissions.Extensions = m.Permissions.Extensions
	}
	return nil
}

type sshTestCertModifier string

func (m sshTestCertModifier) Modify(cert *ssh.Certificate) error {
	if m == "" {
		return nil
	}
	return fmt.Errorf(string(m))
}

type sshTestCertValidator string

func (v sshTestCertValidator) Valid(crt *ssh.Certificate) error {
	if v == "" {
		return nil
	}
	return fmt.Errorf(string(v))
}

type sshTestOptionsValidator string

func (v sshTestOptionsValidator) Valid(opts provisioner.SSHOptions) error {
	if v == "" {
		return nil
	}
	return fmt.Errorf(string(v))
}

type sshTestOptionsModifier string

func (m sshTestOptionsModifier) Option(opts provisioner.SSHOptions) provisioner.SSHCertificateModifier {
	return sshTestCertModifier(string(m))
}

func TestAuthority_SignSSH(t *testing.T) {
	key, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
	assert.FatalError(t, err)
	pub, err := ssh.NewPublicKey(key.Public())
	assert.FatalError(t, err)
	signKey, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
	assert.FatalError(t, err)

	userOptions := sshTestModifier{
		CertType: ssh.UserCert,
	}
	hostOptions := sshTestModifier{
		CertType: ssh.HostCert,
	}

	now := time.Now()

	type fields struct {
		sshCAUserCertSignKey crypto.Signer
		sshCAHostCertSignKey crypto.Signer
	}
	type args struct {
		key      ssh.PublicKey
		opts     provisioner.SSHOptions
		signOpts []provisioner.SignOption
	}
	type want struct {
		CertType    uint32
		Principals  []string
		ValidAfter  uint64
		ValidBefore uint64
	}
	tests := []struct {
		name    string
		fields  fields
		args    args
		want    want
		wantErr bool
	}{
		{"ok-user", fields{signKey, signKey}, args{pub, provisioner.SSHOptions{}, []provisioner.SignOption{userOptions}}, want{CertType: ssh.UserCert}, false},
		{"ok-host", fields{signKey, signKey}, args{pub, provisioner.SSHOptions{}, []provisioner.SignOption{hostOptions}}, want{CertType: ssh.HostCert}, false},
		{"ok-opts-type-user", fields{signKey, signKey}, args{pub, provisioner.SSHOptions{CertType: "user"}, []provisioner.SignOption{}}, want{CertType: ssh.UserCert}, false},
		{"ok-opts-type-host", fields{signKey, signKey}, args{pub, provisioner.SSHOptions{CertType: "host"}, []provisioner.SignOption{}}, want{CertType: ssh.HostCert}, false},
		{"ok-opts-principals", fields{signKey, signKey}, args{pub, provisioner.SSHOptions{CertType: "user", Principals: []string{"user"}}, []provisioner.SignOption{}}, want{CertType: ssh.UserCert, Principals: []string{"user"}}, false},
		{"ok-opts-principals", fields{signKey, signKey}, args{pub, provisioner.SSHOptions{CertType: "host", Principals: []string{"foo.test.com", "bar.test.com"}}, []provisioner.SignOption{}}, want{CertType: ssh.HostCert, Principals: []string{"foo.test.com", "bar.test.com"}}, false},
		{"ok-opts-valid-after", fields{signKey, signKey}, args{pub, provisioner.SSHOptions{CertType: "user", ValidAfter: provisioner.NewTimeDuration(now)}, []provisioner.SignOption{}}, want{CertType: ssh.UserCert, ValidAfter: uint64(now.Unix())}, false},
		{"ok-opts-valid-before", fields{signKey, signKey}, args{pub, provisioner.SSHOptions{CertType: "host", ValidBefore: provisioner.NewTimeDuration(now)}, []provisioner.SignOption{}}, want{CertType: ssh.HostCert, ValidBefore: uint64(now.Unix())}, false},
		{"ok-cert-validator", fields{signKey, signKey}, args{pub, provisioner.SSHOptions{}, []provisioner.SignOption{userOptions, sshTestCertValidator("")}}, want{CertType: ssh.UserCert}, false},
		{"ok-cert-modifier", fields{signKey, signKey}, args{pub, provisioner.SSHOptions{}, []provisioner.SignOption{userOptions, sshTestCertModifier("")}}, want{CertType: ssh.UserCert}, false},
		{"ok-opts-validator", fields{signKey, signKey}, args{pub, provisioner.SSHOptions{}, []provisioner.SignOption{userOptions, sshTestOptionsValidator("")}}, want{CertType: ssh.UserCert}, false},
		{"ok-opts-modifier", fields{signKey, signKey}, args{pub, provisioner.SSHOptions{}, []provisioner.SignOption{userOptions, sshTestOptionsModifier("")}}, want{CertType: ssh.UserCert}, false},
		{"fail-opts-type", fields{signKey, signKey}, args{pub, provisioner.SSHOptions{CertType: "foo"}, []provisioner.SignOption{}}, want{}, true},
		{"fail-cert-validator", fields{signKey, signKey}, args{pub, provisioner.SSHOptions{}, []provisioner.SignOption{userOptions, sshTestCertValidator("an error")}}, want{}, true},
		{"fail-cert-modifier", fields{signKey, signKey}, args{pub, provisioner.SSHOptions{}, []provisioner.SignOption{userOptions, sshTestCertModifier("an error")}}, want{}, true},
		{"fail-opts-validator", fields{signKey, signKey}, args{pub, provisioner.SSHOptions{}, []provisioner.SignOption{userOptions, sshTestOptionsValidator("an error")}}, want{}, true},
		{"fail-opts-modifier", fields{signKey, signKey}, args{pub, provisioner.SSHOptions{}, []provisioner.SignOption{userOptions, sshTestOptionsModifier("an error")}}, want{}, true},
		{"fail-bad-sign-options", fields{signKey, signKey}, args{pub, provisioner.SSHOptions{}, []provisioner.SignOption{userOptions, "wrong type"}}, want{}, true},
		{"fail-no-user-key", fields{nil, signKey}, args{pub, provisioner.SSHOptions{CertType: "user"}, []provisioner.SignOption{}}, want{}, true},
		{"fail-no-host-key", fields{signKey, nil}, args{pub, provisioner.SSHOptions{CertType: "host"}, []provisioner.SignOption{}}, want{}, true},
		{"fail-bad-type", fields{signKey, nil}, args{pub, provisioner.SSHOptions{}, []provisioner.SignOption{sshTestModifier{CertType: 0}}}, want{}, true},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			a := testAuthority(t)
			a.sshCAUserCertSignKey = tt.fields.sshCAUserCertSignKey
			a.sshCAHostCertSignKey = tt.fields.sshCAHostCertSignKey

			got, err := a.SignSSH(tt.args.key, tt.args.opts, tt.args.signOpts...)
			if (err != nil) != tt.wantErr {
				t.Errorf("Authority.SignSSH() error = %v, wantErr %v", err, tt.wantErr)
				return
			}
			if err == nil && assert.NotNil(t, got) {
				assert.Equals(t, tt.want.CertType, got.CertType)
				assert.Equals(t, tt.want.Principals, got.ValidPrincipals)
				assert.Equals(t, tt.want.ValidAfter, got.ValidAfter)
				assert.Equals(t, tt.want.ValidBefore, got.ValidBefore)
				assert.NotNil(t, got.Key)
				assert.NotNil(t, got.Nonce)
				assert.NotEquals(t, 0, got.Serial)
				assert.NotNil(t, got.Signature)
				assert.NotNil(t, got.SignatureKey)
			}
		})
	}
}

func TestAuthority_SignSSHAddUser(t *testing.T) {
	key, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
	assert.FatalError(t, err)
	pub, err := ssh.NewPublicKey(key.Public())
	assert.FatalError(t, err)
	signKey, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
	assert.FatalError(t, err)

	type fields struct {
		sshCAUserCertSignKey crypto.Signer
		sshCAHostCertSignKey crypto.Signer
		addUserPrincipal     string
		addUserCommand       string
	}
	type args struct {
		key     ssh.PublicKey
		subject *ssh.Certificate
	}
	type want struct {
		CertType     uint32
		Principals   []string
		ValidAfter   uint64
		ValidBefore  uint64
		ForceCommand string
	}

	now := time.Now()
	validCert := &ssh.Certificate{
		CertType:        ssh.UserCert,
		ValidPrincipals: []string{"user"},
		ValidAfter:      uint64(now.Unix()),
		ValidBefore:     uint64(now.Add(time.Hour).Unix()),
	}
	validWant := want{
		CertType:     ssh.UserCert,
		Principals:   []string{"provisioner"},
		ValidAfter:   uint64(now.Unix()),
		ValidBefore:  uint64(now.Add(time.Hour).Unix()),
		ForceCommand: "sudo useradd -m user; nc -q0 localhost 22",
	}

	tests := []struct {
		name    string
		fields  fields
		args    args
		want    want
		wantErr bool
	}{
		{"ok", fields{signKey, signKey, "", ""}, args{pub, validCert}, validWant, false},
		{"ok-no-host-key", fields{signKey, nil, "", ""}, args{pub, validCert}, validWant, false},
		{"ok-custom-principal", fields{signKey, signKey, "my-principal", ""}, args{pub, &ssh.Certificate{CertType: ssh.UserCert, ValidPrincipals: []string{"user"}}}, want{CertType: ssh.UserCert, Principals: []string{"my-principal"}, ForceCommand: "sudo useradd -m user; nc -q0 localhost 22"}, false},
		{"ok-custom-command", fields{signKey, signKey, "", "foo <principal> <principal>"}, args{pub, &ssh.Certificate{CertType: ssh.UserCert, ValidPrincipals: []string{"user"}}}, want{CertType: ssh.UserCert, Principals: []string{"provisioner"}, ForceCommand: "foo user user"}, false},
		{"ok-custom-principal-and-command", fields{signKey, signKey, "my-principal", "foo <principal> <principal>"}, args{pub, &ssh.Certificate{CertType: ssh.UserCert, ValidPrincipals: []string{"user"}}}, want{CertType: ssh.UserCert, Principals: []string{"my-principal"}, ForceCommand: "foo user user"}, false},
		{"fail-no-user-key", fields{nil, signKey, "", ""}, args{pub, validCert}, want{}, true},
		{"fail-no-user-cert", fields{signKey, signKey, "", ""}, args{pub, &ssh.Certificate{CertType: ssh.HostCert, ValidPrincipals: []string{"foo"}}}, want{}, true},
		{"fail-no-principals", fields{signKey, signKey, "", ""}, args{pub, &ssh.Certificate{CertType: ssh.UserCert, ValidPrincipals: []string{}}}, want{}, true},
		{"fail-many-principals", fields{signKey, signKey, "", ""}, args{pub, &ssh.Certificate{CertType: ssh.UserCert, ValidPrincipals: []string{"foo", "bar"}}}, want{}, true},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			a := testAuthority(t)
			a.sshCAUserCertSignKey = tt.fields.sshCAUserCertSignKey
			a.sshCAHostCertSignKey = tt.fields.sshCAHostCertSignKey
			a.config.SSH = &SSHConfig{
				AddUserPrincipal: tt.fields.addUserPrincipal,
				AddUserCommand:   tt.fields.addUserCommand,
			}
			got, err := a.SignSSHAddUser(tt.args.key, tt.args.subject)
			if (err != nil) != tt.wantErr {
				t.Errorf("Authority.SignSSHAddUser() error = %v, wantErr %v", err, tt.wantErr)
				return
			}
			if err == nil && assert.NotNil(t, got) {
				assert.Equals(t, tt.want.CertType, got.CertType)
				assert.Equals(t, tt.want.Principals, got.ValidPrincipals)
				assert.Equals(t, tt.args.subject.ValidPrincipals[0]+"-"+tt.want.Principals[0], got.KeyId)
				assert.Equals(t, tt.want.ValidAfter, got.ValidAfter)
				assert.Equals(t, tt.want.ValidBefore, got.ValidBefore)
				assert.Equals(t, map[string]string{"force-command": tt.want.ForceCommand}, got.CriticalOptions)
				assert.Equals(t, nil, got.Extensions)
				assert.NotNil(t, got.Key)
				assert.NotNil(t, got.Nonce)
				assert.NotEquals(t, 0, got.Serial)
				assert.NotNil(t, got.Signature)
				assert.NotNil(t, got.SignatureKey)
			}
		})
	}
}