module-transaction: Add support for binary conversations

A module can now initiate a binary conversation decoding the native
pointer value as it wants.

Added tests to verify the main cases

cmd/pam-moduler/tests/integration-tester-module/integration-tester-module.go

@@ -59,6 +59,9 @@ func (m *integrationTesterModule) handleRequest(authReq *authRequest, r *Request
 		case SerializableStringConvRequest:
 			args = append(args, reflect.ValueOf(
 				pam.NewStringConvRequest(v.Style, v.Request)))
+		case SerializableBinaryConvRequest:
+			args = append(args, reflect.ValueOf(
+				pam.NewBinaryConvRequestFromBytes(v.Request)))
 		default:
 			if arg == nil {
 				args = append(args, reflect.Zero(method.Type().In(i)))
@@ -83,6 +86,24 @@ func (m *integrationTesterModule) handleRequest(authReq *authRequest, r *Request
 			} else {
 				res.ActionArgs = append(res.ActionArgs, nil)
 			}
+		case pam.BinaryConvResponse:
+			data, err := value.Decode(utils.TestBinaryDataDecoder)
+			if err != nil {
+				return nil, err
+			}
+			res.ActionArgs = append(res.ActionArgs,
+				SerializableBinaryConvResponse{data})
+		case *pam.BinaryConvResponse:
+			if value != nil {
+				data, err := value.Decode(utils.TestBinaryDataDecoder)
+				if err != nil {
+					return nil, err
+				}
+				res.ActionArgs = append(res.ActionArgs,
+					SerializableBinaryConvResponse{data})
+			} else {
+				res.ActionArgs = append(res.ActionArgs, nil)
+			}
 		case pam.ReturnType:
 			authReq.lastError = value
 			res.ActionArgs = append(res.ActionArgs, value)

cmd/pam-moduler/tests/integration-tester-module/integration-tester-module_test.go

@@ -808,6 +808,70 @@ func Test_Moduler_IntegrationTesterModule(t *testing.T) {
 				},
 			},
 		},
+		"start-conv-binary": {
+			expectedStatus: pam.Success,
+			credentials: utils.NewBinaryTransactionWithData([]byte(
+				"\x00This is a binary data request\xC5\x00\xffYes it is!"),
+				[]byte{0x01, 0x02, 0x03, 0x05, 0x00, 0x99}),
+			checkedRequests: []checkedRequest{
+				{
+					r: NewRequest("StartConv", SerializableBinaryConvRequest{
+						utils.TestBinaryDataEncoder(
+							[]byte("\x00This is a binary data request\xC5\x00\xffYes it is!")),
+					}),
+					exp: []interface{}{SerializableBinaryConvResponse{
+						[]byte{0x01, 0x02, 0x03, 0x05, 0x00, 0x99},
+					}, nil},
+				},
+				{
+					r: NewRequest("StartBinaryConv",
+						utils.TestBinaryDataEncoder(
+							[]byte("\x00This is a binary data request\xC5\x00\xffYes it is!"))),
+					exp: []interface{}{SerializableBinaryConvResponse{
+						[]byte{0x01, 0x02, 0x03, 0x05, 0x00, 0x99},
+					}, nil},
+				},
+			},
+		},
+		"start-conv-binary-in-nil": {
+			expectedStatus: pam.Success,
+			credentials: utils.NewBinaryTransactionWithData(nil,
+				[]byte{0x01, 0x02, 0x03, 0x05, 0x00, 0x99}),
+			checkedRequests: []checkedRequest{
+				{
+					r: NewRequest("StartConv", SerializableBinaryConvRequest{}),
+					exp: []interface{}{SerializableBinaryConvResponse{
+						[]byte{0x01, 0x02, 0x03, 0x05, 0x00, 0x99},
+					}, nil},
+				},
+				{
+					r: NewRequest("StartBinaryConv", nil),
+					exp: []interface{}{SerializableBinaryConvResponse{
+						[]byte{0x01, 0x02, 0x03, 0x05, 0x00, 0x99},
+					}, nil},
+				},
+			},
+		},
+		"start-conv-binary-out-nil": {
+			expectedStatus: pam.Success,
+			credentials: utils.NewBinaryTransactionWithData([]byte(
+				"\x00This is a binary data request\xC5\x00\xffGimme nil!"), nil),
+			checkedRequests: []checkedRequest{
+				{
+					r: NewRequest("StartConv", SerializableBinaryConvRequest{
+						utils.TestBinaryDataEncoder(
+							[]byte("\x00This is a binary data request\xC5\x00\xffGimme nil!")),
+					}),
+					exp: []interface{}{SerializableBinaryConvResponse{}, nil},
+				},
+				{
+					r: NewRequest("StartBinaryConv",
+						utils.TestBinaryDataEncoder(
+							[]byte("\x00This is a binary data request\xC5\x00\xffGimme nil!"))),
+					exp: []interface{}{SerializableBinaryConvResponse{}, nil},
+				},
+			},
+		},
 	}
 
 	for name, tc := range tests {
@@ -1112,6 +1176,15 @@ func Test_Moduler_IntegrationTesterModule_Authenticate(t *testing.T) {
 				exp: []interface{}{nil, pam.SystemErr},
 			}},
 		},
+		"StartConv-Binary": {
+			expectedStatus: pam.SystemErr,
+			checkedRequests: []checkedRequest{{
+				r: NewRequest("StartConv", SerializableBinaryConvRequest{
+					[]byte{0x01, 0x02, 0x03, 0x05, 0x00, 0x99},
+				}),
+				exp: []interface{}{nil, pam.SystemErr},
+			}},
+		},
 	}
 
 	for name, tc := range tests {

cmd/pam-moduler/tests/integration-tester-module/serialization.go

@@ -29,6 +29,14 @@ type SerializableStringConvResponse struct {
 	Response string
 }
 
+type SerializableBinaryConvRequest struct {
+	Request []byte
+}
+
+type SerializableBinaryConvResponse struct {
+	Response []byte
+}
+
 func init() {
 	gob.Register(map[string]string{})
 	gob.Register(Request{})
@@ -42,5 +50,9 @@ func init() {
 		SerializableStringConvRequest{})
 	gob.RegisterName("main.SerializableStringConvResponse",
 		SerializableStringConvResponse{})
+	gob.RegisterName("main.SerializableBinaryConvRequest",
+		SerializableBinaryConvRequest{})
+	gob.RegisterName("main.SerializableBinaryConvResponse",
+		SerializableBinaryConvResponse{})
 	gob.Register(utils.SerializableError{})
 }

cmd/pam-moduler/tests/internal/utils/test-utils.go

@@ -1,7 +1,14 @@
 package utils
 
+//#include <stdint.h>
+import "C"
+
 import (
+	"crypto/rand"
+	"encoding/binary"
 	"fmt"
+	"reflect"
+	"unsafe"
 
 	"github.com/msteinert/pam"
 )
@@ -148,3 +155,76 @@ func (c Credentials) RespondPAM(s pam.Style, msg string) (string, error) {
 	return "", pam.NewTransactionError(
 		&SerializableError{fmt.Sprintf("unhandled style: %v", s)}, pam.ConvErr)
 }
+
+type BinaryTransaction struct {
+	data         []byte
+	ExpectedNull bool
+	ReturnedData []byte
+}
+
+func TestBinaryDataEncoder(bytes []byte) []byte {
+	if len(bytes) > 0xff {
+		panic("Binary transaction size not supported")
+	}
+
+	data := make([]byte, 0, len(bytes)+1)
+	data = append(data, byte(len(bytes)))
+	data = append(data, bytes...)
+	return data
+}
+
+func TestBinaryDataDecoder(ptr pam.BinaryPointer) ([]byte, error) {
+	if ptr == nil {
+		return nil, nil
+	}
+
+	length := uint8(*((*C.uint8_t)(ptr)))
+	return C.GoBytes(unsafe.Pointer(ptr), C.int(length+1))[1:], nil
+}
+
+func NewBinaryTransactionWithData(data []byte, retData []byte) BinaryTransaction {
+	t := BinaryTransaction{ReturnedData: retData}
+	t.data = TestBinaryDataEncoder(data)
+	t.ExpectedNull = data == nil
+	return t
+}
+
+func NewBinaryTransactionWithRandomData(size uint8, retData []byte) BinaryTransaction {
+	t := BinaryTransaction{ReturnedData: retData}
+	randomData := make([]byte, size)
+	if err := binary.Read(rand.Reader, binary.LittleEndian, &randomData); err != nil {
+		panic(err)
+	}
+
+	t.data = TestBinaryDataEncoder(randomData)
+	return t
+}
+
+func (b BinaryTransaction) Data() []byte {
+	return b.data
+}
+
+func (b BinaryTransaction) RespondPAM(s pam.Style, msg string) (string, error) {
+	return "", pam.NewTransactionError(
+		&SerializableError{"unexpected non-binary request"}, pam.ConvErr)
+}
+
+func (b BinaryTransaction) RespondPAMBinary(ptr pam.BinaryPointer) ([]byte, error) {
+	if ptr == nil && !b.ExpectedNull {
+		return nil, pam.NewTransactionError(
+			&SerializableError{"unexpected null binary data"}, pam.ConvErr)
+	} else if ptr == nil {
+		return TestBinaryDataEncoder(b.ReturnedData), nil
+	}
+
+	bytes, _ := TestBinaryDataDecoder(ptr)
+	if !reflect.DeepEqual(bytes, b.data[1:]) {
+		return nil, pam.NewTransactionError(
+			&SerializableError{
+				fmt.Sprintf("data mismatch %v vs %v", bytes, b.data[1:]),
+			},
+			pam.ConvErr)
+	}
+
+	return TestBinaryDataEncoder(b.ReturnedData), nil
+}

module-transaction.go

@@ -19,6 +19,7 @@ import "C"
 import (
 	"errors"
 	"fmt"
+	"runtime"
 	"runtime/cgo"
 	"sync/atomic"
 	"unsafe"
@@ -204,6 +205,60 @@ func (s StringConvResponse) Response() string {
 	return s.response
 }
 
+// StringConvRequest is a ConvRequest for performing binary conversations
+type BinaryConvRequest struct {
+	ptr BinaryPointer
+}
+
+// NewBinaryConvRequest creates a new BinaryConvRequest
+func NewBinaryConvRequest(ptr BinaryPointer) BinaryConvRequest {
+	return BinaryConvRequest{ptr}
+}
+
+// NewBinaryConvRequest creates a new BinaryConvRequest from an array
+// pointer, the lifetime of the data is bound to the object
+func NewBinaryConvRequestFromBytes(bytes []byte) BinaryConvRequest {
+	m := BinaryConvRequest{}
+	if bytes != nil {
+		m.ptr = BinaryPointer(C.CBytes(bytes))
+		runtime.SetFinalizer(&m, func(m *BinaryConvRequest) {
+			defer C.free(unsafe.Pointer(m.ptr))
+		})
+	}
+	return m
+}
+
+// Style returns the response style for the request, so always BinaryPrompt
+func (b BinaryConvRequest) Style() Style {
+	return BinaryPrompt
+}
+
+// StringConvResponse is a ConvResponse implementation used for binary
+// conversation responses
+type BinaryConvResponse struct {
+	ptr BinaryPointer
+}
+
+// Style returns the response style for the response, so always BinaryPrompt
+func (b BinaryConvResponse) Style() Style {
+	return BinaryPrompt
+}
+
+// Data returns the response native pointer, it's up to the protocol to parse
+// it accordingly
+func (b BinaryConvResponse) Data() BinaryPointer {
+	return b.ptr
+}
+
+// Decode decodes the binary data using the provided decoder function
+func (b BinaryConvResponse) Decode(decoder func(BinaryPointer) ([]byte, error)) (
+	[]byte, error) {
+	if decoder == nil {
+		errors.New("nil decoder provided")
+	}
+	return decoder(b.ptr)
+}
+
 // StartStringConv starts a text-based conversation using the provided style
 // and prompt
 func (m *ModuleTransaction) StartStringConv(style Style, prompt string) (
@@ -229,6 +284,18 @@ func (m *ModuleTransaction) StartStringConvf(style Style, format string, args ..
 	return m.StartStringConv(style, fmt.Sprintf(format, args...))
 }
 
+// StartBinaryConv starts a binary conversation using the provided bytes
+func (m *ModuleTransaction) StartBinaryConv(bytes []byte) (
+	*BinaryConvResponse, error) {
+	res, err := m.StartConv(NewBinaryConvRequestFromBytes(bytes))
+	if err != nil {
+		return nil, err
+	}
+
+	stringRes := res.(BinaryConvResponse)
+	return &stringRes, nil
+}
+
 // StartConv initiates a PAM conversation using the provided ConvRequest
 func (m *ModuleTransaction) StartConv(req ConvRequest) (
 	ConvResponse, error) {
@@ -273,6 +340,8 @@ func (m *ModuleTransaction) StartConvMulti(requests []ConvRequest) (
 		case StringConvRequest:
 			cBytes = unsafe.Pointer(C.CString(r.prompt))
 			defer C.free(unsafe.Pointer(cBytes))
+		case BinaryConvRequest:
+			cBytes = unsafe.Pointer(r.ptr)
 		default:
 			return nil, NewTransactionError(
 				fmt.Errorf(
@@ -293,6 +362,14 @@ func (m *ModuleTransaction) StartConvMulti(requests []ConvRequest) (
 		case StringConvRequest:
 			cBytes = unsafe.Pointer(C.CString(r.prompt))
 			defer C.free(unsafe.Pointer(cBytes))
+		case BinaryConvRequest:
+			if !CheckPamHasBinaryProtocol() {
+				return nil, NewTransactionError(
+					fmt.Errorf(
+						"binary protocol is not supported"),
+					ConvErr)
+			}
+			cBytes = unsafe.Pointer(r.ptr)
 		default:
 			return nil, NewTransactionError(
 				fmt.Errorf(
@@ -328,6 +405,10 @@ func (m *ModuleTransaction) StartConvMulti(requests []ConvRequest) (
 				style:    msgStyle,
 				response: C.GoString(resp.resp),
 			})
+		case BinaryPrompt:
+			fmt.Println("Setting binary reply to", resp.resp)
+			goReplies = append(goReplies, BinaryConvResponse{
+				BinaryPointer(resp.resp)})
 		default:
 			atomic.StoreInt32(&m.status, int32(ConvErr))
 			return nil, NewTransactionError(

module-transaction_test.go

@@ -96,6 +96,8 @@ func Test_NewNullModuleTransaction(t *testing.T) {
 				return mt.StartConvMulti([]ConvRequest{
 					NewStringConvRequest(TextInfo, "a prompt"),
 					NewStringConvRequest(ErrorMsg, "another prompt"),
+					NewBinaryConvRequest(BinaryPointer(&mt)),
+					NewBinaryConvRequestFromBytes([]byte("These are bytes!")),
 				})
 			},
 		},