Implement fetch action, normalize error response params (#13)

PROTOCOL.md

@@ -41,18 +41,23 @@ should be supplied as a `message` parameter.
 
 ## List of Error Codes
 
-| Code | Description                                                             | Parameters              |
-| ---- | ----------------------------------------------------------------------- | ----------------------- |
-| 10   | Unable to parse browser request length                                  | error                   |
-| 11   | Unable to parse browser request                                         | error                   |
-| 12   | Invalid request action                                                  | action                  |
-| 13   | Inaccessible user-configured password store                             | error, name, path       |
-| 14   | Inaccessible default password store                                     | error, path             |
-| 15   | Unable to determine the location of the default password store          | error                   |
-| 16   | Unable to read the default settings of a user-configured password store | error, name, path       |
-| 17   | Unable to read the default settings of the default password store       | error, path             |
-| 18   | Unable to list files in a password store                                | error, name, path       |
-| 19   | Unable to determine a relative path for a file in a password store      | error, file, name, path |
+| Code | Description                                                             | Parameters                                         |
+| ---- | ----------------------------------------------------------------------- | -------------------------------------------------- |
+| 10   | Unable to parse browser request length                                  | message, error                                     |
+| 11   | Unable to parse browser request                                         | message, error                                     |
+| 12   | Invalid request action                                                  | message, action                                    |
+| 13   | Inaccessible user-configured password store                             | message, action, error, storePath, storeName       |
+| 14   | Inaccessible default password store                                     | message, action, error, storePath                  |
+| 15   | Unable to determine the location of the default password store          | message, action, error                             |
+| 16   | Unable to read the default settings of a user-configured password store | message, action, error, storePath, storeName       |
+| 17   | Unable to read the default settings of the default password store       | message, action, error, storePath                  |
+| 18   | Unable to list files in a password store                                | message, action, error, storePath, storeName       |
+| 19   | Unable to determine a relative path for a file in a password store      | message, action, error, storePath, storeName, file |
+| 20   | Invalid password store name                                             | message, action, storeName                         |
+| 21   | Invalid gpg path                                                        | message, action, error, gpgPath                    |
+| 22   | Unable to detect the location of the gpg binary                         | message, action, error                             |
+| 23   | Invalid password file extension                                         | message, action, file                              |
+| 24   | Unable to decrypt the password file                                     | message, action, error, storePath, storeName, file |
 
 ## Settings
 

errors/errors.go

@@ -17,28 +17,69 @@ const (
 	CodeParseRequest Code = 11
 
 	// CodeInvalidRequestAction error parsing a request action
-	CodeInvalidRequestAction = 12
+	CodeInvalidRequestAction Code = 12
 
 	// CodeInaccessiblePasswordStore error accessing a user-configured password store
-	CodeInaccessiblePasswordStore = 13
+	CodeInaccessiblePasswordStore Code = 13
 
 	// CodeInaccessibleDefaultPasswordStore error accessing the default password store
-	CodeInaccessibleDefaultPasswordStore = 14
+	CodeInaccessibleDefaultPasswordStore Code = 14
 
 	// CodeUnknownDefaultPasswordStoreLocation error determining the location of the default password store
-	CodeUnknownDefaultPasswordStoreLocation = 15
+	CodeUnknownDefaultPasswordStoreLocation Code = 15
 
 	// CodeUnreadablePasswordStoreDefaultSettings error reading the default settings of a user-configured password store
-	CodeUnreadablePasswordStoreDefaultSettings = 16
+	CodeUnreadablePasswordStoreDefaultSettings Code = 16
 
 	// CodeUnreadableDefaultPasswordStoreDefaultSettings error reading the default settings of the default password store
-	CodeUnreadableDefaultPasswordStoreDefaultSettings = 17
+	CodeUnreadableDefaultPasswordStoreDefaultSettings Code = 17
 
 	// CodeUnableToListFilesInPasswordStore error listing files in a password store
-	CodeUnableToListFilesInPasswordStore = 18
+	CodeUnableToListFilesInPasswordStore Code = 18
 
 	// CodeUnableToDetermineRelativeFilePathInPasswordStore error determining a relative path for a file in a password store
-	CodeUnableToDetermineRelativeFilePathInPasswordStore = 19
+	CodeUnableToDetermineRelativeFilePathInPasswordStore Code = 19
+
+	// CodeInvalidPasswordStore error looking for a password store with the given name
+	CodeInvalidPasswordStore Code = 20
+
+	// CodeInvalidGpgPath error looking for a gpg binary at the given path
+	CodeInvalidGpgPath Code = 21
+
+	// CodeUnableToDetectGpgPath error detecting the location of the gpg binary
+	CodeUnableToDetectGpgPath Code = 22
+
+	// CodeInvalidPasswordFileExtension error unexpected password file extension
+	CodeInvalidPasswordFileExtension Code = 23
+
+	// CodeUnableToDecryptPasswordFile error decrypting a password file
+	CodeUnableToDecryptPasswordFile Code = 24
+)
+
+// Field extra field in the error response params
+type Field string
+
+const (
+	// FieldMessage a user-friendly error message, always present
+	FieldMessage Field = "message"
+
+	// FieldAction a browser request action that resulted in a failure
+	FieldAction Field = "action"
+
+	// FieldError an error message returned from an external system
+	FieldError Field = "error"
+
+	// FieldStoreName a password store name
+	FieldStoreName Field = "storeName"
+
+	// FieldStorePath a password store path
+	FieldStorePath Field = "storePath"
+
+	// FieldFile a password file
+	FieldFile Field = "file"
+
+	// FieldGpgPath a path to the gpg binary
+	FieldGpgPath Field = "gpgPath"
 )
 
 // ExitWithCode exit with error code

request/configure.go

@@ -23,12 +23,16 @@ func configure(request request) {
 				"The password store '%v' is not accessible at the location '%v': %+v",
 				store.Name, store.Path, err,
 			)
-			response.SendError(
+			response.SendErrorAndExit(
 				errors.CodeInaccessiblePasswordStore,
-				"The password store is not accessible",
-				&map[string]string{"error": err.Error(), "name": store.Name, "path": store.Path},
+				&map[errors.Field]string{
+					errors.FieldMessage:   "The password store is not accessible",
+					errors.FieldAction:    "configure",
+					errors.FieldError:     err.Error(),
+					errors.FieldStoreName: store.Name,
+					errors.FieldStorePath: store.Path,
+				},
 			)
-			errors.ExitWithCode(errors.CodeInaccessiblePasswordStore)
 		}
 
 		store.Path = normalizedStorePath
@@ -39,12 +43,16 @@ func configure(request request) {
 				"Unable to read the default settings of the user-configured password store '%v' in '%v': %+v",
 				store.Name, store.Path, err,
 			)
-			response.SendError(
+			response.SendErrorAndExit(
 				errors.CodeUnreadablePasswordStoreDefaultSettings,
-				"Unable to read the default settings of the password store",
-				&map[string]string{"error": err.Error(), "name": store.Name, "path": store.Path},
+				&map[errors.Field]string{
+					errors.FieldMessage:   "Unable to read the default settings of the password store",
+					errors.FieldAction:    "configure",
+					errors.FieldError:     err.Error(),
+					errors.FieldStoreName: store.Name,
+					errors.FieldStorePath: store.Path,
+				},
 			)
-			errors.ExitWithCode(errors.CodeUnreadablePasswordStoreDefaultSettings)
 		}
 	}
 
@@ -55,12 +63,14 @@ func configure(request request) {
 	if err != nil {
 		if len(request.Settings.Stores) == 0 {
 			log.Error("Unable to determine the location of the default password store: ", err)
-			response.SendError(
+			response.SendErrorAndExit(
 				errors.CodeUnknownDefaultPasswordStoreLocation,
-				"Unable to determine the location of the default password store",
-				&map[string]string{"error": err.Error()},
+				&map[errors.Field]string{
+					errors.FieldMessage: "Unable to determine the location of the default password store",
+					errors.FieldAction:  "configure",
+					errors.FieldError:   err.Error(),
+				},
 			)
-			errors.ExitWithCode(errors.CodeUnknownDefaultPasswordStoreLocation)
 		}
 	} else {
 		responseData.DefaultStore.Path, err = normalizePasswordStorePath(possibleDefaultStorePath)
@@ -70,12 +80,15 @@ func configure(request request) {
 					"The default password store is not accessible at the location '%v': %+v",
 					possibleDefaultStorePath, err,
 				)
-				response.SendError(
+				response.SendErrorAndExit(
 					errors.CodeInaccessibleDefaultPasswordStore,
-					"The default password store is not accessible",
-					&map[string]string{"error": err.Error(), "path": possibleDefaultStorePath},
+					&map[errors.Field]string{
+						errors.FieldMessage:   "The default password store is not accessible",
+						errors.FieldAction:    "configure",
+						errors.FieldError:     err.Error(),
+						errors.FieldStorePath: possibleDefaultStorePath,
+					},
 				)
-				errors.ExitWithCode(errors.CodeInaccessibleDefaultPasswordStore)
 			}
 		}
 	}
@@ -87,12 +100,15 @@ func configure(request request) {
 				"Unable to read the default settings of the default password store in '%v': %+v",
 				responseData.DefaultStore.Path, err,
 			)
-			response.SendError(
+			response.SendErrorAndExit(
 				errors.CodeUnreadableDefaultPasswordStoreDefaultSettings,
-				"Unable to read the default settings of the default password store",
-				&map[string]string{"error": err.Error(), "path": responseData.DefaultStore.Path},
+				&map[errors.Field]string{
+					errors.FieldMessage:   "Unable to read the default settings of the default password store",
+					errors.FieldAction:    "configure",
+					errors.FieldError:     err.Error(),
+					errors.FieldStorePath: responseData.DefaultStore.Path,
+				},
 			)
-			errors.ExitWithCode(errors.CodeUnreadableDefaultPasswordStoreDefaultSettings)
 		}
 	}
 

request/fetch.go

@@ -0,0 +1,164 @@
+package request
+
+import (
+	"bytes"
+	goerrors "errors"
+	"fmt"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+
+	"github.com/browserpass/browserpass-native/errors"
+	"github.com/browserpass/browserpass-native/response"
+	log "github.com/sirupsen/logrus"
+)
+
+func fetchDecryptedContents(request request) {
+	responseData := response.MakeFetchResponse()
+
+	if !strings.HasSuffix(request.File, ".gpg") {
+		log.Errorf("The requested password file '%v' does not have the expected '.gpg' extension", request.File)
+		response.SendErrorAndExit(
+			errors.CodeInvalidPasswordFileExtension,
+			&map[errors.Field]string{
+				errors.FieldMessage: "The requested password file does not have the expected '.gpg' extension",
+				errors.FieldAction:  "fetch",
+				errors.FieldFile:    request.File,
+			},
+		)
+	}
+
+	store, ok := request.Settings.Stores[request.Store]
+	if !ok {
+		log.Errorf(
+			"The password store '%v' is not present in the list of stores '%v'",
+			request.Store, request.Settings.Stores,
+		)
+		response.SendErrorAndExit(
+			errors.CodeInvalidPasswordStore,
+			&map[errors.Field]string{
+				errors.FieldMessage:   "The password store is not present in the list of stores",
+				errors.FieldAction:    "fetch",
+				errors.FieldStoreName: request.Store,
+			},
+		)
+	}
+
+	normalizedStorePath, err := normalizePasswordStorePath(store.Path)
+	if err != nil {
+		log.Errorf(
+			"The password store '%v' is not accessible at the location '%v': %+v",
+			store.Name, store.Path, err,
+		)
+		response.SendErrorAndExit(
+			errors.CodeInaccessiblePasswordStore,
+			&map[errors.Field]string{
+				errors.FieldMessage:   "The password store is not accessible",
+				errors.FieldAction:    "fetch",
+				errors.FieldError:     err.Error(),
+				errors.FieldStoreName: store.Name,
+				errors.FieldStorePath: store.Path,
+			},
+		)
+	}
+	store.Path = normalizedStorePath
+
+	gpgPath := request.Settings.GpgPath
+	if gpgPath != "" {
+		err = validateGpgBinary(gpgPath)
+		if err != nil {
+			log.Errorf(
+				"The provided gpg binary path '%v' is invalid: %+v",
+				gpgPath, err,
+			)
+			response.SendErrorAndExit(
+				errors.CodeInvalidGpgPath,
+				&map[errors.Field]string{
+					errors.FieldMessage: "The provided gpg binary path is invalid",
+					errors.FieldAction:  "fetch",
+					errors.FieldError:   err.Error(),
+					errors.FieldGpgPath: gpgPath,
+				},
+			)
+		}
+	} else {
+		gpgPath, err = detectGpgBinary()
+		if err != nil {
+			log.Error("Unable to detect the location of the gpg binary: ", err)
+			response.SendErrorAndExit(
+				errors.CodeUnableToDetectGpgPath,
+				&map[errors.Field]string{
+					errors.FieldMessage: "Unable to detect the location of the gpg binary",
+					errors.FieldAction:  "fetch",
+					errors.FieldError:   err.Error(),
+				},
+			)
+		}
+	}
+
+	responseData.Contents, err = decryptFile(store, request.File, gpgPath)
+	if err != nil {
+		log.Errorf(
+			"Unable to decrypt the password file '%v' in the password store '%v' located in '%v': %+v",
+			request.File, store.Name, store.Path, err,
+		)
+		response.SendErrorAndExit(
+			errors.CodeUnableToDecryptPasswordFile,
+			&map[errors.Field]string{
+				errors.FieldMessage:   "Unable to decrypt the password file",
+				errors.FieldAction:    "fetch",
+				errors.FieldError:     err.Error(),
+				errors.FieldFile:      request.File,
+				errors.FieldStoreName: store.Name,
+				errors.FieldStorePath: store.Path,
+			},
+		)
+	}
+
+	response.SendOk(responseData)
+}
+
+func detectGpgBinary() (string, error) {
+	// Look in $PATH first, then check common locations - the first successful result wins
+	gpgBinaryPriorityList := []string{
+		"gpg2", "gpg",
+		"/bin/gpg2", "/usr/bin/gpg2", "/usr/local/bin/gpg2",
+		"/bin/gpg", "/usr/bin/gpg", "/usr/local/bin/gpg",
+	}
+
+	for _, binary := range gpgBinaryPriorityList {
+		err := validateGpgBinary(binary)
+		if err == nil {
+			return binary, nil
+		}
+	}
+
+	return "", goerrors.New("Unable to detect the location of the gpg binary to use")
+}
+
+func validateGpgBinary(gpgPath string) error {
+	return exec.Command(gpgPath, "--version").Run()
+}
+
+func decryptFile(store store, file string, gpgPath string) (string, error) {
+	passwordFilePath := filepath.Join(store.Path, file)
+	passwordFile, err := os.Open(passwordFilePath)
+	if err != nil {
+		return "", err
+	}
+
+	var stdout, stderr bytes.Buffer
+	gpgOptions := []string{"--decrypt", "--yes", "--quiet", "--batch", "-"}
+
+	cmd := exec.Command(gpgPath, gpgOptions...)
+	cmd.Stdin = passwordFile
+	cmd.Stdout = &stdout
+	cmd.Stderr = &stderr
+
+	if err := cmd.Run(); err != nil {
+		return "", goerrors.New(fmt.Sprintf("Error: %s, Stderr: %s", err.Error(), stderr.String()))
+	}
+
+	return stdout.String(), nil
+}

request/list.go

@@ -20,12 +20,16 @@ func listFiles(request request) {
 				"The password store '%v' is not accessible at the location '%v': %+v",
 				store.Name, store.Path, err,
 			)
-			response.SendError(
+			response.SendErrorAndExit(
 				errors.CodeInaccessiblePasswordStore,
-				"The password store is not accessible",
-				&map[string]string{"error": err.Error(), "name": store.Name, "path": store.Path},
+				&map[errors.Field]string{
+					errors.FieldMessage:   "The password store is not accessible",
+					errors.FieldAction:    "list",
+					errors.FieldError:     err.Error(),
+					errors.FieldStoreName: store.Name,
+					errors.FieldStorePath: store.Path,
+				},
 			)
-			errors.ExitWithCode(errors.CodeInaccessiblePasswordStore)
 		}
 
 		store.Path = normalizedStorePath
@@ -36,12 +40,16 @@ func listFiles(request request) {
 				"Unable to list the files in the password store '%v' at the location '%v': %+v",
 				store.Name, store.Path, err,
 			)
-			response.SendError(
+			response.SendErrorAndExit(
 				errors.CodeUnableToListFilesInPasswordStore,
-				"Unable to list the files in the password store",
-				&map[string]string{"error": err.Error(), "name": store.Name, "path": store.Path},
+				&map[errors.Field]string{
+					errors.FieldMessage:   "Unable to list the files in the password store",
+					errors.FieldAction:    "list",
+					errors.FieldError:     err.Error(),
+					errors.FieldStoreName: store.Name,
+					errors.FieldStorePath: store.Path,
+				},
 			)
-			errors.ExitWithCode(errors.CodeUnableToListFilesInPasswordStore)
 		}
 
 		for i, file := range files {
@@ -51,12 +59,17 @@ func listFiles(request request) {
 					"Unable to determine the relative path for a file '%v' in the password store '%v' at the location '%v': %+v",
 					file, store.Name, store.Path, err,
 				)
-				response.SendError(
+				response.SendErrorAndExit(
 					errors.CodeUnableToDetermineRelativeFilePathInPasswordStore,
-					"Unable to determine the relative path for a file in the password store",
-					&map[string]string{"error": err.Error(), "file": file, "name": store.Name, "path": store.Path},
+					&map[errors.Field]string{
+						errors.FieldMessage:   "Unable to determine the relative path for a file in the password store",
+						errors.FieldAction:    "list",
+						errors.FieldError:     err.Error(),
+						errors.FieldFile:      file,
+						errors.FieldStoreName: store.Name,
+						errors.FieldStorePath: store.Path,
+					},
 				)
-				errors.ExitWithCode(errors.CodeUnableToDetermineRelativeFilePathInPasswordStore)
 			}
 			files[i] = relativePath
 		}

request/process.go

@@ -11,15 +11,21 @@ import (
 	log "github.com/sirupsen/logrus"
 )
 
+type store struct {
+	Name string `json:"name"`
+	Path string `json:"path"`
+}
+
+type settings struct {
+	GpgPath string           `json:"gpgPath"`
+	Stores  map[string]store `json:"stores"`
+}
+
 type request struct {
-	Action   string `json:"action"`
-	Settings struct {
-		GpgPath string `json:"gpgPath"`
-		Stores  map[string]struct {
-			Name string `json:"name"`
-			Path string `json:"path"`
-		}
-	} `json:"settings"`
+	Action   string   `json:"action"`
+	Settings settings `json:"settings"`
+	File     string   `json:"file"`
+	Store    string   `json:"store"`
 }
 
 // Process handles browser request
@@ -33,15 +39,16 @@ func Process() {
 	case "list":
 		listFiles(request)
 	case "fetch":
-		break
+		fetchDecryptedContents(request)
 	default:
 		log.Errorf("Received a browser request with an unknown action: %+v", request)
-		response.SendError(
+		response.SendErrorAndExit(
 			errors.CodeInvalidRequestAction,
-			"Invalid request action",
-			&map[string]string{"action": request.Action},
+			&map[errors.Field]string{
+				errors.FieldMessage: "Invalid request action",
+				errors.FieldAction:  request.Action,
+			},
 		)
-		errors.ExitWithCode(errors.CodeInvalidRequestAction)
 	}
 }
 
@@ -49,17 +56,14 @@ func Process() {
 func parseRequestLength() uint32 {
 	var length uint32
 	if err := binary.Read(os.Stdin, binary.LittleEndian, &length); err != nil {
-		// TODO: Original browserpass ignores EOF as if it is expected, is it true?
-		// if err == io.EOF {
-		// 	return
-		// }
 		log.Error("Unable to parse the length of the browser request: ", err)
-		response.SendError(
+		response.SendErrorAndExit(
 			errors.CodeParseRequestLength,
-			"Unable to parse the length of the browser request",
-			&map[string]string{"error": err.Error()},
+			&map[errors.Field]string{
+				errors.FieldMessage: "Unable to parse the length of the browser request",
+				errors.FieldError:   err.Error(),
+			},
 		)
-		errors.ExitWithCode(errors.CodeParseRequestLength)
 	}
 	return length
 }
@@ -70,12 +74,13 @@ func parseRequest(messageLength uint32) request {
 	reader := &io.LimitedReader{R: os.Stdin, N: int64(messageLength)}
 	if err := json.NewDecoder(reader).Decode(&parsed); err != nil {
 		log.Error("Unable to parse the browser request: ", err)
-		response.SendError(
+		response.SendErrorAndExit(
 			errors.CodeParseRequest,
-			"Unable to parse the browser request",
-			&map[string]string{"error": err.Error()},
+			&map[errors.Field]string{
+				errors.FieldMessage: "Unable to parse the browser request",
+				errors.FieldError:   err.Error(),
+			},
 		)
-		errors.ExitWithCode(errors.CodeParseRequest)
 	}
 	return parsed
 }

response/response.go

@@ -52,6 +52,16 @@ func MakeListResponse() *ListResponse {
 	}
 }
 
+// FetchResponse a response format for the "fetch" request
+type FetchResponse struct {
+	Contents string `json:"contents"`
+}
+
+// MakeFetchResponse initializes an empty fetch response
+func MakeFetchResponse() *FetchResponse {
+	return &FetchResponse{}
+}
+
 // SendOk sends a success response to the browser extension in the predefined json format
 func SendOk(data interface{}) {
 	send(&okResponse{
@@ -61,22 +71,16 @@ func SendOk(data interface{}) {
 	})
 }
 
-// SendError sends an error response to the browser extension in the predefined json format
-func SendError(errorCode errors.Code, errorMsg string, extraParams *map[string]string) {
-	params := map[string]string{
-		"message": errorMsg,
-	}
-	if extraParams != nil {
-		for key, value := range *extraParams {
-			params[key] = value
-		}
-	}
+// SendErrorAndExit sends an error response to the browser extension in the predefined json format and exits with the specified exit code
+func SendErrorAndExit(errorCode errors.Code, params *map[errors.Field]string) {
 	send(&errorResponse{
 		Status:  "error",
 		Code:    errorCode,
 		Version: version.Code,
 		Params:  params,
 	})
+
+	errors.ExitWithCode(errorCode)
 }
 
 func send(data interface{}) {