Validate canonical comparison manifests

internal/comparison/publish.go

@@ -239,6 +239,9 @@ func readBundleFile(directory, name string) ([]byte, error) {
 }
 
 func decodeManifest(data []byte) (Manifest, error) {
+	if err := validateManifestJSON(data); err != nil {
+		return Manifest{}, unrecognizedBundleError("decode manifest", err)
+	}
 	decoder := json.NewDecoder(bytes.NewReader(data))
 	decoder.DisallowUnknownFields()
 	var manifest Manifest
@@ -255,6 +258,162 @@ func decodeManifest(data []byte) (Manifest, error) {
 	return manifest, nil
 }
 
+var manifestFields = map[string]jsonValueValidator{
+	"schemaVersion": nil,
+	"comparisonId":  nil,
+	"startedAt":     nil,
+	"finishedAt":    nil,
+	"reportId":      nil,
+	"validPeriod":   validateValidPeriodJSON,
+	"timezone":      nil,
+	"promptId":      nil,
+	"promptVersion": nil,
+	"promptHash":    nil,
+	"dataPackage":   validateDataPackageJSON,
+	"total":         nil,
+	"succeeded":     nil,
+	"failed":        nil,
+	"results":       validateResultsJSON,
+}
+
+var validPeriodFields = map[string]jsonValueValidator{
+	"start": nil,
+	"end":   nil,
+}
+
+var dataPackageFields = map[string]jsonValueValidator{
+	"path":   nil,
+	"sha256": nil,
+}
+
+var resultFields = map[string]jsonValueValidator{
+	"position":         nil,
+	"profileId":        nil,
+	"backendId":        nil,
+	"modelName":        nil,
+	"status":           nil,
+	"validationStatus": nil,
+	"reportPath":       nil,
+	"error":            validateSafeErrorJSON,
+}
+
+var safeErrorFields = map[string]jsonValueValidator{
+	"category": nil,
+	"message":  nil,
+}
+
+type jsonValueValidator func(*json.Decoder) error
+
+func validateManifestJSON(data []byte) error {
+	decoder := json.NewDecoder(bytes.NewReader(data))
+	if err := validateJSONObject(decoder, manifestFields); err != nil {
+		return err
+	}
+	if _, err := decoder.Token(); err != io.EOF {
+		if err == nil {
+			return fmt.Errorf("manifest has multiple JSON values")
+		}
+		return err
+	}
+	return nil
+}
+
+func validateValidPeriodJSON(decoder *json.Decoder) error {
+	return validateJSONObject(decoder, validPeriodFields)
+}
+
+func validateDataPackageJSON(decoder *json.Decoder) error {
+	return validateJSONObject(decoder, dataPackageFields)
+}
+
+func validateResultsJSON(decoder *json.Decoder) error {
+	token, err := decoder.Token()
+	if err != nil {
+		return err
+	}
+	if delimiter, ok := token.(json.Delim); !ok || delimiter != '[' {
+		return fmt.Errorf("results must be an array")
+	}
+	for decoder.More() {
+		if err := validateJSONObject(decoder, resultFields); err != nil {
+			return err
+		}
+	}
+	token, err = decoder.Token()
+	if err != nil {
+		return err
+	}
+	if delimiter, ok := token.(json.Delim); !ok || delimiter != ']' {
+		return fmt.Errorf("results has an invalid array terminator")
+	}
+	return nil
+}
+
+func validateSafeErrorJSON(decoder *json.Decoder) error {
+	token, err := decoder.Token()
+	if err != nil {
+		return err
+	}
+	if token == nil {
+		return nil
+	}
+	if delimiter, ok := token.(json.Delim); !ok || delimiter != '{' {
+		return fmt.Errorf("error must be an object")
+	}
+	return validateJSONObjectBody(decoder, safeErrorFields)
+}
+
+func validateJSONObject(decoder *json.Decoder, fields map[string]jsonValueValidator) error {
+	token, err := decoder.Token()
+	if err != nil {
+		return err
+	}
+	if delimiter, ok := token.(json.Delim); !ok || delimiter != '{' {
+		return fmt.Errorf("manifest value must be an object")
+	}
+	return validateJSONObjectBody(decoder, fields)
+}
+
+func validateJSONObjectBody(decoder *json.Decoder, fields map[string]jsonValueValidator) error {
+	seen := make(map[string]struct{}, len(fields))
+	for decoder.More() {
+		token, err := decoder.Token()
+		if err != nil {
+			return err
+		}
+		name, ok := token.(string)
+		if !ok {
+			return fmt.Errorf("manifest field name is invalid")
+		}
+		validator, known := fields[name]
+		if !known {
+			return fmt.Errorf("manifest field %q is not canonical", name)
+		}
+		if _, duplicate := seen[name]; duplicate {
+			return fmt.Errorf("manifest field %q is duplicated", name)
+		}
+		seen[name] = struct{}{}
+		if validator == nil {
+			var value json.RawMessage
+			if err := decoder.Decode(&value); err != nil {
+				return err
+			}
+			continue
+		}
+		if err := validator(decoder); err != nil {
+			return err
+		}
+	}
+	token, err := decoder.Token()
+	if err != nil {
+		return err
+	}
+	if delimiter, ok := token.(json.Delim); !ok || delimiter != '}' {
+		return fmt.Errorf("manifest object has an invalid terminator")
+	}
+	return nil
+}
+
 func unrecognizedBundleError(action string, err error) error {
 	if err == nil {
 		return fmt.Errorf("%w: %s", ErrUnrecognizedBundle, action)