| // Copyright 2014 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "mojo/public/cpp/bindings/lib/message_header_validator.h" |
| |
| #include "mojo/public/cpp/bindings/lib/bounds_checker.h" |
| #include "mojo/public/cpp/bindings/lib/validation_errors.h" |
| #include "mojo/public/cpp/bindings/lib/validation_util.h" |
| |
| namespace mojo { |
| namespace internal { |
| namespace { |
| |
| bool IsValidMessageHeader(const MessageHeader* header) { |
| // NOTE: Our goal is to preserve support for future extension of the message |
| // header. If we encounter fields we do not understand, we must ignore them. |
| |
| // Extra validation of the struct header: |
| if (header->version == 0) { |
| if (header->num_bytes != sizeof(MessageHeader)) { |
| ReportValidationError(VALIDATION_ERROR_UNEXPECTED_STRUCT_HEADER); |
| return false; |
| } |
| } else if (header->version == 1) { |
| if (header->num_bytes != sizeof(MessageHeaderWithRequestID)) { |
| ReportValidationError(VALIDATION_ERROR_UNEXPECTED_STRUCT_HEADER); |
| return false; |
| } |
| } else if (header->version > 1) { |
| if (header->num_bytes < sizeof(MessageHeaderWithRequestID)) { |
| ReportValidationError(VALIDATION_ERROR_UNEXPECTED_STRUCT_HEADER); |
| return false; |
| } |
| } |
| |
| // Validate flags (allow unknown bits): |
| |
| // These flags require a RequestID. |
| if (header->version < 1 && ((header->flags & kMessageExpectsResponse) || |
| (header->flags & kMessageIsResponse))) { |
| ReportValidationError(VALIDATION_ERROR_MESSAGE_HEADER_MISSING_REQUEST_ID); |
| return false; |
| } |
| |
| // These flags are mutually exclusive. |
| if ((header->flags & kMessageExpectsResponse) && |
| (header->flags & kMessageIsResponse)) { |
| ReportValidationError(VALIDATION_ERROR_MESSAGE_HEADER_INVALID_FLAGS); |
| return false; |
| } |
| |
| return true; |
| } |
| |
| } // namespace |
| |
| MessageHeaderValidator::MessageHeaderValidator(MessageReceiver* sink) |
| : MessageFilter(sink) { |
| } |
| |
| bool MessageHeaderValidator::Accept(Message* message) { |
| // Pass 0 as number of handles because we don't expect any in the header, even |
| // if |message| contains handles. |
| BoundsChecker bounds_checker(message->data(), message->data_num_bytes(), 0); |
| |
| if (!ValidateStructHeaderAndClaimMemory(message->data(), &bounds_checker)) |
| return false; |
| |
| if (!IsValidMessageHeader(message->header())) |
| return false; |
| |
| return sink_->Accept(message); |
| } |
| |
| } // namespace internal |
| } // namespace mojo |