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// 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 "chrome/common/safe_browsing/binary_feature_extractor.h"
#include <windows.h>
#include <softpub.h>
#include <wintrust.h>
#include "base/files/file_path.h"
#include "base/logging.h"
#include "chrome/common/safe_browsing/csd.pb.h"
#include "chrome/common/safe_browsing/pe_image_reader_win.h"
#pragma comment(lib, "wintrust.lib")
namespace safe_browsing {
namespace {
// An EnumCertificatesCallback that collects each SignedData blob.
bool OnCertificateEntry(uint16_t revision,
uint16_t certificate_type,
const uint8_t* certificate_data,
size_t certificate_data_size,
void* context) {
google::protobuf::RepeatedPtrField<std::string>* signed_data =
reinterpret_cast<google::protobuf::RepeatedPtrField<std::string>*>(
context);
if (revision == WIN_CERT_REVISION_2_0 &&
certificate_type == WIN_CERT_TYPE_PKCS_SIGNED_DATA) {
signed_data->Add()->assign(certificate_data,
certificate_data + certificate_data_size);
}
return true;
}
} // namespace
void BinaryFeatureExtractor::CheckSignature(
const base::FilePath& file_path,
ClientDownloadRequest_SignatureInfo* signature_info) {
DVLOG(2) << "Checking signature for " << file_path.value();
WINTRUST_FILE_INFO file_info = {0};
file_info.cbStruct = sizeof(file_info);
file_info.pcwszFilePath = file_path.value().c_str();
file_info.hFile = NULL;
file_info.pgKnownSubject = NULL;
WINTRUST_DATA wintrust_data = {0};
wintrust_data.cbStruct = sizeof(wintrust_data);
wintrust_data.pPolicyCallbackData = NULL;
wintrust_data.pSIPClientData = NULL;
wintrust_data.dwUIChoice = WTD_UI_NONE;
wintrust_data.fdwRevocationChecks = WTD_REVOKE_NONE;
wintrust_data.dwUnionChoice = WTD_CHOICE_FILE;
wintrust_data.pFile = &file_info;
wintrust_data.dwStateAction = WTD_STATEACTION_VERIFY;
wintrust_data.hWVTStateData = NULL;
wintrust_data.pwszURLReference = NULL;
// Disallow revocation checks over the network.
wintrust_data.dwProvFlags = WTD_CACHE_ONLY_URL_RETRIEVAL;
wintrust_data.dwUIContext = WTD_UICONTEXT_EXECUTE;
// The WINTRUST_ACTION_GENERIC_VERIFY_V2 policy verifies that the certificate
// chains up to a trusted root CA, and that it has appropriate permission to
// sign code.
GUID policy_guid = WINTRUST_ACTION_GENERIC_VERIFY_V2;
LONG result = WinVerifyTrust(static_cast<HWND>(INVALID_HANDLE_VALUE),
&policy_guid,
&wintrust_data);
CRYPT_PROVIDER_DATA* prov_data = WTHelperProvDataFromStateData(
wintrust_data.hWVTStateData);
if (prov_data) {
if (prov_data->csSigners > 0) {
signature_info->set_trusted(result == ERROR_SUCCESS);
}
for (DWORD i = 0; i < prov_data->csSigners; ++i) {
const CERT_CHAIN_CONTEXT* cert_chain_context =
prov_data->pasSigners[i].pChainContext;
if (!cert_chain_context)
break;
for (DWORD j = 0; j < cert_chain_context->cChain; ++j) {
CERT_SIMPLE_CHAIN* simple_chain = cert_chain_context->rgpChain[j];
ClientDownloadRequest_CertificateChain* chain =
signature_info->add_certificate_chain();
if (!simple_chain)
break;
for (DWORD k = 0; k < simple_chain->cElement; ++k) {
CERT_CHAIN_ELEMENT* element = simple_chain->rgpElement[k];
chain->add_element()->set_certificate(
element->pCertContext->pbCertEncoded,
element->pCertContext->cbCertEncoded);
}
}
}
// Free the provider data.
wintrust_data.dwStateAction = WTD_STATEACTION_CLOSE;
WinVerifyTrust(static_cast<HWND>(INVALID_HANDLE_VALUE),
&policy_guid, &wintrust_data);
}
}
bool BinaryFeatureExtractor::ExtractImageFeaturesFromData(
const uint8_t* data, size_t data_size,
ExtractHeadersOption options,
ClientDownloadRequest_ImageHeaders* image_headers,
google::protobuf::RepeatedPtrField<std::string>* signed_data) {
PeImageReader pe_image;
if (!pe_image.Initialize(data, data_size))
return false;
// Copy the headers.
ClientDownloadRequest_PEImageHeaders* pe_headers =
image_headers->mutable_pe_headers();
pe_headers->set_dos_header(pe_image.GetDosHeader(), sizeof(IMAGE_DOS_HEADER));
pe_headers->set_file_header(pe_image.GetCoffFileHeader(),
sizeof(IMAGE_FILE_HEADER));
size_t optional_header_size = 0;
const uint8_t* optional_header_data =
pe_image.GetOptionalHeaderData(&optional_header_size);
if (pe_image.GetWordSize() == PeImageReader::WORD_SIZE_32) {
pe_headers->set_optional_headers32(optional_header_data,
optional_header_size);
} else {
pe_headers->set_optional_headers64(optional_header_data,
optional_header_size);
}
const size_t number_of_sections = pe_image.GetNumberOfSections();
for (size_t i = 0; i != number_of_sections; ++i) {
pe_headers->add_section_header(pe_image.GetSectionHeaderAt(i),
sizeof(IMAGE_SECTION_HEADER));
}
if (!(options & BinaryFeatureExtractor::kOmitExports)) {
size_t export_size = 0;
const uint8_t* export_section = pe_image.GetExportSection(&export_size);
if (export_section)
pe_headers->set_export_section_data(export_section, export_size);
}
size_t number_of_debug_entries = pe_image.GetNumberOfDebugEntries();
for (size_t i = 0; i != number_of_debug_entries; ++i) {
const uint8_t* raw_data = NULL;
size_t raw_data_size = 0;
const IMAGE_DEBUG_DIRECTORY* directory_entry =
pe_image.GetDebugEntry(i, &raw_data, &raw_data_size);
if (directory_entry) {
ClientDownloadRequest_PEImageHeaders_DebugData* debug_data =
pe_headers->add_debug_data();
debug_data->set_directory_entry(directory_entry,
sizeof(*directory_entry));
if (raw_data)
debug_data->set_raw_data(raw_data, raw_data_size);
}
}
if (signed_data)
pe_image.EnumCertificates(&OnCertificateEntry, signed_data);
return true;
}
} // namespace safe_browsing
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