[win] Create utilities for helping to populate ModuleDatabase.

chrome/browser/conflicts/module_info_util_win.cc

+// Copyright 2017 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/browser/conflicts/module_info_util_win.h"
+
+#include <tlhelp32.h>
+#include <wincrypt.h>
+#include <wintrust.h>
+#include <mscat.h>  // NOLINT: This must be after wincrypt and wintrust.
+
+#include "base/scoped_generic.h"
+#include "base/win/scoped_handle.h"
+
+namespace {
+
+// Helper for scoped tracking an HCERTSTORE.
+struct ScopedHCERTSTORETraits {
+  static HCERTSTORE InvalidValue() { return nullptr; }
+  static void Free(HCERTSTORE store) { ::CertCloseStore(store, 0); }
+};
+using ScopedHCERTSTORE =
+    base::ScopedGeneric<HCERTSTORE, ScopedHCERTSTORETraits>;
+
+// Helper for scoped tracking an HCRYPTMSG.
+struct ScopedHCRYPTMSGTraits {
+  static HCRYPTMSG InvalidValue() { return nullptr; }
+  static void Free(HCRYPTMSG message) { ::CryptMsgClose(message); }
+};
+using ScopedHCRYPTMSG = base::ScopedGeneric<HCRYPTMSG, ScopedHCRYPTMSGTraits>;
+
+// Returns the "Subject" field from the digital signature in the provided
+// binary, if any is present. Returns an empty string on failure.
+base::string16 GetSubjectNameInFile(const base::FilePath& filename) {
+  ScopedHCERTSTORE store;
+  ScopedHCRYPTMSG message;
+
+  // Find the crypto message for this filename.
+  {
+    HCERTSTORE temp_store = nullptr;
+    HCRYPTMSG temp_message = nullptr;
+    bool result =
+        !!CryptQueryObject(CERT_QUERY_OBJECT_FILE, filename.value().c_str(),
+                           CERT_QUERY_CONTENT_FLAG_PKCS7_SIGNED_EMBED,
+                           CERT_QUERY_FORMAT_FLAG_BINARY, 0, nullptr, nullptr,
+                           nullptr, &temp_store, &temp_message, nullptr);
+    store.reset(temp_store);
+    message.reset(temp_message);
+    if (!result)
+      return base::string16();
+  }
+
+  // Determine the size of the signer info data.
+  DWORD signer_info_size = 0;
+  bool result = !!CryptMsgGetParam(message.get(), CMSG_SIGNER_INFO_PARAM, 0,
+                                   nullptr, &signer_info_size);
+  if (!result)
+    return base::string16();
+
+  // Allocate enough space to hold the signer info.
+  std::unique_ptr<BYTE[]> signer_info_buffer(new BYTE[signer_info_size]);
+  CMSG_SIGNER_INFO* signer_info =
+      reinterpret_cast<CMSG_SIGNER_INFO*>(signer_info_buffer.get());
+
+  // Obtain the signer info.
+  result = !!CryptMsgGetParam(message.get(), CMSG_SIGNER_INFO_PARAM, 0,
+                              signer_info, &signer_info_size);
+  if (!result)
+    return base::string16();
+
+  // Search for the signer certificate.
+  CERT_INFO CertInfo = {0};
+  PCCERT_CONTEXT cert_context = nullptr;
+  CertInfo.Issuer = signer_info->Issuer;
+  CertInfo.SerialNumber = signer_info->SerialNumber;
+
+  cert_context = CertFindCertificateInStore(
+      store.get(), X509_ASN_ENCODING | PKCS_7_ASN_ENCODING, 0,
+      CERT_FIND_SUBJECT_CERT, &CertInfo, nullptr);
+  if (!cert_context)
+    return base::string16();
+
+  // Determine the size of the Subject name.
+  DWORD subject_name_size = CertGetNameString(
+      cert_context, CERT_NAME_SIMPLE_DISPLAY_TYPE, 0, nullptr, nullptr, 0);
+  if (!subject_name_size)
+    return base::string16();
+
+  base::string16 subject_name;
+  subject_name.resize(subject_name_size);
+
+  // Get subject name.
+  if (!(CertGetNameString(cert_context, CERT_NAME_SIMPLE_DISPLAY_TYPE, 0,
+                          nullptr, const_cast<LPWSTR>(subject_name.c_str()),
+                          subject_name_size))) {
+    return base::string16();
+  }
+
+  return subject_name;
+}
+
+// Helper for scoped tracking a catalog admin context.
+struct CryptCATContextScopedTraits {
+  static PVOID InvalidValue() { return nullptr; }
+  static void Free(PVOID context) { CryptCATAdminReleaseContext(context, 0); }
+};
+using ScopedCryptCATContext =
+    base::ScopedGeneric<PVOID, CryptCATContextScopedTraits>;
+
+// Helper for scoped tracking of a catalog context. A catalog context is only
+// valid with an associated admin context, so this is effectively a std::pair.
+// A custom operator!= is required in order for a null |catalog_context| but
+// non-null |context| to compare equal to the InvalidValue exposed by the
+// traits class.
+class CryptCATCatalogContext {
+ public:
+  CryptCATCatalogContext(PVOID context, PVOID catalog_context)
+      : context_(context), catalog_context_(catalog_context) {}
+
+  bool operator!=(const CryptCATCatalogContext& rhs) const {
+    return catalog_context_ != rhs.catalog_context_;
+  }
+
+  PVOID context() const { return context_; }
+  PVOID catalog_context() const { return catalog_context_; }
+
+ private:
+  PVOID context_;
+  PVOID catalog_context_;
+};
+
+struct CryptCATCatalogContextScopedTraits {
+  static CryptCATCatalogContext InvalidValue() {
+    return CryptCATCatalogContext(nullptr, nullptr);
+  }
+  static void Free(const CryptCATCatalogContext& c) {
+    CryptCATAdminReleaseCatalogContext(c.context(), c.catalog_context(), 0);
+  }
+};
+using ScopedCryptCATCatalogContext =
+    base::ScopedGeneric<CryptCATCatalogContext,
+                        CryptCATCatalogContextScopedTraits>;
+
+// Extracts the subject name and catalog path if the provided file is present in
+// a catalog file.
+void GetCatalogCertificateInfo(const base::FilePath& filename,
+                               ModuleDatabase::CertificateInfo* cert_info) {
+  // Get a crypt context for signature verification.
+  ScopedCryptCATContext context;
+  {
+    PVOID raw_context = nullptr;
+    if (!CryptCATAdminAcquireContext(&raw_context, nullptr, 0))
+      return;
+    context.reset(raw_context);
+  }
+
+  // Open the file of interest.
+  base::win::ScopedHandle file_handle(
+      CreateFileW(filename.value().c_str(), GENERIC_READ,
+                  FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
+                  nullptr, OPEN_EXISTING, 0, nullptr));
+  if (!file_handle.IsValid())
+    return;
+
+  // Get the size we need for our hash.
+  DWORD hash_size = 0;
+  CryptCATAdminCalcHashFromFileHandle(file_handle.Get(), &hash_size, nullptr,
+                                      0);
+  if (hash_size == 0)
+    return;
+
+  // Calculate the hash. If this fails then bail.
+  std::vector<BYTE> buffer(hash_size);
+  if (!CryptCATAdminCalcHashFromFileHandle(file_handle.Get(), &hash_size,
+                                           buffer.data(), 0)) {
+    return;
+  }
+
+  // Get catalog for our context.
+  ScopedCryptCATCatalogContext catalog_context(CryptCATCatalogContext(
+      context.get(), CryptCATAdminEnumCatalogFromHash(
+                         context.get(), buffer.data(), hash_size, 0, nullptr)));
+  if (!catalog_context.is_valid())
+    return;
+
+  // Get the catalog info. This includes the path to the catalog itself, which
+  // contains the signature of interest.
+  CATALOG_INFO catalog_info = {};
+  catalog_info.cbStruct = sizeof(catalog_info);
+  if (!CryptCATCatalogInfoFromContext(catalog_context.get().catalog_context(),
+                                      &catalog_info, 0)) {
+    return;
+  }
+
+  // Attempt to get the "Subject" field from the signature of the catalog file
+  // itself.
+  base::FilePath catalog_path(catalog_info.wszCatalogFile);
+  base::string16 subject = GetSubjectNameInFile(catalog_path);
+
+  if (subject.empty())
+    return;
+
+  cert_info->type = ModuleDatabase::CERTIFICATE_IN_CATALOG;
+  cert_info->path = catalog_path;
+  cert_info->subject = subject;
+}
+
+}  // namespace
+
+// Extracts information about the certificate of the given file, if any is
+// found.
+void GetCertificateInfo(const base::FilePath& filename,
+                        ModuleDatabase::CertificateInfo* cert_info) {
+  DCHECK_EQ(ModuleDatabase::NO_CERTIFICATE, cert_info->type);
+  DCHECK(cert_info->path.empty());
+  DCHECK(cert_info->subject.empty());
+
+  GetCatalogCertificateInfo(filename, cert_info);
+  if (cert_info->type == ModuleDatabase::CERTIFICATE_IN_CATALOG)
+    return;
+
+  base::string16 subject = GetSubjectNameInFile(filename);
+  if (subject.empty())
+    return;
+
+  cert_info->type = ModuleDatabase::CERTIFICATE_IN_FILE;
+  cert_info->path = filename;
+  cert_info->subject = subject;
+}