Remove legacy Module Verifier.

chrome/browser/safe_browsing/incident_reporting/module_integrity_verifier_win.cc

Index: chrome/browser/safe_browsing/incident_reporting/module_integrity_verifier_win.cc
diff --git a/chrome/browser/safe_browsing/incident_reporting/module_integrity_verifier_win.cc b/chrome/browser/safe_browsing/incident_reporting/module_integrity_verifier_win.cc
index 6ea499b241ba2a56255c1df64ee9d3a7f9a4b05f..55ea230e501dd62138cc46cc81445985e9b9e18a 100644
--- a/chrome/browser/safe_browsing/incident_reporting/module_integrity_verifier_win.cc
+++ b/chrome/browser/safe_browsing/incident_reporting/module_integrity_verifier_win.cc
@@ -5,22 +5,22 @@
 #include "chrome/browser/safe_browsing/incident_reporting/module_integrity_verifier_win.h"
 
 #include <algorithm>
+#include <string>
 #include <vector>
 
-#include "base/containers/hash_tables.h"
 #include "base/files/file_path.h"
 #include "base/files/memory_mapped_file.h"
 #include "base/metrics/sparse_histogram.h"
 #include "base/scoped_native_library.h"
+#include "base/strings/utf_string_conversions.h"
 #include "base/win/pe_image.h"
-#include "build/build_config.h"
+#include "chrome/common/safe_browsing/csd.pb.h"
 
 namespace safe_browsing {
 
 namespace {
 
-// The maximum amount of bytes that can be reported as modified by
-// NewVerifyModule.
+// The maximum amount of bytes that can be reported as modified by VerifyModule.
 const int kMaxModuleModificationBytes = 256;
 
 struct Export {
@@ -55,9 +55,6 @@ struct ModuleVerificationState {
   // mem_peimage module's code section.
   intptr_t code_section_delta;
 
-  // The bytes corrected by relocs.
-  base::hash_set<uintptr_t> reloc_addr;
-
   // Set true if the relocation table contains a reloc of type that we don't
   // currently handle.
   bool unknown_reloc_type;
@@ -75,18 +72,18 @@ struct ModuleVerificationState {
   std::vector<Export> exports;
 
   // The location in the in-memory binary of the latest reloc encountered by
-  // |NewEnumRelocsCallback|.
+  // |EnumRelocsCallback|.
   uint8_t* last_mem_reloc_position;
 
   // The location in the on-disk binary of the latest reloc encountered by
-  // |NewEnumRelocsCallback|.
+  // |EnumRelocsCallback|.
   uint8_t* last_disk_reloc_position;
 
   // The number of bytes with a different value on disk and in memory, as
-  // computed by |NewVerifyModule|.
+  // computed by |VerifyModule|.
   int bytes_different;
 
-  // The module state protobuf object that |NewVerifyModule| will populate.
+  // The module state protobuf object that |VerifyModule| will populate.
   ClientIncidentReport_EnvironmentData_Process_ModuleState* module_state;
 
  private:
@@ -97,7 +94,6 @@ ModuleVerificationState::ModuleVerificationState(HMODULE hModule)
     : disk_peimage(hModule),
       image_base_delta(0),
       code_section_delta(0),
-      reloc_addr(),
       unknown_reloc_type(false),
       mem_code_addr(nullptr),
       disk_code_addr(nullptr),
@@ -111,11 +107,6 @@ ModuleVerificationState::ModuleVerificationState(HMODULE hModule)
 ModuleVerificationState::~ModuleVerificationState() {
 }
 
-bool ByteAccountedForByReloc(uint8_t* byte_addr,
-                             const ModuleVerificationState& state) {
-  return ((state.reloc_addr.count(reinterpret_cast<uintptr_t>(byte_addr))) > 0);
-}
-
 // Find which export a modification at address |mem_address| is in. Looks for
 // the largest export address still smaller than |mem_address|. |start| and
 // |end| must come from a sorted collection.
@@ -174,71 +165,16 @@ int ExamineByteRangeDiff(uint8_t* disk_start,
   return bytes_different;
 }
 
-// Checks each byte in the module's code section again the corresponding byte on
-// disk, returning the number of bytes differing between the two.  Also adds the
-// names of any modfied functions exported by name to |modified_exports|.
-// |state.exports| must be sorted.
-int ExamineBytesDiffInMemory(uint8_t* disk_code_start,
-                             uint8_t* mem_code_start,
-                             uint32_t code_size,
-                             const ModuleVerificationState& state,
-                             std::set<std::string>* modified_exports) {
-  int bytes_different = 0;
-  std::vector<Export>::const_iterator export_it = state.exports.begin();
-
-  for (uint8_t* end = mem_code_start + code_size; mem_code_start != end;
-       ++mem_code_start) {
-    if ((*disk_code_start++ != *mem_code_start) &&
-        !ByteAccountedForByReloc(mem_code_start, state)) {
-      std::vector<Export>::const_iterator modified_export_it =
-          FindModifiedExport(mem_code_start, export_it, state.exports.end());
-
-      if (modified_export_it != state.exports.begin())
-        modified_exports->insert((modified_export_it - 1)->name);
-      ++bytes_different;
-
-      // No later byte can belong to an earlier export.
-      export_it = modified_export_it;
-    }
-  }
-  return bytes_different;
-}
-
-// Adds to |state->reloc_addr| the bytes of the pointer at |address| that are
-// corrected by adding |image_base_delta|.
-void AddBytesCorrectedByReloc(uintptr_t address,
-                              ModuleVerificationState* state) {
-#if defined(ARCH_CPU_LITTLE_ENDIAN)
-#  define OFFSET(i) i
-#else
-#  define OFFSET(i) (sizeof(uintptr_t) - i)
-#endif
-
-  uintptr_t orig_mem_value = *reinterpret_cast<uintptr_t*>(address);
-  uintptr_t fixed_mem_value = orig_mem_value + state->image_base_delta;
-  uintptr_t disk_value =
-      *reinterpret_cast<uintptr_t*>(address + state->code_section_delta);
-
-  uintptr_t diff_before = orig_mem_value ^ disk_value;
-  uintptr_t shared_after = ~(fixed_mem_value ^ disk_value);
-  int i = 0;
-  for (uintptr_t fixed = diff_before & shared_after; fixed; fixed >>= 8, ++i) {
-    if (fixed & 0xFF)
-      state->reloc_addr.insert(address + OFFSET(i));
-  }
-#undef OFFSET
-}
-
 bool AddrIsInCodeSection(void* address,
                          uint8_t* code_addr,
                          uint32_t code_size) {
   return (code_addr <= address && address < code_addr + code_size);
 }
 
-bool NewEnumRelocsCallback(const base::win::PEImage& mem_peimage,
-                           WORD type,
-                           void* address,
-                           void* cookie) {
+bool EnumRelocsCallback(const base::win::PEImage& mem_peimage,
+                        WORD type,
+                        void* address,
+                        void* cookie) {
   ModuleVerificationState* state =
       reinterpret_cast<ModuleVerificationState*>(cookie);
 
@@ -319,52 +255,6 @@ bool NewEnumRelocsCallback(const base::win::PEImage& mem_peimage,
   return true;
 }
 
-bool EnumRelocsCallback(const base::win::PEImage& mem_peimage,
-                        WORD type,
-                        void* address,
-                        void* cookie) {
-  ModuleVerificationState* state =
-      reinterpret_cast<ModuleVerificationState*>(cookie);
-
-  uint8_t* mem_code_addr = NULL;
-  uint8_t* disk_code_addr = NULL;
-  uint32_t code_size = 0;
-  if (!GetCodeAddrsAndSize(mem_peimage,
-                           state->disk_peimage,
-                           &mem_code_addr,
-                           &disk_code_addr,
-                           &code_size))
-    return false;
-
-  // If not in the code section return true to continue to the next reloc.
-  if (!AddrIsInCodeSection(address, mem_code_addr, code_size))
-    return true;
-
-  switch (type) {
-    case IMAGE_REL_BASED_ABSOLUTE:  // 0
-      // Absolute type relocations are a noop, sometimes used to pad a section
-      // of relocations.
-      break;
-    case IMAGE_REL_BASED_HIGHLOW:  // 3
-      // The base relocation applies all 32 bits of the difference to the 32-bit
-      // field at offset.
-      AddBytesCorrectedByReloc(reinterpret_cast<uintptr_t>(address), state);
-      break;
-    case IMAGE_REL_BASED_DIR64:  // 10
-      // The base relocation applies the difference to the 64-bit field at
-      // offset.
-      // TODO(robertshield): Handle this type of reloc.
-      break;
-    default:
-      // TODO(robertshield): Find a reliable description of the behaviour of the
-      // remaining types of relocation and handle them.
-      UMA_HISTOGRAM_SPARSE_SLOWLY("SafeBrowsing.ModuleBaseRelocation", type);
-      state->unknown_reloc_type = true;
-      break;
-  }
-  return true;
-}
-
 bool EnumExportsCallback(const base::win::PEImage& mem_peimage,
                          DWORD ordinal,
                          DWORD hint,
@@ -410,32 +300,36 @@ bool GetCodeAddrsAndSize(const base::win::PEImage& mem_peimage,
   return true;
 }
 
-VerificationResult NewVerifyModule(
+bool VerifyModule(
     const wchar_t* module_name,
-    ClientIncidentReport_EnvironmentData_Process_ModuleState* module_state) {
-  VerificationResult result = { MODULE_STATE_UNKNOWN, 0, false, };
+    ClientIncidentReport_EnvironmentData_Process_ModuleState* module_state,
+    int* num_bytes_different) {
+  using ModuleState = ClientIncidentReport_EnvironmentData_Process_ModuleState;
+  *num_bytes_different = 0;
+  module_state->set_name(base::WideToUTF8(module_name));
+  module_state->set_modified_state(ModuleState::MODULE_STATE_UNKNOWN);
 
   // Get module handle, load a copy from disk as data and create PEImages.
   HMODULE module_handle = NULL;
   if (!GetModuleHandleEx(0, module_name, &module_handle))
-    return result;
+    return false;
   base::ScopedNativeLibrary native_library(module_handle);
 
   WCHAR module_path[MAX_PATH] = {};
   DWORD length =
       GetModuleFileName(module_handle, module_path, arraysize(module_path));
   if (!length || length == arraysize(module_path))
-    return result;
+    return false;
 
   base::MemoryMappedFile mapped_module;
   if (!mapped_module.Initialize(base::FilePath(module_path)))
-    return result;
+    return false;
   ModuleVerificationState state(
       reinterpret_cast<HMODULE>(const_cast<uint8*>(mapped_module.data())));
 
   base::win::PEImage mem_peimage(module_handle);
   if (!mem_peimage.VerifyMagic() || !state.disk_peimage.VerifyMagic())
-    return result;
+    return false;
 
   // Get the list of exports and sort them by address for efficient lookups.
   mem_peimage.EnumExports(EnumExportsCallback, &state.exports);
@@ -448,7 +342,7 @@ VerificationResult NewVerifyModule(
                            &state.mem_code_addr,
                            &state.disk_code_addr,
                            &state.code_size))
-    return result;
+    return false;
 
   state.module_state = module_state;
   state.last_mem_reloc_position = state.mem_code_addr;
@@ -464,10 +358,9 @@ VerificationResult NewVerifyModule(
   state.last_disk_reloc_position = state.disk_code_addr;
 
   // Enumerate relocations and verify the bytes between them.
-  result.verification_completed =
-      mem_peimage.EnumRelocs(NewEnumRelocsCallback, &state);
+  bool scan_complete = mem_peimage.EnumRelocs(EnumRelocsCallback, &state);
 
-  if (result.verification_completed) {
+  if (scan_complete) {
     size_t range_size =
         state.code_size - (state.last_mem_reloc_position - state.mem_code_addr);
     // Inspect the last chunk spanning from the furthest relocation to the end
@@ -478,81 +371,17 @@ VerificationResult NewVerifyModule(
         range_size,
         &state);
   }
-  result.num_bytes_different = state.bytes_different;
+  *num_bytes_different = state.bytes_different;
 
   // Report STATE_MODIFIED if any difference was found, regardless of whether or
   // not the entire module was scanned. Report STATE_UNMODIFIED only if the
   // entire module was scanned and understood.
   if (state.bytes_different)
-    result.state = MODULE_STATE_MODIFIED;
-  else if (!state.unknown_reloc_type && result.verification_completed)
-    result.state = MODULE_STATE_UNMODIFIED;
-
-  return result;
-}
-
-ModuleState VerifyModule(const wchar_t* module_name,
-                         std::set<std::string>* modified_exports,
-                         int* num_bytes_different) {
-  // Get module handle, load a copy from disk as data and create PEImages.
-  HMODULE module_handle = NULL;
-  if (!GetModuleHandleEx(0, module_name, &module_handle))
-    return MODULE_STATE_UNKNOWN;
-  base::ScopedNativeLibrary native_library(module_handle);
-
-  WCHAR module_path[MAX_PATH] = {};
-  DWORD length =
-      GetModuleFileName(module_handle, module_path, arraysize(module_path));
-  if (!length || length == arraysize(module_path))
-    return MODULE_STATE_UNKNOWN;
-
-  base::MemoryMappedFile mapped_module;
-  if (!mapped_module.Initialize(base::FilePath(module_path)))
-    return MODULE_STATE_UNKNOWN;
-  ModuleVerificationState state(
-      reinterpret_cast<HMODULE>(const_cast<uint8*>(mapped_module.data())));
-
-  base::win::PEImage mem_peimage(module_handle);
-  if (!mem_peimage.VerifyMagic() || !state.disk_peimage.VerifyMagic())
-    return MODULE_STATE_UNKNOWN;
-
-  // Get the list of exports.
-  mem_peimage.EnumExports(EnumExportsCallback, &state.exports);
-  std::sort(state.exports.begin(), state.exports.end());
-
-  // Get the addresses of the code sections then calculate |code_section_delta|
-  // and |image_base_delta|.
-  uint8_t* mem_code_addr = NULL;
-  uint8_t* disk_code_addr = NULL;
-  uint32_t code_size = 0;
-  if (!GetCodeAddrsAndSize(mem_peimage,
-                           state.disk_peimage,
-                           &mem_code_addr,
-                           &disk_code_addr,
-                           &code_size))
-    return MODULE_STATE_UNKNOWN;
-
-  state.code_section_delta = disk_code_addr - mem_code_addr;
-
-  uint8_t* preferred_image_base = reinterpret_cast<uint8_t*>(
-      state.disk_peimage.GetNTHeaders()->OptionalHeader.ImageBase);
-  state.image_base_delta =
-      preferred_image_base - reinterpret_cast<uint8_t*>(mem_peimage.module());
-
-  // Get the relocations.
-  mem_peimage.EnumRelocs(EnumRelocsCallback, &state);
-  if (state.unknown_reloc_type)
-    return MODULE_STATE_UNKNOWN;
-
-  // Count the modified bytes (after accounting for relocs) and get the set of
-  // modified functions.
-  *num_bytes_different = ExamineBytesDiffInMemory(disk_code_addr,
-                                                     mem_code_addr,
-                                                     code_size,
-                                                     state,
-                                                     modified_exports);
+    module_state->set_modified_state(ModuleState::MODULE_STATE_MODIFIED);
+  else if (!state.unknown_reloc_type && scan_complete)
+    module_state->set_modified_state(ModuleState::MODULE_STATE_UNMODIFIED);
 
-  return *num_bytes_different ? MODULE_STATE_MODIFIED : MODULE_STATE_UNMODIFIED;
+  return scan_complete;
 }
 
 }  // namespace safe_browsing