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comparison: security/sandbox/chromium/base/win/registry.cc

security/sandbox/chromium/base/win/registry.cc

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1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #include "base/win/registry.h"
6
7 #include <shlwapi.h>
8 #include <algorithm>
9
10 #include "base/logging.h"
11 #include "base/strings/string_util.h"
12 #include "base/threading/thread_restrictions.h"
13
14 #pragma comment(lib, "shlwapi.lib") // for SHDeleteKey
15
16 namespace base {
17 namespace win {
18
19 namespace {
20
21 // RegEnumValue() reports the number of characters from the name that were
22 // written to the buffer, not how many there are. This constant is the maximum
23 // name size, such that a buffer with this size should read any name.
24 const DWORD MAX_REGISTRY_NAME_SIZE = 16384;
25
26 // Registry values are read as BYTE* but can have wchar_t* data whose last
27 // wchar_t is truncated. This function converts the reported |byte_size| to
28 // a size in wchar_t that can store a truncated wchar_t if necessary.
29 inline DWORD to_wchar_size(DWORD byte_size) {
30 return (byte_size + sizeof(wchar_t) - 1) / sizeof(wchar_t);
31 }
32
33 } // namespace
34
35 // RegKey ----------------------------------------------------------------------
36
37 RegKey::RegKey()
38 : key_(NULL),
39 watch_event_(0) {
40 }
41
42 RegKey::RegKey(HKEY key)
43 : key_(key),
44 watch_event_(0) {
45 }
46
47 RegKey::RegKey(HKEY rootkey, const wchar_t* subkey, REGSAM access)
48 : key_(NULL),
49 watch_event_(0) {
50 if (rootkey) {
51 if (access & (KEY_SET_VALUE | KEY_CREATE_SUB_KEY | KEY_CREATE_LINK))
52 Create(rootkey, subkey, access);
53 else
54 Open(rootkey, subkey, access);
55 } else {
56 DCHECK(!subkey);
57 }
58 }
59
60 RegKey::~RegKey() {
61 Close();
62 }
63
64 LONG RegKey::Create(HKEY rootkey, const wchar_t* subkey, REGSAM access) {
65 DWORD disposition_value;
66 return CreateWithDisposition(rootkey, subkey, &disposition_value, access);
67 }
68
69 LONG RegKey::CreateWithDisposition(HKEY rootkey, const wchar_t* subkey,
70 DWORD* disposition, REGSAM access) {
71 DCHECK(rootkey && subkey && access && disposition);
72 Close();
73
74 LONG result = RegCreateKeyEx(rootkey, subkey, 0, NULL,
75 REG_OPTION_NON_VOLATILE, access, NULL, &key_,
76 disposition);
77 return result;
78 }
79
80 LONG RegKey::CreateKey(const wchar_t* name, REGSAM access) {
81 DCHECK(name && access);
82 HKEY subkey = NULL;
83 LONG result = RegCreateKeyEx(key_, name, 0, NULL, REG_OPTION_NON_VOLATILE,
84 access, NULL, &subkey, NULL);
85 Close();
86
87 key_ = subkey;
88 return result;
89 }
90
91 LONG RegKey::Open(HKEY rootkey, const wchar_t* subkey, REGSAM access) {
92 DCHECK(rootkey && subkey && access);
93 Close();
94
95 LONG result = RegOpenKeyEx(rootkey, subkey, 0, access, &key_);
96 return result;
97 }
98
99 LONG RegKey::OpenKey(const wchar_t* relative_key_name, REGSAM access) {
100 DCHECK(relative_key_name && access);
101 HKEY subkey = NULL;
102 LONG result = RegOpenKeyEx(key_, relative_key_name, 0, access, &subkey);
103
104 // We have to close the current opened key before replacing it with the new
105 // one.
106 Close();
107
108 key_ = subkey;
109 return result;
110 }
111
112 void RegKey::Close() {
113 StopWatching();
114 if (key_) {
115 ::RegCloseKey(key_);
116 key_ = NULL;
117 }
118 }
119
120 void RegKey::Set(HKEY key) {
121 if (key_ != key) {
122 Close();
123 key_ = key;
124 }
125 }
126
127 HKEY RegKey::Take() {
128 StopWatching();
129 HKEY key = key_;
130 key_ = NULL;
131 return key;
132 }
133
134 bool RegKey::HasValue(const wchar_t* name) const {
135 return RegQueryValueEx(key_, name, 0, NULL, NULL, NULL) == ERROR_SUCCESS;
136 }
137
138 DWORD RegKey::GetValueCount() const {
139 DWORD count = 0;
140 LONG result = RegQueryInfoKey(key_, NULL, 0, NULL, NULL, NULL, NULL, &count,
141 NULL, NULL, NULL, NULL);
142 return (result == ERROR_SUCCESS) ? count : 0;
143 }
144
145 LONG RegKey::GetValueNameAt(int index, std::wstring* name) const {
146 wchar_t buf[256];
147 DWORD bufsize = arraysize(buf);
148 LONG r = ::RegEnumValue(key_, index, buf, &bufsize, NULL, NULL, NULL, NULL);
149 if (r == ERROR_SUCCESS)
150 *name = buf;
151
152 return r;
153 }
154
155 LONG RegKey::DeleteKey(const wchar_t* name) {
156 DCHECK(key_);
157 DCHECK(name);
158 LONG result = SHDeleteKey(key_, name);
159 return result;
160 }
161
162 LONG RegKey::DeleteValue(const wchar_t* value_name) {
163 DCHECK(key_);
164 LONG result = RegDeleteValue(key_, value_name);
165 return result;
166 }
167
168 LONG RegKey::ReadValueDW(const wchar_t* name, DWORD* out_value) const {
169 DCHECK(out_value);
170 DWORD type = REG_DWORD;
171 DWORD size = sizeof(DWORD);
172 DWORD local_value = 0;
173 LONG result = ReadValue(name, &local_value, &size, &type);
174 if (result == ERROR_SUCCESS) {
175 if ((type == REG_DWORD || type == REG_BINARY) && size == sizeof(DWORD))
176 *out_value = local_value;
177 else
178 result = ERROR_CANTREAD;
179 }
180
181 return result;
182 }
183
184 LONG RegKey::ReadInt64(const wchar_t* name, int64* out_value) const {
185 DCHECK(out_value);
186 DWORD type = REG_QWORD;
187 int64 local_value = 0;
188 DWORD size = sizeof(local_value);
189 LONG result = ReadValue(name, &local_value, &size, &type);
190 if (result == ERROR_SUCCESS) {
191 if ((type == REG_QWORD || type == REG_BINARY) &&
192 size == sizeof(local_value))
193 *out_value = local_value;
194 else
195 result = ERROR_CANTREAD;
196 }
197
198 return result;
199 }
200
201 LONG RegKey::ReadValue(const wchar_t* name, std::wstring* out_value) const {
202 DCHECK(out_value);
203 const size_t kMaxStringLength = 1024; // This is after expansion.
204 // Use the one of the other forms of ReadValue if 1024 is too small for you.
205 wchar_t raw_value[kMaxStringLength];
206 DWORD type = REG_SZ, size = sizeof(raw_value);
207 LONG result = ReadValue(name, raw_value, &size, &type);
208 if (result == ERROR_SUCCESS) {
209 if (type == REG_SZ) {
210 *out_value = raw_value;
211 } else if (type == REG_EXPAND_SZ) {
212 wchar_t expanded[kMaxStringLength];
213 size = ExpandEnvironmentStrings(raw_value, expanded, kMaxStringLength);
214 // Success: returns the number of wchar_t's copied
215 // Fail: buffer too small, returns the size required
216 // Fail: other, returns 0
217 if (size == 0 || size > kMaxStringLength) {
218 result = ERROR_MORE_DATA;
219 } else {
220 *out_value = expanded;
221 }
222 } else {
223 // Not a string. Oops.
224 result = ERROR_CANTREAD;
225 }
226 }
227
228 return result;
229 }
230
231 LONG RegKey::ReadValue(const wchar_t* name,
232 void* data,
233 DWORD* dsize,
234 DWORD* dtype) const {
235 LONG result = RegQueryValueEx(key_, name, 0, dtype,
236 reinterpret_cast<LPBYTE>(data), dsize);
237 return result;
238 }
239
240 LONG RegKey::ReadValues(const wchar_t* name,
241 std::vector<std::wstring>* values) {
242 values->clear();
243
244 DWORD type = REG_MULTI_SZ;
245 DWORD size = 0;
246 LONG result = ReadValue(name, NULL, &size, &type);
247 if (FAILED(result) || size == 0)
248 return result;
249
250 if (type != REG_MULTI_SZ)
251 return ERROR_CANTREAD;
252
253 std::vector<wchar_t> buffer(size / sizeof(wchar_t));
254 result = ReadValue(name, &buffer[0], &size, NULL);
255 if (FAILED(result) || size == 0)
256 return result;
257
258 // Parse the double-null-terminated list of strings.
259 // Note: This code is paranoid to not read outside of |buf|, in the case where
260 // it may not be properly terminated.
261 const wchar_t* entry = &buffer[0];
262 const wchar_t* buffer_end = entry + (size / sizeof(wchar_t));
263 while (entry < buffer_end && entry[0] != '\0') {
264 const wchar_t* entry_end = std::find(entry, buffer_end, L'\0');
265 values->push_back(std::wstring(entry, entry_end));
266 entry = entry_end + 1;
267 }
268 return 0;
269 }
270
271 LONG RegKey::WriteValue(const wchar_t* name, DWORD in_value) {
272 return WriteValue(
273 name, &in_value, static_cast<DWORD>(sizeof(in_value)), REG_DWORD);
274 }
275
276 LONG RegKey::WriteValue(const wchar_t * name, const wchar_t* in_value) {
277 return WriteValue(name, in_value,
278 static_cast<DWORD>(sizeof(*in_value) * (wcslen(in_value) + 1)), REG_SZ);
279 }
280
281 LONG RegKey::WriteValue(const wchar_t* name,
282 const void* data,
283 DWORD dsize,
284 DWORD dtype) {
285 DCHECK(data || !dsize);
286
287 LONG result = RegSetValueEx(key_, name, 0, dtype,
288 reinterpret_cast<LPBYTE>(const_cast<void*>(data)), dsize);
289 return result;
290 }
291
292 LONG RegKey::StartWatching() {
293 DCHECK(key_);
294 if (!watch_event_)
295 watch_event_ = CreateEvent(NULL, TRUE, FALSE, NULL);
296
297 DWORD filter = REG_NOTIFY_CHANGE_NAME |
298 REG_NOTIFY_CHANGE_ATTRIBUTES |
299 REG_NOTIFY_CHANGE_LAST_SET |
300 REG_NOTIFY_CHANGE_SECURITY;
301
302 // Watch the registry key for a change of value.
303 LONG result = RegNotifyChangeKeyValue(key_, TRUE, filter, watch_event_, TRUE);
304 if (result != ERROR_SUCCESS) {
305 CloseHandle(watch_event_);
306 watch_event_ = 0;
307 }
308
309 return result;
310 }
311
312 bool RegKey::HasChanged() {
313 if (watch_event_) {
314 if (WaitForSingleObject(watch_event_, 0) == WAIT_OBJECT_0) {
315 StartWatching();
316 return true;
317 }
318 }
319 return false;
320 }
321
322 LONG RegKey::StopWatching() {
323 LONG result = ERROR_INVALID_HANDLE;
324 if (watch_event_) {
325 CloseHandle(watch_event_);
326 watch_event_ = 0;
327 result = ERROR_SUCCESS;
328 }
329 return result;
330 }
331
332 // RegistryValueIterator ------------------------------------------------------
333
334 RegistryValueIterator::RegistryValueIterator(HKEY root_key,
335 const wchar_t* folder_key)
336 : name_(MAX_PATH, L'\0'),
337 value_(MAX_PATH, L'\0') {
338 LONG result = RegOpenKeyEx(root_key, folder_key, 0, KEY_READ, &key_);
339 if (result != ERROR_SUCCESS) {
340 key_ = NULL;
341 } else {
342 DWORD count = 0;
343 result = ::RegQueryInfoKey(key_, NULL, 0, NULL, NULL, NULL, NULL, &count,
344 NULL, NULL, NULL, NULL);
345
346 if (result != ERROR_SUCCESS) {
347 ::RegCloseKey(key_);
348 key_ = NULL;
349 } else {
350 index_ = count - 1;
351 }
352 }
353
354 Read();
355 }
356
357 RegistryValueIterator::~RegistryValueIterator() {
358 if (key_)
359 ::RegCloseKey(key_);
360 }
361
362 DWORD RegistryValueIterator::ValueCount() const {
363 DWORD count = 0;
364 LONG result = ::RegQueryInfoKey(key_, NULL, 0, NULL, NULL, NULL, NULL,
365 &count, NULL, NULL, NULL, NULL);
366 if (result != ERROR_SUCCESS)
367 return 0;
368
369 return count;
370 }
371
372 bool RegistryValueIterator::Valid() const {
373 return key_ != NULL && index_ >= 0;
374 }
375
376 void RegistryValueIterator::operator++() {
377 --index_;
378 Read();
379 }
380
381 bool RegistryValueIterator::Read() {
382 if (Valid()) {
383 DWORD capacity = static_cast<DWORD>(name_.capacity());
384 DWORD name_size = capacity;
385 // |value_size_| is in bytes. Reserve the last character for a NUL.
386 value_size_ = static_cast<DWORD>((value_.size() - 1) * sizeof(wchar_t));
387 LONG result = ::RegEnumValue(
388 key_, index_, WriteInto(&name_, name_size), &name_size, NULL, &type_,
389 reinterpret_cast<BYTE*>(vector_as_array(&value_)), &value_size_);
390
391 if (result == ERROR_MORE_DATA) {
392 // Registry key names are limited to 255 characters and fit within
393 // MAX_PATH (which is 260) but registry value names can use up to 16,383
394 // characters and the value itself is not limited
395 // (from http://msdn.microsoft.com/en-us/library/windows/desktop/
396 // ms724872(v=vs.85).aspx).
397 // Resize the buffers and retry if their size caused the failure.
398 DWORD value_size_in_wchars = to_wchar_size(value_size_);
399 if (value_size_in_wchars + 1 > value_.size())
400 value_.resize(value_size_in_wchars + 1, L'\0');
401 value_size_ = static_cast<DWORD>((value_.size() - 1) * sizeof(wchar_t));
402 name_size = name_size == capacity ? MAX_REGISTRY_NAME_SIZE : capacity;
403 result = ::RegEnumValue(
404 key_, index_, WriteInto(&name_, name_size), &name_size, NULL, &type_,
405 reinterpret_cast<BYTE*>(vector_as_array(&value_)), &value_size_);
406 }
407
408 if (result == ERROR_SUCCESS) {
409 DCHECK_LT(to_wchar_size(value_size_), value_.size());
410 value_[to_wchar_size(value_size_)] = L'\0';
411 return true;
412 }
413 }
414
415 name_[0] = L'\0';
416 value_[0] = L'\0';
417 value_size_ = 0;
418 return false;
419 }
420
421 // RegistryKeyIterator --------------------------------------------------------
422
423 RegistryKeyIterator::RegistryKeyIterator(HKEY root_key,
424 const wchar_t* folder_key) {
425 LONG result = RegOpenKeyEx(root_key, folder_key, 0, KEY_READ, &key_);
426 if (result != ERROR_SUCCESS) {
427 key_ = NULL;
428 } else {
429 DWORD count = 0;
430 LONG result = ::RegQueryInfoKey(key_, NULL, 0, NULL, &count, NULL, NULL,
431 NULL, NULL, NULL, NULL, NULL);
432
433 if (result != ERROR_SUCCESS) {
434 ::RegCloseKey(key_);
435 key_ = NULL;
436 } else {
437 index_ = count - 1;
438 }
439 }
440
441 Read();
442 }
443
444 RegistryKeyIterator::~RegistryKeyIterator() {
445 if (key_)
446 ::RegCloseKey(key_);
447 }
448
449 DWORD RegistryKeyIterator::SubkeyCount() const {
450 DWORD count = 0;
451 LONG result = ::RegQueryInfoKey(key_, NULL, 0, NULL, &count, NULL, NULL,
452 NULL, NULL, NULL, NULL, NULL);
453 if (result != ERROR_SUCCESS)
454 return 0;
455
456 return count;
457 }
458
459 bool RegistryKeyIterator::Valid() const {
460 return key_ != NULL && index_ >= 0;
461 }
462
463 void RegistryKeyIterator::operator++() {
464 --index_;
465 Read();
466 }
467
468 bool RegistryKeyIterator::Read() {
469 if (Valid()) {
470 DWORD ncount = arraysize(name_);
471 FILETIME written;
472 LONG r = ::RegEnumKeyEx(key_, index_, name_, &ncount, NULL, NULL,
473 NULL, &written);
474 if (ERROR_SUCCESS == r)
475 return true;
476 }
477
478 name_[0] = '\0';
479 return false;
480 }
481
482 } // namespace win
483 } // namespace base

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