sandbox/win/src/filesystem_policy.cc

   1 // Copyright (c) 2011 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 <string>
   6
   7 #include "sandbox/win/src/filesystem_policy.h"
   8
   9 #include "base/logging.h"
  10 #include "base/win/scoped_handle.h"
  11 #include "base/win/windows_version.h"
  12 #include "sandbox/win/src/ipc_tags.h"
  13 #include "sandbox/win/src/policy_engine_opcodes.h"
  14 #include "sandbox/win/src/policy_params.h"
  15 #include "sandbox/win/src/sandbox_utils.h"
  16 #include "sandbox/win/src/sandbox_types.h"
  17 #include "sandbox/win/src/win_utils.h"
  18
  19 namespace {
  20
  21 NTSTATUS NtCreateFileInTarget(HANDLE* target_file_handle,
  22                               ACCESS_MASK desired_access,
  23                               OBJECT_ATTRIBUTES* obj_attributes,
  24                               IO_STATUS_BLOCK* io_status_block,
  25                               ULONG file_attributes,
  26                               ULONG share_access,
  27                               ULONG create_disposition,
  28                               ULONG create_options,
  29                               PVOID ea_buffer,
  30                               ULONG ea_lenght,
  31                               HANDLE target_process) {
  32   NtCreateFileFunction NtCreateFile = NULL;
  33   ResolveNTFunctionPtr("NtCreateFile", &NtCreateFile);
  34
  35   HANDLE local_handle = INVALID_HANDLE_VALUE;
  36   NTSTATUS status = NtCreateFile(&local_handle, desired_access, obj_attributes,
  37                                  io_status_block, NULL, file_attributes,
  38                                  share_access, create_disposition,
  39                                  create_options, ea_buffer, ea_lenght);
  40   if (!NT_SUCCESS(status)) {
  41     return status;
  42   }
  43
  44   if (!sandbox::SameObject(local_handle, obj_attributes->ObjectName->Buffer)) {
  45     // The handle points somewhere else. Fail the operation.
  46     ::CloseHandle(local_handle);
  47     return STATUS_ACCESS_DENIED;
  48   }
  49
  50   if (!::DuplicateHandle(::GetCurrentProcess(), local_handle,
  51                          target_process, target_file_handle, 0, FALSE,
  52                          DUPLICATE_CLOSE_SOURCE | DUPLICATE_SAME_ACCESS)) {
  53     return STATUS_ACCESS_DENIED;
  54   }
  55   return STATUS_SUCCESS;
  56 }
  57
  58 // Get an initialized anonymous level Security QOS.
  59 SECURITY_QUALITY_OF_SERVICE GetAnonymousQOS() {
  60   SECURITY_QUALITY_OF_SERVICE security_qos = {0};
  61   security_qos.Length = sizeof(security_qos);
  62   security_qos.ImpersonationLevel = SecurityAnonymous;
  63   // Set dynamic tracking so that a pipe doesn't capture the broker's token
  64   security_qos.ContextTrackingMode = SECURITY_DYNAMIC_TRACKING;
  65   security_qos.EffectiveOnly = TRUE;
  66
  67   return security_qos;
  68 }
  69
  70 }  // namespace.
  71
  72 namespace sandbox {
  73
  74 bool FileSystemPolicy::GenerateRules(const wchar_t* name,
  75                                      TargetPolicy::Semantics semantics,
  76                                      LowLevelPolicy* policy) {
  77   base::string16 mod_name(name);
  78   if (mod_name.empty()) {
  79     return false;
  80   }
  81
  82   if (!PreProcessName(&mod_name)) {
  83     // The path to be added might contain a reparse point.
  84     NOTREACHED();
  85     return false;
  86   }
  87
  88   // TODO(cpu) bug 32224: This prefix add is a hack because we don't have the
  89   // infrastructure to normalize names. In any case we need to escape the
  90   // question marks.
  91   if (_wcsnicmp(mod_name.c_str(), kNTDevicePrefix, kNTDevicePrefixLen)) {
  92     mod_name = FixNTPrefixForMatch(mod_name);
  93     name = mod_name.c_str();
  94   }
  95
  96   EvalResult result = ASK_BROKER;
  97
  98   // List of supported calls for the filesystem.
  99   const unsigned kCallNtCreateFile = 0x1;
 100   const unsigned kCallNtOpenFile = 0x2;
 101   const unsigned kCallNtQueryAttributesFile = 0x4;
 102   const unsigned kCallNtQueryFullAttributesFile = 0x8;
 103   const unsigned kCallNtSetInfoRename = 0x10;
 104
 105   DWORD  rule_to_add = kCallNtOpenFile | kCallNtCreateFile |
 106                        kCallNtQueryAttributesFile |
 107                        kCallNtQueryFullAttributesFile | kCallNtSetInfoRename;
 108
 109   PolicyRule create(result);
 110   PolicyRule open(result);
 111   PolicyRule query(result);
 112   PolicyRule query_full(result);
 113   PolicyRule rename(result);
 114
 115   switch (semantics) {
 116     case TargetPolicy::FILES_ALLOW_DIR_ANY: {
 117       open.AddNumberMatch(IF, OpenFile::OPTIONS, FILE_DIRECTORY_FILE, AND);
 118       create.AddNumberMatch(IF, OpenFile::OPTIONS, FILE_DIRECTORY_FILE, AND);
 119       break;
 120     }
 121     case TargetPolicy::FILES_ALLOW_READONLY: {
 122       // We consider all flags that are not known to be readonly as potentially
 123       // used for write.
 124       DWORD allowed_flags = FILE_READ_DATA | FILE_READ_ATTRIBUTES |
 125                             FILE_READ_EA | SYNCHRONIZE | FILE_EXECUTE |
 126                             GENERIC_READ | GENERIC_EXECUTE | READ_CONTROL;
 127       DWORD restricted_flags = ~allowed_flags;
 128       open.AddNumberMatch(IF_NOT, OpenFile::ACCESS, restricted_flags, AND);
 129       open.AddNumberMatch(IF, OpenFile::DISPOSITION, FILE_OPEN, EQUAL);
 130       create.AddNumberMatch(IF_NOT, OpenFile::ACCESS, restricted_flags, AND);
 131       create.AddNumberMatch(IF, OpenFile::DISPOSITION, FILE_OPEN, EQUAL);
 132
 133       // Read only access don't work for rename.
 134       rule_to_add &= ~kCallNtSetInfoRename;
 135       break;
 136     }
 137     case TargetPolicy::FILES_ALLOW_QUERY: {
 138       // Here we don't want to add policy for the open or the create.
 139       rule_to_add &= ~(kCallNtOpenFile | kCallNtCreateFile |
 140                        kCallNtSetInfoRename);
 141       break;
 142     }
 143     case TargetPolicy::FILES_ALLOW_ANY: {
 144       break;
 145     }
 146     default: {
 147       NOTREACHED();
 148       return false;
 149     }
 150   }
 151
 152   if ((rule_to_add & kCallNtCreateFile) &&
 153       (!create.AddStringMatch(IF, OpenFile::NAME, name, CASE_INSENSITIVE) ||
 154        !policy->AddRule(IPC_NTCREATEFILE_TAG, &create))) {
 155     return false;
 156   }
 157
 158   if ((rule_to_add & kCallNtOpenFile) &&
 159       (!open.AddStringMatch(IF, OpenFile::NAME, name, CASE_INSENSITIVE) ||
 160        !policy->AddRule(IPC_NTOPENFILE_TAG, &open))) {
 161     return false;
 162   }
 163
 164   if ((rule_to_add & kCallNtQueryAttributesFile) &&
 165       (!query.AddStringMatch(IF, FileName::NAME, name, CASE_INSENSITIVE) ||
 166        !policy->AddRule(IPC_NTQUERYATTRIBUTESFILE_TAG, &query))) {
 167     return false;
 168   }
 169
 170   if ((rule_to_add & kCallNtQueryFullAttributesFile) &&
 171       (!query_full.AddStringMatch(IF, FileName::NAME, name, CASE_INSENSITIVE)
 172        || !policy->AddRule(IPC_NTQUERYFULLATTRIBUTESFILE_TAG,
 173                            &query_full))) {
 174     return false;
 175   }
 176
 177   if ((rule_to_add & kCallNtSetInfoRename) &&
 178       (!rename.AddStringMatch(IF, FileName::NAME, name, CASE_INSENSITIVE) ||
 179        !policy->AddRule(IPC_NTSETINFO_RENAME_TAG, &rename))) {
 180     return false;
 181   }
 182
 183   return true;
 184 }
 185
 186 // Right now we insert two rules, to be evaluated before any user supplied rule:
 187 // - go to the broker if the path doesn't look like the paths that we push on
 188 //    the policy (namely \??\something).
 189 // - go to the broker if it looks like this is a short-name path.
 190 //
 191 // It is possible to add a rule to go to the broker in any case; it would look
 192 // something like:
 193 //    rule = new PolicyRule(ASK_BROKER);
 194 //    rule->AddNumberMatch(IF_NOT, FileName::BROKER, TRUE, AND);
 195 //    policy->AddRule(service, rule);
 196 bool FileSystemPolicy::SetInitialRules(LowLevelPolicy* policy) {
 197   PolicyRule format(ASK_BROKER);
 198   PolicyRule short_name(ASK_BROKER);
 199
 200   bool rv = format.AddNumberMatch(IF_NOT, FileName::BROKER, TRUE, AND);
 201   rv &= format.AddStringMatch(IF_NOT, FileName::NAME, L"\\/?/?\\*",
 202                               CASE_SENSITIVE);
 203
 204   rv &= short_name.AddNumberMatch(IF_NOT, FileName::BROKER, TRUE, AND);
 205   rv &= short_name.AddStringMatch(IF, FileName::NAME, L"*~*", CASE_SENSITIVE);
 206
 207   if (!rv || !policy->AddRule(IPC_NTCREATEFILE_TAG, &format))
 208     return false;
 209
 210   if (!policy->AddRule(IPC_NTCREATEFILE_TAG, &short_name))
 211     return false;
 212
 213   if (!policy->AddRule(IPC_NTOPENFILE_TAG, &format))
 214     return false;
 215
 216   if (!policy->AddRule(IPC_NTOPENFILE_TAG, &short_name))
 217     return false;
 218
 219   if (!policy->AddRule(IPC_NTQUERYATTRIBUTESFILE_TAG, &format))
 220     return false;
 221
 222   if (!policy->AddRule(IPC_NTQUERYATTRIBUTESFILE_TAG, &short_name))
 223     return false;
 224
 225   if (!policy->AddRule(IPC_NTQUERYFULLATTRIBUTESFILE_TAG, &format))
 226     return false;
 227
 228   if (!policy->AddRule(IPC_NTQUERYFULLATTRIBUTESFILE_TAG, &short_name))
 229     return false;
 230
 231   if (!policy->AddRule(IPC_NTSETINFO_RENAME_TAG, &format))
 232     return false;
 233
 234   if (!policy->AddRule(IPC_NTSETINFO_RENAME_TAG, &short_name))
 235     return false;
 236
 237   return true;
 238 }
 239
 240 bool FileSystemPolicy::CreateFileAction(EvalResult eval_result,
 241                                         const ClientInfo& client_info,
 242                                         const base::string16 &file,
 243                                         uint32 attributes,
 244                                         uint32 desired_access,
 245                                         uint32 file_attributes,
 246                                         uint32 share_access,
 247                                         uint32 create_disposition,
 248                                         uint32 create_options,
 249                                         HANDLE *handle,
 250                                         NTSTATUS* nt_status,
 251                                         ULONG_PTR *io_information) {
 252   // The only action supported is ASK_BROKER which means create the requested
 253   // file as specified.
 254   if (ASK_BROKER != eval_result) {
 255     *nt_status = STATUS_ACCESS_DENIED;
 256     return false;
 257   }
 258   IO_STATUS_BLOCK io_block = {};
 259   UNICODE_STRING uni_name = {};
 260   OBJECT_ATTRIBUTES obj_attributes = {};
 261   SECURITY_QUALITY_OF_SERVICE security_qos = GetAnonymousQOS();
 262
 263   InitObjectAttribs(file, attributes, NULL, &obj_attributes,
 264                     &uni_name, IsPipe(file) ? &security_qos : NULL);
 265   *nt_status = NtCreateFileInTarget(handle, desired_access, &obj_attributes,
 266                                     &io_block, file_attributes, share_access,
 267                                     create_disposition, create_options, NULL,
 268                                     0, client_info.process);
 269
 270   *io_information = io_block.Information;
 271   return true;
 272 }
 273
 274 bool FileSystemPolicy::OpenFileAction(EvalResult eval_result,
 275                                       const ClientInfo& client_info,
 276                                       const base::string16 &file,
 277                                       uint32 attributes,
 278                                       uint32 desired_access,
 279                                       uint32 share_access,
 280                                       uint32 open_options,
 281                                       HANDLE *handle,
 282                                       NTSTATUS* nt_status,
 283                                       ULONG_PTR *io_information) {
 284   // The only action supported is ASK_BROKER which means open the requested
 285   // file as specified.
 286   if (ASK_BROKER != eval_result) {
 287     *nt_status = STATUS_ACCESS_DENIED;
 288     return true;
 289   }
 290   // An NtOpen is equivalent to an NtCreate with FileAttributes = 0 and
 291   // CreateDisposition = FILE_OPEN.
 292   IO_STATUS_BLOCK io_block = {};
 293   UNICODE_STRING uni_name = {};
 294   OBJECT_ATTRIBUTES obj_attributes = {};
 295   SECURITY_QUALITY_OF_SERVICE security_qos = GetAnonymousQOS();
 296
 297   InitObjectAttribs(file, attributes, NULL, &obj_attributes,
 298                     &uni_name, IsPipe(file) ? &security_qos : NULL);
 299   *nt_status = NtCreateFileInTarget(handle, desired_access, &obj_attributes,
 300                                     &io_block, 0, share_access, FILE_OPEN,
 301                                     open_options, NULL, 0,
 302                                     client_info.process);
 303
 304   *io_information = io_block.Information;
 305   return true;
 306 }
 307
 308 bool FileSystemPolicy::QueryAttributesFileAction(
 309     EvalResult eval_result,
 310     const ClientInfo& client_info,
 311     const base::string16 &file,
 312     uint32 attributes,
 313     FILE_BASIC_INFORMATION* file_info,
 314     NTSTATUS* nt_status) {
 315   // The only action supported is ASK_BROKER which means query the requested
 316   // file as specified.
 317   if (ASK_BROKER != eval_result) {
 318     *nt_status = STATUS_ACCESS_DENIED;
 319     return true;
 320   }
 321
 322   NtQueryAttributesFileFunction NtQueryAttributesFile = NULL;
 323   ResolveNTFunctionPtr("NtQueryAttributesFile", &NtQueryAttributesFile);
 324
 325   UNICODE_STRING uni_name = {0};
 326   OBJECT_ATTRIBUTES obj_attributes = {0};
 327   SECURITY_QUALITY_OF_SERVICE security_qos = GetAnonymousQOS();
 328
 329   InitObjectAttribs(file, attributes, NULL, &obj_attributes,
 330                     &uni_name, IsPipe(file) ? &security_qos : NULL);
 331   *nt_status = NtQueryAttributesFile(&obj_attributes, file_info);
 332
 333   return true;
 334 }
 335
 336 bool FileSystemPolicy::QueryFullAttributesFileAction(
 337     EvalResult eval_result,
 338     const ClientInfo& client_info,
 339     const base::string16 &file,
 340     uint32 attributes,
 341     FILE_NETWORK_OPEN_INFORMATION* file_info,
 342     NTSTATUS* nt_status) {
 343   // The only action supported is ASK_BROKER which means query the requested
 344   // file as specified.
 345   if (ASK_BROKER != eval_result) {
 346     *nt_status = STATUS_ACCESS_DENIED;
 347     return true;
 348   }
 349
 350   NtQueryFullAttributesFileFunction NtQueryFullAttributesFile = NULL;
 351   ResolveNTFunctionPtr("NtQueryFullAttributesFile", &NtQueryFullAttributesFile);
 352
 353   UNICODE_STRING uni_name = {0};
 354   OBJECT_ATTRIBUTES obj_attributes = {0};
 355   SECURITY_QUALITY_OF_SERVICE security_qos = GetAnonymousQOS();
 356
 357   InitObjectAttribs(file, attributes, NULL, &obj_attributes,
 358                     &uni_name, IsPipe(file) ? &security_qos : NULL);
 359   *nt_status = NtQueryFullAttributesFile(&obj_attributes, file_info);
 360
 361   return true;
 362 }
 363
 364 bool FileSystemPolicy::SetInformationFileAction(
 365     EvalResult eval_result, const ClientInfo& client_info,
 366     HANDLE target_file_handle, void* file_info, uint32 length,
 367     uint32 info_class, IO_STATUS_BLOCK* io_block,
 368     NTSTATUS* nt_status) {
 369   // The only action supported is ASK_BROKER which means open the requested
 370   // file as specified.
 371   if (ASK_BROKER != eval_result) {
 372     *nt_status = STATUS_ACCESS_DENIED;
 373     return true;
 374   }
 375
 376   NtSetInformationFileFunction NtSetInformationFile = NULL;
 377   ResolveNTFunctionPtr("NtSetInformationFile", &NtSetInformationFile);
 378
 379   HANDLE local_handle = NULL;
 380   if (!::DuplicateHandle(client_info.process, target_file_handle,
 381                          ::GetCurrentProcess(), &local_handle, 0, FALSE,
 382                          DUPLICATE_SAME_ACCESS)) {
 383     *nt_status = STATUS_ACCESS_DENIED;
 384     return true;
 385   }
 386
 387   base::win::ScopedHandle handle(local_handle);
 388
 389   FILE_INFORMATION_CLASS file_info_class =
 390       static_cast<FILE_INFORMATION_CLASS>(info_class);
 391   *nt_status = NtSetInformationFile(local_handle, io_block, file_info, length,
 392                                     file_info_class);
 393
 394   return true;
 395 }
 396
 397 bool PreProcessName(base::string16* path) {
 398   ConvertToLongPath(path);
 399
 400   if (ERROR_NOT_A_REPARSE_POINT == IsReparsePoint(*path))
 401     return true;
 402
 403   // We can't process a reparsed file.
 404   return false;
 405 }
 406
 407 base::string16 FixNTPrefixForMatch(const base::string16& name) {
 408   base::string16 mod_name = name;
 409
 410   // NT prefix escaped for rule matcher
 411   const wchar_t kNTPrefixEscaped[] = L"\\/?/?\\";
 412   const int kNTPrefixEscapedLen = arraysize(kNTPrefixEscaped) - 1;
 413
 414   if (0 != mod_name.compare(0, kNTPrefixLen, kNTPrefix)) {
 415     if (0 != mod_name.compare(0, kNTPrefixEscapedLen, kNTPrefixEscaped)) {
 416       // TODO(nsylvain): Find a better way to do name resolution. Right now we
 417       // take the name and we expand it.
 418       mod_name.insert(0, kNTPrefixEscaped);
 419     }
 420   } else {
 421     // Start of name matches NT prefix, replace with escaped format
 422     // Fixes bug: 334882
 423     mod_name.replace(0, kNTPrefixLen, kNTPrefixEscaped);
 424   }
 425
 426   return mod_name;
 427 }
 428
 429 }  // namespace sandbox