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