DXR is a code search and navigation tool aimed at making sense of large projects. It supports full-text and regex searches as well as structural queries.

Line Code
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311
// Copyright (c) 2012 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 <aclapi.h>
#include <sddl.h>
#include <vector>

#include "sandbox/win/src/restricted_token_utils.h"

#include "base/logging.h"
#include "base/win/scoped_handle.h"
#include "base/win/windows_version.h"
#include "sandbox/win/src/job.h"
#include "sandbox/win/src/restricted_token.h"
#include "sandbox/win/src/security_level.h"
#include "sandbox/win/src/sid.h"

namespace sandbox {

DWORD CreateRestrictedToken(TokenLevel security_level,
                            IntegrityLevel integrity_level,
                            TokenType token_type,
                            base::win::ScopedHandle* token) {
  RestrictedToken restricted_token;
  restricted_token.Init(NULL);  // Initialized with the current process token

  std::vector<base::string16> privilege_exceptions;
  std::vector<Sid> sid_exceptions;

  bool deny_sids = true;
  bool remove_privileges = true;

  switch (security_level) {
    case USER_UNPROTECTED: {
      deny_sids = false;
      remove_privileges = false;
      break;
    }
    case USER_RESTRICTED_SAME_ACCESS: {
      deny_sids = false;
      remove_privileges = false;

      unsigned err_code = restricted_token.AddRestrictingSidAllSids();
      if (ERROR_SUCCESS != err_code)
        return err_code;

      break;
    }
    case USER_NON_ADMIN: {
      sid_exceptions.push_back(WinBuiltinUsersSid);
      sid_exceptions.push_back(WinWorldSid);
      sid_exceptions.push_back(WinInteractiveSid);
      sid_exceptions.push_back(WinAuthenticatedUserSid);
      privilege_exceptions.push_back(SE_CHANGE_NOTIFY_NAME);
      break;
    }
    case USER_INTERACTIVE: {
      sid_exceptions.push_back(WinBuiltinUsersSid);
      sid_exceptions.push_back(WinWorldSid);
      sid_exceptions.push_back(WinInteractiveSid);
      sid_exceptions.push_back(WinAuthenticatedUserSid);
      privilege_exceptions.push_back(SE_CHANGE_NOTIFY_NAME);
      restricted_token.AddRestrictingSid(WinBuiltinUsersSid);
      restricted_token.AddRestrictingSid(WinWorldSid);
      restricted_token.AddRestrictingSid(WinRestrictedCodeSid);
      restricted_token.AddRestrictingSidCurrentUser();
      restricted_token.AddRestrictingSidLogonSession();
      break;
    }
    case USER_LIMITED: {
      sid_exceptions.push_back(WinBuiltinUsersSid);
      sid_exceptions.push_back(WinWorldSid);
      sid_exceptions.push_back(WinInteractiveSid);
      privilege_exceptions.push_back(SE_CHANGE_NOTIFY_NAME);
      restricted_token.AddRestrictingSid(WinBuiltinUsersSid);
      restricted_token.AddRestrictingSid(WinWorldSid);
      restricted_token.AddRestrictingSid(WinRestrictedCodeSid);

      // This token has to be able to create objects in BNO.
      // Unfortunately, on vista, it needs the current logon sid
      // in the token to achieve this. You should also set the process to be
      // low integrity level so it can't access object created by other
      // processes.
      if (base::win::GetVersion() >= base::win::VERSION_VISTA)
        restricted_token.AddRestrictingSidLogonSession();
      break;
    }
    case USER_RESTRICTED: {
      privilege_exceptions.push_back(SE_CHANGE_NOTIFY_NAME);
      restricted_token.AddUserSidForDenyOnly();
      restricted_token.AddRestrictingSid(WinRestrictedCodeSid);
      break;
    }
    case USER_LOCKDOWN: {
      restricted_token.AddUserSidForDenyOnly();
      restricted_token.AddRestrictingSid(WinNullSid);
      break;
    }
    default: {
      return ERROR_BAD_ARGUMENTS;
    }
  }

  DWORD err_code = ERROR_SUCCESS;
  if (deny_sids) {
    err_code = restricted_token.AddAllSidsForDenyOnly(&sid_exceptions);
    if (ERROR_SUCCESS != err_code)
      return err_code;
  }

  if (remove_privileges) {
    err_code = restricted_token.DeleteAllPrivileges(&privilege_exceptions);
    if (ERROR_SUCCESS != err_code)
      return err_code;
  }

  restricted_token.SetIntegrityLevel(integrity_level);

  switch (token_type) {
    case PRIMARY: {
      err_code = restricted_token.GetRestrictedToken(token);
      break;
    }
    case IMPERSONATION: {
      err_code = restricted_token.GetRestrictedTokenForImpersonation(token);
      break;
    }
    default: {
      err_code = ERROR_BAD_ARGUMENTS;
      break;
    }
  }

  return err_code;
}

DWORD SetObjectIntegrityLabel(HANDLE handle, SE_OBJECT_TYPE type,
                              const wchar_t* ace_access,
                              const wchar_t* integrity_level_sid) {
  // Build the SDDL string for the label.
  base::string16 sddl = L"S:(";   // SDDL for a SACL.
  sddl += SDDL_MANDATORY_LABEL;   // Ace Type is "Mandatory Label".
  sddl += L";;";                  // No Ace Flags.
  sddl += ace_access;             // Add the ACE access.
  sddl += L";;;";                 // No ObjectType and Inherited Object Type.
  sddl += integrity_level_sid;    // Trustee Sid.
  sddl += L")";

  DWORD error = ERROR_SUCCESS;
  PSECURITY_DESCRIPTOR sec_desc = NULL;

  PACL sacl = NULL;
  BOOL sacl_present = FALSE;
  BOOL sacl_defaulted = FALSE;

  if (::ConvertStringSecurityDescriptorToSecurityDescriptorW(sddl.c_str(),
                                                             SDDL_REVISION,
                                                             &sec_desc, NULL)) {
    if (::GetSecurityDescriptorSacl(sec_desc, &sacl_present, &sacl,
                                    &sacl_defaulted)) {
      error = ::SetSecurityInfo(handle, type,
                                LABEL_SECURITY_INFORMATION, NULL, NULL, NULL,
                                sacl);
    } else {
      error = ::GetLastError();
    }

    ::LocalFree(sec_desc);
  } else {
    return::GetLastError();
  }

  return error;
}

const wchar_t* GetIntegrityLevelString(IntegrityLevel integrity_level) {
  switch (integrity_level) {
    case INTEGRITY_LEVEL_SYSTEM:
      return L"S-1-16-16384";
    case INTEGRITY_LEVEL_HIGH:
      return L"S-1-16-12288";
    case INTEGRITY_LEVEL_MEDIUM:
      return L"S-1-16-8192";
    case INTEGRITY_LEVEL_MEDIUM_LOW:
      return L"S-1-16-6144";
    case INTEGRITY_LEVEL_LOW:
      return L"S-1-16-4096";
    case INTEGRITY_LEVEL_BELOW_LOW:
      return L"S-1-16-2048";
    case INTEGRITY_LEVEL_UNTRUSTED:
      return L"S-1-16-0";
    case INTEGRITY_LEVEL_LAST:
      return NULL;
  }

  NOTREACHED();
  return NULL;
}
DWORD SetTokenIntegrityLevel(HANDLE token, IntegrityLevel integrity_level) {
  if (base::win::GetVersion() < base::win::VERSION_VISTA)
    return ERROR_SUCCESS;

  const wchar_t* integrity_level_str = GetIntegrityLevelString(integrity_level);
  if (!integrity_level_str) {
    // No mandatory level specified, we don't change it.
    return ERROR_SUCCESS;
  }

  PSID integrity_sid = NULL;
  if (!::ConvertStringSidToSid(integrity_level_str, &integrity_sid))
    return ::GetLastError();

  TOKEN_MANDATORY_LABEL label = {};
  label.Label.Attributes = SE_GROUP_INTEGRITY;
  label.Label.Sid = integrity_sid;

  DWORD size = sizeof(TOKEN_MANDATORY_LABEL) + ::GetLengthSid(integrity_sid);
  BOOL result = ::SetTokenInformation(token, TokenIntegrityLevel, &label,
                                      size);
  auto last_error = ::GetLastError();
  ::LocalFree(integrity_sid);

  return result ? ERROR_SUCCESS : last_error;
}

DWORD SetProcessIntegrityLevel(IntegrityLevel integrity_level) {
  if (base::win::GetVersion() < base::win::VERSION_VISTA)
    return ERROR_SUCCESS;

  // We don't check for an invalid level here because we'll just let it
  // fail on the SetTokenIntegrityLevel call later on.
  if (integrity_level == INTEGRITY_LEVEL_LAST) {
    // No mandatory level specified, we don't change it.
    return ERROR_SUCCESS;
  }

  HANDLE token_handle;
  if (!::OpenProcessToken(GetCurrentProcess(), TOKEN_ADJUST_DEFAULT,
                          &token_handle))
    return ::GetLastError();

  base::win::ScopedHandle token(token_handle);

  return SetTokenIntegrityLevel(token.Get(), integrity_level);
}

DWORD HardenTokenIntegrityLevelPolicy(HANDLE token) {
  if (base::win::GetVersion() < base::win::VERSION_WIN7)
    return ERROR_SUCCESS;

  DWORD last_error = 0;
  DWORD length_needed = 0;

  ::GetKernelObjectSecurity(token, LABEL_SECURITY_INFORMATION,
                            NULL, 0, &length_needed);

  last_error = ::GetLastError();
  if (last_error != ERROR_INSUFFICIENT_BUFFER)
    return last_error;

  std::vector<char> security_desc_buffer(length_needed);
  PSECURITY_DESCRIPTOR security_desc =
      reinterpret_cast<PSECURITY_DESCRIPTOR>(&security_desc_buffer[0]);

  if (!::GetKernelObjectSecurity(token, LABEL_SECURITY_INFORMATION,
                                 security_desc, length_needed,
                                 &length_needed))
    return ::GetLastError();

  PACL sacl = NULL;
  BOOL sacl_present = FALSE;
  BOOL sacl_defaulted = FALSE;

  if (!::GetSecurityDescriptorSacl(security_desc, &sacl_present,
                                   &sacl, &sacl_defaulted))
    return ::GetLastError();

  for (DWORD ace_index = 0; ace_index < sacl->AceCount; ++ace_index) {
    PSYSTEM_MANDATORY_LABEL_ACE ace;

    if (::GetAce(sacl, ace_index, reinterpret_cast<LPVOID*>(&ace))
        && ace->Header.AceType == SYSTEM_MANDATORY_LABEL_ACE_TYPE) {
      ace->Mask |= SYSTEM_MANDATORY_LABEL_NO_READ_UP
                |  SYSTEM_MANDATORY_LABEL_NO_EXECUTE_UP;
      break;
    }
  }

  if (!::SetKernelObjectSecurity(token, LABEL_SECURITY_INFORMATION,
                                 security_desc))
    return ::GetLastError();

  return ERROR_SUCCESS;
}

DWORD HardenProcessIntegrityLevelPolicy() {
  if (base::win::GetVersion() < base::win::VERSION_WIN7)
    return ERROR_SUCCESS;

  HANDLE token_handle;
  if (!::OpenProcessToken(GetCurrentProcess(), READ_CONTROL | WRITE_OWNER,
                          &token_handle))
    return ::GetLastError();

  base::win::ScopedHandle token(token_handle);

  return HardenTokenIntegrityLevelPolicy(token.Get());
}

}  // namespace sandbox