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// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "sandbox/win/src/acl.h"
#include <memory>
#include <windows.h>
#include <accctrl.h>
#include <aclapi.h>
#include <sddl.h>
#include "base/check.h"
#include "base/memory/free_deleter.h"
#include "base/notreached.h"
#include "base/win/access_token.h"
#include "base/win/scoped_localalloc.h"
namespace sandbox {
namespace {
ACCESS_MODE ConvertAccessMode(SecurityAccessMode access_mode) {
switch (access_mode) {
case SecurityAccessMode::kGrant:
return GRANT_ACCESS;
case SecurityAccessMode::kSet:
return SET_ACCESS;
case SecurityAccessMode::kDeny:
return DENY_ACCESS;
case SecurityAccessMode::kRevoke:
return REVOKE_ACCESS;
default:
NOTREACHED();
break;
}
return NOT_USED_ACCESS;
}
absl::optional<base::win::ScopedLocalAllocTyped<ACL>> AddSidToDacl(
const base::win::Sid& sid,
ACL* old_dacl,
SecurityAccessMode access_mode,
ACCESS_MASK access) {
EXPLICIT_ACCESS new_access = {};
new_access.grfAccessMode = ConvertAccessMode(access_mode);
new_access.grfAccessPermissions = access;
new_access.grfInheritance = NO_INHERITANCE;
::BuildTrusteeWithSid(&new_access.Trustee, sid.GetPSID());
ACL* new_dacl = nullptr;
if (ERROR_SUCCESS != ::SetEntriesInAcl(1, &new_access, old_dacl, &new_dacl))
return absl::nullopt;
DCHECK(::IsValidAcl(new_dacl));
return base::win::TakeLocalAlloc(new_dacl);
}
SE_OBJECT_TYPE ConvertObjectType(SecurityObjectType object_type) {
switch (object_type) {
case SecurityObjectType::kFile:
return SE_FILE_OBJECT;
case SecurityObjectType::kRegistry:
return SE_REGISTRY_KEY;
case SecurityObjectType::kWindow:
return SE_WINDOW_OBJECT;
case SecurityObjectType::kKernel:
return SE_KERNEL_OBJECT;
default:
NOTREACHED();
break;
}
return SE_UNKNOWN_OBJECT_TYPE;
}
absl::optional<DWORD> GetIntegrityLevelValue(IntegrityLevel integrity_level) {
switch (integrity_level) {
case INTEGRITY_LEVEL_SYSTEM:
return SECURITY_MANDATORY_SYSTEM_RID;
case INTEGRITY_LEVEL_HIGH:
return SECURITY_MANDATORY_HIGH_RID;
case INTEGRITY_LEVEL_MEDIUM:
return SECURITY_MANDATORY_MEDIUM_RID;
case INTEGRITY_LEVEL_MEDIUM_LOW:
return SECURITY_MANDATORY_MEDIUM_RID - 2048;
case INTEGRITY_LEVEL_LOW:
return SECURITY_MANDATORY_LOW_RID;
case INTEGRITY_LEVEL_BELOW_LOW:
return SECURITY_MANDATORY_LOW_RID - 2048;
case INTEGRITY_LEVEL_UNTRUSTED:
return SECURITY_MANDATORY_UNTRUSTED_RID;
case INTEGRITY_LEVEL_LAST:
return absl::nullopt;
}
NOTREACHED();
return absl::nullopt;
}
bool AddSidToDefaultDacl(HANDLE token,
const base::win::AccessToken& query_token,
const base::win::Sid& sid,
SecurityAccessMode access_mode,
ACCESS_MASK access) {
if (!token)
return false;
absl::optional<base::win::AccessToken::Dacl> dacl = query_token.DefaultDacl();
if (!dacl)
return false;
auto new_dacl = AddSidToDacl(sid, dacl->GetAcl(), access_mode, access);
if (!new_dacl)
return false;
TOKEN_DEFAULT_DACL new_token_dacl = {0};
new_token_dacl.DefaultDacl = new_dacl->get();
return !!::SetTokenInformation(token, TokenDefaultDacl, &new_token_dacl,
sizeof(new_token_dacl));
}
} // namespace
bool AddSidToDefaultDacl(HANDLE token,
const base::win::Sid& sid,
SecurityAccessMode access_mode,
ACCESS_MASK access) {
absl::optional<base::win::AccessToken> query_token =
base::win::AccessToken::FromToken(token);
if (!query_token)
return false;
return AddSidToDefaultDacl(token, *query_token, sid, access_mode, access);
}
bool AddSidToDefaultDacl(HANDLE token,
base::win::WellKnownSid known_sid,
SecurityAccessMode access_mode,
ACCESS_MASK access) {
absl::optional<base::win::Sid> sid = base::win::Sid::FromKnownSid(known_sid);
if (!sid)
return false;
return AddSidToDefaultDacl(token, *sid, access_mode, access);
}
bool RevokeLogonSidFromDefaultDacl(HANDLE token) {
absl::optional<base::win::AccessToken> query_token =
base::win::AccessToken::FromToken(token);
if (!query_token)
return false;
absl::optional<base::win::Sid> logon_sid = query_token->LogonId();
if (!logon_sid)
return ::GetLastError() == ERROR_NOT_FOUND;
return AddSidToDefaultDacl(token, *query_token, *logon_sid,
SecurityAccessMode::kRevoke, 0);
}
bool AddUserSidToDefaultDacl(HANDLE token, ACCESS_MASK access) {
absl::optional<base::win::AccessToken> query_token =
base::win::AccessToken::FromToken(token);
if (!query_token)
return false;
return AddSidToDefaultDacl(token, *query_token, query_token->User(),
SecurityAccessMode::kGrant, access);
}
bool AddKnownSidToObject(HANDLE object,
SecurityObjectType object_type,
const base::win::Sid& sid,
SecurityAccessMode access_mode,
ACCESS_MASK access) {
PSECURITY_DESCRIPTOR descriptor_ptr = nullptr;
PACL old_dacl = nullptr;
SE_OBJECT_TYPE native_object_type = ConvertObjectType(object_type);
if (native_object_type == SE_UNKNOWN_OBJECT_TYPE)
return false;
if (ERROR_SUCCESS != ::GetSecurityInfo(object, native_object_type,
DACL_SECURITY_INFORMATION, nullptr,
nullptr, &old_dacl, nullptr,
&descriptor_ptr)) {
return false;
}
auto descriptor = base::win::TakeLocalAlloc(descriptor_ptr);
auto new_dacl = AddSidToDacl(sid, old_dacl, access_mode, access);
if (!new_dacl)
return false;
return ::SetSecurityInfo(object, native_object_type,
DACL_SECURITY_INFORMATION, nullptr, nullptr,
new_dacl->get(), nullptr) == ERROR_SUCCESS;
}
bool AddKnownSidToObject(HANDLE object,
SecurityObjectType object_type,
base::win::WellKnownSid known_sid,
SecurityAccessMode access_mode,
ACCESS_MASK access) {
absl::optional<base::win::Sid> sid = base::win::Sid::FromKnownSid(known_sid);
if (!sid)
return false;
return AddKnownSidToObject(object, object_type, *sid, access_mode, access);
}
bool ReplacePackageSidInDacl(HANDLE object,
SecurityObjectType object_type,
const base::win::Sid& package_sid,
ACCESS_MASK access) {
if (!AddKnownSidToObject(object, object_type, package_sid,
SecurityAccessMode::kRevoke, 0)) {
return false;
}
return AddKnownSidToObject(
object, object_type,
*base::win::Sid::FromKnownSid(
base::win::WellKnownSid::kAllApplicationPackages),
SecurityAccessMode::kGrant, access);
}
absl::optional<base::win::Sid> GetIntegrityLevelSid(
IntegrityLevel integrity_level) {
absl::optional<DWORD> value = GetIntegrityLevelValue(integrity_level);
if (!value)
return absl::nullopt;
return base::win::Sid::FromIntegrityLevel(*value);
}
DWORD SetObjectIntegrityLabel(HANDLE handle,
SecurityObjectType object_type,
DWORD mandatory_policy,
IntegrityLevel integrity_level) {
absl::optional<base::win::Sid> sid = GetIntegrityLevelSid(integrity_level);
if (!sid)
return ERROR_INVALID_SID;
// Get total ACL length. SYSTEM_MANDATORY_LABEL_ACE contains the first DWORD
// of the SID so remove it from total.
DWORD length = sizeof(ACL) + sizeof(SYSTEM_MANDATORY_LABEL_ACE) +
::GetLengthSid(sid->GetPSID()) - sizeof(DWORD);
std::vector<char> sacl_buffer(length);
PACL sacl = reinterpret_cast<PACL>(sacl_buffer.data());
if (!::InitializeAcl(sacl, length, ACL_REVISION))
return ::GetLastError();
if (!::AddMandatoryAce(sacl, ACL_REVISION, 0, mandatory_policy,
sid->GetPSID())) {
return ::GetLastError();
}
DCHECK(::IsValidAcl(sacl));
return ::SetSecurityInfo(handle, ConvertObjectType(object_type),
LABEL_SECURITY_INFORMATION, nullptr, nullptr,
nullptr, sacl);
}
} // namespace sandbox
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