Refactor process protection

This commit is contained in:
momo5502 2016-10-30 21:15:30 +01:00
parent 49d0528dfa
commit 3e95fe4344
2 changed files with 122 additions and 214 deletions

View File

@ -405,232 +405,140 @@ namespace Components
} }
} }
// TODO: Beautify that unsigned long AntiCheat::ProtectProcess()
DWORD AntiCheat::ProtectProcess()
{ {
// Returned to caller Utils::Memory::Allocator allocator;
DWORD dwResult = (DWORD)-1;
// Released on exit // If this fails, you can try to fallback to OpenThreadToken
HANDLE hToken = NULL; HANDLE hToken = nullptr;
PVOID pTokenInfo = NULL; if (!OpenProcessToken(GetCurrentProcess(), TOKEN_READ, &hToken))
PSID psidEveryone = NULL;
PSID psidSystem = NULL;
PSID psidAdmins = NULL;
PACL pDacl = NULL;
PSECURITY_DESCRIPTOR pSecDesc = NULL;
__try
{ {
// Scratch return GetLastError();
DWORD dwSize = 0;
BOOL bResult = FALSE;
// If this fails, you can try to fallback to OpenThreadToken
if (!OpenProcessToken(GetCurrentProcess(), TOKEN_READ, &hToken))
{
dwResult = GetLastError();
assert(FALSE);
__leave; /*failed*/
}
bResult = GetTokenInformation(hToken, TokenUser, NULL, 0, &dwSize);
dwResult = GetLastError();
assert(bResult == FALSE && ERROR_INSUFFICIENT_BUFFER == dwResult);
if (!(bResult == FALSE && ERROR_INSUFFICIENT_BUFFER == dwResult)) { __leave; /*failed*/ }
if (dwSize)
{
pTokenInfo = HeapAlloc(GetProcessHeap(), 0, dwSize);
dwResult = GetLastError();
assert(NULL != pTokenInfo);
if (NULL == pTokenInfo) { __leave; /*failed*/ }
}
bResult = GetTokenInformation(hToken, TokenUser, pTokenInfo, dwSize, &dwSize);
dwResult = GetLastError();
assert(bResult && pTokenInfo);
if (!(bResult && pTokenInfo)) { __leave; /*failed*/ }
PSID psidCurUser = ((TOKEN_USER*)pTokenInfo)->User.Sid;
SID_IDENTIFIER_AUTHORITY sidEveryone = SECURITY_WORLD_SID_AUTHORITY;
bResult = AllocateAndInitializeSid(&sidEveryone, 1,
SECURITY_WORLD_RID, 0, 0, 0, 0, 0, 0, 0, &psidEveryone);
dwResult = GetLastError();
assert(bResult && psidEveryone);
if (!(bResult && psidEveryone)) { __leave; /*failed*/ }
SID_IDENTIFIER_AUTHORITY sidSystem = SECURITY_NT_AUTHORITY;
bResult = AllocateAndInitializeSid(&sidSystem, 1,
SECURITY_LOCAL_SYSTEM_RID, 0, 0, 0, 0, 0, 0, 0, &psidSystem);
dwResult = GetLastError();
assert(bResult && psidSystem);
if (!(bResult && psidSystem)) { __leave; /*failed*/ }
SID_IDENTIFIER_AUTHORITY sidAdministrators = SECURITY_NT_AUTHORITY;
bResult = AllocateAndInitializeSid(&sidAdministrators, 2,
SECURITY_BUILTIN_DOMAIN_RID, DOMAIN_ALIAS_RID_ADMINS,
0, 0, 0, 0, 0, 0, &psidAdmins);
dwResult = GetLastError();
assert(bResult && psidAdmins);
if (!(bResult && psidAdmins)) { __leave; /*failed*/ }
const PSID psidArray[] =
{
psidEveryone, /* Deny most rights to everyone */
psidCurUser, /* Allow what was not denied */
psidSystem, /* Full control */
psidAdmins, /* Full control */
};
// Determine required size of the ACL
dwSize = sizeof(ACL);
// First the DENY, then the ALLOW
dwSize += GetLengthSid(psidArray[0]);
dwSize += sizeof(ACCESS_DENIED_ACE) - sizeof(DWORD);
for (UINT i = 1; i < _countof(psidArray); i++)
{
// DWORD is the SidStart field, which is not used for absolute format
dwSize += GetLengthSid(psidArray[i]);
dwSize += sizeof(ACCESS_ALLOWED_ACE) - sizeof(DWORD);
}
pDacl = (PACL)HeapAlloc(GetProcessHeap(), 0, dwSize);
dwResult = GetLastError();
assert(NULL != pDacl);
if (NULL == pDacl) { __leave; /*failed*/ }
bResult = InitializeAcl(pDacl, dwSize, ACL_REVISION);
dwResult = GetLastError();
assert(TRUE == bResult);
if (FALSE == bResult) { __leave; /*failed*/ }
// Mimic Protected Process
// http://www.microsoft.com/whdc/system/vista/process_vista.mspx
// Protected processes allow PROCESS_TERMINATE, which is
// probably not appropriate for high integrity software.
static const DWORD dwPoison =
/*READ_CONTROL |*/ WRITE_DAC | WRITE_OWNER |
PROCESS_CREATE_PROCESS | PROCESS_CREATE_THREAD |
PROCESS_DUP_HANDLE | PROCESS_QUERY_INFORMATION |
PROCESS_SET_QUOTA | PROCESS_SET_INFORMATION |
PROCESS_VM_OPERATION | PROCESS_VM_READ | PROCESS_VM_WRITE |
// In addition to protected process
PROCESS_SUSPEND_RESUME | PROCESS_TERMINATE;
bResult = AddAccessDeniedAce(pDacl, ACL_REVISION, dwPoison, psidArray[0]);
dwResult = GetLastError();
assert(TRUE == bResult);
if (FALSE == bResult) { __leave; /*failed*/ }
// Standard and specific rights not explicitly denied
static const DWORD dwAllowed = ~dwPoison & 0x1FFF;
bResult = AddAccessAllowedAce(pDacl, ACL_REVISION, dwAllowed, psidArray[1]);
dwResult = GetLastError();
assert(TRUE == bResult);
if (FALSE == bResult) { __leave; /*failed*/ }
// Because of ACE ordering, System will effectively have dwAllowed even
// though the ACE specifies PROCESS_ALL_ACCESS (unless software uses
// SeDebugPrivilege or SeTcbName and increases access).
// As an exercise, check behavior of tools such as Process Explorer under XP,
// Vista, and above. Vista and above should exhibit slightly different behavior
// due to Restricted tokens.
bResult = AddAccessAllowedAce(pDacl, ACL_REVISION, PROCESS_ALL_ACCESS, psidArray[2]);
dwResult = GetLastError();
assert(TRUE == bResult);
if (FALSE == bResult) { __leave; /*failed*/ }
// Because of ACE ordering, Administrators will effectively have dwAllowed
// even though the ACE specifies PROCESS_ALL_ACCESS (unless the Administrator
// invokes 'discretionary security' by taking ownership and increasing access).
// As an exercise, check behavior of tools such as Process Explorer under XP,
// Vista, and above. Vista and above should exhibit slightly different behavior
// due to Restricted tokens.
bResult = AddAccessAllowedAce(pDacl, ACL_REVISION, PROCESS_ALL_ACCESS, psidArray[3]);
dwResult = GetLastError();
assert(TRUE == bResult);
if (FALSE == bResult) { __leave; /*failed*/ }
pSecDesc = (PSECURITY_DESCRIPTOR)HeapAlloc(GetProcessHeap(), 0, SECURITY_DESCRIPTOR_MIN_LENGTH);
dwResult = GetLastError();
assert(NULL != pSecDesc);
if (NULL == pSecDesc) { __leave; /*failed*/ }
// InitializeSecurityDescriptor initializes a security descriptor in
// absolute format, rather than self-relative format. See
// http://msdn.microsoft.com/en-us/library/aa378863(VS.85).aspx
bResult = InitializeSecurityDescriptor(pSecDesc, SECURITY_DESCRIPTOR_REVISION);
dwResult = GetLastError();
assert(TRUE == bResult);
if (FALSE == bResult) { __leave; /*failed*/ }
bResult = SetSecurityDescriptorDacl(pSecDesc, TRUE, pDacl, FALSE);
dwResult = GetLastError();
assert(TRUE == bResult);
if (FALSE == bResult) { __leave; /*failed*/ }
dwResult = SetSecurityInfo(
GetCurrentProcess(),
SE_KERNEL_OBJECT, // process object
OWNER_SECURITY_INFORMATION | DACL_SECURITY_INFORMATION,
psidCurUser, // NULL, // Owner SID
NULL, // Group SID
pDacl,
NULL // SACL
);
dwResult = GetLastError();
assert(ERROR_SUCCESS == dwResult);
if (ERROR_SUCCESS != dwResult) { __leave; /*failed*/ }
dwResult = ERROR_SUCCESS;
} }
__finally
auto freeSid = [] (void* sid)
{ {
if (NULL != pSecDesc) if (sid)
{ {
HeapFree(GetProcessHeap(), 0, pSecDesc); FreeSid(reinterpret_cast<PSID>(sid));
}
if (NULL != pDacl)
{
HeapFree(GetProcessHeap(), 0, pDacl);
} }
};
if (psidAdmins) allocator.Reference(hToken, [] (void* hToken)
{ {
FreeSid(psidAdmins); if (hToken)
}
if (psidSystem)
{
FreeSid(psidSystem);
}
if (psidEveryone)
{
FreeSid(psidEveryone);
}
if (NULL != pTokenInfo)
{
HeapFree(GetProcessHeap(), 0, pTokenInfo);
}
if (NULL != hToken)
{ {
CloseHandle(hToken); CloseHandle(hToken);
} }
});
DWORD dwSize = 0;
PVOID pTokenInfo = nullptr;
if (GetTokenInformation(hToken, TokenUser, NULL, 0, &dwSize) || GetLastError() != ERROR_INSUFFICIENT_BUFFER) return GetLastError();
if (dwSize)
{
pTokenInfo = allocator.Allocate(dwSize);
if (!pTokenInfo) return GetLastError();
} }
return dwResult; if (!GetTokenInformation(hToken, TokenUser, pTokenInfo, dwSize, &dwSize) || !pTokenInfo) return GetLastError();
PSID psidCurUser = reinterpret_cast<TOKEN_USER*>(pTokenInfo)->User.Sid;
PSID psidEveryone = nullptr;
SID_IDENTIFIER_AUTHORITY sidEveryone = SECURITY_WORLD_SID_AUTHORITY;
if (!AllocateAndInitializeSid(&sidEveryone, 1, SECURITY_WORLD_RID, 0, 0, 0, 0, 0, 0, 0, &psidEveryone) || !psidEveryone) return GetLastError();
allocator.Reference(psidEveryone, freeSid);
PSID psidSystem = nullptr;
SID_IDENTIFIER_AUTHORITY sidSystem = SECURITY_NT_AUTHORITY;
if (!AllocateAndInitializeSid(&sidSystem, 1, SECURITY_LOCAL_SYSTEM_RID, 0, 0, 0, 0, 0, 0, 0, &psidSystem) || !psidSystem) return GetLastError();
allocator.Reference(psidSystem, freeSid);
PSID psidAdmins = nullptr;
SID_IDENTIFIER_AUTHORITY sidAdministrators = SECURITY_NT_AUTHORITY;
if (!AllocateAndInitializeSid(&sidAdministrators, 2, SECURITY_BUILTIN_DOMAIN_RID, DOMAIN_ALIAS_RID_ADMINS, 0, 0, 0, 0, 0, 0, &psidAdmins) || !psidAdmins) return GetLastError();
allocator.Reference(psidAdmins, freeSid);
const PSID psidArray[] =
{
psidEveryone, /* Deny most rights to everyone */
psidCurUser, /* Allow what was not denied */
psidSystem, /* Full control */
psidAdmins, /* Full control */
};
// Determine required size of the ACL
dwSize = sizeof(ACL);
// First the DENY, then the ALLOW
dwSize += GetLengthSid(psidArray[0]);
dwSize += sizeof(ACCESS_DENIED_ACE) - sizeof(DWORD);
for (UINT i = 1; i < _countof(psidArray); i++)
{
// DWORD is the SidStart field, which is not used for absolute format
dwSize += GetLengthSid(psidArray[i]);
dwSize += sizeof(ACCESS_ALLOWED_ACE) - sizeof(DWORD);
}
PACL pDacl = reinterpret_cast<PACL>(allocator.Allocate(dwSize));
if (!pDacl || !InitializeAcl(pDacl, dwSize, ACL_REVISION)) return GetLastError();
// Mimic Protected Process
// http://www.microsoft.com/whdc/system/vista/process_vista.mspx
// Protected processes allow PROCESS_TERMINATE, which is
// probably not appropriate for high integrity software.
static const DWORD dwPoison =
/*READ_CONTROL |*/ WRITE_DAC | WRITE_OWNER |
PROCESS_CREATE_PROCESS | PROCESS_CREATE_THREAD |
PROCESS_DUP_HANDLE | PROCESS_QUERY_INFORMATION |
PROCESS_SET_QUOTA | PROCESS_SET_INFORMATION |
PROCESS_VM_OPERATION | PROCESS_VM_READ | PROCESS_VM_WRITE |
// In addition to protected process
PROCESS_SUSPEND_RESUME | PROCESS_TERMINATE;
if (!AddAccessDeniedAce(pDacl, ACL_REVISION, dwPoison, psidArray[0])) return GetLastError();
// Standard and specific rights not explicitly denied
static const DWORD dwAllowed = ~dwPoison & 0x1FFF;
if (!AddAccessAllowedAce(pDacl, ACL_REVISION, dwAllowed, psidArray[1])) return GetLastError();
// Because of ACE ordering, System will effectively have dwAllowed even
// though the ACE specifies PROCESS_ALL_ACCESS (unless software uses
// SeDebugPrivilege or SeTcbName and increases access).
// As an exercise, check behavior of tools such as Process Explorer under XP,
// Vista, and above. Vista and above should exhibit slightly different behavior
// due to Restricted tokens.
if (!AddAccessAllowedAce(pDacl, ACL_REVISION, PROCESS_ALL_ACCESS, psidArray[2])) return GetLastError();
// Because of ACE ordering, Administrators will effectively have dwAllowed
// even though the ACE specifies PROCESS_ALL_ACCESS (unless the Administrator
// invokes 'discretionary security' by taking ownership and increasing access).
// As an exercise, check behavior of tools such as Process Explorer under XP,
// Vista, and above. Vista and above should exhibit slightly different behavior
// due to Restricted tokens.
if (!AddAccessAllowedAce(pDacl, ACL_REVISION, PROCESS_ALL_ACCESS, psidArray[3])) return GetLastError();
PSECURITY_DESCRIPTOR pSecDesc = allocator.Allocate<SECURITY_DESCRIPTOR>();
if (!pSecDesc) return GetLastError();
// InitializeSecurityDescriptor initializes a security descriptor in
// absolute format, rather than self-relative format. See
// http://msdn.microsoft.com/en-us/library/aa378863(VS.85).aspx
if (!InitializeSecurityDescriptor(pSecDesc, SECURITY_DESCRIPTOR_REVISION)) return GetLastError();
if (!SetSecurityDescriptorDacl(pSecDesc, TRUE, pDacl, FALSE)) return GetLastError();
return SetSecurityInfo(
GetCurrentProcess(),
SE_KERNEL_OBJECT, // process object
OWNER_SECURITY_INFORMATION | DACL_SECURITY_INFORMATION,
psidCurUser, // NULL, // Owner SID
NULL, // Group SID
pDacl,
NULL // SACL
);
} }
AntiCheat::AntiCheat() AntiCheat::AntiCheat()

View File

@ -44,7 +44,7 @@ namespace Components
static void PerformCheck(); static void PerformCheck();
static void PatchWinAPI(); static void PatchWinAPI();
static DWORD ProtectProcess(); static unsigned long ProtectProcess();
static void NullSub(); static void NullSub();