From 6f55786c65f1ab7116fde77dcd269b5025ac08d2 Mon Sep 17 00:00:00 2001 From: Simon Rozman Date: Fri, 3 Jul 2020 16:49:47 +0200 Subject: api: port tun\wintun\namespace_windows.go from wireguard-go Signed-off-by: Simon Rozman --- api/namespace.c | 200 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 200 insertions(+) create mode 100644 api/namespace.c (limited to 'api/namespace.c') diff --git a/api/namespace.c b/api/namespace.c new file mode 100644 index 0000000..98abf12 --- /dev/null +++ b/api/namespace.c @@ -0,0 +1,200 @@ +/* SPDX-License-Identifier: GPL-2.0 + * + * Copyright (C) 2018-2020 WireGuard LLC. All Rights Reserved. + */ + +#include "api.h" +#include +#include + +static SECURITY_ATTRIBUTES SecurityAttributes = { .nLength = sizeof(SECURITY_ATTRIBUTES) }; +static BOOL HasInitialized = FALSE; +static CRITICAL_SECTION Initializing; +static BCRYPT_ALG_HANDLE AlgProvider; + +static LPWSTR +NormalizeStringAlloc(_In_ NORM_FORM NormForm, _In_z_ LPCWSTR Source) +{ + LPWSTR Result = NULL; + HANDLE Heap = GetProcessHeap(); + int Len = NormalizeString(NormForm, Source, -1, NULL, 0); + for (int i = 0; i < 10; ++i) + { + if (Result) + HeapFree(Heap, 0, Result); + Result = HeapAlloc(Heap, 0, sizeof(WCHAR) * Len); + Len = NormalizeString(NormForm, Source, -1, Result, Len); + if (Len > 0) + return Result; + if (GetLastError() != ERROR_INSUFFICIENT_BUFFER) + break; + Len = -Len; + } + if (Result) + HeapFree(Heap, 0, Result); + return NULL; +} + +static void +Bin2Hex(_In_bytecount_(Size) const void *Source, size_t Size, _Out_capcount_(Size * 2) LPWSTR Destination) +{ + for (size_t i = 0; i < Size; ++i) + { + static const WCHAR nibble[] = L"0123456789ABCDEF"; + *(Destination++) = nibble[(((unsigned char *)Source)[i] & 0xf0) >> 4]; + *(Destination++) = nibble[(((unsigned char *)Source)[i] & 0x0f)]; + } +} + +static DWORD +NamespaceRuntimeInit() +{ + DWORD Result; + + EnterCriticalSection(&Initializing); + if (HasInitialized) + { + LeaveCriticalSection(&Initializing); + return ERROR_SUCCESS; + } + + /* TODO: wireguard-go uses Blake2s hashing in tun\wintun\namespace_windows.go, unfortunately not available in + * Windows API. SHA-256 is used instead. */ + if (!BCRYPT_SUCCESS(BCryptOpenAlgorithmProvider(&AlgProvider, BCRYPT_SHA256_ALGORITHM, NULL, 0))) + { + Result = ERROR_GEN_FAILURE; + goto cleanupLeaveCriticalSection; + } + + ULONG SecDescrSize; + if (!ConvertStringSecurityDescriptorToSecurityDescriptorW( + L"O:SYD:P(A;;GA;;;SY)", 1, &SecurityAttributes.lpSecurityDescriptor, &SecDescrSize)) + { + Result = GetLastError(); + goto cleanupBCryptCloseAlgorithmProvider; + } + BYTE Sid[MAX_SID_SIZE]; + DWORD SidSize = MAX_SID_SIZE; + if (!CreateWellKnownSid(WinLocalSystemSid, NULL, Sid, &SidSize)) + { + Result = GetLastError(); + goto cleanupSecurityDescriptor; + } + + HANDLE Boundary = CreateBoundaryDescriptorW(L"Wintun", 0); + if (!Boundary) + { + Result = GetLastError(); + goto cleanupSecurityDescriptor; + } + if (!AddSIDToBoundaryDescriptor(&Boundary, Sid)) + { + Result = GetLastError(); + goto cleanupSecurityDescriptor; + } + + for (;;) + { + if (CreatePrivateNamespaceW(&SecurityAttributes, Boundary, L"Wintun")) + break; + Result = GetLastError(); + if (Result == ERROR_ALREADY_EXISTS) + { + if (OpenPrivateNamespaceW(Boundary, L"Wintun")) + break; + Result = GetLastError(); + if (Result == ERROR_PATH_NOT_FOUND) + continue; + } + goto cleanupSecurityDescriptor; + } + + HasInitialized = TRUE; + Result = ERROR_SUCCESS; + goto cleanupLeaveCriticalSection; + +cleanupSecurityDescriptor: + LocalFree(SecurityAttributes.lpSecurityDescriptor); +cleanupBCryptCloseAlgorithmProvider: + BCryptCloseAlgorithmProvider(AlgProvider, 0); +cleanupLeaveCriticalSection: + LeaveCriticalSection(&Initializing); + return Result; +} + +_Check_return_ +HANDLE +TakeNameMutex(_In_z_ LPCWSTR Pool) +{ + HANDLE Mutex = NULL; + + if (NamespaceRuntimeInit() != ERROR_SUCCESS) + return NULL; + + /* TODO: wireguard-go uses Blake2s hashing in tun\wintun\namespace_windows.go, unfortunately not available in + * Windows API. SHA-256 is used instead. */ + BCRYPT_HASH_HANDLE Sha256 = NULL; + if (!BCRYPT_SUCCESS(BCryptCreateHash(AlgProvider, &Sha256, NULL, 0, NULL, 0, 0))) + return NULL; + static const char mutex_label[] = "WireGuard Adapter Name Mutex Stable Suffix v1 jason@zx2c4.com"; + if (!BCRYPT_SUCCESS(BCryptHashData(Sha256, (PUCHAR)mutex_label, sizeof(mutex_label) - sizeof(char), 0))) + goto cleanupSha256; + LPWSTR PoolNorm = NormalizeStringAlloc(NormalizationC, Pool); + if (!PoolNorm) + goto cleanupSha256; + /* TODO: wireguard-go hashes UTF-8 normalized pool name. We hash UTF-16 here. */ + if (!BCRYPT_SUCCESS(BCryptHashData(Sha256, (PUCHAR)PoolNorm, (int)wcslen(PoolNorm), 0))) + goto cleanupPoolNorm; + BYTE Hash[32]; + if (!BCRYPT_SUCCESS(BCryptFinishHash(Sha256, Hash, sizeof(Hash), 0))) + goto cleanupPoolNorm; + static const WCHAR MutexNamePrefix[] = L"Wintun\\Wintun-Name-Mutex-"; + WCHAR MutexName[_countof(MutexNamePrefix) /*<= incl. terminator*/ + sizeof(Hash) * 2]; + memcpy(MutexName, MutexNamePrefix, sizeof(MutexNamePrefix) - sizeof(WCHAR)); + Bin2Hex(Hash, sizeof(Hash), MutexName + _countof(MutexNamePrefix) - 1); + MutexName[_countof(MutexName) - 1] = 0; + Mutex = CreateMutexW(&SecurityAttributes, FALSE, MutexName); + if (!Mutex) + goto cleanupPoolNorm; + switch (WaitForSingleObject(Mutex, INFINITE)) + { + case WAIT_OBJECT_0: + case WAIT_ABANDONED: + goto cleanupPoolNorm; + } + + CloseHandle(Mutex); + Mutex = NULL; +cleanupPoolNorm: + HeapFree(GetProcessHeap(), 0, PoolNorm); +cleanupSha256: + BCryptDestroyHash(Sha256); + return Mutex; +} + +void +ReleaseNameMutex(_In_ HANDLE Mutex) +{ + ReleaseMutex(Mutex); + CloseHandle(Mutex); +} + +void +NamespaceInit() +{ + InitializeCriticalSection(&Initializing); +} + +void +NamespaceCleanup() +{ + EnterCriticalSection(&Initializing); + if (HasInitialized) + { + LocalFree(SecurityAttributes.lpSecurityDescriptor); + BCryptCloseAlgorithmProvider(AlgProvider, 0); + HasInitialized = FALSE; + } + LeaveCriticalSection(&Initializing); + DeleteCriticalSection(&Initializing); +} -- cgit v1.2.3-59-g8ed1b