1 //===-- asan_win.cpp
2 //------------------------------------------------------===//>
3 //
4 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5 // See https://llvm.org/LICENSE.txt for license information.
6 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file is a part of AddressSanitizer, an address sanity checker.
11 //
12 // Windows-specific details.
13 //===----------------------------------------------------------------------===//
14
15 #include "sanitizer_common/sanitizer_platform.h"
16 #if SANITIZER_WINDOWS
17 # define WIN32_LEAN_AND_MEAN
18 # include <stdlib.h>
19 # include <windows.h>
20
21 # include "asan_interceptors.h"
22 # include "asan_internal.h"
23 # include "asan_mapping.h"
24 # include "asan_report.h"
25 # include "asan_stack.h"
26 # include "asan_thread.h"
27 # include "sanitizer_common/sanitizer_libc.h"
28 # include "sanitizer_common/sanitizer_mutex.h"
29 # include "sanitizer_common/sanitizer_win.h"
30 # include "sanitizer_common/sanitizer_win_defs.h"
31
32 using namespace __asan;
33
34 extern "C" {
35 SANITIZER_INTERFACE_ATTRIBUTE
__asan_should_detect_stack_use_after_return()36 int __asan_should_detect_stack_use_after_return() {
37 __asan_init();
38 return __asan_option_detect_stack_use_after_return;
39 }
40
41 SANITIZER_INTERFACE_ATTRIBUTE
__asan_get_shadow_memory_dynamic_address()42 uptr __asan_get_shadow_memory_dynamic_address() {
43 __asan_init();
44 return __asan_shadow_memory_dynamic_address;
45 }
46 } // extern "C"
47
48 // ---------------------- Windows-specific interceptors ---------------- {{{
49 static LPTOP_LEVEL_EXCEPTION_FILTER default_seh_handler;
50 static LPTOP_LEVEL_EXCEPTION_FILTER user_seh_handler;
51
__asan_unhandled_exception_filter(EXCEPTION_POINTERS * info)52 extern "C" SANITIZER_INTERFACE_ATTRIBUTE long __asan_unhandled_exception_filter(
53 EXCEPTION_POINTERS *info) {
54 EXCEPTION_RECORD *exception_record = info->ExceptionRecord;
55 CONTEXT *context = info->ContextRecord;
56
57 // FIXME: Handle EXCEPTION_STACK_OVERFLOW here.
58
59 SignalContext sig(exception_record, context);
60 ReportDeadlySignal(sig);
61 UNREACHABLE("returned from reporting deadly signal");
62 }
63
64 // Wrapper SEH Handler. If the exception should be handled by asan, we call
65 // __asan_unhandled_exception_filter, otherwise, we execute the user provided
66 // exception handler or the default.
SEHHandler(EXCEPTION_POINTERS * info)67 static long WINAPI SEHHandler(EXCEPTION_POINTERS *info) {
68 DWORD exception_code = info->ExceptionRecord->ExceptionCode;
69 if (__sanitizer::IsHandledDeadlyException(exception_code))
70 return __asan_unhandled_exception_filter(info);
71 if (user_seh_handler)
72 return user_seh_handler(info);
73 // Bubble out to the default exception filter.
74 if (default_seh_handler)
75 return default_seh_handler(info);
76 return EXCEPTION_CONTINUE_SEARCH;
77 }
78
INTERCEPTOR_WINAPI(LPTOP_LEVEL_EXCEPTION_FILTER,SetUnhandledExceptionFilter,LPTOP_LEVEL_EXCEPTION_FILTER ExceptionFilter)79 INTERCEPTOR_WINAPI(LPTOP_LEVEL_EXCEPTION_FILTER, SetUnhandledExceptionFilter,
80 LPTOP_LEVEL_EXCEPTION_FILTER ExceptionFilter) {
81 CHECK(REAL(SetUnhandledExceptionFilter));
82 if (ExceptionFilter == &SEHHandler)
83 return REAL(SetUnhandledExceptionFilter)(ExceptionFilter);
84 // We record the user provided exception handler to be called for all the
85 // exceptions unhandled by asan.
86 Swap(ExceptionFilter, user_seh_handler);
87 return ExceptionFilter;
88 }
89
INTERCEPTOR_WINAPI(void,RtlRaiseException,EXCEPTION_RECORD * ExceptionRecord)90 INTERCEPTOR_WINAPI(void, RtlRaiseException, EXCEPTION_RECORD *ExceptionRecord) {
91 CHECK(REAL(RtlRaiseException));
92 // This is a noreturn function, unless it's one of the exceptions raised to
93 // communicate with the debugger, such as the one from OutputDebugString.
94 if (ExceptionRecord->ExceptionCode != DBG_PRINTEXCEPTION_C)
95 __asan_handle_no_return();
96 REAL(RtlRaiseException)(ExceptionRecord);
97 }
98
INTERCEPTOR_WINAPI(void,RaiseException,void * a,void * b,void * c,void * d)99 INTERCEPTOR_WINAPI(void, RaiseException, void *a, void *b, void *c, void *d) {
100 CHECK(REAL(RaiseException));
101 __asan_handle_no_return();
102 REAL(RaiseException)(a, b, c, d);
103 }
104
105 #ifdef _WIN64
106
INTERCEPTOR_WINAPI(EXCEPTION_DISPOSITION,__C_specific_handler,_EXCEPTION_RECORD * a,void * b,_CONTEXT * c,_DISPATCHER_CONTEXT * d)107 INTERCEPTOR_WINAPI(EXCEPTION_DISPOSITION, __C_specific_handler,
108 _EXCEPTION_RECORD *a, void *b, _CONTEXT *c,
109 _DISPATCHER_CONTEXT *d) {
110 CHECK(REAL(__C_specific_handler));
111 __asan_handle_no_return();
112 return REAL(__C_specific_handler)(a, b, c, d);
113 }
114
115 #else
116
INTERCEPTOR(int,_except_handler3,void * a,void * b,void * c,void * d)117 INTERCEPTOR(int, _except_handler3, void *a, void *b, void *c, void *d) {
118 CHECK(REAL(_except_handler3));
119 __asan_handle_no_return();
120 return REAL(_except_handler3)(a, b, c, d);
121 }
122
123 #if ASAN_DYNAMIC
124 // This handler is named differently in -MT and -MD CRTs.
125 #define _except_handler4 _except_handler4_common
126 #endif
INTERCEPTOR(int,_except_handler4,void * a,void * b,void * c,void * d)127 INTERCEPTOR(int, _except_handler4, void *a, void *b, void *c, void *d) {
128 CHECK(REAL(_except_handler4));
129 __asan_handle_no_return();
130 return REAL(_except_handler4)(a, b, c, d);
131 }
132 #endif
133
134 struct ThreadStartParams {
135 thread_callback_t start_routine;
136 void *arg;
137 };
138
asan_thread_start(void * arg)139 static thread_return_t THREAD_CALLING_CONV asan_thread_start(void *arg) {
140 AsanThread *t = (AsanThread *)arg;
141 SetCurrentThread(t);
142 t->ThreadStart(GetTid());
143
144 ThreadStartParams params;
145 t->GetStartData(params);
146
147 auto res = (*params.start_routine)(params.arg);
148 t->Destroy(); // POSIX calls this from TSD destructor.
149 return res;
150 }
151
INTERCEPTOR_WINAPI(HANDLE,CreateThread,LPSECURITY_ATTRIBUTES security,SIZE_T stack_size,LPTHREAD_START_ROUTINE start_routine,void * arg,DWORD thr_flags,DWORD * tid)152 INTERCEPTOR_WINAPI(HANDLE, CreateThread, LPSECURITY_ATTRIBUTES security,
153 SIZE_T stack_size, LPTHREAD_START_ROUTINE start_routine,
154 void *arg, DWORD thr_flags, DWORD *tid) {
155 // Strict init-order checking is thread-hostile.
156 if (flags()->strict_init_order)
157 StopInitOrderChecking();
158 GET_STACK_TRACE_THREAD;
159 // FIXME: The CreateThread interceptor is not the same as a pthread_create
160 // one. This is a bandaid fix for PR22025.
161 bool detached = false; // FIXME: how can we determine it on Windows?
162 u32 current_tid = GetCurrentTidOrInvalid();
163 ThreadStartParams params = {start_routine, arg};
164 AsanThread *t = AsanThread::Create(params, current_tid, &stack, detached);
165 return REAL(CreateThread)(security, stack_size, asan_thread_start, t,
166 thr_flags, tid);
167 }
168
169 // }}}
170
171 namespace __asan {
172
InitializePlatformInterceptors()173 void InitializePlatformInterceptors() {
174 __interception::SetErrorReportCallback(Report);
175
176 // The interceptors were not designed to be removable, so we have to keep this
177 // module alive for the life of the process.
178 HMODULE pinned;
179 CHECK(GetModuleHandleExW(
180 GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS | GET_MODULE_HANDLE_EX_FLAG_PIN,
181 (LPCWSTR)&InitializePlatformInterceptors, &pinned));
182
183 ASAN_INTERCEPT_FUNC(CreateThread);
184 ASAN_INTERCEPT_FUNC(SetUnhandledExceptionFilter);
185
186 #ifdef _WIN64
187 ASAN_INTERCEPT_FUNC(__C_specific_handler);
188 #else
189 ASAN_INTERCEPT_FUNC(_except_handler3);
190 ASAN_INTERCEPT_FUNC(_except_handler4);
191 #endif
192
193 // Try to intercept kernel32!RaiseException, and if that fails, intercept
194 // ntdll!RtlRaiseException instead.
195 if (!::__interception::OverrideFunction("RaiseException",
196 (uptr)WRAP(RaiseException),
197 (uptr *)&REAL(RaiseException))) {
198 CHECK(::__interception::OverrideFunction("RtlRaiseException",
199 (uptr)WRAP(RtlRaiseException),
200 (uptr *)&REAL(RtlRaiseException)));
201 }
202 }
203
InstallAtExitCheckLeaks()204 void InstallAtExitCheckLeaks() {}
205
InstallAtForkHandler()206 void InstallAtForkHandler() {}
207
AsanApplyToGlobals(globals_op_fptr op,const void * needle)208 void AsanApplyToGlobals(globals_op_fptr op, const void *needle) {
209 UNIMPLEMENTED();
210 }
211
FlushUnneededASanShadowMemory(uptr p,uptr size)212 void FlushUnneededASanShadowMemory(uptr p, uptr size) {
213 // Only asan on 64-bit Windows supports committing shadow memory on demand.
214 #if SANITIZER_WINDOWS64
215 // Since asan's mapping is compacting, the shadow chunk may be
216 // not page-aligned, so we only flush the page-aligned portion.
217 ReleaseMemoryPagesToOS(MemToShadow(p), MemToShadow(p + size));
218 #endif
219 }
220
221 // ---------------------- TSD ---------------- {{{
222 static bool tsd_key_inited = false;
223
224 static __declspec(thread) void *fake_tsd = 0;
225
226 // https://docs.microsoft.com/en-us/windows/desktop/api/winternl/ns-winternl-_teb
227 // "[This structure may be altered in future versions of Windows. Applications
228 // should use the alternate functions listed in this topic.]"
229 typedef struct _TEB {
230 PVOID Reserved1[12];
231 // PVOID ThreadLocalStoragePointer; is here, at the last field in Reserved1.
232 PVOID ProcessEnvironmentBlock;
233 PVOID Reserved2[399];
234 BYTE Reserved3[1952];
235 PVOID TlsSlots[64];
236 BYTE Reserved4[8];
237 PVOID Reserved5[26];
238 PVOID ReservedForOle;
239 PVOID Reserved6[4];
240 PVOID TlsExpansionSlots;
241 } TEB, *PTEB;
242
243 constexpr size_t TEB_RESERVED_FIELDS_THREAD_LOCAL_STORAGE_OFFSET = 11;
IsTlsInitialized()244 BOOL IsTlsInitialized() {
245 PTEB teb = (PTEB)NtCurrentTeb();
246 return teb->Reserved1[TEB_RESERVED_FIELDS_THREAD_LOCAL_STORAGE_OFFSET] !=
247 nullptr;
248 }
249
AsanTSDInit(void (* destructor)(void * tsd))250 void AsanTSDInit(void (*destructor)(void *tsd)) {
251 // FIXME: we're ignoring the destructor for now.
252 tsd_key_inited = true;
253 }
254
AsanTSDGet()255 void *AsanTSDGet() {
256 CHECK(tsd_key_inited);
257 return IsTlsInitialized() ? fake_tsd : nullptr;
258 }
259
AsanTSDSet(void * tsd)260 void AsanTSDSet(void *tsd) {
261 CHECK(tsd_key_inited);
262 fake_tsd = tsd;
263 }
264
PlatformTSDDtor(void * tsd)265 void PlatformTSDDtor(void *tsd) { AsanThread::TSDDtor(tsd); }
266 // }}}
267
268 // ---------------------- Various stuff ---------------- {{{
AsanDoesNotSupportStaticLinkage()269 void *AsanDoesNotSupportStaticLinkage() { return 0; }
270
FindDynamicShadowStart()271 uptr FindDynamicShadowStart() {
272 return MapDynamicShadow(MemToShadowSize(kHighMemEnd), ASAN_SHADOW_SCALE,
273 /*min_shadow_base_alignment*/ 0, kHighMemEnd);
274 }
275
AsanCheckDynamicRTPrereqs()276 void AsanCheckDynamicRTPrereqs() {}
277
AsanCheckIncompatibleRT()278 void AsanCheckIncompatibleRT() {}
279
AsanOnDeadlySignal(int,void * siginfo,void * context)280 void AsanOnDeadlySignal(int, void *siginfo, void *context) { UNIMPLEMENTED(); }
281
PlatformUnpoisonStacks()282 bool PlatformUnpoisonStacks() { return false; }
283
284 #if SANITIZER_WINDOWS64
285 // Exception handler for dealing with shadow memory.
286 static LONG CALLBACK
ShadowExceptionHandler(PEXCEPTION_POINTERS exception_pointers)287 ShadowExceptionHandler(PEXCEPTION_POINTERS exception_pointers) {
288 uptr page_size = GetPageSizeCached();
289 // Only handle access violations.
290 if (exception_pointers->ExceptionRecord->ExceptionCode !=
291 EXCEPTION_ACCESS_VIOLATION ||
292 exception_pointers->ExceptionRecord->NumberParameters < 2) {
293 __asan_handle_no_return();
294 return EXCEPTION_CONTINUE_SEARCH;
295 }
296
297 // Only handle access violations that land within the shadow memory.
298 uptr addr =
299 (uptr)(exception_pointers->ExceptionRecord->ExceptionInformation[1]);
300
301 // Check valid shadow range.
302 if (!AddrIsInShadow(addr)) {
303 __asan_handle_no_return();
304 return EXCEPTION_CONTINUE_SEARCH;
305 }
306
307 // This is an access violation while trying to read from the shadow. Commit
308 // the relevant page and let execution continue.
309
310 // Determine the address of the page that is being accessed.
311 uptr page = RoundDownTo(addr, page_size);
312
313 // Commit the page.
314 uptr result =
315 (uptr)::VirtualAlloc((LPVOID)page, page_size, MEM_COMMIT, PAGE_READWRITE);
316 if (result != page)
317 return EXCEPTION_CONTINUE_SEARCH;
318
319 // The page mapping succeeded, so continue execution as usual.
320 return EXCEPTION_CONTINUE_EXECUTION;
321 }
322
323 #endif
324
InitializePlatformExceptionHandlers()325 void InitializePlatformExceptionHandlers() {
326 #if SANITIZER_WINDOWS64
327 // On Win64, we map memory on demand with access violation handler.
328 // Install our exception handler.
329 CHECK(AddVectoredExceptionHandler(TRUE, &ShadowExceptionHandler));
330 #endif
331 }
332
IsSystemHeapAddress(uptr addr)333 bool IsSystemHeapAddress(uptr addr) {
334 return ::HeapValidate(GetProcessHeap(), 0, (void *)addr) != FALSE;
335 }
336
337 // We want to install our own exception handler (EH) to print helpful reports
338 // on access violations and whatnot. Unfortunately, the CRT initializers assume
339 // they are run before any user code and drop any previously-installed EHs on
340 // the floor, so we can't install our handler inside __asan_init.
341 // (See crt0dat.c in the CRT sources for the details)
342 //
343 // Things get even more complicated with the dynamic runtime, as it finishes its
344 // initialization before the .exe module CRT begins to initialize.
345 //
346 // For the static runtime (-MT), it's enough to put a callback to
347 // __asan_set_seh_filter in the last section for C initializers.
348 //
349 // For the dynamic runtime (-MD), we want link the same
350 // asan_dynamic_runtime_thunk.lib to all the modules, thus __asan_set_seh_filter
351 // will be called for each instrumented module. This ensures that at least one
352 // __asan_set_seh_filter call happens after the .exe module CRT is initialized.
__asan_set_seh_filter()353 extern "C" SANITIZER_INTERFACE_ATTRIBUTE int __asan_set_seh_filter() {
354 // We should only store the previous handler if it's not our own handler in
355 // order to avoid loops in the EH chain.
356 auto prev_seh_handler = SetUnhandledExceptionFilter(SEHHandler);
357 if (prev_seh_handler != &SEHHandler)
358 default_seh_handler = prev_seh_handler;
359 return 0;
360 }
361
HandleDlopenInit()362 bool HandleDlopenInit() {
363 // Not supported on this platform.
364 static_assert(!SANITIZER_SUPPORTS_INIT_FOR_DLOPEN,
365 "Expected SANITIZER_SUPPORTS_INIT_FOR_DLOPEN to be false");
366 return false;
367 }
368
369 #if !ASAN_DYNAMIC
370 // The CRT runs initializers in this order:
371 // - C initializers, from XIA to XIZ
372 // - C++ initializers, from XCA to XCZ
373 // Prior to 2015, the CRT set the unhandled exception filter at priority XIY,
374 // near the end of C initialization. Starting in 2015, it was moved to the
375 // beginning of C++ initialization. We set our priority to XCAB to run
376 // immediately after the CRT runs. This way, our exception filter is called
377 // first and we can delegate to their filter if appropriate.
378 #pragma section(".CRT$XCAB", long, read)
379 __declspec(allocate(".CRT$XCAB")) int (*__intercept_seh)() =
380 __asan_set_seh_filter;
381
382 // Piggyback on the TLS initialization callback directory to initialize asan as
383 // early as possible. Initializers in .CRT$XL* are called directly by ntdll,
384 // which run before the CRT. Users also add code to .CRT$XLC, so it's important
385 // to run our initializers first.
asan_thread_init(void * module,DWORD reason,void * reserved)386 static void NTAPI asan_thread_init(void *module, DWORD reason, void *reserved) {
387 if (reason == DLL_PROCESS_ATTACH)
388 __asan_init();
389 }
390
391 #pragma section(".CRT$XLAB", long, read)
392 __declspec(allocate(".CRT$XLAB")) void(NTAPI *__asan_tls_init)(
393 void *, unsigned long, void *) = asan_thread_init;
394 #endif
395
asan_thread_exit(void * module,DWORD reason,void * reserved)396 static void NTAPI asan_thread_exit(void *module, DWORD reason, void *reserved) {
397 if (reason == DLL_THREAD_DETACH) {
398 // Unpoison the thread's stack because the memory may be re-used.
399 NT_TIB *tib = (NT_TIB *)NtCurrentTeb();
400 uptr stackSize = (uptr)tib->StackBase - (uptr)tib->StackLimit;
401 __asan_unpoison_memory_region(tib->StackLimit, stackSize);
402 }
403 }
404
405 #pragma section(".CRT$XLY", long, read)
406 __declspec(allocate(".CRT$XLY")) void(NTAPI *__asan_tls_exit)(
407 void *, unsigned long, void *) = asan_thread_exit;
408
409 WIN_FORCE_LINK(__asan_dso_reg_hook)
410
411 // }}}
412 } // namespace __asan
413
414 #endif // SANITIZER_WINDOWS
415