1//===-- hwasan_fuchsia.cpp --------------------------------------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8///
9/// \file
10/// This file is a part of HWAddressSanitizer and contains Fuchsia-specific
11/// code.
12///
13//===----------------------------------------------------------------------===//
14
15#include "sanitizer_common/sanitizer_fuchsia.h"
16#if SANITIZER_FUCHSIA
17
18#include <zircon/features.h>
19#include <zircon/syscalls.h>
20
21#include "hwasan.h"
22#include "hwasan_interface_internal.h"
23#include "hwasan_report.h"
24#include "hwasan_thread.h"
25#include "hwasan_thread_list.h"
26
27// This TLS variable contains the location of the stack ring buffer and can be
28// used to always find the hwasan thread object associated with the current
29// running thread.
30[[gnu::tls_model("initial-exec")]]
31SANITIZER_INTERFACE_ATTRIBUTE
32THREADLOCAL uptr __hwasan_tls;
33
34namespace __hwasan {
35
36bool InitShadow() {
37 __sanitizer::InitShadowBounds();
38 CHECK_NE(__sanitizer::ShadowBounds.shadow_limit, 0);
39
40 // These variables are used by MemIsShadow for asserting we have a correct
41 // shadow address. On Fuchsia, we only have one region of shadow, so the
42 // bounds of Low shadow can be zero while High shadow represents the true
43 // bounds. Note that these are inclusive ranges.
44 kLowShadowStart = 0;
45 kLowShadowEnd = 0;
46 kHighShadowStart = __sanitizer::ShadowBounds.shadow_base;
47 kHighShadowEnd = __sanitizer::ShadowBounds.shadow_limit - 1;
48
49 return true;
50}
51
52bool MemIsApp(uptr p) {
53 CHECK(GetTagFromPointer(p) == 0);
54 return __sanitizer::ShadowBounds.shadow_limit <= p &&
55 p <= (__sanitizer::ShadowBounds.memory_limit - 1);
56}
57
58// These are known parameters passed to the hwasan runtime on thread creation.
59struct Thread::InitState {
60 uptr stack_bottom, stack_top;
61};
62
63static void FinishThreadInitialization(Thread *thread);
64
65void InitThreads() {
66 // This is the minimal alignment needed for the storage where hwasan threads
67 // and their stack ring buffers are placed. This alignment is necessary so the
68 // stack ring buffer can perform a simple calculation to get the next element
69 // in the RB. The instructions for this calculation are emitted by the
70 // compiler. (Full explanation in hwasan_thread_list.h.)
71 uptr alloc_size = UINT64_C(1) << kShadowBaseAlignment;
72 uptr thread_start = reinterpret_cast<uptr>(
73 MmapAlignedOrDieOnFatalError(alloc_size, alloc_size, __func__));
74
75 InitThreadList(thread_start, alloc_size);
76
77 // Create the hwasan thread object for the current (main) thread. Stack info
78 // for this thread is known from information passed via
79 // __sanitizer_startup_hook.
80 const Thread::InitState state = {
81 .stack_bottom = __sanitizer::MainThreadStackBase,
82 .stack_top =
83 __sanitizer::MainThreadStackBase + __sanitizer::MainThreadStackSize,
84 };
85 FinishThreadInitialization(hwasanThreadList().CreateCurrentThread(&state));
86}
87
88uptr *GetCurrentThreadLongPtr() { return &__hwasan_tls; }
89
90// This is called from the parent thread before the new thread is created. Here
91// we can propagate known info like the stack bounds to Thread::Init before
92// jumping into the thread. We cannot initialize the stack ring buffer yet since
93// we have not entered the new thread.
94static void *BeforeThreadCreateHook(uptr user_id, bool detached,
95 const char *name, uptr stack_bottom,
96 uptr stack_size) {
97 const Thread::InitState state = {
98 .stack_bottom = stack_bottom,
99 .stack_top = stack_bottom + stack_size,
100 };
101 return hwasanThreadList().CreateCurrentThread(&state);
102}
103
104// This sets the stack top and bottom according to the InitState passed to
105// CreateCurrentThread above.
106void Thread::InitStackAndTls(const InitState *state) {
107 CHECK_NE(state->stack_bottom, 0);
108 CHECK_NE(state->stack_top, 0);
109 stack_bottom_ = state->stack_bottom;
110 stack_top_ = state->stack_top;
111 tls_end_ = tls_begin_ = 0;
112}
113
114// This is called after creating a new thread with the pointer returned by
115// BeforeThreadCreateHook. We are still in the creating thread and should check
116// if it was actually created correctly.
117static void ThreadCreateHook(void *hook, bool aborted) {
118 Thread *thread = static_cast<Thread *>(hook);
119 if (!aborted) {
120 // The thread was created successfully.
121 // ThreadStartHook can already be running in the new thread.
122 } else {
123 // The thread wasn't created after all.
124 // Clean up everything we set up in BeforeThreadCreateHook.
125 atomic_signal_fence(memory_order_seq_cst);
126 hwasanThreadList().ReleaseThread(thread);
127 }
128}
129
130// This is called in the newly-created thread before it runs anything else,
131// with the pointer returned by BeforeThreadCreateHook (above). Here we can
132// setup the stack ring buffer.
133static void ThreadStartHook(void *hook, thrd_t self) {
134 Thread *thread = static_cast<Thread *>(hook);
135 FinishThreadInitialization(thread);
136 thread->EnsureRandomStateInited();
137}
138
139// This is the function that sets up the stack ring buffer and enables us to use
140// GetCurrentThread. This function should only be called while IN the thread
141// that we want to create the hwasan thread object for so __hwasan_tls can be
142// properly referenced.
143static void FinishThreadInitialization(Thread *thread) {
144 CHECK_NE(thread, nullptr);
145
146 // The ring buffer is located immediately before the thread object.
147 uptr stack_buffer_size = hwasanThreadList().GetRingBufferSize();
148 uptr stack_buffer_start = reinterpret_cast<uptr>(thread) - stack_buffer_size;
149 thread->InitStackRingBuffer(stack_buffer_start, stack_buffer_size);
150}
151
152static void ThreadExitHook(void *hook, thrd_t self) {
153 Thread *thread = static_cast<Thread *>(hook);
154 atomic_signal_fence(memory_order_seq_cst);
155 hwasanThreadList().ReleaseThread(thread);
156}
157
158uptr TagMemoryAligned(uptr p, uptr size, tag_t tag) {
159 CHECK(IsAligned(p, kShadowAlignment));
160 CHECK(IsAligned(size, kShadowAlignment));
161 __sanitizer_fill_shadow(p, size, tag,
162 common_flags()->clear_shadow_mmap_threshold);
163 return AddTagToPointer(p, tag);
164}
165
166// Not implemented because Fuchsia does not use signal handlers.
167void HwasanOnDeadlySignal(int signo, void *info, void *context) {}
168
169// Not implemented because Fuchsia does not use interceptors.
170void InitializeInterceptors() {}
171
172// Not implemented because this is only relevant for Android.
173void AndroidTestTlsSlot() {}
174
175// TSD was normally used on linux as a means of calling the hwasan thread exit
176// handler passed to pthread_key_create. This is not needed on Fuchsia because
177// we will be using __sanitizer_thread_exit_hook.
178void HwasanTSDInit() {}
179void HwasanTSDThreadInit() {}
180
181// On linux, this just would call `atexit(HwasanAtExit)`. The functions in
182// HwasanAtExit are unimplemented for Fuchsia and effectively no-ops, so this
183// function is unneeded.
184void InstallAtExitHandler() {}
185
186void HwasanInstallAtForkHandler() {}
187
188void InstallAtExitCheckLeaks() {}
189
190void InitializeOsSupport() {
191#ifdef __aarch64__
192 uint32_t features = 0;
193 CHECK_EQ(zx_system_get_features(ZX_FEATURE_KIND_ADDRESS_TAGGING, &features),
194 ZX_OK);
195 if (!(features & ZX_ARM64_FEATURE_ADDRESS_TAGGING_TBI) &&
196 flags()->fail_without_syscall_abi) {
197 Printf(
198 "FATAL: HWAddressSanitizer requires "
199 "ZX_ARM64_FEATURE_ADDRESS_TAGGING_TBI.\n");
200 Die();
201 }
202#endif
203}
204
205} // namespace __hwasan
206
207namespace __lsan {
208
209bool UseExitcodeOnLeak() { return __hwasan::flags()->halt_on_error; }
210
211} // namespace __lsan
212
213extern "C" {
214
215void *__sanitizer_before_thread_create_hook(thrd_t thread, bool detached,
216 const char *name, void *stack_base,
217 size_t stack_size) {
218 return __hwasan::BeforeThreadCreateHook(
219 reinterpret_cast<uptr>(thread), detached, name,
220 reinterpret_cast<uptr>(stack_base), stack_size);
221}
222
223void __sanitizer_thread_create_hook(void *hook, thrd_t thread, int error) {
224 __hwasan::ThreadCreateHook(hook, error != thrd_success);
225}
226
227void __sanitizer_thread_start_hook(void *hook, thrd_t self) {
228 __hwasan::ThreadStartHook(hook, reinterpret_cast<uptr>(self));
229}
230
231void __sanitizer_thread_exit_hook(void *hook, thrd_t self) {
232 __hwasan::ThreadExitHook(hook, self);
233}
234
235void __sanitizer_module_loaded(const struct dl_phdr_info *info, size_t) {
236 __hwasan_library_loaded(info->dlpi_addr, info->dlpi_phdr, info->dlpi_phnum);
237}
238
239} // extern "C"
240
241#endif // SANITIZER_FUCHSIA
242

source code of compiler-rt/lib/hwasan/hwasan_fuchsia.cpp