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//===-- hwasan_linux.cc -----------------------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file is a part of HWAddressSanitizer.
//
// Linux-, NetBSD- and FreeBSD-specific code.
//===----------------------------------------------------------------------===//
#include "sanitizer_common/sanitizer_platform.h"
#if SANITIZER_FREEBSD || SANITIZER_LINUX || SANITIZER_NETBSD
#include "hwasan.h"
#include "hwasan_thread.h"
#include <elf.h>
#include <link.h>
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <unistd.h>
#include <unwind.h>
#include <sys/time.h>
#include <sys/resource.h>
#include "sanitizer_common/sanitizer_common.h"
#include "sanitizer_common/sanitizer_procmaps.h"
uptr __hwasan_shadow_memory_dynamic_address;
__attribute__((alias("__hwasan_shadow_memory_dynamic_address")))
extern uptr __hwasan_shadow_memory_dynamic_address_internal;
namespace __hwasan {
bool InitShadow() {
const uptr maxVirtualAddress = GetMaxUserVirtualAddress();
uptr shadow_size = MEM_TO_SHADOW_OFFSET(maxVirtualAddress) + 1;
__hwasan_shadow_memory_dynamic_address =
reinterpret_cast<uptr>(MmapNoReserveOrDie(shadow_size, "shadow"));
return true;
}
static void HwasanAtExit(void) {
if (flags()->print_stats && (flags()->atexit || hwasan_report_count > 0))
ReportStats();
if (hwasan_report_count > 0) {
// ReportAtExitStatistics();
if (common_flags()->exitcode)
internal__exit(common_flags()->exitcode);
}
}
void InstallAtExitHandler() {
atexit(HwasanAtExit);
}
// ---------------------- TSD ---------------- {{{1
static pthread_key_t tsd_key;
static bool tsd_key_inited = false;
void HwasanTSDInit(void (*destructor)(void *tsd)) {
CHECK(!tsd_key_inited);
tsd_key_inited = true;
CHECK_EQ(0, pthread_key_create(&tsd_key, destructor));
}
HwasanThread *GetCurrentThread() {
return (HwasanThread*)pthread_getspecific(tsd_key);
}
void SetCurrentThread(HwasanThread *t) {
// Make sure that HwasanTSDDtor gets called at the end.
CHECK(tsd_key_inited);
// Make sure we do not reset the current HwasanThread.
CHECK_EQ(0, pthread_getspecific(tsd_key));
pthread_setspecific(tsd_key, (void *)t);
}
void HwasanTSDDtor(void *tsd) {
HwasanThread *t = (HwasanThread*)tsd;
if (t->destructor_iterations_ > 1) {
t->destructor_iterations_--;
CHECK_EQ(0, pthread_setspecific(tsd_key, tsd));
return;
}
// Make sure that signal handler can not see a stale current thread pointer.
atomic_signal_fence(memory_order_seq_cst);
HwasanThread::TSDDtor(tsd);
}
struct AccessInfo {
uptr addr;
uptr size;
bool is_store;
bool is_load;
};
#if defined(__aarch64__)
static AccessInfo GetAccessInfo(siginfo_t *info, ucontext_t *uc) {
AccessInfo ai;
uptr pc = (uptr)info->si_addr;
struct {
uptr addr;
unsigned size;
bool is_store;
} handlers[] = {
{(uptr)&__hwasan_load1, 1, false}, {(uptr)&__hwasan_load2, 2, false},
{(uptr)&__hwasan_load4, 4, false}, {(uptr)&__hwasan_load8, 8, false},
{(uptr)&__hwasan_load16, 16, false}, {(uptr)&__hwasan_load, 0, false},
{(uptr)&__hwasan_store1, 1, true}, {(uptr)&__hwasan_store2, 2, true},
{(uptr)&__hwasan_store4, 4, true}, {(uptr)&__hwasan_store8, 8, true},
{(uptr)&__hwasan_store16, 16, true}, {(uptr)&__hwasan_store, 0, true}};
int best = -1;
uptr best_distance = 0;
for (size_t i = 0; i < sizeof(handlers) / sizeof(handlers[0]); ++i) {
uptr handler = handlers[i].addr;
// Don't accept pc == handler: HLT is never the first instruction.
if (pc <= handler) continue;
uptr distance = pc - handler;
if (distance > 256) continue;
if (best == -1 || best_distance > distance) {
best = i;
best_distance = distance;
}
}
// Not ours.
if (best == -1)
return AccessInfo{0, 0, false, false};
ai.is_store = handlers[best].is_store;
ai.is_load = !handlers[best].is_store;
ai.size = handlers[best].size;
ai.addr = uc->uc_mcontext.regs[0];
if (ai.size == 0)
ai.size = uc->uc_mcontext.regs[1];
return ai;
}
#else
static AccessInfo GetAccessInfo(siginfo_t *info, ucontext_t *uc) {
return AccessInfo{0, 0, false, false};
}
#endif
static void HwasanOnSIGILL(int signo, siginfo_t *info, ucontext_t *uc) {
SignalContext sig{info, uc};
AccessInfo ai = GetAccessInfo(info, uc);
if (!ai.is_store && !ai.is_load)
return;
InternalScopedBuffer<BufferedStackTrace> stack_buffer(1);
BufferedStackTrace *stack = stack_buffer.data();
stack->Reset();
GetStackTrace(stack, kStackTraceMax, sig.pc, sig.bp, uc,
common_flags()->fast_unwind_on_fatal);
ReportTagMismatch(stack, ai.addr, ai.size, ai.is_store);
++hwasan_report_count;
if (flags()->halt_on_error)
Die();
else
uc->uc_mcontext.pc += 4;
}
static void OnStackUnwind(const SignalContext &sig, const void *,
BufferedStackTrace *stack) {
GetStackTrace(stack, kStackTraceMax, sig.pc, sig.bp, sig.context,
common_flags()->fast_unwind_on_fatal);
}
void HwasanOnDeadlySignal(int signo, void *info, void *context) {
// Probably a tag mismatch.
// FIXME: detect pc range in __hwasan_load* or __hwasan_store*.
if (signo == SIGILL)
HwasanOnSIGILL(signo, (siginfo_t *)info, (ucontext_t*)context);
else
HandleDeadlySignal(info, context, GetTid(), &OnStackUnwind, nullptr);
}
} // namespace __hwasan
#endif // SANITIZER_FREEBSD || SANITIZER_LINUX || SANITIZER_NETBSD
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