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| //===-- msan_linux.cpp ----------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file is a part of MemorySanitizer.
//
// Linux-, NetBSD- and FreeBSD-specific code.
//===----------------------------------------------------------------------===//
#include "sanitizer_common/sanitizer_platform.h"
#if SANITIZER_FREEBSD || SANITIZER_LINUX || SANITIZER_NETBSD
#include "msan.h"
#include "msan_report.h"
#include "msan_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 <execinfo.h>
#include <sys/time.h>
#include <sys/resource.h>
#include "sanitizer_common/sanitizer_common.h"
#include "sanitizer_common/sanitizer_procmaps.h"
namespace __msan {
void ReportMapRange(const char *descr, uptr beg, uptr size) {
if (size > 0) {
uptr end = beg + size - 1;
VPrintf(1, "%s : %p - %p\n", descr, beg, end);
}
}
static bool CheckMemoryRangeAvailability(uptr beg, uptr size) {
if (size > 0) {
uptr end = beg + size - 1;
if (!MemoryRangeIsAvailable(beg, end)) {
Printf("FATAL: Memory range %p - %p is not available.\n", beg, end);
return false;
}
}
return true;
}
static bool ProtectMemoryRange(uptr beg, uptr size, const char *name) {
if (size > 0) {
void *addr = MmapFixedNoAccess(beg, size, name);
if (beg == 0 && addr) {
// Depending on the kernel configuration, we may not be able to protect
// the page at address zero.
uptr gap = 16 * GetPageSizeCached();
beg += gap;
size -= gap;
addr = MmapFixedNoAccess(beg, size, name);
}
if ((uptr)addr != beg) {
uptr end = beg + size - 1;
Printf("FATAL: Cannot protect memory range %p - %p (%s).\n", beg, end,
name);
return false;
}
}
return true;
}
static void CheckMemoryLayoutSanity() {
uptr prev_end = 0;
for (unsigned i = 0; i < kMemoryLayoutSize; ++i) {
uptr start = kMemoryLayout[i].start;
uptr end = kMemoryLayout[i].end;
MappingDesc::Type type = kMemoryLayout[i].type;
CHECK_LT(start, end);
CHECK_EQ(prev_end, start);
CHECK(addr_is_type(start, type));
CHECK(addr_is_type((start + end) / 2, type));
CHECK(addr_is_type(end - 1, type));
if (type == MappingDesc::APP) {
uptr addr = start;
CHECK(MEM_IS_SHADOW(MEM_TO_SHADOW(addr)));
CHECK(MEM_IS_ORIGIN(MEM_TO_ORIGIN(addr)));
CHECK_EQ(MEM_TO_ORIGIN(addr), SHADOW_TO_ORIGIN(MEM_TO_SHADOW(addr)));
addr = (start + end) / 2;
CHECK(MEM_IS_SHADOW(MEM_TO_SHADOW(addr)));
CHECK(MEM_IS_ORIGIN(MEM_TO_ORIGIN(addr)));
CHECK_EQ(MEM_TO_ORIGIN(addr), SHADOW_TO_ORIGIN(MEM_TO_SHADOW(addr)));
addr = end - 1;
CHECK(MEM_IS_SHADOW(MEM_TO_SHADOW(addr)));
CHECK(MEM_IS_ORIGIN(MEM_TO_ORIGIN(addr)));
CHECK_EQ(MEM_TO_ORIGIN(addr), SHADOW_TO_ORIGIN(MEM_TO_SHADOW(addr)));
}
prev_end = end;
}
}
bool InitShadow(bool init_origins) {
// Let user know mapping parameters first.
VPrintf(1, "__msan_init %p\n", &__msan_init);
for (unsigned i = 0; i < kMemoryLayoutSize; ++i)
VPrintf(1, "%s: %zx - %zx\n", kMemoryLayout[i].name, kMemoryLayout[i].start,
kMemoryLayout[i].end - 1);
CheckMemoryLayoutSanity();
if (!MEM_IS_APP(&__msan_init)) {
Printf("FATAL: Code %p is out of application range. Non-PIE build?\n",
(uptr)&__msan_init);
return false;
}
const uptr maxVirtualAddress = GetMaxUserVirtualAddress();
for (unsigned i = 0; i < kMemoryLayoutSize; ++i) {
uptr start = kMemoryLayout[i].start;
uptr end = kMemoryLayout[i].end;
uptr size = end - start;
MappingDesc::Type type = kMemoryLayout[i].type;
// Check if the segment should be mapped based on platform constraints.
if (start >= maxVirtualAddress)
continue;
bool map = type == MappingDesc::SHADOW ||
(init_origins && type == MappingDesc::ORIGIN);
bool protect = type == MappingDesc::INVALID ||
(!init_origins && type == MappingDesc::ORIGIN);
CHECK(!(map && protect));
if (!map && !protect)
CHECK(type == MappingDesc::APP);
if (map) {
if (!CheckMemoryRangeAvailability(start, size))
return false;
if (!MmapFixedNoReserve(start, size, kMemoryLayout[i].name))
return false;
if (common_flags()->use_madv_dontdump)
DontDumpShadowMemory(start, size);
}
if (protect) {
if (!CheckMemoryRangeAvailability(start, size))
return false;
if (!ProtectMemoryRange(start, size, kMemoryLayout[i].name))
return false;
}
}
return true;
}
static void MsanAtExit(void) {
if (flags()->print_stats && (flags()->atexit || msan_report_count > 0))
ReportStats();
if (msan_report_count > 0) {
ReportAtExitStatistics();
if (common_flags()->exitcode)
internal__exit(common_flags()->exitcode);
}
}
void InstallAtExitHandler() {
atexit(MsanAtExit);
}
// ---------------------- TSD ---------------- {{{1
#if SANITIZER_NETBSD
// Thread Static Data cannot be used in early init on NetBSD.
// Reuse the MSan TSD API for compatibility with existing code
// with an alternative implementation.
static void (*tsd_destructor)(void *tsd) = nullptr;
struct tsd_key {
tsd_key() : key(nullptr) {}
~tsd_key() {
CHECK(tsd_destructor);
if (key)
(*tsd_destructor)(key);
}
MsanThread *key;
};
static thread_local struct tsd_key key;
void MsanTSDInit(void (*destructor)(void *tsd)) {
CHECK(!tsd_destructor);
tsd_destructor = destructor;
}
MsanThread *GetCurrentThread() {
CHECK(tsd_destructor);
return key.key;
}
void SetCurrentThread(MsanThread *tsd) {
CHECK(tsd_destructor);
CHECK(tsd);
CHECK(!key.key);
key.key = tsd;
}
void MsanTSDDtor(void *tsd) {
CHECK(tsd_destructor);
CHECK_EQ(key.key, tsd);
key.key = nullptr;
// Make sure that signal handler can not see a stale current thread pointer.
atomic_signal_fence(memory_order_seq_cst);
MsanThread::TSDDtor(tsd);
}
#else
static pthread_key_t tsd_key;
static bool tsd_key_inited = false;
void MsanTSDInit(void (*destructor)(void *tsd)) {
CHECK(!tsd_key_inited);
tsd_key_inited = true;
CHECK_EQ(0, pthread_key_create(&tsd_key, destructor));
}
static THREADLOCAL MsanThread* msan_current_thread;
MsanThread *GetCurrentThread() {
return msan_current_thread;
}
void SetCurrentThread(MsanThread *t) {
// Make sure we do not reset the current MsanThread.
CHECK_EQ(0, msan_current_thread);
msan_current_thread = t;
// Make sure that MsanTSDDtor gets called at the end.
CHECK(tsd_key_inited);
pthread_setspecific(tsd_key, (void *)t);
}
void MsanTSDDtor(void *tsd) {
MsanThread *t = (MsanThread*)tsd;
if (t->destructor_iterations_ > 1) {
t->destructor_iterations_--;
CHECK_EQ(0, pthread_setspecific(tsd_key, tsd));
return;
}
msan_current_thread = nullptr;
// Make sure that signal handler can not see a stale current thread pointer.
atomic_signal_fence(memory_order_seq_cst);
MsanThread::TSDDtor(tsd);
}
#endif
} // namespace __msan
#endif // SANITIZER_FREEBSD || SANITIZER_LINUX || SANITIZER_NETBSD
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