//===-- asan_rtl.cc ---------------------------------------------*- C++ -*-===//
//
// 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 AddressSanitizer, an address sanity checker.
//
// Main file of the ASan run-time library.
//===----------------------------------------------------------------------===//
#include "asan_allocator.h"
#include "asan_interceptors.h"
#include "asan_interface.h"
#include "asan_internal.h"
#include "asan_lock.h"
#include "asan_mapping.h"
#include "asan_stack.h"
#include "asan_stats.h"
#include "asan_thread.h"
#include "asan_thread_registry.h"
namespace __asan {
// -------------------------- Flags ------------------------- {{{1
static const size_t kMallocContextSize = 30;
static int FLAG_atexit;
size_t FLAG_redzone; // power of two, >= 32
size_t FLAG_quarantine_size;
int FLAG_demangle;
bool FLAG_symbolize;
int FLAG_v;
int FLAG_debug;
bool FLAG_poison_shadow;
int FLAG_report_globals;
size_t FLAG_malloc_context_size = kMallocContextSize;
uintptr_t FLAG_large_malloc;
bool FLAG_handle_segv;
bool FLAG_use_sigaltstack;
bool FLAG_replace_str;
bool FLAG_replace_intrin;
bool FLAG_replace_cfallocator; // Used on Mac only.
size_t FLAG_max_malloc_fill_size = 0;
bool FLAG_use_fake_stack;
bool FLAG_abort_on_error;
int FLAG_exitcode = ASAN_DEFAULT_FAILURE_EXITCODE;
bool FLAG_allow_user_poisoning;
int FLAG_sleep_before_dying;
bool FLAG_unmap_shadow_on_exit;
bool FLAG_disable_core;
// -------------------------- Globals --------------------- {{{1
int asan_inited;
bool asan_init_is_running;
static void (*death_callback)(void);
static void (*error_report_callback)(const char*);
char *error_message_buffer = NULL;
size_t error_message_buffer_pos = 0;
size_t error_message_buffer_size = 0;
// -------------------------- Misc ---------------- {{{1
void ShowStatsAndAbort() {
__asan_print_accumulated_stats();
AsanDie();
}
static void PrintBytes(const char *before, uintptr_t *a) {
uint8_t *bytes = (uint8_t*)a;
size_t byte_num = (__WORDSIZE) / 8;
Printf("%s%p:", before, (void*)a);
for (size_t i = 0; i < byte_num; i++) {
Printf(" %x%x", bytes[i] >> 4, bytes[i] & 15);
}
Printf("\n");
}
size_t ReadFileToBuffer(const char *file_name, char **buff,
size_t *buff_size, size_t max_len) {
const size_t kMinFileLen = kPageSize;
size_t read_len = 0;
*buff = 0;
*buff_size = 0;
// The files we usually open are not seekable, so try different buffer sizes.
for (size_t size = kMinFileLen; size <= max_len; size *= 2) {
int fd = AsanOpenReadonly(file_name);
if (fd < 0) return -1;
AsanUnmapOrDie(*buff, *buff_size);
*buff = (char*)AsanMmapSomewhereOrDie(size, __FUNCTION__);
*buff_size = size;
// Read up to one page at a time.
read_len = 0;
bool reached_eof = false;
while (read_len + kPageSize <= size) {
size_t just_read = AsanRead(fd, *buff + read_len, kPageSize);
if (just_read == 0) {
reached_eof = true;
break;
}
read_len += just_read;
}
AsanClose(fd);
if (reached_eof) // We've read the whole file.
break;
}
return read_len;
}
void AsanDie() {
static int num_calls = 0;
if (AtomicInc(&num_calls) > 1) {
// Don't die twice - run a busy loop.
while (1) { }
}
if (FLAG_sleep_before_dying) {
Report("Sleeping for %d second(s)\n", FLAG_sleep_before_dying);
SleepForSeconds(FLAG_sleep_before_dying);
}
if (FLAG_unmap_shadow_on_exit)
AsanUnmapOrDie((void*)kLowShadowBeg, kHighShadowEnd - kLowShadowBeg);
if (death_callback)
death_callback();
if (FLAG_abort_on_error)
Abort();
Exit(FLAG_exitcode);
}
// ---------------------- mmap -------------------- {{{1
void OutOfMemoryMessageAndDie(const char *mem_type, size_t size) {
Report("ERROR: AddressSanitizer failed to allocate "
"0x%zx (%zd) bytes of %s\n",
size, size, mem_type);
PRINT_CURRENT_STACK();
ShowStatsAndAbort();
}
// Reserve memory range [beg, end].
static void ReserveShadowMemoryRange(uintptr_t beg, uintptr_t end) {
CHECK((beg % kPageSize) == 0);
CHECK(((end + 1) % kPageSize) == 0);
size_t size = end - beg + 1;
void *res = AsanMmapFixedNoReserve(beg, size);
CHECK(res == (void*)beg && "ReserveShadowMemoryRange failed");
}
// ---------------------- LowLevelAllocator ------------- {{{1
void *LowLevelAllocator::Allocate(size_t size) {
CHECK((size & (size - 1)) == 0 && "size must be a power of two");
if (allocated_end_ - allocated_current_ < size) {
size_t size_to_allocate = Max(size, kPageSize);
allocated_current_ =
(char*)AsanMmapSomewhereOrDie(size_to_allocate, __FUNCTION__);
allocated_end_ = allocated_current_ + size_to_allocate;
PoisonShadow((uintptr_t)allocated_current_, size_to_allocate,
kAsanInternalHeapMagic);
}
CHECK(allocated_end_ - allocated_current_ >= size);
void *res = allocated_current_;
allocated_current_ += size;
return res;
}
// ---------------------- DescribeAddress -------------------- {{{1
static bool DescribeStackAddress(uintptr_t addr, uintptr_t access_size) {
AsanThread *t = asanThreadRegistry().FindThreadByStackAddress(addr);
if (!t) return false;
const intptr_t kBufSize = 4095;
char buf[kBufSize];
uintptr_t offset = 0;
const char *frame_descr = t->GetFrameNameByAddr(addr, &offset);
// This string is created by the compiler and has the following form:
// "FunctioName n alloc_1 alloc_2 ... alloc_n"
// where alloc_i looks like "offset size len ObjectName ".
CHECK(frame_descr);
// Report the function name and the offset.
const char *name_end = internal_strchr(frame_descr, ' ');
CHECK(name_end);
buf[0] = 0;
internal_strncat(buf, frame_descr,
Min(kBufSize,
static_cast<intptr_t>(name_end - frame_descr)));
Printf("Address %p is located at offset %zu "
"in frame <%s> of T%d's stack:\n",
addr, offset, buf, t->tid());
// Report the number of stack objects.
char *p;
size_t n_objects = internal_simple_strtoll(name_end, &p, 10);
CHECK(n_objects > 0);
Printf(" This frame has %zu object(s):\n", n_objects);
// Report all objects in this frame.
for (size_t i = 0; i < n_objects; i++) {
size_t beg, size;
intptr_t len;
beg = internal_simple_strtoll(p, &p, 10);
size = internal_simple_strtoll(p, &p, 10);
len = internal_simple_strtoll(p, &p, 10);
if (beg <= 0 || size <= 0 || len < 0 || *p != ' ') {
Printf("AddressSanitizer can't parse the stack frame descriptor: |%s|\n",
frame_descr);
break;
}
p++;
buf[0] = 0;
internal_strncat(buf, p, Min(kBufSize, len));
p += len;
Printf(" [%zu, %zu) '%s'\n", beg, beg + size, buf);
}
Printf("HINT: this may be a false positive if your program uses "
"some custom stack unwind mechanism\n"
" (longjmp and C++ exceptions *are* supported)\n");
t->summary()->Announce();
return true;
}
static NOINLINE void DescribeAddress(uintptr_t addr, uintptr_t access_size) {
// Check if this is a global.
if (DescribeAddrIfGlobal(addr))
return;
if (DescribeStackAddress(addr, access_size))
return;
// finally, check if this is a heap.
DescribeHeapAddress(addr, access_size);
}
// -------------------------- Run-time entry ------------------- {{{1
// exported functions
#define ASAN_REPORT_ERROR(type, is_write, size) \
extern "C" NOINLINE ASAN_INTERFACE_ATTRIBUTE \
void __asan_report_ ## type ## size(uintptr_t addr); \
void __asan_report_ ## type ## size(uintptr_t addr) { \
GET_CALLER_PC_BP_SP; \
__asan_report_error(pc, bp, sp, addr, is_write, size); \
}
ASAN_REPORT_ERROR(load, false, 1)
ASAN_REPORT_ERROR(load, false, 2)
ASAN_REPORT_ERROR(load, false, 4)
ASAN_REPORT_ERROR(load, false, 8)
ASAN_REPORT_ERROR(load, false, 16)
ASAN_REPORT_ERROR(store, true, 1)
ASAN_REPORT_ERROR(store, true, 2)
ASAN_REPORT_ERROR(store, true, 4)
ASAN_REPORT_ERROR(store, true, 8)
ASAN_REPORT_ERROR(store, true, 16)
// Force the linker to keep the symbols for various ASan interface functions.
// We want to keep those in the executable in order to let the instrumented
// dynamic libraries access the symbol even if it is not used by the executable
// itself. This should help if the build system is removing dead code at link
// time.
static NOINLINE void force_interface_symbols() {
volatile int fake_condition = 0; // prevent dead condition elimination.
if (fake_condition) {
__asan_report_load1(0);
__asan_report_load2(0);
__asan_report_load4(0);
__asan_report_load8(0);
__asan_report_load16(0);
__asan_report_store1(0);
__asan_report_store2(0);
__asan_report_store4(0);
__asan_report_store8(0);
__asan_report_store16(0);
__asan_register_global(0, 0, NULL);
__asan_register_globals(NULL, 0);
__asan_unregister_globals(NULL, 0);
__asan_set_death_callback(NULL);
__asan_set_error_report_callback(NULL);
__asan_handle_no_return();
}
}
// -------------------------- Init ------------------- {{{1
static int64_t IntFlagValue(const char *flags, const char *flag,
int64_t default_val) {
if (!flags) return default_val;
const char *str = internal_strstr(flags, flag);
if (!str) return default_val;
return internal_atoll(str + internal_strlen(flag));
}
static void asan_atexit() {
Printf("AddressSanitizer exit stats:\n");
__asan_print_accumulated_stats();
}
void CheckFailed(const char *cond, const char *file, int line) {
Report("CHECK failed: %s at %s:%d\n", cond, file, line);
PRINT_CURRENT_STACK();
ShowStatsAndAbort();
}
} // namespace __asan
// ---------------------- Interface ---------------- {{{1
using namespace __asan; // NOLINT
int __asan_set_error_exit_code(int exit_code) {
int old = FLAG_exitcode;
FLAG_exitcode = exit_code;
return old;
}
void NOINLINE __asan_handle_no_return() {
int local_stack;
AsanThread *curr_thread = asanThreadRegistry().GetCurrent();
CHECK(curr_thread);
uintptr_t top = curr_thread->stack_top();
uintptr_t bottom = ((uintptr_t)&local_stack - kPageSize) & ~(kPageSize-1);
PoisonShadow(bottom, top - bottom, 0);
}
void NOINLINE __asan_set_death_callback(void (*callback)(void)) {
death_callback = callback;
}
void NOINLINE __asan_set_error_report_callback(void (*callback)(const char*)) {
error_report_callback = callback;
if (callback) {
error_message_buffer_size = 1 << 14;
error_message_buffer =
(char*)AsanMmapSomewhereOrDie(error_message_buffer_size, __FUNCTION__);
error_message_buffer_pos = 0;
}
}
void __asan_report_error(uintptr_t pc, uintptr_t bp, uintptr_t sp,
uintptr_t addr, bool is_write, size_t access_size) {
// Do not print more than one report, otherwise they will mix up.
static int num_calls = 0;
if (AtomicInc(&num_calls) > 1) return;
Printf("=================================================================\n");
const char *bug_descr = "unknown-crash";
if (AddrIsInMem(addr)) {
uint8_t *shadow_addr = (uint8_t*)MemToShadow(addr);
// If we are accessing 16 bytes, look at the second shadow byte.
if (*shadow_addr == 0 && access_size > SHADOW_GRANULARITY)
shadow_addr++;
// If we are in the partial right redzone, look at the next shadow byte.
if (*shadow_addr > 0 && *shadow_addr < 128)
shadow_addr++;
switch (*shadow_addr) {
case kAsanHeapLeftRedzoneMagic:
case kAsanHeapRightRedzoneMagic:
bug_descr = "heap-buffer-overflow";
break;
case kAsanHeapFreeMagic:
bug_descr = "heap-use-after-free";
break;
case kAsanStackLeftRedzoneMagic:
bug_descr = "stack-buffer-underflow";
break;
case kAsanStackMidRedzoneMagic:
case kAsanStackRightRedzoneMagic:
case kAsanStackPartialRedzoneMagic:
bug_descr = "stack-buffer-overflow";
break;
case kAsanStackAfterReturnMagic:
bug_descr = "stack-use-after-return";
break;
case kAsanUserPoisonedMemoryMagic:
bug_descr = "use-after-poison";
break;
case kAsanGlobalRedzoneMagic:
bug_descr = "global-buffer-overflow";
break;
}
}
AsanThread *curr_thread = asanThreadRegistry().GetCurrent();
int curr_tid = asanThreadRegistry().GetCurrentTidOrMinusOne();
if (curr_thread) {
// We started reporting an error message. Stop using the fake stack
// in case we will call an instrumented function from a symbolizer.
curr_thread->fake_stack().StopUsingFakeStack();
}
Report("ERROR: AddressSanitizer %s on address "
"%p at pc 0x%zx bp 0x%zx sp 0x%zx\n",
bug_descr, addr, pc, bp, sp);
Printf("%s of size %zu at %p thread T%d\n",
access_size ? (is_write ? "WRITE" : "READ") : "ACCESS",
access_size, addr, curr_tid);
if (FLAG_debug) {
PrintBytes("PC: ", (uintptr_t*)pc);
}
GET_STACK_TRACE_WITH_PC_AND_BP(kStackTraceMax, pc, bp);
stack.PrintStack();
CHECK(AddrIsInMem(addr));
DescribeAddress(addr, access_size);
uintptr_t shadow_addr = MemToShadow(addr);
Report("ABORTING\n");
__asan_print_accumulated_stats();
Printf("Shadow byte and word:\n");
Printf(" %p: %x\n", shadow_addr, *(unsigned char*)shadow_addr);
uintptr_t aligned_shadow = shadow_addr & ~(kWordSize - 1);
PrintBytes(" ", (uintptr_t*)(aligned_shadow));
Printf("More shadow bytes:\n");
PrintBytes(" ", (uintptr_t*)(aligned_shadow-4*kWordSize));
PrintBytes(" ", (uintptr_t*)(aligned_shadow-3*kWordSize));
PrintBytes(" ", (uintptr_t*)(aligned_shadow-2*kWordSize));
PrintBytes(" ", (uintptr_t*)(aligned_shadow-1*kWordSize));
PrintBytes("=>", (uintptr_t*)(aligned_shadow+0*kWordSize));
PrintBytes(" ", (uintptr_t*)(aligned_shadow+1*kWordSize));
PrintBytes(" ", (uintptr_t*)(aligned_shadow+2*kWordSize));
PrintBytes(" ", (uintptr_t*)(aligned_shadow+3*kWordSize));
PrintBytes(" ", (uintptr_t*)(aligned_shadow+4*kWordSize));
if (error_report_callback) {
error_report_callback(error_message_buffer);
}
AsanDie();
}
void __asan_init() {
if (asan_inited) return;
asan_init_is_running = true;
// Make sure we are not statically linked.
AsanDoesNotSupportStaticLinkage();
// flags
const char *options = AsanGetEnv("ASAN_OPTIONS");
FLAG_malloc_context_size =
IntFlagValue(options, "malloc_context_size=", kMallocContextSize);
CHECK(FLAG_malloc_context_size <= kMallocContextSize);
FLAG_max_malloc_fill_size =
IntFlagValue(options, "max_malloc_fill_size=", 0);
FLAG_v = IntFlagValue(options, "verbosity=", 0);
FLAG_redzone = IntFlagValue(options, "redzone=",
(ASAN_LOW_MEMORY) ? 64 : 128);
CHECK(FLAG_redzone >= 32);
CHECK((FLAG_redzone & (FLAG_redzone - 1)) == 0);
FLAG_atexit = IntFlagValue(options, "atexit=", 0);
FLAG_poison_shadow = IntFlagValue(options, "poison_shadow=", 1);
FLAG_report_globals = IntFlagValue(options, "report_globals=", 1);
FLAG_handle_segv = IntFlagValue(options, "handle_segv=", ASAN_NEEDS_SEGV);
FLAG_use_sigaltstack = IntFlagValue(options, "use_sigaltstack=", 0);
FLAG_symbolize = IntFlagValue(options, "symbolize=", 1);
FLAG_demangle = IntFlagValue(options, "demangle=", 1);
FLAG_debug = IntFlagValue(options, "debug=", 0);
FLAG_replace_cfallocator = IntFlagValue(options, "replace_cfallocator=", 1);
FLAG_replace_str = IntFlagValue(options, "replace_str=", 1);
FLAG_replace_intrin = IntFlagValue(options, "replace_intrin=", 1);
FLAG_use_fake_stack = IntFlagValue(options, "use_fake_stack=", 1);
FLAG_exitcode = IntFlagValue(options, "exitcode=",
ASAN_DEFAULT_FAILURE_EXITCODE);
FLAG_allow_user_poisoning = IntFlagValue(options,
"allow_user_poisoning=", 1);
FLAG_sleep_before_dying = IntFlagValue(options, "sleep_before_dying=", 0);
FLAG_abort_on_error = IntFlagValue(options, "abort_on_error=", 0);
FLAG_unmap_shadow_on_exit = IntFlagValue(options, "unmap_shadow_on_exit=", 0);
// By default, disable core dumper on 64-bit --
// it makes little sense to dump 16T+ core.
FLAG_disable_core = IntFlagValue(options, "disable_core=", __WORDSIZE == 64);
FLAG_quarantine_size = IntFlagValue(options, "quarantine_size=",
(ASAN_LOW_MEMORY) ? 1UL << 24 : 1UL << 28);
if (FLAG_v) {
Report("Parsed ASAN_OPTIONS: %s\n", options);
}
if (FLAG_atexit) {
Atexit(asan_atexit);
}
// interceptors
InitializeAsanInterceptors();
ReplaceSystemMalloc();
ReplaceOperatorsNewAndDelete();
if (FLAG_v) {
Printf("|| `[%p, %p]` || HighMem ||\n", kHighMemBeg, kHighMemEnd);
Printf("|| `[%p, %p]` || HighShadow ||\n",
kHighShadowBeg, kHighShadowEnd);
Printf("|| `[%p, %p]` || ShadowGap ||\n",
kShadowGapBeg, kShadowGapEnd);
Printf("|| `[%p, %p]` || LowShadow ||\n",
kLowShadowBeg, kLowShadowEnd);
Printf("|| `[%p, %p]` || LowMem ||\n", kLowMemBeg, kLowMemEnd);
Printf("MemToShadow(shadow): %p %p %p %p\n",
MEM_TO_SHADOW(kLowShadowBeg),
MEM_TO_SHADOW(kLowShadowEnd),
MEM_TO_SHADOW(kHighShadowBeg),
MEM_TO_SHADOW(kHighShadowEnd));
Printf("red_zone=%zu\n", (size_t)FLAG_redzone);
Printf("malloc_context_size=%zu\n", (size_t)FLAG_malloc_context_size);
Printf("SHADOW_SCALE: %zx\n", (size_t)SHADOW_SCALE);
Printf("SHADOW_GRANULARITY: %zx\n", (size_t)SHADOW_GRANULARITY);
Printf("SHADOW_OFFSET: %zx\n", (size_t)SHADOW_OFFSET);
CHECK(SHADOW_SCALE >= 3 && SHADOW_SCALE <= 7);
}
if (FLAG_disable_core) {
AsanDisableCoreDumper();
}
if (AsanShadowRangeIsAvailable()) {
if (kLowShadowBeg != kLowShadowEnd) {
// mmap the low shadow plus at least one page.
ReserveShadowMemoryRange(kLowShadowBeg - kMmapGranularity, kLowShadowEnd);
}
// mmap the high shadow.
ReserveShadowMemoryRange(kHighShadowBeg, kHighShadowEnd);
// protect the gap
void *prot = AsanMprotect(kShadowGapBeg, kShadowGapEnd - kShadowGapBeg + 1);
CHECK(prot == (void*)kShadowGapBeg);
} else {
Report("Shadow memory range interleaves with an existing memory mapping. "
"ASan cannot proceed correctly. ABORTING.\n");
AsanDumpProcessMap();
AsanDie();
}
InstallSignalHandlers();
// On Linux AsanThread::ThreadStart() calls malloc() that's why asan_inited
// should be set to 1 prior to initializing the threads.
asan_inited = 1;
asan_init_is_running = false;
asanThreadRegistry().Init();
asanThreadRegistry().GetMain()->ThreadStart();
force_interface_symbols(); // no-op.
if (FLAG_v) {
Report("AddressSanitizer Init done\n");
}
}
#if defined(ASAN_USE_PREINIT_ARRAY)
// On Linux, we force __asan_init to be called before anyone else
// by placing it into .preinit_array section.
// FIXME: do we have anything like this on Mac?
__attribute__((section(".preinit_array")))
typeof(__asan_init) *__asan_preinit =__asan_init;
#elif defined(_WIN32) && defined(_DLL)
// On Windows, when using dynamic CRT (/MD), we can put a pointer
// to __asan_init into the global list of C initializers.
// See crt0dat.c in the CRT sources for the details.
#pragma section(".CRT$XIB", long, read) // NOLINT
__declspec(allocate(".CRT$XIB")) void (*__asan_preinit)() = __asan_init;
#endif