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//===-- asan_rtl.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 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"
#include "sanitizer_common/sanitizer_atomic.h"
#include "sanitizer_common/sanitizer_flags.h"
#include "sanitizer_common/sanitizer_libc.h"
namespace __sanitizer {
using namespace __asan;
void Die() {
static atomic_uint32_t num_calls;
if (atomic_fetch_add(&num_calls, 1, memory_order_relaxed) != 0) {
// Don't die twice - run a busy loop.
while (1) { }
}
if (flags()->sleep_before_dying) {
Report("Sleeping for %zd second(s)\n", flags()->sleep_before_dying);
SleepForSeconds(flags()->sleep_before_dying);
}
if (flags()->unmap_shadow_on_exit)
UnmapOrDie((void*)kLowShadowBeg, kHighShadowEnd - kLowShadowBeg);
if (death_callback)
death_callback();
if (flags()->abort_on_error)
Abort();
Exit(flags()->exitcode);
}
void CheckFailed(const char *file, int line, const char *cond, u64 v1, u64 v2) {
AsanReport("AddressSanitizer CHECK failed: %s:%d \"%s\" (0x%zx, 0x%zx)\n",
file, line, cond, (uptr)v1, (uptr)v2);
PRINT_CURRENT_STACK();
ShowStatsAndAbort();
}
} // namespace __sanitizer
namespace __asan {
// -------------------------- Flags ------------------------- {{{1
static const int kMallocContextSize = 30;
static Flags asan_flags;
Flags *flags() {
return &asan_flags;
}
static void ParseFlagsFromString(Flags *f, const char *str) {
ParseFlag(str, &f->quarantine_size, "quarantine_size");
ParseFlag(str, &f->symbolize, "symbolize");
ParseFlag(str, &f->verbosity, "verbosity");
ParseFlag(str, &f->redzone, "redzone");
CHECK(f->redzone >= 16);
CHECK(IsPowerOfTwo(f->redzone));
ParseFlag(str, &f->debug, "debug");
ParseFlag(str, &f->report_globals, "report_globals");
ParseFlag(str, &f->malloc_context_size, "malloc_context_size");
CHECK(f->malloc_context_size <= kMallocContextSize);
ParseFlag(str, &f->replace_str, "replace_str");
ParseFlag(str, &f->replace_intrin, "replace_intrin");
ParseFlag(str, &f->replace_cfallocator, "replace_cfallocator");
ParseFlag(str, &f->mac_ignore_invalid_free, "mac_ignore_invalid_free");
ParseFlag(str, &f->use_fake_stack, "use_fake_stack");
ParseFlag(str, &f->max_malloc_fill_size, "max_malloc_fill_size");
ParseFlag(str, &f->exitcode, "exitcode");
ParseFlag(str, &f->allow_user_poisoning, "allow_user_poisoning");
ParseFlag(str, &f->sleep_before_dying, "sleep_before_dying");
ParseFlag(str, &f->handle_segv, "handle_segv");
ParseFlag(str, &f->use_sigaltstack, "use_sigaltstack");
ParseFlag(str, &f->check_malloc_usable_size, "check_malloc_usable_size");
ParseFlag(str, &f->unmap_shadow_on_exit, "unmap_shadow_on_exit");
ParseFlag(str, &f->abort_on_error, "abort_on_error");
ParseFlag(str, &f->atexit, "atexit");
ParseFlag(str, &f->disable_core, "disable_core");
}
void InitializeFlags(Flags *f, const char *env) {
internal_memset(f, 0, sizeof(*f));
f->quarantine_size = (ASAN_LOW_MEMORY) ? 1UL << 24 : 1UL << 28;
f->symbolize = false;
f->verbosity = 0;
f->redzone = (ASAN_LOW_MEMORY) ? 64 : 128;
f->debug = false;
f->report_globals = 1;
f->malloc_context_size = kMallocContextSize;
f->replace_str = true;
f->replace_intrin = true;
f->replace_cfallocator = true;
f->mac_ignore_invalid_free = false;
f->use_fake_stack = true;
f->max_malloc_fill_size = 0;
f->exitcode = ASAN_DEFAULT_FAILURE_EXITCODE;
f->allow_user_poisoning = true;
f->sleep_before_dying = 0;
f->handle_segv = ASAN_NEEDS_SEGV;
f->use_sigaltstack = false;
f->check_malloc_usable_size = true;
f->unmap_shadow_on_exit = false;
f->abort_on_error = false;
f->atexit = false;
f->disable_core = (__WORDSIZE == 64);
// Override from user-specified string.
#if !defined(_WIN32)
if (__asan_default_options) {
ParseFlagsFromString(f, __asan_default_options());
if (flags()->verbosity) {
Report("Using the defaults from __asan_default_options: %s\n",
__asan_default_options());
}
}
#endif
// Override from command line.
ParseFlagsFromString(f, env);
}
// -------------------------- Globals --------------------- {{{1
int asan_inited;
bool asan_init_is_running;
void (*death_callback)(void);
static void (*error_report_callback)(const char*);
char *error_message_buffer = 0;
uptr error_message_buffer_pos = 0;
uptr error_message_buffer_size = 0;
// -------------------------- Misc ---------------- {{{1
void ShowStatsAndAbort() {
__asan_print_accumulated_stats();
Die();
}
static void PrintBytes(const char *before, uptr *a) {
u8 *bytes = (u8*)a;
uptr byte_num = (__WORDSIZE) / 8;
AsanPrintf("%s%p:", before, (void*)a);
for (uptr i = 0; i < byte_num; i++) {
AsanPrintf(" %x%x", bytes[i] >> 4, bytes[i] & 15);
}
AsanPrintf("\n");
}
void AppendToErrorMessageBuffer(const char *buffer) {
if (error_message_buffer) {
uptr length = internal_strlen(buffer);
CHECK_GE(error_message_buffer_size, error_message_buffer_pos);
uptr remaining = error_message_buffer_size - error_message_buffer_pos;
internal_strncpy(error_message_buffer + error_message_buffer_pos,
buffer, remaining);
error_message_buffer[error_message_buffer_size - 1] = '\0';
// FIXME: reallocate the buffer instead of truncating the message.
error_message_buffer_pos += remaining > length ? length : remaining;
}
}
// ---------------------- mmap -------------------- {{{1
// Reserve memory range [beg, end].
static void ReserveShadowMemoryRange(uptr beg, uptr end) {
CHECK((beg % kPageSize) == 0);
CHECK(((end + 1) % kPageSize) == 0);
uptr size = end - beg + 1;
void *res = MmapFixedNoReserve(beg, size);
CHECK(res == (void*)beg && "ReserveShadowMemoryRange failed");
}
// ---------------------- LowLevelAllocator ------------- {{{1
void *LowLevelAllocator::Allocate(uptr size) {
CHECK((size & (size - 1)) == 0 && "size must be a power of two");
if (allocated_end_ - allocated_current_ < (sptr)size) {
uptr size_to_allocate = Max(size, kPageSize);
allocated_current_ =
(char*)MmapOrDie(size_to_allocate, __FUNCTION__);
allocated_end_ = allocated_current_ + size_to_allocate;
PoisonShadow((uptr)allocated_current_, size_to_allocate,
kAsanInternalHeapMagic);
}
CHECK(allocated_end_ - allocated_current_ >= (sptr)size);
void *res = allocated_current_;
allocated_current_ += size;
return res;
}
// ---------------------- DescribeAddress -------------------- {{{1
static bool DescribeStackAddress(uptr addr, uptr access_size) {
AsanThread *t = asanThreadRegistry().FindThreadByStackAddress(addr);
if (!t) return false;
const sptr kBufSize = 4095;
char buf[kBufSize];
uptr 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<sptr>(name_end - frame_descr)));
AsanPrintf("Address %p is located at offset %zu "
"in frame <%s> of T%d's stack:\n",
(void*)addr, offset, buf, t->tid());
// Report the number of stack objects.
char *p;
uptr n_objects = internal_simple_strtoll(name_end, &p, 10);
CHECK(n_objects > 0);
AsanPrintf(" This frame has %zu object(s):\n", n_objects);
// Report all objects in this frame.
for (uptr i = 0; i < n_objects; i++) {
uptr beg, size;
sptr 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 != ' ') {
AsanPrintf("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;
AsanPrintf(" [%zu, %zu) '%s'\n", beg, beg + size, buf);
}
AsanPrintf("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 bool DescribeAddrIfShadow(uptr addr) {
if (AddrIsInMem(addr))
return false;
static const char kAddrInShadowReport[] =
"Address %p is located in the %s.\n";
if (AddrIsInShadowGap(addr)) {
AsanPrintf(kAddrInShadowReport, addr, "shadow gap area");
return true;
}
if (AddrIsInHighShadow(addr)) {
AsanPrintf(kAddrInShadowReport, addr, "high shadow area");
return true;
}
if (AddrIsInLowShadow(addr)) {
AsanPrintf(kAddrInShadowReport, addr, "low shadow area");
return true;
}
CHECK(0); // Unreachable.
return false;
}
static NOINLINE void DescribeAddress(uptr addr, uptr access_size) {
// Check if this is shadow or shadow gap.
if (DescribeAddrIfShadow(addr))
return;
CHECK(AddrIsInMem(addr));
// 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 INTERFACE_ATTRIBUTE \
void __asan_report_ ## type ## size(uptr addr); \
void __asan_report_ ## type ## size(uptr 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, 0);
__asan_register_globals(0, 0);
__asan_unregister_globals(0, 0);
__asan_set_death_callback(0);
__asan_set_error_report_callback(0);
__asan_handle_no_return();
}
}
// -------------------------- Init ------------------- {{{1
static void asan_atexit() {
AsanPrintf("AddressSanitizer exit stats:\n");
__asan_print_accumulated_stats();
}
} // namespace __asan
// ---------------------- Interface ---------------- {{{1
using namespace __asan; // NOLINT
int __asan_set_error_exit_code(int exit_code) {
int old = flags()->exitcode;
flags()->exitcode = exit_code;
return old;
}
void NOINLINE __asan_handle_no_return() {
int local_stack;
AsanThread *curr_thread = asanThreadRegistry().GetCurrent();
CHECK(curr_thread);
uptr top = curr_thread->stack_top();
uptr bottom = ((uptr)&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 << 16;
error_message_buffer =
(char*)MmapOrDie(error_message_buffer_size, __FUNCTION__);
error_message_buffer_pos = 0;
}
}
void __asan_report_error(uptr pc, uptr bp, uptr sp,
uptr addr, bool is_write, uptr access_size) {
// Do not print more than one report, otherwise they will mix up.
static atomic_uint32_t num_calls;
if (atomic_fetch_add(&num_calls, 1, memory_order_relaxed) != 0) return;
AsanPrintf("===================================================="
"=============\n");
const char *bug_descr = "unknown-crash";
if (AddrIsInMem(addr)) {
u8 *shadow_addr = (u8*)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();
u32 curr_tid = asanThreadRegistry().GetCurrentTidOrInvalid();
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();
}
AsanReport("ERROR: AddressSanitizer %s on address "
"%p at pc 0x%zx bp 0x%zx sp 0x%zx\n",
bug_descr, (void*)addr, pc, bp, sp);
AsanPrintf("%s of size %zu at %p thread T%d\n",
access_size ? (is_write ? "WRITE" : "READ") : "ACCESS",
access_size, (void*)addr, curr_tid);
if (flags()->debug) {
PrintBytes("PC: ", (uptr*)pc);
}
GET_STACK_TRACE_WITH_PC_AND_BP(kStackTraceMax, pc, bp);
stack.PrintStack();
DescribeAddress(addr, access_size);
if (AddrIsInMem(addr)) {
uptr shadow_addr = MemToShadow(addr);
AsanReport("ABORTING\n");
__asan_print_accumulated_stats();
AsanPrintf("Shadow byte and word:\n");
AsanPrintf(" %p: %x\n", (void*)shadow_addr, *(unsigned char*)shadow_addr);
uptr aligned_shadow = shadow_addr & ~(kWordSize - 1);
PrintBytes(" ", (uptr*)(aligned_shadow));
AsanPrintf("More shadow bytes:\n");
PrintBytes(" ", (uptr*)(aligned_shadow-4*kWordSize));
PrintBytes(" ", (uptr*)(aligned_shadow-3*kWordSize));
PrintBytes(" ", (uptr*)(aligned_shadow-2*kWordSize));
PrintBytes(" ", (uptr*)(aligned_shadow-1*kWordSize));
PrintBytes("=>", (uptr*)(aligned_shadow+0*kWordSize));
PrintBytes(" ", (uptr*)(aligned_shadow+1*kWordSize));
PrintBytes(" ", (uptr*)(aligned_shadow+2*kWordSize));
PrintBytes(" ", (uptr*)(aligned_shadow+3*kWordSize));
PrintBytes(" ", (uptr*)(aligned_shadow+4*kWordSize));
}
if (error_report_callback) {
error_report_callback(error_message_buffer);
}
Die();
}
void __asan_init() {
if (asan_inited) return;
asan_init_is_running = true;
// Make sure we are not statically linked.
AsanDoesNotSupportStaticLinkage();
// Initialize flags.
const char *options = GetEnv("ASAN_OPTIONS");
InitializeFlags(flags(), options);
if (flags()->verbosity && options) {
Report("Parsed ASAN_OPTIONS: %s\n", options);
}
if (flags()->atexit) {
Atexit(asan_atexit);
}
// interceptors
InitializeAsanInterceptors();
ReplaceSystemMalloc();
ReplaceOperatorsNewAndDelete();
if (flags()->verbosity) {
Printf("|| `[%p, %p]` || HighMem ||\n",
(void*)kHighMemBeg, (void*)kHighMemEnd);
Printf("|| `[%p, %p]` || HighShadow ||\n",
(void*)kHighShadowBeg, (void*)kHighShadowEnd);
Printf("|| `[%p, %p]` || ShadowGap ||\n",
(void*)kShadowGapBeg, (void*)kShadowGapEnd);
Printf("|| `[%p, %p]` || LowShadow ||\n",
(void*)kLowShadowBeg, (void*)kLowShadowEnd);
Printf("|| `[%p, %p]` || LowMem ||\n",
(void*)kLowMemBeg, (void*)kLowMemEnd);
Printf("MemToShadow(shadow): %p %p %p %p\n",
(void*)MEM_TO_SHADOW(kLowShadowBeg),
(void*)MEM_TO_SHADOW(kLowShadowEnd),
(void*)MEM_TO_SHADOW(kHighShadowBeg),
(void*)MEM_TO_SHADOW(kHighShadowEnd));
Printf("red_zone=%zu\n", (uptr)flags()->redzone);
Printf("malloc_context_size=%zu\n", (uptr)flags()->malloc_context_size);
Printf("SHADOW_SCALE: %zx\n", (uptr)SHADOW_SCALE);
Printf("SHADOW_GRANULARITY: %zx\n", (uptr)SHADOW_GRANULARITY);
Printf("SHADOW_OFFSET: %zx\n", (uptr)SHADOW_OFFSET);
CHECK(SHADOW_SCALE >= 3 && SHADOW_SCALE <= 7);
}
if (flags()->disable_core) {
DisableCoreDumper();
}
uptr shadow_start = kLowShadowBeg;
if (kLowShadowBeg > 0) shadow_start -= kMmapGranularity;
uptr shadow_end = kHighShadowEnd;
if (MemoryRangeIsAvailable(shadow_start, shadow_end)) {
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 = Mprotect(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");
DumpProcessMap();
Die();
}
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 (flags()->verbosity) {
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