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//===-- asan_globals.cc ---------------------------------------------------===//
//
// 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.
//
// Handle globals.
//===----------------------------------------------------------------------===//
#include "asan_interceptors.h"
#include "asan_internal.h"
#include "asan_mapping.h"
#include "asan_report.h"
#include "asan_stack.h"
#include "asan_stats.h"
#include "asan_thread.h"
#include "sanitizer/asan_interface.h"
#include "sanitizer_common/sanitizer_mutex.h"
namespace __asan {
typedef __asan_global Global;
struct ListOfGlobals {
const Global *g;
ListOfGlobals *next;
};
static BlockingMutex mu_for_globals(LINKER_INITIALIZED);
static LowLevelAllocator allocator_for_globals;
static ListOfGlobals *list_of_all_globals;
static ListOfGlobals *list_of_dynamic_init_globals;
void PoisonRedZones(const Global &g) {
uptr shadow_rz_size = kGlobalAndStackRedzone >> SHADOW_SCALE;
CHECK(shadow_rz_size == 1 || shadow_rz_size == 2 || shadow_rz_size == 4);
// full right redzone
uptr g_aligned_size = kGlobalAndStackRedzone *
((g.size + kGlobalAndStackRedzone - 1) / kGlobalAndStackRedzone);
PoisonShadow(g.beg + g_aligned_size,
kGlobalAndStackRedzone, kAsanGlobalRedzoneMagic);
if ((g.size % kGlobalAndStackRedzone) != 0) {
// partial right redzone
u64 g_aligned_down_size = kGlobalAndStackRedzone *
(g.size / kGlobalAndStackRedzone);
CHECK(g_aligned_down_size == g_aligned_size - kGlobalAndStackRedzone);
PoisonShadowPartialRightRedzone(g.beg + g_aligned_down_size,
g.size % kGlobalAndStackRedzone,
kGlobalAndStackRedzone,
kAsanGlobalRedzoneMagic);
}
}
bool DescribeAddressIfGlobal(uptr addr) {
if (!flags()->report_globals) return false;
BlockingMutexLock lock(&mu_for_globals);
bool res = false;
for (ListOfGlobals *l = list_of_all_globals; l; l = l->next) {
const Global &g = *l->g;
if (flags()->report_globals >= 2)
Report("Search Global: beg=%p size=%zu name=%s\n",
(void*)g.beg, g.size, (char*)g.name);
res |= DescribeAddressRelativeToGlobal(addr, g);
}
return res;
}
// Register a global variable.
// This function may be called more than once for every global
// so we store the globals in a map.
static void RegisterGlobal(const Global *g) {
CHECK(asan_inited);
if (flags()->report_globals >= 2)
Report("Added Global: beg=%p size=%zu/%zu name=%s dyn.init=%zu\n",
(void*)g->beg, g->size, g->size_with_redzone, g->name,
g->has_dynamic_init);
CHECK(flags()->report_globals);
CHECK(AddrIsInMem(g->beg));
CHECK(AddrIsAlignedByGranularity(g->beg));
CHECK(AddrIsAlignedByGranularity(g->size_with_redzone));
PoisonRedZones(*g);
ListOfGlobals *l =
(ListOfGlobals*)allocator_for_globals.Allocate(sizeof(ListOfGlobals));
l->g = g;
l->next = list_of_all_globals;
list_of_all_globals = l;
if (g->has_dynamic_init) {
l = (ListOfGlobals*)allocator_for_globals.Allocate(sizeof(ListOfGlobals));
l->g = g;
l->next = list_of_dynamic_init_globals;
list_of_dynamic_init_globals = l;
}
}
static void UnregisterGlobal(const Global *g) {
CHECK(asan_inited);
CHECK(flags()->report_globals);
CHECK(AddrIsInMem(g->beg));
CHECK(AddrIsAlignedByGranularity(g->beg));
CHECK(AddrIsAlignedByGranularity(g->size_with_redzone));
PoisonShadow(g->beg, g->size_with_redzone, 0);
// We unpoison the shadow memory for the global but we do not remove it from
// the list because that would require O(n^2) time with the current list
// implementation. It might not be worth doing anyway.
}
// Poison all shadow memory for a single global.
static void PoisonGlobalAndRedzones(const Global *g) {
CHECK(asan_inited);
CHECK(flags()->check_initialization_order);
CHECK(AddrIsInMem(g->beg));
CHECK(AddrIsAlignedByGranularity(g->beg));
CHECK(AddrIsAlignedByGranularity(g->size_with_redzone));
if (flags()->report_globals >= 3)
Printf("DynInitPoison : %s\n", g->name);
PoisonShadow(g->beg, g->size_with_redzone, kAsanInitializationOrderMagic);
}
static void UnpoisonGlobal(const Global *g) {
CHECK(asan_inited);
CHECK(flags()->check_initialization_order);
CHECK(AddrIsInMem(g->beg));
CHECK(AddrIsAlignedByGranularity(g->beg));
CHECK(AddrIsAlignedByGranularity(g->size_with_redzone));
if (flags()->report_globals >= 3)
Printf("DynInitUnpoison: %s\n", g->name);
PoisonShadow(g->beg, g->size_with_redzone, 0);
PoisonRedZones(*g);
}
} // namespace __asan
// ---------------------- Interface ---------------- {{{1
using namespace __asan; // NOLINT
// Register an array of globals.
void __asan_register_globals(__asan_global *globals, uptr n) {
if (!flags()->report_globals) return;
BlockingMutexLock lock(&mu_for_globals);
for (uptr i = 0; i < n; i++) {
RegisterGlobal(&globals[i]);
}
}
// Unregister an array of globals.
// We must do this when a shared objects gets dlclosed.
void __asan_unregister_globals(__asan_global *globals, uptr n) {
if (!flags()->report_globals) return;
BlockingMutexLock lock(&mu_for_globals);
for (uptr i = 0; i < n; i++) {
UnregisterGlobal(&globals[i]);
}
}
// This method runs immediately prior to dynamic initialization in each TU,
// when all dynamically initialized globals are unpoisoned. This method
// poisons all global variables not defined in this TU, so that a dynamic
// initializer can only touch global variables in the same TU.
void __asan_before_dynamic_init(uptr first_addr, uptr last_addr) {
if (!flags()->check_initialization_order) return;
CHECK(list_of_dynamic_init_globals);
BlockingMutexLock lock(&mu_for_globals);
bool from_current_tu = false;
// The list looks like:
// a => ... => b => last_addr => ... => first_addr => c => ...
// The globals of the current TU reside between last_addr and first_addr.
for (ListOfGlobals *l = list_of_dynamic_init_globals; l; l = l->next) {
if (l->g->beg == last_addr)
from_current_tu = true;
if (!from_current_tu)
PoisonGlobalAndRedzones(l->g);
if (l->g->beg == first_addr)
from_current_tu = false;
}
CHECK(!from_current_tu);
}
// This method runs immediately after dynamic initialization in each TU, when
// all dynamically initialized globals except for those defined in the current
// TU are poisoned. It simply unpoisons all dynamically initialized globals.
void __asan_after_dynamic_init() {
if (!flags()->check_initialization_order) return;
BlockingMutexLock lock(&mu_for_globals);
for (ListOfGlobals *l = list_of_dynamic_init_globals; l; l = l->next)
UnpoisonGlobal(l->g);
}
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