asan_poisoning.cc revision 9aead37421a6e4bf43265e5195c6ac31fc519982
11e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany//===-- asan_poisoning.cc ---------------------------------------*- C++ -*-===// 21e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany// 31e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany// The LLVM Compiler Infrastructure 41e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany// 51e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany// This file is distributed under the University of Illinois Open Source 61e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany// License. See LICENSE.TXT for details. 71e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany// 81e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany//===----------------------------------------------------------------------===// 91e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany// 101e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany// This file is a part of AddressSanitizer, an address sanity checker. 111e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany// 12218a9b70d7338cf5b727b7dad6b080ad7869c6c2Kostya Serebryany// Shadow memory poisoning by ASan RTL and by user application. 131e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany//===----------------------------------------------------------------------===// 141e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany 151e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany#include "asan_interceptors.h" 161e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany#include "asan_interface.h" 171e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany#include "asan_internal.h" 181e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany#include "asan_mapping.h" 191e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany 201e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryanynamespace __asan { 211e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany 22218a9b70d7338cf5b727b7dad6b080ad7869c6c2Kostya Serebryanyvoid PoisonShadow(uintptr_t addr, size_t size, uint8_t value) { 23218a9b70d7338cf5b727b7dad6b080ad7869c6c2Kostya Serebryany CHECK(AddrIsAlignedByGranularity(addr)); 24218a9b70d7338cf5b727b7dad6b080ad7869c6c2Kostya Serebryany CHECK(AddrIsAlignedByGranularity(addr + size)); 25218a9b70d7338cf5b727b7dad6b080ad7869c6c2Kostya Serebryany uintptr_t shadow_beg = MemToShadow(addr); 26218a9b70d7338cf5b727b7dad6b080ad7869c6c2Kostya Serebryany uintptr_t shadow_end = MemToShadow(addr + size); 2709672caefb5694f1981a1712fdefa44840a95e67Alexey Samsonov CHECK(REAL(memset) != NULL); 2809672caefb5694f1981a1712fdefa44840a95e67Alexey Samsonov REAL(memset)((void*)shadow_beg, value, shadow_end - shadow_beg); 29218a9b70d7338cf5b727b7dad6b080ad7869c6c2Kostya Serebryany} 30218a9b70d7338cf5b727b7dad6b080ad7869c6c2Kostya Serebryany 31218a9b70d7338cf5b727b7dad6b080ad7869c6c2Kostya Serebryanyvoid PoisonShadowPartialRightRedzone(uintptr_t addr, 32218a9b70d7338cf5b727b7dad6b080ad7869c6c2Kostya Serebryany uintptr_t size, 33218a9b70d7338cf5b727b7dad6b080ad7869c6c2Kostya Serebryany uintptr_t redzone_size, 34218a9b70d7338cf5b727b7dad6b080ad7869c6c2Kostya Serebryany uint8_t value) { 35218a9b70d7338cf5b727b7dad6b080ad7869c6c2Kostya Serebryany CHECK(AddrIsAlignedByGranularity(addr)); 36218a9b70d7338cf5b727b7dad6b080ad7869c6c2Kostya Serebryany uint8_t *shadow = (uint8_t*)MemToShadow(addr); 37218a9b70d7338cf5b727b7dad6b080ad7869c6c2Kostya Serebryany for (uintptr_t i = 0; i < redzone_size; 38218a9b70d7338cf5b727b7dad6b080ad7869c6c2Kostya Serebryany i += SHADOW_GRANULARITY, shadow++) { 39218a9b70d7338cf5b727b7dad6b080ad7869c6c2Kostya Serebryany if (i + SHADOW_GRANULARITY <= size) { 40218a9b70d7338cf5b727b7dad6b080ad7869c6c2Kostya Serebryany *shadow = 0; // fully addressable 41218a9b70d7338cf5b727b7dad6b080ad7869c6c2Kostya Serebryany } else if (i >= size) { 42218a9b70d7338cf5b727b7dad6b080ad7869c6c2Kostya Serebryany *shadow = (SHADOW_GRANULARITY == 128) ? 0xff : value; // unaddressable 43218a9b70d7338cf5b727b7dad6b080ad7869c6c2Kostya Serebryany } else { 44218a9b70d7338cf5b727b7dad6b080ad7869c6c2Kostya Serebryany *shadow = size - i; // first size-i bytes are addressable 45218a9b70d7338cf5b727b7dad6b080ad7869c6c2Kostya Serebryany } 46218a9b70d7338cf5b727b7dad6b080ad7869c6c2Kostya Serebryany } 47218a9b70d7338cf5b727b7dad6b080ad7869c6c2Kostya Serebryany} 48218a9b70d7338cf5b727b7dad6b080ad7869c6c2Kostya Serebryany 49218a9b70d7338cf5b727b7dad6b080ad7869c6c2Kostya Serebryany 501e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryanystruct ShadowSegmentEndpoint { 511e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany uint8_t *chunk; 521e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany int8_t offset; // in [0, SHADOW_GRANULARITY) 531e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany int8_t value; // = *chunk; 541e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany 551e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany explicit ShadowSegmentEndpoint(uintptr_t address) { 561e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany chunk = (uint8_t*)MemToShadow(address); 571e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany offset = address & (SHADOW_GRANULARITY - 1); 581e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany value = *chunk; 591e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany } 601e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany}; 611e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany 621e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany} // namespace __asan 631e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany 641e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany// ---------------------- Interface ---------------- {{{1 651e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryanyusing namespace __asan; // NOLINT 661e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany 671e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany// Current implementation of __asan_(un)poison_memory_region doesn't check 681e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany// that user program (un)poisons the memory it owns. It poisons memory 691e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany// conservatively, and unpoisons progressively to make sure asan shadow 701e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany// mapping invariant is preserved (see detailed mapping description here: 711e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany// http://code.google.com/p/address-sanitizer/wiki/AddressSanitizerAlgorithm). 721e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany// 731e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany// * if user asks to poison region [left, right), the program poisons 741e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany// at least [left, AlignDown(right)). 751e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany// * if user asks to unpoison region [left, right), the program unpoisons 761e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany// at most [AlignDown(left), right). 779aead37421a6e4bf43265e5195c6ac31fc519982Kostya Serebryanyvoid __asan_poison_memory_region(void const volatile *addr, uptr size) { 781e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany if (!FLAG_allow_user_poisoning || size == 0) return; 791e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany uintptr_t beg_addr = (uintptr_t)addr; 801e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany uintptr_t end_addr = beg_addr + size; 811e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany if (FLAG_v >= 1) { 821e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany Printf("Trying to poison memory region [%p, %p)\n", beg_addr, end_addr); 831e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany } 841e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany ShadowSegmentEndpoint beg(beg_addr); 851e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany ShadowSegmentEndpoint end(end_addr); 861e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany if (beg.chunk == end.chunk) { 871e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany CHECK(beg.offset < end.offset); 881e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany int8_t value = beg.value; 891e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany CHECK(value == end.value); 901e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany // We can only poison memory if the byte in end.offset is unaddressable. 911e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany // No need to re-poison memory if it is poisoned already. 921e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany if (value > 0 && value <= end.offset) { 931e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany if (beg.offset > 0) { 942d8b3bdb112ebb8ed3f15ee41d4cebcd683b41b0Kostya Serebryany *beg.chunk = Min(value, beg.offset); 951e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany } else { 961e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany *beg.chunk = kAsanUserPoisonedMemoryMagic; 971e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany } 981e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany } 991e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany return; 1001e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany } 1011e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany CHECK(beg.chunk < end.chunk); 1021e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany if (beg.offset > 0) { 1031e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany // Mark bytes from beg.offset as unaddressable. 1041e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany if (beg.value == 0) { 1051e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany *beg.chunk = beg.offset; 1061e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany } else { 1072d8b3bdb112ebb8ed3f15ee41d4cebcd683b41b0Kostya Serebryany *beg.chunk = Min(beg.value, beg.offset); 1081e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany } 1091e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany beg.chunk++; 1101e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany } 11109672caefb5694f1981a1712fdefa44840a95e67Alexey Samsonov REAL(memset)(beg.chunk, kAsanUserPoisonedMemoryMagic, end.chunk - beg.chunk); 1121e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany // Poison if byte in end.offset is unaddressable. 1131e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany if (end.value > 0 && end.value <= end.offset) { 1141e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany *end.chunk = kAsanUserPoisonedMemoryMagic; 1151e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany } 1161e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany} 1171e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany 1189aead37421a6e4bf43265e5195c6ac31fc519982Kostya Serebryanyvoid __asan_unpoison_memory_region(void const volatile *addr, uptr size) { 1191e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany if (!FLAG_allow_user_poisoning || size == 0) return; 1201e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany uintptr_t beg_addr = (uintptr_t)addr; 1211e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany uintptr_t end_addr = beg_addr + size; 1221e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany if (FLAG_v >= 1) { 1231e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany Printf("Trying to unpoison memory region [%p, %p)\n", beg_addr, end_addr); 1241e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany } 1251e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany ShadowSegmentEndpoint beg(beg_addr); 1261e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany ShadowSegmentEndpoint end(end_addr); 1271e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany if (beg.chunk == end.chunk) { 1281e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany CHECK(beg.offset < end.offset); 1291e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany int8_t value = beg.value; 1301e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany CHECK(value == end.value); 1311e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany // We unpoison memory bytes up to enbytes up to end.offset if it is not 1321e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany // unpoisoned already. 1331e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany if (value != 0) { 1342d8b3bdb112ebb8ed3f15ee41d4cebcd683b41b0Kostya Serebryany *beg.chunk = Max(value, end.offset); 1351e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany } 1361e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany return; 1371e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany } 1381e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany CHECK(beg.chunk < end.chunk); 1391e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany if (beg.offset > 0) { 1401e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany *beg.chunk = 0; 1411e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany beg.chunk++; 1421e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany } 14309672caefb5694f1981a1712fdefa44840a95e67Alexey Samsonov REAL(memset)(beg.chunk, 0, end.chunk - beg.chunk); 1441e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany if (end.offset > 0 && end.value != 0) { 1452d8b3bdb112ebb8ed3f15ee41d4cebcd683b41b0Kostya Serebryany *end.chunk = Max(end.value, end.offset); 1461e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany } 1471e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany} 1481e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany 1491e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryanybool __asan_address_is_poisoned(void const volatile *addr) { 1508599762021935ccfce4db9b054f092af8ef001abKostya Serebryany return __asan::AddressIsPoisoned((uintptr_t)addr); 1511e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany} 152