asan_poisoning.cc revision d4b5db8cb8a7a13bb5cc1d4ce53e8e088303c854
1e5f5895bda30f374b0b51412fd4d837fa59aed66Alexey Samsonov//===-- asan_poisoning.cc -------------------------------------------------===// 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_internal.h" 171e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany#include "asan_mapping.h" 18d865fecddccebf898ceed24d096fc58fb29a6e57Chandler Carruth#include "sanitizer/asan_interface.h" 191e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany 201e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryanynamespace __asan { 211e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany 22ee3925515e4c7966f3ef489f687aa7e5692806a9Kostya Serebryanyvoid PoisonShadow(uptr addr, uptr size, u8 value) { 23218a9b70d7338cf5b727b7dad6b080ad7869c6c2Kostya Serebryany CHECK(AddrIsAlignedByGranularity(addr)); 24218a9b70d7338cf5b727b7dad6b080ad7869c6c2Kostya Serebryany CHECK(AddrIsAlignedByGranularity(addr + size)); 253f4c3875c42078e22c7e5356c5746fd18756d958Kostya Serebryany uptr shadow_beg = MemToShadow(addr); 263f4c3875c42078e22c7e5356c5746fd18756d958Kostya Serebryany uptr shadow_end = MemToShadow(addr + size); 273f4c3875c42078e22c7e5356c5746fd18756d958Kostya Serebryany CHECK(REAL(memset) != 0); 2809672caefb5694f1981a1712fdefa44840a95e67Alexey Samsonov REAL(memset)((void*)shadow_beg, value, shadow_end - shadow_beg); 29218a9b70d7338cf5b727b7dad6b080ad7869c6c2Kostya Serebryany} 30218a9b70d7338cf5b727b7dad6b080ad7869c6c2Kostya Serebryany 313f4c3875c42078e22c7e5356c5746fd18756d958Kostya Serebryanyvoid PoisonShadowPartialRightRedzone(uptr addr, 323f4c3875c42078e22c7e5356c5746fd18756d958Kostya Serebryany uptr size, 333f4c3875c42078e22c7e5356c5746fd18756d958Kostya Serebryany uptr redzone_size, 34ee3925515e4c7966f3ef489f687aa7e5692806a9Kostya Serebryany u8 value) { 35218a9b70d7338cf5b727b7dad6b080ad7869c6c2Kostya Serebryany CHECK(AddrIsAlignedByGranularity(addr)); 36ee3925515e4c7966f3ef489f687aa7e5692806a9Kostya Serebryany u8 *shadow = (u8*)MemToShadow(addr); 373f4c3875c42078e22c7e5356c5746fd18756d958Kostya Serebryany for (uptr 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 { 51ee3925515e4c7966f3ef489f687aa7e5692806a9Kostya Serebryany u8 *chunk; 52ee3925515e4c7966f3ef489f687aa7e5692806a9Kostya Serebryany s8 offset; // in [0, SHADOW_GRANULARITY) 53ee3925515e4c7966f3ef489f687aa7e5692806a9Kostya Serebryany s8 value; // = *chunk; 541e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany 553f4c3875c42078e22c7e5356c5746fd18756d958Kostya Serebryany explicit ShadowSegmentEndpoint(uptr address) { 56ee3925515e4c7966f3ef489f687aa7e5692806a9Kostya Serebryany chunk = (u8*)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) { 78cb8c4dce691097718d5af41b36899b72ef4b1d84Alexey Samsonov if (!flags()->allow_user_poisoning || size == 0) return; 793f4c3875c42078e22c7e5356c5746fd18756d958Kostya Serebryany uptr beg_addr = (uptr)addr; 803f4c3875c42078e22c7e5356c5746fd18756d958Kostya Serebryany uptr end_addr = beg_addr + size; 81cb8c4dce691097718d5af41b36899b72ef4b1d84Alexey Samsonov if (flags()->verbosity >= 1) { 825bcca4e33ececdddd8e9e07619c129e870492251Alexey Samsonov Printf("Trying to poison memory region [%p, %p)\n", 835bcca4e33ececdddd8e9e07619c129e870492251Alexey Samsonov (void*)beg_addr, (void*)end_addr); 841e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany } 851e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany ShadowSegmentEndpoint beg(beg_addr); 861e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany ShadowSegmentEndpoint end(end_addr); 871e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany if (beg.chunk == end.chunk) { 881e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany CHECK(beg.offset < end.offset); 89ee3925515e4c7966f3ef489f687aa7e5692806a9Kostya Serebryany s8 value = beg.value; 901e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany CHECK(value == end.value); 911e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany // We can only poison memory if the byte in end.offset is unaddressable. 921e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany // No need to re-poison memory if it is poisoned already. 931e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany if (value > 0 && value <= end.offset) { 941e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany if (beg.offset > 0) { 952d8b3bdb112ebb8ed3f15ee41d4cebcd683b41b0Kostya Serebryany *beg.chunk = Min(value, beg.offset); 961e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany } else { 971e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany *beg.chunk = kAsanUserPoisonedMemoryMagic; 981e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany } 991e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany } 1001e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany return; 1011e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany } 1021e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany CHECK(beg.chunk < end.chunk); 1031e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany if (beg.offset > 0) { 1041e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany // Mark bytes from beg.offset as unaddressable. 1051e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany if (beg.value == 0) { 1061e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany *beg.chunk = beg.offset; 1071e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany } else { 1082d8b3bdb112ebb8ed3f15ee41d4cebcd683b41b0Kostya Serebryany *beg.chunk = Min(beg.value, beg.offset); 1091e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany } 1101e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany beg.chunk++; 1111e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany } 11209672caefb5694f1981a1712fdefa44840a95e67Alexey Samsonov REAL(memset)(beg.chunk, kAsanUserPoisonedMemoryMagic, end.chunk - beg.chunk); 1131e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany // Poison if byte in end.offset is unaddressable. 1141e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany if (end.value > 0 && end.value <= end.offset) { 1151e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany *end.chunk = kAsanUserPoisonedMemoryMagic; 1161e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany } 1171e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany} 1181e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany 1199aead37421a6e4bf43265e5195c6ac31fc519982Kostya Serebryanyvoid __asan_unpoison_memory_region(void const volatile *addr, uptr size) { 120cb8c4dce691097718d5af41b36899b72ef4b1d84Alexey Samsonov if (!flags()->allow_user_poisoning || size == 0) return; 1213f4c3875c42078e22c7e5356c5746fd18756d958Kostya Serebryany uptr beg_addr = (uptr)addr; 1223f4c3875c42078e22c7e5356c5746fd18756d958Kostya Serebryany uptr end_addr = beg_addr + size; 123cb8c4dce691097718d5af41b36899b72ef4b1d84Alexey Samsonov if (flags()->verbosity >= 1) { 1245bcca4e33ececdddd8e9e07619c129e870492251Alexey Samsonov Printf("Trying to unpoison memory region [%p, %p)\n", 1255bcca4e33ececdddd8e9e07619c129e870492251Alexey Samsonov (void*)beg_addr, (void*)end_addr); 1261e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany } 1271e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany ShadowSegmentEndpoint beg(beg_addr); 1281e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany ShadowSegmentEndpoint end(end_addr); 1291e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany if (beg.chunk == end.chunk) { 1301e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany CHECK(beg.offset < end.offset); 131ee3925515e4c7966f3ef489f687aa7e5692806a9Kostya Serebryany s8 value = beg.value; 1321e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany CHECK(value == end.value); 1331e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany // We unpoison memory bytes up to enbytes up to end.offset if it is not 1341e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany // unpoisoned already. 1351e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany if (value != 0) { 1362d8b3bdb112ebb8ed3f15ee41d4cebcd683b41b0Kostya Serebryany *beg.chunk = Max(value, end.offset); 1371e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany } 1381e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany return; 1391e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany } 1401e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany CHECK(beg.chunk < end.chunk); 1411e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany if (beg.offset > 0) { 1421e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany *beg.chunk = 0; 1431e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany beg.chunk++; 1441e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany } 14509672caefb5694f1981a1712fdefa44840a95e67Alexey Samsonov REAL(memset)(beg.chunk, 0, end.chunk - beg.chunk); 1461e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany if (end.offset > 0 && end.value != 0) { 1472d8b3bdb112ebb8ed3f15ee41d4cebcd683b41b0Kostya Serebryany *end.chunk = Max(end.value, end.offset); 1481e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany } 1491e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany} 1501e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany 1511e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryanybool __asan_address_is_poisoned(void const volatile *addr) { 1523f4c3875c42078e22c7e5356c5746fd18756d958Kostya Serebryany return __asan::AddressIsPoisoned((uptr)addr); 1531e172b4bdec57329bf904f063a29f99cddf2d85fKostya Serebryany} 154d4b5db8cb8a7a13bb5cc1d4ce53e8e088303c854Alexey Samsonov 155d4b5db8cb8a7a13bb5cc1d4ce53e8e088303c854Alexey Samsonov// This is a simplified version of __asan_(un)poison_memory_region, which 156d4b5db8cb8a7a13bb5cc1d4ce53e8e088303c854Alexey Samsonov// assumes that left border of region to be poisoned is properly aligned. 157d4b5db8cb8a7a13bb5cc1d4ce53e8e088303c854Alexey Samsonovstatic void PoisonAlignedStackMemory(uptr addr, uptr size, bool do_poison) { 158d4b5db8cb8a7a13bb5cc1d4ce53e8e088303c854Alexey Samsonov if (size == 0) return; 159d4b5db8cb8a7a13bb5cc1d4ce53e8e088303c854Alexey Samsonov uptr aligned_size = size & ~(SHADOW_GRANULARITY - 1); 160d4b5db8cb8a7a13bb5cc1d4ce53e8e088303c854Alexey Samsonov PoisonShadow(addr, aligned_size, 161d4b5db8cb8a7a13bb5cc1d4ce53e8e088303c854Alexey Samsonov do_poison ? kAsanStackUseAfterScopeMagic : 0); 162d4b5db8cb8a7a13bb5cc1d4ce53e8e088303c854Alexey Samsonov if (size == aligned_size) 163d4b5db8cb8a7a13bb5cc1d4ce53e8e088303c854Alexey Samsonov return; 164d4b5db8cb8a7a13bb5cc1d4ce53e8e088303c854Alexey Samsonov s8 end_offset = (s8)(size - aligned_size); 165d4b5db8cb8a7a13bb5cc1d4ce53e8e088303c854Alexey Samsonov s8* shadow_end = (s8*)MemToShadow(addr + aligned_size); 166d4b5db8cb8a7a13bb5cc1d4ce53e8e088303c854Alexey Samsonov s8 end_value = *shadow_end; 167d4b5db8cb8a7a13bb5cc1d4ce53e8e088303c854Alexey Samsonov if (do_poison) { 168d4b5db8cb8a7a13bb5cc1d4ce53e8e088303c854Alexey Samsonov // If possible, mark all the bytes mapping to last shadow byte as 169d4b5db8cb8a7a13bb5cc1d4ce53e8e088303c854Alexey Samsonov // unaddressable. 170d4b5db8cb8a7a13bb5cc1d4ce53e8e088303c854Alexey Samsonov if (end_value > 0 && end_value <= end_offset) 171d4b5db8cb8a7a13bb5cc1d4ce53e8e088303c854Alexey Samsonov *shadow_end = kAsanStackUseAfterScopeMagic; 172d4b5db8cb8a7a13bb5cc1d4ce53e8e088303c854Alexey Samsonov } else { 173d4b5db8cb8a7a13bb5cc1d4ce53e8e088303c854Alexey Samsonov // If necessary, mark few first bytes mapping to last shadow byte 174d4b5db8cb8a7a13bb5cc1d4ce53e8e088303c854Alexey Samsonov // as addressable 175d4b5db8cb8a7a13bb5cc1d4ce53e8e088303c854Alexey Samsonov if (end_value != 0) 176d4b5db8cb8a7a13bb5cc1d4ce53e8e088303c854Alexey Samsonov *shadow_end = Max(end_value, end_offset); 177d4b5db8cb8a7a13bb5cc1d4ce53e8e088303c854Alexey Samsonov } 178d4b5db8cb8a7a13bb5cc1d4ce53e8e088303c854Alexey Samsonov} 179d4b5db8cb8a7a13bb5cc1d4ce53e8e088303c854Alexey Samsonov 180d4b5db8cb8a7a13bb5cc1d4ce53e8e088303c854Alexey Samsonovvoid __asan_poison_stack_memory(uptr addr, uptr size) { 181d4b5db8cb8a7a13bb5cc1d4ce53e8e088303c854Alexey Samsonov if (flags()->verbosity > 0) 182d4b5db8cb8a7a13bb5cc1d4ce53e8e088303c854Alexey Samsonov Report("poisoning: %p %zx\n", (void*)addr, size); 183d4b5db8cb8a7a13bb5cc1d4ce53e8e088303c854Alexey Samsonov PoisonAlignedStackMemory(addr, size, true); 184d4b5db8cb8a7a13bb5cc1d4ce53e8e088303c854Alexey Samsonov} 185d4b5db8cb8a7a13bb5cc1d4ce53e8e088303c854Alexey Samsonov 186d4b5db8cb8a7a13bb5cc1d4ce53e8e088303c854Alexey Samsonovvoid __asan_unpoison_stack_memory(uptr addr, uptr size) { 187d4b5db8cb8a7a13bb5cc1d4ce53e8e088303c854Alexey Samsonov if (flags()->verbosity > 0) 188d4b5db8cb8a7a13bb5cc1d4ce53e8e088303c854Alexey Samsonov Report("unpoisoning: %p %zx\n", (void*)addr, size); 189d4b5db8cb8a7a13bb5cc1d4ce53e8e088303c854Alexey Samsonov PoisonAlignedStackMemory(addr, size, false); 190d4b5db8cb8a7a13bb5cc1d4ce53e8e088303c854Alexey Samsonov} 191