| //===-- hwasan_checks.h -----------------------------------------*- 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 HWAddressSanitizer. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef HWASAN_CHECKS_H |
| #define HWASAN_CHECKS_H |
| |
| #include "hwasan_mapping.h" |
| |
| namespace __hwasan { |
| template <unsigned X> |
| __attribute__((always_inline)) static void SigTrap(uptr p) { |
| #if defined(__aarch64__) |
| (void)p; |
| // 0x900 is added to do not interfere with the kernel use of lower values of |
| // brk immediate. |
| // FIXME: Add a constraint to put the pointer into x0, the same as x86 branch. |
| asm("brk %0\n\t" ::"n"(0x900 + X)); |
| #elif defined(__x86_64__) |
| // INT3 + NOP DWORD ptr [EAX + X] to pass X to our signal handler, 5 bytes |
| // total. The pointer is passed via rdi. |
| // 0x40 is added as a safeguard, to help distinguish our trap from others and |
| // to avoid 0 offsets in the command (otherwise it'll be reduced to a |
| // different nop command, the three bytes one). |
| asm volatile( |
| "int3\n" |
| "nopl %c0(%%rax)\n" ::"n"(0x40 + X), |
| "D"(p)); |
| #else |
| // FIXME: not always sigill. |
| __builtin_trap(); |
| #endif |
| // __builtin_unreachable(); |
| } |
| |
| enum class ErrorAction { Abort, Recover }; |
| enum class AccessType { Load, Store }; |
| |
| template <ErrorAction EA, AccessType AT, unsigned LogSize> |
| __attribute__((always_inline, nodebug)) static void CheckAddress(uptr p) { |
| tag_t ptr_tag = GetTagFromPointer(p); |
| uptr ptr_raw = p & ~kAddressTagMask; |
| tag_t mem_tag = *(tag_t *)MemToShadow(ptr_raw); |
| if (UNLIKELY(ptr_tag != mem_tag)) { |
| SigTrap<0x20 * (EA == ErrorAction::Recover) + |
| 0x10 * (AT == AccessType::Store) + LogSize>(p); |
| if (EA == ErrorAction::Abort) |
| __builtin_unreachable(); |
| } |
| } |
| |
| template <ErrorAction EA, AccessType AT> |
| __attribute__((always_inline, nodebug)) static void CheckAddressSized(uptr p, |
| uptr sz) { |
| if (sz == 0) |
| return; |
| tag_t ptr_tag = GetTagFromPointer(p); |
| uptr ptr_raw = p & ~kAddressTagMask; |
| tag_t *shadow_first = (tag_t *)MemToShadow(ptr_raw); |
| tag_t *shadow_last = (tag_t *)MemToShadow(ptr_raw + sz - 1); |
| for (tag_t *t = shadow_first; t <= shadow_last; ++t) |
| if (UNLIKELY(ptr_tag != *t)) { |
| SigTrap<0x20 * (EA == ErrorAction::Recover) + |
| 0x10 * (AT == AccessType::Store) + 0xf>(p); |
| if (EA == ErrorAction::Abort) |
| __builtin_unreachable(); |
| } |
| } |
| } // end namespace __hwasan |
| |
| #endif // HWASAN_CHECKS_H |