34 lines · c
1// RUN: %clang %s -pie -fPIE -o %t && %run %t2// REQUIRES: x86_64-target-arch3 4// FIXME: Fails Asan, as expected, with 5lvl page tables.5// UNSUPPORTED: x86_64-target-arch6 7#include <assert.h>8#include <stdio.h>9#include <sys/mman.h>10 11int main() {12 for (int j = 0; j < 1024; j++) {13 // Try 1TB offsets. This attempts to find memory addresses where the14 // shadow mappings - which assume a 47-bit address space - are invalid.15 unsigned long long target = (1ULL << 56) - (2 * 4096) - (j * (1ULL << 40));16 17 // Since we don't use MAP_FIXED, mmap might return an address that is18 // lower in the address space (due to sanitizer and/or kernel limits).19 // That is fine - if the app is also restricted from making high20 // allocations, then they are safe.21 char* ptr = (char*) mmap ((void*) target, 4096, PROT_READ | PROT_WRITE,22 MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);23 printf ("Allocated at %p\n", ptr);24 25 assert (ptr != MAP_FAILED);26 for (int i = 0; i < 100; i++) {27 ptr [i] = 0;28 }29 munmap (ptr, 4096);30 }31 32 return 0;33}34