1 // RUN: %clang %s -pie -fPIE -o %t && %run %t
2 // REQUIRES: x86_64-target-arch
3
4 // FIXME: Fails Asan, as expected, with 5lvl page tables.
5 // UNSUPPORTED: x86_64-target-arch
6
7 #include <assert.h>
8 #include <stdio.h>
9 #include <sys/mman.h>
10
main()11 int main() {
12 for (int j = 0; j < 1024; j++) {
13 // Try 1TB offsets. This attempts to find memory addresses where the
14 // 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 is
18 // lower in the address space (due to sanitizer and/or kernel limits).
19 // That is fine - if the app is also restricted from making high
20 // 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