| 1 | // A shadow call stack runtime is not yet included with compiler-rt, provide a |
|---|
| 2 | // minimal runtime to allocate a shadow call stack and assign an |
|---|
| 3 | // architecture-specific register to point at it. |
|---|
| 4 | |
|---|
| 5 | #pragma once |
|---|
| 6 | |
|---|
| 7 | #include <stdlib.h> |
|---|
| 8 | #include <sys/mman.h> |
|---|
| 9 | #include <sys/prctl.h> |
|---|
| 10 | |
|---|
| 11 | #include "libc_support.h" |
|---|
| 12 | |
|---|
| 13 | __attribute__((no_sanitize("shadow-call-stack" ))) |
|---|
| 14 | static void __shadowcallstack_init() { |
|---|
| 15 | void *stack = mmap(NULL, len: 8192, PROT_READ | PROT_WRITE, |
|---|
| 16 | MAP_PRIVATE | MAP_ANONYMOUS, fd: -1, offset: 0); |
|---|
| 17 | if (stack == MAP_FAILED) |
|---|
| 18 | abort(); |
|---|
| 19 | |
|---|
| 20 | #if defined(__aarch64__) |
|---|
| 21 | __asm__ __volatile__("mov x18, %0" ::"r" (stack)); |
|---|
| 22 | #else |
|---|
| 23 | #error Unsupported platform |
|---|
| 24 | #endif |
|---|
| 25 | } |
|---|
| 26 | |
|---|
| 27 | int scs_main(void); |
|---|
| 28 | |
|---|
| 29 | __attribute__((no_sanitize("shadow-call-stack" ))) int main(void) { |
|---|
| 30 | __shadowcallstack_init(); |
|---|
| 31 | |
|---|
| 32 | // We can't simply return scs_main() because scs_main might have corrupted our |
|---|
| 33 | // return address for testing purposes (see overflow.c), so we need to exit |
|---|
| 34 | // ourselves. |
|---|
| 35 | exit(status: scs_main()); |
|---|
| 36 | } |
|---|
| 37 | |
|---|
