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1/* SPDX-License-Identifier: LGPL-2.1 OR MIT */
2/*
3 * Stack protector support for NOLIBC
4 * Copyright (C) 2023 Thomas Weißschuh <linux@weissschuh.net>
5 */
6
7#ifndef _NOLIBC_STACKPROTECTOR_H
8#define _NOLIBC_STACKPROTECTOR_H
9
10#include "arch.h"
11
12#if defined(NOLIBC_STACKPROTECTOR)
13
14#if !defined(__ARCH_SUPPORTS_STACK_PROTECTOR)
15#error "nolibc does not support stack protectors on this arch"
16#endif
17
18#include "sys.h"
19#include "stdlib.h"
20
21/* The functions in this header are using raw syscall macros to avoid
22 * triggering stack protector errors themselves
23 */
24
25__attribute__((weak,noreturn,section(".text.nolibc_stack_chk")))
26void __stack_chk_fail(void)
27{
28 pid_t pid;
29 my_syscall3(__NR_write, STDERR_FILENO, "!!Stack smashing detected!!\n", 28);
30 pid = my_syscall0(__NR_getpid);
31 my_syscall2(__NR_kill, pid, SIGABRT);
32 for (;;);
33}
34
35__attribute__((weak,noreturn,section(".text.nolibc_stack_chk")))
36void __stack_chk_fail_local(void)
37{
38 __stack_chk_fail();
39}
40
41__attribute__((weak,section(".data.nolibc_stack_chk")))
42uintptr_t __stack_chk_guard;
43
44__attribute__((weak,no_stack_protector,section(".text.nolibc_stack_chk")))
45void __stack_chk_init(void)
46{
47 my_syscall3(__NR_getrandom, &__stack_chk_guard, sizeof(__stack_chk_guard), 0);
48 /* a bit more randomness in case getrandom() fails */
49 __stack_chk_guard ^= (uintptr_t) &__stack_chk_guard;
50}
51#endif // defined(NOLIBC_STACKPROTECTOR)
52
53#endif // _NOLIBC_STACKPROTECTOR_H