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"))) 26 void __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"))) 36 void __stack_chk_fail_local(void) 37 { 38 __stack_chk_fail(); 39 } 40 41 __attribute__((weak,section(".data.nolibc_stack_chk"))) 42 uintptr_t __stack_chk_guard; 43 44 __attribute__((weak,no_stack_protector,section(".text.nolibc_stack_chk"))) 45 void __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 54