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 "compiler.h" 11 12 #if defined(_NOLIBC_STACKPROTECTOR) 13 14 #include "sys.h" 15 #include "stdlib.h" 16 17 /* The functions in this header are using raw syscall macros to avoid 18 * triggering stack protector errors themselves 19 */ 20 21 __attribute__((weak,noreturn,section(".text.nolibc_stack_chk"))) 22 void __stack_chk_fail(void) 23 { 24 pid_t pid; 25 my_syscall3(__NR_write, STDERR_FILENO, "!!Stack smashing detected!!\n", 28); 26 pid = my_syscall0(__NR_getpid); 27 my_syscall2(__NR_kill, pid, SIGABRT); 28 for (;;); 29 } 30 31 __attribute__((weak,noreturn,section(".text.nolibc_stack_chk"))) 32 void __stack_chk_fail_local(void) 33 { 34 __stack_chk_fail(); 35 } 36 37 __attribute__((weak,section(".data.nolibc_stack_chk"))) 38 uintptr_t __stack_chk_guard; 39 40 static __no_stack_protector void __stack_chk_init(void) 41 { 42 my_syscall3(__NR_getrandom, &__stack_chk_guard, sizeof(__stack_chk_guard), 0); 43 /* a bit more randomness in case getrandom() fails, ensure the guard is never 0 */ 44 if (__stack_chk_guard != (uintptr_t) &__stack_chk_guard) 45 __stack_chk_guard ^= (uintptr_t) &__stack_chk_guard; 46 } 47 #else /* !defined(_NOLIBC_STACKPROTECTOR) */ 48 static void __stack_chk_init(void) {} 49 #endif /* defined(_NOLIBC_STACKPROTECTOR) */ 50 51 #endif /* _NOLIBC_STACKPROTECTOR_H */ 52