1 /* SPDX-License-Identifier: LGPL-2.1 OR MIT */ 1 /* SPDX-License-Identifier: LGPL-2.1 OR MIT */
2 /* 2 /*
3 * Stack protector support for NOLIBC 3 * Stack protector support for NOLIBC
4 * Copyright (C) 2023 Thomas Weißschuh <linux 4 * Copyright (C) 2023 Thomas Weißschuh <linux@weissschuh.net>
5 */ 5 */
6 6
7 #ifndef _NOLIBC_STACKPROTECTOR_H 7 #ifndef _NOLIBC_STACKPROTECTOR_H
8 #define _NOLIBC_STACKPROTECTOR_H 8 #define _NOLIBC_STACKPROTECTOR_H
9 9
10 #include "compiler.h" 10 #include "compiler.h"
11 11
12 #if defined(_NOLIBC_STACKPROTECTOR) 12 #if defined(_NOLIBC_STACKPROTECTOR)
13 13
14 #include "sys.h" 14 #include "sys.h"
15 #include "stdlib.h" 15 #include "stdlib.h"
16 16
17 /* The functions in this header are using raw 17 /* The functions in this header are using raw syscall macros to avoid
18 * triggering stack protector errors themselve 18 * triggering stack protector errors themselves
19 */ 19 */
20 20
21 __attribute__((weak,used,noreturn,section(".te 21 __attribute__((weak,used,noreturn,section(".text.nolibc_stack_chk")))
22 void __stack_chk_fail(void) 22 void __stack_chk_fail(void)
23 { 23 {
24 pid_t pid; 24 pid_t pid;
25 my_syscall3(__NR_write, STDERR_FILENO, 25 my_syscall3(__NR_write, STDERR_FILENO, "!!Stack smashing detected!!\n", 28);
26 pid = my_syscall0(__NR_getpid); 26 pid = my_syscall0(__NR_getpid);
27 my_syscall2(__NR_kill, pid, SIGABRT); 27 my_syscall2(__NR_kill, pid, SIGABRT);
28 for (;;); 28 for (;;);
29 } 29 }
30 30
31 __attribute__((weak,noreturn,section(".text.no 31 __attribute__((weak,noreturn,section(".text.nolibc_stack_chk")))
32 void __stack_chk_fail_local(void) 32 void __stack_chk_fail_local(void)
33 { 33 {
34 __stack_chk_fail(); 34 __stack_chk_fail();
35 } 35 }
36 36
37 __attribute__((weak,used,section(".data.nolibc 37 __attribute__((weak,used,section(".data.nolibc_stack_chk")))
38 uintptr_t __stack_chk_guard; 38 uintptr_t __stack_chk_guard;
39 39
40 static __no_stack_protector void __stack_chk_i 40 static __no_stack_protector void __stack_chk_init(void)
41 { 41 {
42 my_syscall3(__NR_getrandom, &__stack_c 42 my_syscall3(__NR_getrandom, &__stack_chk_guard, sizeof(__stack_chk_guard), 0);
43 /* a bit more randomness in case getra 43 /* a bit more randomness in case getrandom() fails, ensure the guard is never 0 */
44 if (__stack_chk_guard != (uintptr_t) & 44 if (__stack_chk_guard != (uintptr_t) &__stack_chk_guard)
45 __stack_chk_guard ^= (uintptr_ 45 __stack_chk_guard ^= (uintptr_t) &__stack_chk_guard;
46 } 46 }
47 #else /* !defined(_NOLIBC_STACKPROTECTOR) */ 47 #else /* !defined(_NOLIBC_STACKPROTECTOR) */
48 static void __stack_chk_init(void) {} 48 static void __stack_chk_init(void) {}
49 #endif /* defined(_NOLIBC_STACKPROTECTOR) */ 49 #endif /* defined(_NOLIBC_STACKPROTECTOR) */
50 50
51 #endif /* _NOLIBC_STACKPROTECTOR_H */ 51 #endif /* _NOLIBC_STACKPROTECTOR_H */
52 52
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.