Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * GCC stack protector support.
4 *
5 * Stack protector works by putting predefined pattern at the start of
6 * the stack frame and verifying that it hasn't been overwritten when
7 * returning from the function. The pattern is called stack canary
8 * and gcc expects it to be defined by a global variable called
9 * "__stack_chk_guard" on ARM. This unfortunately means that on SMP
10 * we cannot have a different canary value per task.
11 */
12
13#ifndef __ASM_STACKPROTECTOR_H
14#define __ASM_STACKPROTECTOR_H
15
16#include <linux/random.h>
17#include <linux/version.h>
18#include <asm/pointer_auth.h>
19
20extern unsigned long __stack_chk_guard;
21
22/*
23 * Initialize the stackprotector canary value.
24 *
25 * NOTE: this must only be called from functions that never return,
26 * and it must always be inlined.
27 */
28static __always_inline void boot_init_stack_canary(void)
29{
30#if defined(CONFIG_STACKPROTECTOR)
31 unsigned long canary;
32
33 /* Try to get a semi random initial value. */
34 get_random_bytes(&canary, sizeof(canary));
35 canary ^= LINUX_VERSION_CODE;
36 canary &= CANARY_MASK;
37
38 current->stack_canary = canary;
39 if (!IS_ENABLED(CONFIG_STACKPROTECTOR_PER_TASK))
40 __stack_chk_guard = current->stack_canary;
41#endif
42 ptrauth_thread_init_kernel(current);
43 ptrauth_thread_switch_kernel(current);
44 ptrauth_enable();
45}
46
47#endif /* _ASM_STACKPROTECTOR_H */