1 | /* SPDX-License-Identifier: GPL-2.0 */ |
2 | #ifndef _LINUX_STACKPROTECTOR_H |
3 | #define _LINUX_STACKPROTECTOR_H 1 |
4 | |
5 | #include <linux/compiler.h> |
6 | #include <linux/sched.h> |
7 | #include <linux/random.h> |
8 | |
9 | /* |
10 | * On 64-bit architectures, protect against non-terminated C string overflows |
11 | * by zeroing out the first byte of the canary; this leaves 56 bits of entropy. |
12 | */ |
13 | #ifdef CONFIG_64BIT |
14 | # ifdef __LITTLE_ENDIAN |
15 | # define CANARY_MASK 0xffffffffffffff00UL |
16 | # else /* big endian, 64 bits: */ |
17 | # define CANARY_MASK 0x00ffffffffffffffUL |
18 | # endif |
19 | #else /* 32 bits: */ |
20 | # define CANARY_MASK 0xffffffffUL |
21 | #endif |
22 | |
23 | static inline unsigned long get_random_canary(void) |
24 | { |
25 | return get_random_long() & CANARY_MASK; |
26 | } |
27 | |
28 | #if defined(CONFIG_STACKPROTECTOR) || defined(CONFIG_ARM64_PTR_AUTH) |
29 | # include <asm/stackprotector.h> |
30 | #else |
31 | static inline void boot_init_stack_canary(void) |
32 | { |
33 | } |
34 | #endif |
35 | |
36 | #endif |
37 | |