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