| 1 | |
| 2 | * GCC stack protector support.
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| 3 | *
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| 4 | * (This is directly adopted from the ARM implementation)
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| 5 | *
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| 6 | * Stack protector works by putting predefined pattern at the start of
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| 7 | * the stack frame and verifying that it hasn't been overwritten when
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| 8 | * returning from the function. The pattern is called stack canary
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| 9 | * and gcc expects it to be defined by a global variable called
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| 10 | * "__stack_chk_guard" on Xtensa. This unfortunately means that on SMP
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| 11 | * we cannot have a different canary value per task.
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| 12 |
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| 13 |
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| 14 | #ifndef _ASM_STACKPROTECTOR_H
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| 15 | #define _ASM_STACKPROTECTOR_H 1
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| 16 |
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| 17 | extern unsigned long __stack_chk_guard;
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| 18 |
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| 19 | |
| 20 | * Initialize the stackprotector canary value.
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| 21 | *
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| 22 | * NOTE: this must only be called from functions that never return,
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| 23 | * and it must always be inlined.
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| 24 |
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| 25 | static __always_inline void boot_init_stack_canary(void)
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| 26 | {
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| 27 | unsigned long canary = get_random_canary();
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| 28 |
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| 29 | current->stack_canary = canary;
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| 30 | __stack_chk_guard = current->stack_canary;
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| 31 | }
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| 32 |
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| 33 | #endif
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