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Diffstat (limited to 'arch/arm/include/asm/stackprotector.h')
-rw-r--r-- | arch/arm/include/asm/stackprotector.h | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/arch/arm/include/asm/stackprotector.h b/arch/arm/include/asm/stackprotector.h new file mode 100644 index 0000000000..0bd4979759 --- /dev/null +++ b/arch/arm/include/asm/stackprotector.h @@ -0,0 +1,38 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * GCC stack protector support. + * + * Stack protector works by putting predefined pattern at the start of + * the stack frame and verifying that it hasn't been overwritten when + * returning from the function. The pattern is called stack canary + * and gcc expects it to be defined by a global variable called + * "__stack_chk_guard" on ARM. This prevents SMP systems from using a + * different value for each task unless we enable a GCC plugin that + * replaces these symbol references with references to each task's own + * value. + */ + +#ifndef _ASM_STACKPROTECTOR_H +#define _ASM_STACKPROTECTOR_H 1 + +#include <asm/thread_info.h> + +extern unsigned long __stack_chk_guard; + +/* + * Initialize the stackprotector canary value. + * + * NOTE: this must only be called from functions that never return, + * and it must always be inlined. + */ +static __always_inline void boot_init_stack_canary(void) +{ + unsigned long canary = get_random_canary(); + + current->stack_canary = canary; +#ifndef CONFIG_STACKPROTECTOR_PER_TASK + __stack_chk_guard = current->stack_canary; +#endif +} + +#endif /* _ASM_STACKPROTECTOR_H */ |