linux/arch/riscv/include/asm/stackprotector.h
Jason A. Donenfeld 622754e84b stackprotector: actually use get_random_canary()
The RNG always mixes in the Linux version extremely early in boot. It
also always includes a cycle counter, not only during early boot, but
each and every time it is invoked prior to being fully initialized.
Together, this means that the use of additional xors inside of the
various stackprotector.h files is superfluous and over-complicated.
Instead, we can get exactly the same thing, but better, by just calling
`get_random_canary()`.

Acked-by: Guo Ren <guoren@kernel.org> # for csky
Acked-by: Catalin Marinas <catalin.marinas@arm.com> # for arm64
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-11-18 02:18:10 +01:00

23 lines
589 B
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_RISCV_STACKPROTECTOR_H
#define _ASM_RISCV_STACKPROTECTOR_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;
if (!IS_ENABLED(CONFIG_STACKPROTECTOR_PER_TASK))
__stack_chk_guard = current->stack_canary;
}
#endif /* _ASM_RISCV_STACKPROTECTOR_H */