diff options
author | Guo Ren <guoren@linux.alibaba.com> | 2020-07-10 16:19:57 +0000 |
---|---|---|
committer | Palmer Dabbelt <palmerdabbelt@google.com> | 2020-07-30 11:37:39 -0700 |
commit | f2c9699f65557a31fed4ddb9e5b4d9489b1bf32f (patch) | |
tree | 944424af9ffbfbb6ac6dafef33202045a2e8da4c /arch/riscv | |
parent | 08b5985e7be54d15d058191adda2722bd395df32 (diff) |
riscv: Add STACKPROTECTOR supported
The -fstack-protector & -fstack-protector-strong features are from
gcc. The patch only add basic kernel support to stack-protector
feature and some arch could have its own solution such as
ARM64_PTR_AUTH.
After enabling STACKPROTECTOR and STACKPROTECTOR_STRONG, the .text
size is expanded from 0x7de066 to 0x81fb32 (only 5%) to add canary
checking code.
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
Diffstat (limited to 'arch/riscv')
-rw-r--r-- | arch/riscv/Kconfig | 1 | ||||
-rw-r--r-- | arch/riscv/include/asm/stackprotector.h | 33 | ||||
-rw-r--r-- | arch/riscv/kernel/process.c | 6 |
3 files changed, 40 insertions, 0 deletions
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index b124ca4323bf..b55be0980b2b 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -66,6 +66,7 @@ config RISCV select HAVE_PERF_EVENTS select HAVE_PERF_REGS select HAVE_PERF_USER_STACK_DUMP + select HAVE_STACKPROTECTOR select HAVE_SYSCALL_TRACEPOINTS select IRQ_DOMAIN select MODULES_USE_ELF_RELA if MODULES diff --git a/arch/riscv/include/asm/stackprotector.h b/arch/riscv/include/asm/stackprotector.h new file mode 100644 index 000000000000..d95f7b2a7f37 --- /dev/null +++ b/arch/riscv/include/asm/stackprotector.h @@ -0,0 +1,33 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef _ASM_RISCV_STACKPROTECTOR_H +#define _ASM_RISCV_STACKPROTECTOR_H + +#include <linux/random.h> +#include <linux/version.h> +#include <asm/timex.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; + unsigned long tsc; + + /* Try to get a semi random initial value. */ + get_random_bytes(&canary, sizeof(canary)); + tsc = get_cycles(); + canary += tsc + (tsc << BITS_PER_LONG/2); + canary ^= LINUX_VERSION_CODE; + canary &= CANARY_MASK; + + current->stack_canary = canary; + __stack_chk_guard = current->stack_canary; +} +#endif /* _ASM_RISCV_STACKPROTECTOR_H */ diff --git a/arch/riscv/kernel/process.c b/arch/riscv/kernel/process.c index 824d117cf202..65489297ed2e 100644 --- a/arch/riscv/kernel/process.c +++ b/arch/riscv/kernel/process.c @@ -24,6 +24,12 @@ register unsigned long gp_in_global __asm__("gp"); +#ifdef CONFIG_STACKPROTECTOR +#include <linux/stackprotector.h> +unsigned long __stack_chk_guard __read_mostly; +EXPORT_SYMBOL(__stack_chk_guard); +#endif + extern asmlinkage void ret_from_fork(void); extern asmlinkage void ret_from_kernel_thread(void); |