提交 40d1a07b 编写于 作者: M Max Filippov

xtensa: enable stack protector

The implementation is adopted from the ARM arch. GCC 7.3, 8 or newer is
required for building the xtensa kernel with SSP.
Signed-off-by: NMax Filippov <jcmvbkbc@gmail.com>
上级 aa6476f7
......@@ -35,5 +35,5 @@
| um: | TODO |
| unicore32: | TODO |
| x86: | ok |
| xtensa: | TODO |
| xtensa: | ok |
-----------------------
......@@ -15,6 +15,7 @@ config XTENSA
select GENERIC_IRQ_SHOW
select GENERIC_PCI_IOMAP
select GENERIC_SCHED_CLOCK
select HAVE_CC_STACKPROTECTOR
select HAVE_DEBUG_KMEMLEAK
select HAVE_DMA_API_DEBUG
select HAVE_DMA_CONTIGUOUS
......
......@@ -15,6 +15,10 @@ CFLAGS_REMOVE_inftrees.o = -pg
CFLAGS_REMOVE_inffast.o = -pg
endif
CFLAGS_REMOVE_inflate.o += -fstack-protector -fstack-protector-strong
CFLAGS_REMOVE_zmem.o += -fstack-protector -fstack-protector-strong
CFLAGS_REMOVE_inftrees.o += -fstack-protector -fstack-protector-strong
CFLAGS_REMOVE_inffast.o += -fstack-protector -fstack-protector-strong
quiet_cmd_copy_zlib = COPY $@
cmd_copy_zlib = cat $< > $@
......
/*
* GCC stack protector support.
*
* (This is directly adopted from the ARM implementation)
*
* 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 Xtensa. This unfortunately means that on SMP
* we cannot have a different canary value per task.
*/
#ifndef _ASM_STACKPROTECTOR_H
#define _ASM_STACKPROTECTOR_H 1
#include <linux/random.h>
#include <linux/version.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;
/* Try to get a semi random initial value. */
get_random_bytes(&canary, sizeof(canary));
canary ^= LINUX_VERSION_CODE;
current->stack_canary = canary;
__stack_chk_guard = current->stack_canary;
}
#endif /* _ASM_STACKPROTECTOR_H */
......@@ -76,6 +76,9 @@ int main(void)
DEFINE(TASK_PID, offsetof (struct task_struct, pid));
DEFINE(TASK_THREAD, offsetof (struct task_struct, thread));
DEFINE(TASK_THREAD_INFO, offsetof (struct task_struct, stack));
#ifdef CONFIG_CC_STACKPROTECTOR
DEFINE(TASK_STACK_CANARY, offsetof(struct task_struct, stack_canary));
#endif
DEFINE(TASK_STRUCT_SIZE, sizeof (struct task_struct));
/* offsets in thread_info struct */
......
......@@ -1971,6 +1971,12 @@ ENTRY(_switch_to)
s32i a1, a2, THREAD_SP # save stack pointer
#endif
#if defined(CONFIG_CC_STACKPROTECTOR) && !defined(CONFIG_SMP)
movi a6, __stack_chk_guard
l32i a8, a3, TASK_STACK_CANARY
s32i a8, a6, 0
#endif
/* Disable ints while we manipulate the stack pointer. */
irq_save a14, a3
......
......@@ -58,6 +58,12 @@ void (*pm_power_off)(void) = NULL;
EXPORT_SYMBOL(pm_power_off);
#ifdef CONFIG_CC_STACKPROTECTOR
#include <linux/stackprotector.h>
unsigned long __stack_chk_guard __read_mostly;
EXPORT_SYMBOL(__stack_chk_guard);
#endif
#if XTENSA_HAVE_COPROCESSORS
void coprocessor_release_all(struct thread_info *ti)
......
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