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SubjectRe: [PATCH V4] ZBOOT: fix stack protector in compressed boot phase
Hi Huacai,

On Wed, Mar 28, 2018 at 04:38:16PM +0800, Huacai Chen wrote:
> Call __stack_chk_guard_setup() in decompress_kernel() is too late that
> stack checking always fails for decompress_kernel() itself. So remove
> __stack_chk_guard_setup() and initialize __stack_chk_guard before we
> call decompress_kernel().
>
> Original code comes from ARM but also used for MIPS and SH, so fix them
> together. If without this fix, compressed booting of these archs will
> fail because stack checking is enabled by default (>=4.16).
>
> V1 -> V2: Fix build on ARM.
> V2 -> V3: Fix build on SuperH.
> V3 -> V4: Initialize __stack_chk_guard in C code as a constant.
>
> Cc: stable@vger.kernel.org
> Signed-off-by: Huacai Chen <chenhc@lemote.com>
> ---
> arch/arm/boot/compressed/head.S | 4 ++++
> arch/arm/boot/compressed/misc.c | 7 -------
> arch/mips/boot/compressed/decompress.c | 7 -------
> arch/mips/boot/compressed/head.S | 4 ++++
> arch/sh/boot/compressed/head_32.S | 8 ++++++++
> arch/sh/boot/compressed/head_64.S | 4 ++++
> arch/sh/boot/compressed/misc.c | 7 -------
> 7 files changed, 20 insertions(+), 21 deletions(-)

This diffstat doesn't match the patch below. The patch touches no .S file.

baruch

>
> diff --git a/arch/arm/boot/compressed/misc.c b/arch/arm/boot/compressed/misc.c
> index 16a8a80..e8fe51f 100644
> --- a/arch/arm/boot/compressed/misc.c
> +++ b/arch/arm/boot/compressed/misc.c
> @@ -128,12 +128,7 @@ asmlinkage void __div0(void)
> error("Attempting division by 0!");
> }
>
> -unsigned long __stack_chk_guard;
> -
> -void __stack_chk_guard_setup(void)
> -{
> - __stack_chk_guard = 0x000a0dff;
> -}
> +const unsigned long __stack_chk_guard = 0x000a0dff;
>
> void __stack_chk_fail(void)
> {
> @@ -150,8 +145,6 @@ decompress_kernel(unsigned long output_start, unsigned long free_mem_ptr_p,
> {
> int ret;
>
> - __stack_chk_guard_setup();
> -
> output_data = (unsigned char *)output_start;
> free_mem_ptr = free_mem_ptr_p;
> free_mem_end_ptr = free_mem_ptr_end_p;
> diff --git a/arch/mips/boot/compressed/decompress.c b/arch/mips/boot/compressed/decompress.c
> index fdf99e9..81df904 100644
> --- a/arch/mips/boot/compressed/decompress.c
> +++ b/arch/mips/boot/compressed/decompress.c
> @@ -76,12 +76,7 @@ void error(char *x)
> #include "../../../../lib/decompress_unxz.c"
> #endif
>
> -unsigned long __stack_chk_guard;
> -
> -void __stack_chk_guard_setup(void)
> -{
> - __stack_chk_guard = 0x000a0dff;
> -}
> +const unsigned long __stack_chk_guard = 0x000a0dff;
>
> void __stack_chk_fail(void)
> {
> @@ -92,8 +87,6 @@ void decompress_kernel(unsigned long boot_heap_start)
> {
> unsigned long zimage_start, zimage_size;
>
> - __stack_chk_guard_setup();
> -
> zimage_start = (unsigned long)(&__image_begin);
> zimage_size = (unsigned long)(&__image_end) -
> (unsigned long)(&__image_begin);
> diff --git a/arch/sh/boot/compressed/misc.c b/arch/sh/boot/compressed/misc.c
> index 627ce8e..c15cac9 100644
> --- a/arch/sh/boot/compressed/misc.c
> +++ b/arch/sh/boot/compressed/misc.c
> @@ -104,12 +104,7 @@ static void error(char *x)
> while(1); /* Halt */
> }
>
> -unsigned long __stack_chk_guard;
> -
> -void __stack_chk_guard_setup(void)
> -{
> - __stack_chk_guard = 0x000a0dff;
> -}
> +const unsigned long __stack_chk_guard = 0x000a0dff;
>
> void __stack_chk_fail(void)
> {
> @@ -130,8 +125,6 @@ void decompress_kernel(void)
> {
> unsigned long output_addr;
>
> - __stack_chk_guard_setup();
> -
> #ifdef CONFIG_SUPERH64
> output_addr = (CONFIG_MEMORY_START + 0x2000);
> #else

--
http://baruch.siach.name/blog/ ~. .~ Tk Open Systems
=}------------------------------------------------ooO--U--Ooo------------{=
- baruch@tkos.co.il - tel: +972.2.679.5364, http://www.tkos.co.il -

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