Re: [PATCH V2] ZBOOT: fix stack protector in compressed boot phase

[Yoshinori Sato]

On Tue, 13 Mar 2018 17:55:53 +0900,
Huacai Chen wrote:
> 
> Hi, Yoshinori, Rich and SuperH developers,
> 
> I'm not familiar with SuperH assembly, but SuperH has the same bug
> obviously. Could you please fix that?
> 
> Huacai
>

OK. Apply this fix.
SuperH can not handle long int directly.

diff --git a/arch/sh/boot/compressed/head_32.S b/arch/sh/boot/compressed/head_32.S
index a3fdb053f351..7411fcb5764a 100644
--- a/arch/sh/boot/compressed/head_32.S
+++ b/arch/sh/boot/compressed/head_32.S
@@ -76,8 +76,8 @@ l1:
 	mov.l	init_stack_addr, r0
 	mov.l	@r0, r15
 
-	mov.l	__stack_chk_guard, r0
-	mov	#0x000a0dff, r1
+	mov.l	__stack_chk_guard_ptr, r0
+	mov.l	__stack_chk_val, r1
 	mov.l	r1, @r0
 
 	/* Decompress the kernel */
@@ -109,6 +109,10 @@ kernel_start_addr:
 #else
 	.long	_text+PAGE_SIZE
 #endif
+__stack_chk_guard_ptr:
+	.long	__stack_chk_guard
+__stack_chk_val:
+	.long	0x000a0dff
 
 	.align	9
 fake_headers_as_bzImage:

> On Mon, Mar 12, 2018 at 10:04 AM, Huacai Chen <chenhc@xxxxxxxxxx> 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).
> >
> > V2: Fix build on ARM.
> >
> > Cc: stable@xxxxxxxxxxxxxxx
> > Signed-off-by: Huacai Chen <chenhc@xxxxxxxxxx>
> > ---
> >  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      | 4 ++++
> >  arch/sh/boot/compressed/head_64.S      | 4 ++++
> >  arch/sh/boot/compressed/misc.c         | 7 -------
> >  7 files changed, 16 insertions(+), 21 deletions(-)
> >
> > diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S
> > index 45c8823..bae1fc6 100644
> > --- a/arch/arm/boot/compressed/head.S
> > +++ b/arch/arm/boot/compressed/head.S
> > @@ -547,6 +547,10 @@ not_relocated:     mov     r0, #0
> >                 bic     r4, r4, #1
> >                 blne    cache_on
> >
> > +               ldr     r0, =__stack_chk_guard
> > +               ldr     r1, =0x000a0dff
> > +               str     r1, [r0]
> > +
> >  /*
> >   * The C runtime environment should now be setup sufficiently.
> >   * Set up some pointers, and start decompressing.
> > diff --git a/arch/arm/boot/compressed/misc.c b/arch/arm/boot/compressed/misc.c
> > index 16a8a80..e518ef5 100644
> > --- a/arch/arm/boot/compressed/misc.c
> > +++ b/arch/arm/boot/compressed/misc.c
> > @@ -130,11 +130,6 @@ asmlinkage void __div0(void)
> >
> >  unsigned long __stack_chk_guard;
> >
> > -void __stack_chk_guard_setup(void)
> > -{
> > -       __stack_chk_guard = 0x000a0dff;
> > -}
> > -
> >  void __stack_chk_fail(void)
> >  {
> >         error("stack-protector: Kernel stack is corrupted\n");
> > @@ -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..5ba431c 100644
> > --- a/arch/mips/boot/compressed/decompress.c
> > +++ b/arch/mips/boot/compressed/decompress.c
> > @@ -78,11 +78,6 @@ void error(char *x)
> >
> >  unsigned long __stack_chk_guard;
> >
> > -void __stack_chk_guard_setup(void)
> > -{
> > -       __stack_chk_guard = 0x000a0dff;
> > -}
> > -
> >  void __stack_chk_fail(void)
> >  {
> >         error("stack-protector: Kernel stack is corrupted\n");
> > @@ -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/mips/boot/compressed/head.S b/arch/mips/boot/compressed/head.S
> > index 409cb48..00d0ee0 100644
> > --- a/arch/mips/boot/compressed/head.S
> > +++ b/arch/mips/boot/compressed/head.S
> > @@ -32,6 +32,10 @@ start:
> >         bne     a2, a0, 1b
> >          addiu  a0, a0, 4
> >
> > +       PTR_LA  a0, __stack_chk_guard
> > +       PTR_LI  a1, 0x000a0dff
> > +       sw      a1, 0(a0)
> > +
> >         PTR_LA  a0, (.heap)          /* heap address */
> >         PTR_LA  sp, (.stack + 8192)  /* stack address */
> >
> > diff --git a/arch/sh/boot/compressed/head_32.S b/arch/sh/boot/compressed/head_32.S
> > index 7bb1681..a3fdb05 100644
> > --- a/arch/sh/boot/compressed/head_32.S
> > +++ b/arch/sh/boot/compressed/head_32.S
> > @@ -76,6 +76,10 @@ l1:
> >         mov.l   init_stack_addr, r0
> >         mov.l   @r0, r15
> >
> > +       mov.l   __stack_chk_guard, r0
> > +       mov     #0x000a0dff, r1
> > +       mov.l   r1, @r0
> > +
> >         /* Decompress the kernel */
> >         mov.l   decompress_kernel_addr, r0
> >         jsr     @r0
> > diff --git a/arch/sh/boot/compressed/head_64.S b/arch/sh/boot/compressed/head_64.S
> > index 9993113..8b4d540 100644
> > --- a/arch/sh/boot/compressed/head_64.S
> > +++ b/arch/sh/boot/compressed/head_64.S
> > @@ -132,6 +132,10 @@ startup:
> >         addi    r22, 4, r22
> >         bne     r22, r23, tr1
> >
> > +       movi    datalabel __stack_chk_guard, r0
> > +       movi    0x000a0dff, r1
> > +       st.l    r0, 0, r1
> > +
> >         /*
> >          * Decompress the kernel.
> >          */
> > diff --git a/arch/sh/boot/compressed/misc.c b/arch/sh/boot/compressed/misc.c
> > index 627ce8e..fe4c079 100644
> > --- a/arch/sh/boot/compressed/misc.c
> > +++ b/arch/sh/boot/compressed/misc.c
> > @@ -106,11 +106,6 @@ static void error(char *x)
> >
> >  unsigned long __stack_chk_guard;
> >
> > -void __stack_chk_guard_setup(void)
> > -{
> > -       __stack_chk_guard = 0x000a0dff;
> > -}
> > -
> >  void __stack_chk_fail(void)
> >  {
> >         error("stack-protector: Kernel stack is corrupted\n");
> > @@ -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
> > --
> > 2.7.0
> >

--
Yoshinori Sato
<ysato@xxxxxxxxxxxxxxxxxxxx>