[PATCH v4] kasan: remove redundant config option

Walter Wu walter-zh.wu at mediatek.com
Thu Mar 11 01:32:45 GMT 2021


On Wed, 2021-03-03 at 19:48 +0800, Walter Wu wrote:
> On Fri, 2021-02-26 at 09:25 +0800, Walter Wu wrote:
> > CONFIG_KASAN_STACK and CONFIG_KASAN_STACK_ENABLE both enable KASAN stack
> > instrumentation, but we should only need one config, so that we remove
> > CONFIG_KASAN_STACK_ENABLE and make CONFIG_KASAN_STACK workable.  see [1].
> > 
> > When enable KASAN stack instrumentation, then for gcc we could do no
> > prompt and default value y, and for clang prompt and default value n.
> > 
> > [1]: https://bugzilla.kernel.org/show_bug.cgi?id=210221
> > 
> > Signed-off-by: Walter Wu <walter-zh.wu at mediatek.com>
> > Suggested-by: Dmitry Vyukov <dvyukov at google.com>
> > Reviewed-by: Nathan Chancellor <natechancellor at gmail.com>
> > Acked-by: Arnd Bergmann <arnd at arndb.de>
> > Reviewed-by: Andrey Konovalov <andreyknvl at google.com>
> > Cc: Andrey Ryabinin <ryabinin.a.a at gmail.com>
> > Cc: Dmitry Vyukov <dvyukov at google.com>
> > Cc: Alexander Potapenko <glider at google.com>
> > Cc: Andrew Morton <akpm at linux-foundation.org>
> > ---
> > 
> > v4: After this patch sent, someone had modification about KASAN_STACK,
> >     so I need to rebase codebase. Thank Andrey for your pointing.
> > 
> Hi Andrew,
> 
> Could you pick this v4 patch up into mm?
> Thanks.
> 
> Walter
> 
> > ---
> >  arch/arm64/kernel/sleep.S        |  2 +-
> >  arch/x86/kernel/acpi/wakeup_64.S |  2 +-
> >  include/linux/kasan.h            |  2 +-
> >  lib/Kconfig.kasan                |  8 ++------
> >  mm/kasan/common.c                |  2 +-
> >  mm/kasan/kasan.h                 |  2 +-
> >  mm/kasan/report_generic.c        |  2 +-
> >  scripts/Makefile.kasan           | 10 ++++++++--
> >  security/Kconfig.hardening       |  4 ++--
> >  9 files changed, 18 insertions(+), 16 deletions(-)
> > 
> > diff --git a/arch/arm64/kernel/sleep.S b/arch/arm64/kernel/sleep.S
> > index 5bfd9b87f85d..4ea9392f86e0 100644
> > --- a/arch/arm64/kernel/sleep.S
> > +++ b/arch/arm64/kernel/sleep.S
> > @@ -134,7 +134,7 @@ SYM_FUNC_START(_cpu_resume)
> >  	 */
> >  	bl	cpu_do_resume
> >  
> > -#if defined(CONFIG_KASAN) && CONFIG_KASAN_STACK
> > +#if defined(CONFIG_KASAN) && defined(CONFIG_KASAN_STACK)
> >  	mov	x0, sp
> >  	bl	kasan_unpoison_task_stack_below
> >  #endif
> > diff --git a/arch/x86/kernel/acpi/wakeup_64.S b/arch/x86/kernel/acpi/wakeup_64.S
> > index 56b6865afb2a..d5d8a352eafa 100644
> > --- a/arch/x86/kernel/acpi/wakeup_64.S
> > +++ b/arch/x86/kernel/acpi/wakeup_64.S
> > @@ -115,7 +115,7 @@ SYM_FUNC_START(do_suspend_lowlevel)
> >  	movq	pt_regs_r14(%rax), %r14
> >  	movq	pt_regs_r15(%rax), %r15
> >  
> > -#if defined(CONFIG_KASAN) && CONFIG_KASAN_STACK
> > +#if defined(CONFIG_KASAN) && defined(CONFIG_KASAN_STACK)
> >  	/*
> >  	 * The suspend path may have poisoned some areas deeper in the stack,
> >  	 * which we now need to unpoison.
> > diff --git a/include/linux/kasan.h b/include/linux/kasan.h
> > index b91732bd05d7..14f72ec96492 100644
> > --- a/include/linux/kasan.h
> > +++ b/include/linux/kasan.h
> > @@ -330,7 +330,7 @@ static inline bool kasan_check_byte(const void *address)
> >  
> >  #endif /* CONFIG_KASAN */
> >  
> > -#if defined(CONFIG_KASAN) && CONFIG_KASAN_STACK
> > +#if defined(CONFIG_KASAN) && defined(CONFIG_KASAN_STACK)
> >  void kasan_unpoison_task_stack(struct task_struct *task);
> >  #else
> >  static inline void kasan_unpoison_task_stack(struct task_struct *task) {}
> > diff --git a/lib/Kconfig.kasan b/lib/Kconfig.kasan
> > index 624ae1df7984..cffc2ebbf185 100644
> > --- a/lib/Kconfig.kasan
> > +++ b/lib/Kconfig.kasan
> > @@ -138,9 +138,10 @@ config KASAN_INLINE
> >  
> >  endchoice
> >  
> > -config KASAN_STACK_ENABLE
> > +config KASAN_STACK
> >  	bool "Enable stack instrumentation (unsafe)" if CC_IS_CLANG && !COMPILE_TEST
> >  	depends on KASAN_GENERIC || KASAN_SW_TAGS
> > +	default y if CC_IS_GCC
> >  	help
> >  	  The LLVM stack address sanitizer has a know problem that
> >  	  causes excessive stack usage in a lot of functions, see
> > @@ -154,11 +155,6 @@ config KASAN_STACK_ENABLE
> >  	  CONFIG_COMPILE_TEST.	On gcc it is assumed to always be safe
> >  	  to use and enabled by default.
> >  
> > -config KASAN_STACK
> > -	int
> > -	default 1 if KASAN_STACK_ENABLE || CC_IS_GCC
> > -	default 0
> > -

Hi Andrew,

I see my v4 patch is different in the next tree now. please see below
information.
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=ebced5fb0ef969620ecdc4011f600f9e7c229a3c
The different is in lib/Kconfig.kasan.
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/diff/lib/Kconfig.kasan?id=ebced5fb0ef969620ecdc4011f600f9e7c229a3c

Would you please help to check it.
Thanks.

Walter

> >  config KASAN_SW_TAGS_IDENTIFY
> >  	bool "Enable memory corruption identification"
> >  	depends on KASAN_SW_TAGS
> > diff --git a/mm/kasan/common.c b/mm/kasan/common.c
> > index b5e08d4cefec..7b53291dafa1 100644
> > --- a/mm/kasan/common.c
> > +++ b/mm/kasan/common.c
> > @@ -63,7 +63,7 @@ void __kasan_unpoison_range(const void *address, size_t size)
> >  	kasan_unpoison(address, size);
> >  }
> >  
> > -#if CONFIG_KASAN_STACK
> > +#ifdef CONFIG_KASAN_STACK
> >  /* Unpoison the entire stack for a task. */
> >  void kasan_unpoison_task_stack(struct task_struct *task)
> >  {
> > diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
> > index 8c55634d6edd..3436c6bf7c0c 100644
> > --- a/mm/kasan/kasan.h
> > +++ b/mm/kasan/kasan.h
> > @@ -231,7 +231,7 @@ void *kasan_find_first_bad_addr(void *addr, size_t size);
> >  const char *kasan_get_bug_type(struct kasan_access_info *info);
> >  void kasan_metadata_fetch_row(char *buffer, void *row);
> >  
> > -#if defined(CONFIG_KASAN_GENERIC) && CONFIG_KASAN_STACK
> > +#if defined(CONFIG_KASAN_GENERIC) && defined(CONFIG_KASAN_STACK)
> >  void kasan_print_address_stack_frame(const void *addr);
> >  #else
> >  static inline void kasan_print_address_stack_frame(const void *addr) { }
> > diff --git a/mm/kasan/report_generic.c b/mm/kasan/report_generic.c
> > index 41f374585144..de732bc341c5 100644
> > --- a/mm/kasan/report_generic.c
> > +++ b/mm/kasan/report_generic.c
> > @@ -128,7 +128,7 @@ void kasan_metadata_fetch_row(char *buffer, void *row)
> >  	memcpy(buffer, kasan_mem_to_shadow(row), META_BYTES_PER_ROW);
> >  }
> >  
> > -#if CONFIG_KASAN_STACK
> > +#ifdef CONFIG_KASAN_STACK
> >  static bool __must_check tokenize_frame_descr(const char **frame_descr,
> >  					      char *token, size_t max_tok_len,
> >  					      unsigned long *value)
> > diff --git a/scripts/Makefile.kasan b/scripts/Makefile.kasan
> > index 1e000cc2e7b4..abf231d209b1 100644
> > --- a/scripts/Makefile.kasan
> > +++ b/scripts/Makefile.kasan
> > @@ -2,6 +2,12 @@
> >  CFLAGS_KASAN_NOSANITIZE := -fno-builtin
> >  KASAN_SHADOW_OFFSET ?= $(CONFIG_KASAN_SHADOW_OFFSET)
> >  
> > +ifdef CONFIG_KASAN_STACK
> > +	stack_enable := 1
> > +else
> > +	stack_enable := 0
> > +endif
> > +
> >  ifdef CONFIG_KASAN_GENERIC
> >  
> >  ifdef CONFIG_KASAN_INLINE
> > @@ -27,7 +33,7 @@ else
> >  	CFLAGS_KASAN := $(CFLAGS_KASAN_SHADOW) \
> >  	 $(call cc-param,asan-globals=1) \
> >  	 $(call cc-param,asan-instrumentation-with-call-threshold=$(call_threshold)) \
> > -	 $(call cc-param,asan-stack=$(CONFIG_KASAN_STACK)) \
> > +	 $(call cc-param,asan-stack=$(stack_enable)) \
> >  	 $(call cc-param,asan-instrument-allocas=1)
> >  endif
> >  
> > @@ -42,7 +48,7 @@ else
> >  endif
> >  
> >  CFLAGS_KASAN := -fsanitize=kernel-hwaddress \
> > -		-mllvm -hwasan-instrument-stack=$(CONFIG_KASAN_STACK) \
> > +		-mllvm -hwasan-instrument-stack=$(stack_enable) \
> >  		-mllvm -hwasan-use-short-granules=0 \
> >  		$(instrumentation_flags)
> >  
> > diff --git a/security/Kconfig.hardening b/security/Kconfig.hardening
> > index 269967c4fc1b..a56c36470cb1 100644
> > --- a/security/Kconfig.hardening
> > +++ b/security/Kconfig.hardening
> > @@ -64,7 +64,7 @@ choice
> >  	config GCC_PLUGIN_STRUCTLEAK_BYREF
> >  		bool "zero-init structs passed by reference (strong)"
> >  		depends on GCC_PLUGINS
> > -		depends on !(KASAN && KASAN_STACK=1)
> > +		depends on !(KASAN && KASAN_STACK)
> >  		select GCC_PLUGIN_STRUCTLEAK
> >  		help
> >  		  Zero-initialize any structures on the stack that may
> > @@ -82,7 +82,7 @@ choice
> >  	config GCC_PLUGIN_STRUCTLEAK_BYREF_ALL
> >  		bool "zero-init anything passed by reference (very strong)"
> >  		depends on GCC_PLUGINS
> > -		depends on !(KASAN && KASAN_STACK=1)
> > +		depends on !(KASAN && KASAN_STACK)
> >  		select GCC_PLUGIN_STRUCTLEAK
> >  		help
> >  		  Zero-initialize any stack variables that may be passed
> 



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