Commit 687c85af authored by Andrey Konovalov's avatar Andrey Konovalov Committed by Andrew Morton
Browse files

kasan: drop CONFIG_KASAN_TAGS_IDENTIFY 

Drop CONFIG_KASAN_TAGS_IDENTIFY and related code to simplify making
changes to the reporting code.

The dropped functionality will be restored in the following patches in
this series.

Link: https://lkml.kernel.org/r/4c66ba98eb237e9ed9312c19d423bbcf4ecf88f8.1662411799.git.andreyknvl@google.com


Signed-off-by: default avatarAndrey Konovalov <andreyknvl@google.com>
Reviewed-by: default avatarMarco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Peter Collingbourne <pcc@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent ccf643e6

lib/Kconfig.kasan

+0 −8
Original line number Diff line number Diff line
@@ -167,14 +167,6 @@ config KASAN_STACK 
	  as well, as it adds inline-style instrumentation that is run

	  unconditionally.



config KASAN_TAGS_IDENTIFY

	bool "Memory corruption type identification"

	depends on KASAN_SW_TAGS || KASAN_HW_TAGS

	help

	  Enables best-effort identification of the bug types (use-after-free

	  or out-of-bounds) at the cost of increased memory consumption.

	  Only applicable for the tag-based KASAN modes.



config KASAN_VMALLOC

	bool "Check accesses to vmalloc allocations"

	depends on HAVE_ARCH_KASAN_VMALLOC

mm/kasan/kasan.h

+1 −11
Original line number Diff line number Diff line
@@ -169,23 +169,13 @@ struct kasan_track { 
	depot_stack_handle_t stack;

};



#if defined(CONFIG_KASAN_TAGS_IDENTIFY) && defined(CONFIG_KASAN_SW_TAGS)

#define KASAN_NR_FREE_STACKS 5

#else

#define KASAN_NR_FREE_STACKS 1

#endif



struct kasan_alloc_meta {

	struct kasan_track alloc_track;

	/* Generic mode stores free track in kasan_free_meta. */

#ifdef CONFIG_KASAN_GENERIC

	depot_stack_handle_t aux_stack[2];

#else

	struct kasan_track free_track[KASAN_NR_FREE_STACKS];

#endif

#ifdef CONFIG_KASAN_TAGS_IDENTIFY

	u8 free_pointer_tag[KASAN_NR_FREE_STACKS];

	u8 free_track_idx;

	struct kasan_track free_track;

#endif

};

mm/kasan/report_tags.c

+0 −28
Original line number Diff line number Diff line
@@ -5,37 +5,9 @@ 
 */



#include "kasan.h"

#include "../slab.h"



const char *kasan_get_bug_type(struct kasan_report_info *info)

{

#ifdef CONFIG_KASAN_TAGS_IDENTIFY

	struct kasan_alloc_meta *alloc_meta;

	struct kmem_cache *cache;

	struct slab *slab;

	const void *addr;

	void *object;

	u8 tag;

	int i;



	tag = get_tag(info->access_addr);

	addr = kasan_reset_tag(info->access_addr);

	slab = kasan_addr_to_slab(addr);

	if (slab) {

		cache = slab->slab_cache;

		object = nearest_obj(cache, slab, (void *)addr);

		alloc_meta = kasan_get_alloc_meta(cache, object);



		if (alloc_meta) {

			for (i = 0; i < KASAN_NR_FREE_STACKS; i++) {

				if (alloc_meta->free_pointer_tag[i] == tag)

					return "use-after-free";

			}

		}

		return "out-of-bounds";

	}

#endif



	/*

	 * If access_size is a negative number, then it has reason to be

	 * defined as out-of-bounds bug type.

mm/kasan/tags.c

+2 −19
Original line number Diff line number Diff line
@@ -30,39 +30,22 @@ void kasan_save_free_info(struct kmem_cache *cache, 
				void *object, u8 tag)

{

	struct kasan_alloc_meta *alloc_meta;

	u8 idx = 0;



	alloc_meta = kasan_get_alloc_meta(cache, object);

	if (!alloc_meta)

		return;



#ifdef CONFIG_KASAN_TAGS_IDENTIFY

	idx = alloc_meta->free_track_idx;

	alloc_meta->free_pointer_tag[idx] = tag;

	alloc_meta->free_track_idx = (idx + 1) % KASAN_NR_FREE_STACKS;

#endif



	kasan_set_track(&alloc_meta->free_track[idx], GFP_NOWAIT);

	kasan_set_track(&alloc_meta->free_track, GFP_NOWAIT);

}



struct kasan_track *kasan_get_free_track(struct kmem_cache *cache,

				void *object, u8 tag)

{

	struct kasan_alloc_meta *alloc_meta;

	int i = 0;



	alloc_meta = kasan_get_alloc_meta(cache, object);

	if (!alloc_meta)

		return NULL;



#ifdef CONFIG_KASAN_TAGS_IDENTIFY

	for (i = 0; i < KASAN_NR_FREE_STACKS; i++) {

		if (alloc_meta->free_pointer_tag[i] == tag)

			break;

	}

	if (i == KASAN_NR_FREE_STACKS)

		i = alloc_meta->free_track_idx;

#endif



	return &alloc_meta->free_track[i];

	return &alloc_meta->free_track;

}