Commit a0503b8a authored by Kuan-Ying Lee's avatar Kuan-Ying Lee Committed by Linus Torvalds
Browse files

kasan: integrate the common part of two KASAN tag-based modes 

1. Move kasan_get_free_track() and kasan_set_free_info() into tags.c
   and combine these two functions for SW_TAGS and HW_TAGS kasan mode.

2. Move kasan_get_bug_type() to report_tags.c and make this function
   compatible for SW_TAGS and HW_TAGS kasan mode.

Link: https://lkml.kernel.org/r/20210626100931.22794-3-Kuan-Ying.Lee@mediatek.com


Signed-off-by: default avatarKuan-Ying Lee <Kuan-Ying.Lee@mediatek.com>
Suggested-by: default avatarMarco Elver <elver@google.com>
Suggested-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: default avatarAndrey Konovalov <andreyknvl@gmail.com>
Reviewed-by: default avatarMarco Elver <elver@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Chinwen Chang <chinwen.chang@mediatek.com>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Cc: Nicholas Tang <nicholas.tang@mediatek.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent f06f78ab

mm/kasan/Makefile

+2 −2
Original line number Diff line number Diff line
@@ -37,5 +37,5 @@ CFLAGS_sw_tags.o := $(CC_FLAGS_KASAN_RUNTIME) 


obj-$(CONFIG_KASAN) := common.o report.o

obj-$(CONFIG_KASAN_GENERIC) += init.o generic.o report_generic.o shadow.o quarantine.o

obj-$(CONFIG_KASAN_HW_TAGS) += hw_tags.o report_hw_tags.o

obj-$(CONFIG_KASAN_SW_TAGS) += init.o report_sw_tags.o shadow.o sw_tags.o
 
obj-$(CONFIG_KASAN_HW_TAGS) += hw_tags.o report_hw_tags.o tags.o report_tags.o

obj-$(CONFIG_KASAN_SW_TAGS) += init.o report_sw_tags.o shadow.o sw_tags.o tags.o report_tags.o

mm/kasan/hw_tags.c

+0 −22
Original line number Diff line number Diff line
@@ -216,28 +216,6 @@ void __init kasan_init_hw_tags(void) 
	pr_info("KernelAddressSanitizer initialized\n");

}



void kasan_set_free_info(struct kmem_cache *cache,

				void *object, u8 tag)

{

	struct kasan_alloc_meta *alloc_meta;



	alloc_meta = kasan_get_alloc_meta(cache, object);

	if (alloc_meta)

		kasan_set_track(&alloc_meta->free_track[0], GFP_NOWAIT);

}



struct kasan_track *kasan_get_free_track(struct kmem_cache *cache,

				void *object, u8 tag)

{

	struct kasan_alloc_meta *alloc_meta;



	alloc_meta = kasan_get_alloc_meta(cache, object);

	if (!alloc_meta)

		return NULL;



	return &alloc_meta->free_track[0];

}



#if IS_ENABLED(CONFIG_KASAN_KUNIT_TEST)



void kasan_set_tagging_report_once(bool state)

mm/kasan/report_hw_tags.c

+0 −5
Original line number Diff line number Diff line
@@ -15,11 +15,6 @@ 


#include "kasan.h"



const char *kasan_get_bug_type(struct kasan_access_info *info)

{

	return "invalid-access";

}



void *kasan_find_first_bad_addr(void *addr, size_t size)

{

	return kasan_reset_tag(addr);

mm/kasan/report_sw_tags.c

+0 −43
Original line number Diff line number Diff line
@@ -29,49 +29,6 @@ 
#include "kasan.h"

#include "../slab.h"



const char *kasan_get_bug_type(struct kasan_access_info *info)

{

#ifdef CONFIG_KASAN_TAGS_IDENTIFY

	struct kasan_alloc_meta *alloc_meta;

	struct kmem_cache *cache;

	struct page *page;

	const void *addr;

	void *object;

	u8 tag;

	int i;



	tag = get_tag(info->access_addr);

	addr = kasan_reset_tag(info->access_addr);

	page = kasan_addr_to_page(addr);

	if (page && PageSlab(page)) {

		cache = page->slab_cache;

		object = nearest_obj(cache, page, (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.

	 *

	 * Casting negative numbers to size_t would indeed turn up as

	 * a large size_t and its value will be larger than ULONG_MAX/2,

	 * so that this can qualify as out-of-bounds.

	 */

	if (info->access_addr + info->access_size < info->access_addr)

		return "out-of-bounds";



	return "invalid-access";

}



void *kasan_find_first_bad_addr(void *addr, size_t size)

{

	u8 tag = get_tag(addr);

mm/kasan/report_tags.c

0 → 100644
+51 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

/*

 * Copyright (c) 2014 Samsung Electronics Co., Ltd.

 * Copyright (c) 2020 Google, Inc.

 */



#include "kasan.h"

#include "../slab.h"



const char *kasan_get_bug_type(struct kasan_access_info *info)

{

#ifdef CONFIG_KASAN_TAGS_IDENTIFY

	struct kasan_alloc_meta *alloc_meta;

	struct kmem_cache *cache;

	struct page *page;

	const void *addr;

	void *object;

	u8 tag;

	int i;



	tag = get_tag(info->access_addr);

	addr = kasan_reset_tag(info->access_addr);

	page = kasan_addr_to_page(addr);

	if (page && PageSlab(page)) {

		cache = page->slab_cache;

		object = nearest_obj(cache, page, (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.

	 *

	 * Casting negative numbers to size_t would indeed turn up as

	 * a large size_t and its value will be larger than ULONG_MAX/2,

	 * so that this can qualify as out-of-bounds.

	 */

	if (info->access_addr + info->access_size < info->access_addr)

		return "out-of-bounds";



	return "invalid-access";

}