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kasan: drop CONFIG_KASAN_TAGS_IDENTIFY

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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: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Marco 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: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Andrey Konovalov 2022-09-05 23:05:20 +02:00 committed by Andrew Morton
parent ccf643e6da
commit 687c85afa6
4 changed files with 3 additions and 66 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
lib/Kconfig.kasan
View File

@ -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

12
mm/kasan/kasan.h
View File

@ -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
};

28
mm/kasan/report_tags.c
View File

@ -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.

21
mm/kasan/tags.c
View File

@ -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;
}