lkml.org 
[lkml]   [2022]   [Sep]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH mm v3 05/34] kasan: drop CONFIG_KASAN_TAGS_IDENTIFY
    Date
    From: Andrey Konovalov <andreyknvl@google.com>

    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.

    Reviewed-by: Marco Elver <elver@google.com>
    Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
    ---
    lib/Kconfig.kasan | 8 --------
    mm/kasan/kasan.h | 12 +-----------
    mm/kasan/report_tags.c | 28 ----------------------------
    mm/kasan/tags.c | 21 ++-------------------
    4 files changed, 3 insertions(+), 66 deletions(-)

    diff --git a/lib/Kconfig.kasan b/lib/Kconfig.kasan
    index f0973da583e0..ca09b1cf8ee9 100644
    --- a/lib/Kconfig.kasan
    +++ b/lib/Kconfig.kasan
    @@ -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
    diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
    index d401fb770f67..15c718782c1f 100644
    --- a/mm/kasan/kasan.h
    +++ b/mm/kasan/kasan.h
    @@ -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
    };

    diff --git a/mm/kasan/report_tags.c b/mm/kasan/report_tags.c
    index e25d2166e813..35cf3cae4aa4 100644
    --- a/mm/kasan/report_tags.c
    +++ b/mm/kasan/report_tags.c
    @@ -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.
    diff --git a/mm/kasan/tags.c b/mm/kasan/tags.c
    index 1ba3c8399f72..e0e5de8ce834 100644
    --- a/mm/kasan/tags.c
    +++ b/mm/kasan/tags.c
    @@ -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;
    }
    --
    2.25.1
    \
     
     \ /
      Last update: 2022-09-05 23:07    [W:4.911 / U:0.004 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site