Re: [PATCH v6 3/4] kasan: add tests for call_rcu stack recording

[Dmitry Vyukov]

On Fri, May 22, 2020 at 4:02 AM Walter Wu <walter-zh.wu@xxxxxxxxxxxx> wrote:
>
> Test call_rcu() call stack recording and verify whether it correctly
> is printed in KASAN report.

Reviewed-and-tested-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx>

> Signed-off-by: Walter Wu <walter-zh.wu@xxxxxxxxxxxx>
> Cc: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
> Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
> Cc: Alexander Potapenko <glider@xxxxxxxxxx>
> Cc: Matthias Brugger <matthias.bgg@xxxxxxxxx>
> ---
>  lib/test_kasan.c | 30 ++++++++++++++++++++++++++++++
>  1 file changed, 30 insertions(+)
>
> diff --git a/lib/test_kasan.c b/lib/test_kasan.c
> index e3087d90e00d..6e5fb05d42d8 100644
> --- a/lib/test_kasan.c
> +++ b/lib/test_kasan.c
> @@ -792,6 +792,35 @@ static noinline void __init vmalloc_oob(void)
>  static void __init vmalloc_oob(void) {}
>  #endif
>
> +static struct kasan_rcu_info {
> +       int i;
> +       struct rcu_head rcu;
> +} *global_ptr;
> +
> +static noinline void __init kasan_rcu_reclaim(struct rcu_head *rp)
> +{
> +       struct kasan_rcu_info *fp = container_of(rp,
> +                                               struct kasan_rcu_info, rcu);
> +
> +       kfree(fp);
> +       fp->i = 1;
> +}
> +
> +static noinline void __init kasan_rcu_uaf(void)
> +{
> +       struct kasan_rcu_info *ptr;
> +
> +       pr_info("use-after-free in kasan_rcu_reclaim\n");
> +       ptr = kmalloc(sizeof(struct kasan_rcu_info), GFP_KERNEL);
> +       if (!ptr) {
> +               pr_err("Allocation failed\n");
> +               return;
> +       }
> +
> +       global_ptr = rcu_dereference_protected(ptr, NULL);
> +       call_rcu(&global_ptr->rcu, kasan_rcu_reclaim);
> +}
> +
>  static int __init kmalloc_tests_init(void)
>  {
>         /*
> @@ -839,6 +868,7 @@ static int __init kmalloc_tests_init(void)
>         kasan_bitops();
>         kmalloc_double_kzfree();
>         vmalloc_oob();
> +       kasan_rcu_uaf();
>
>         kasan_restore_multi_shot(multishot);
>
> --
> 2.18.0
>
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