2020-05-22 02:04:34

by Walter Wu

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

Test call_rcu() call stack recording and verify whether it correctly
is printed in KASAN report.

Signed-off-by: Walter Wu <[email protected]>
Cc: Andrey Ryabinin <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Cc: Alexander Potapenko <[email protected]>
Cc: Matthias Brugger <[email protected]>
---
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

2020-05-25 10:00:09

by Dmitry Vyukov

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

On Fri, May 22, 2020 at 4:02 AM Walter Wu <[email protected]> wrote:
>
> Test call_rcu() call stack recording and verify whether it correctly
> is printed in KASAN report.

Reviewed-and-tested-by: Dmitry Vyukov <[email protected]>

> Signed-off-by: Walter Wu <[email protected]>
> Cc: Andrey Ryabinin <[email protected]>
> Cc: Dmitry Vyukov <[email protected]>
> Cc: Alexander Potapenko <[email protected]>
> Cc: Matthias Brugger <[email protected]>
> ---
> 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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