From: Marco Elver <elver@google.com>
To: Andrey Konovalov <andreyknvl@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
Vincenzo Frascino <vincenzo.frascino@arm.com>,
Dmitry Vyukov <dvyukov@google.com>,
Alexander Potapenko <glider@google.com>,
Andrew Morton <akpm@linux-foundation.org>,
Will Deacon <will.deacon@arm.com>,
Andrey Ryabinin <aryabinin@virtuozzo.com>,
Evgenii Stepanov <eugenis@google.com>,
Branislav Rankov <Branislav.Rankov@arm.com>,
Kevin Brodsky <kevin.brodsky@arm.com>,
kasan-dev@googlegroups.com, linux-arm-kernel@lists.infradead.org,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 04/11] kasan: add match-all tag tests
Date: Tue, 12 Jan 2021 14:17:34 +0100 [thread overview]
Message-ID: <X/2hboi2Tp87UZFZ@elver.google.com> (raw)
In-Reply-To: <0f20f867d747b678604a68173a5f20fb8df9b756.1609871239.git.andreyknvl@google.com>
On Tue, Jan 05, 2021 at 07:27PM +0100, Andrey Konovalov wrote:
> Add 3 new tests for tag-based KASAN modes:
>
> 1. Check that match-all pointer tag is not assigned randomly.
> 2. Check that 0xff works as a match-all pointer tag.
> 3. Check that there are no match-all memory tags.
>
> Note, that test #3 causes a significant number (255) of KASAN reports
> to be printed during execution for the SW_TAGS mode.
>
> Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
> Link: https://linux-review.googlesource.com/id/I78f1375efafa162b37f3abcb2c5bc2f3955dfd8e
> ---
> lib/test_kasan.c | 93 ++++++++++++++++++++++++++++++++++++++++++++++++
> mm/kasan/kasan.h | 6 ++++
> 2 files changed, 99 insertions(+)
>
> diff --git a/lib/test_kasan.c b/lib/test_kasan.c
> index 46e578c8e842..f1eda0bcc780 100644
> --- a/lib/test_kasan.c
> +++ b/lib/test_kasan.c
> @@ -13,6 +13,7 @@
> #include <linux/mman.h>
> #include <linux/module.h>
> #include <linux/printk.h>
> +#include <linux/random.h>
> #include <linux/slab.h>
> #include <linux/string.h>
> #include <linux/uaccess.h>
> @@ -790,6 +791,95 @@ static void vmalloc_oob(struct kunit *test)
> vfree(area);
> }
>
> +/*
> + * Check that match-all pointer tag is not assigned randomly for
> + * tag-based modes.
> + */
> +static void match_all_not_assigned(struct kunit *test)
> +{
> + char *ptr;
> + struct page *pages;
> + int i, size, order;
> +
> + for (i = 0; i < 256; i++) {
> + size = get_random_int() % KMALLOC_MAX_SIZE;
size appears to be unused?
> + ptr = kmalloc(128, GFP_KERNEL);
> + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
> + KUNIT_EXPECT_NE(test, (u8)get_tag(ptr), (u8)KASAN_TAG_KERNEL);
> + kfree(ptr);
> + }
> +
> + for (i = 0; i < 256; i++) {
> + order = get_random_int() % 4;
> + pages = alloc_pages(GFP_KERNEL, order);
> + ptr = page_address(pages);
> + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
> + KUNIT_EXPECT_NE(test, (u8)get_tag(ptr), (u8)KASAN_TAG_KERNEL);
> + free_pages((unsigned long)ptr, order);
> + }
> +}
> +
> +/* Check that 0xff works as a match-all pointer tag for tag-based modes. */
> +static void match_all_ptr_tag(struct kunit *test)
> +{
> + char *ptr;
> + u8 tag;
> +
> + if (IS_ENABLED(CONFIG_KASAN_GENERIC)) {
> + kunit_info(test, "skipping, CONFIG_KASAN_SW/HW_TAGS required");
> + return;
> + }
> +
> + ptr = kmalloc(128, GFP_KERNEL);
> + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
> +
> + /* Backup the assigned tag. */
> + tag = get_tag(ptr);
> + KUNIT_EXPECT_NE(test, tag, (u8)KASAN_TAG_KERNEL);
> +
> + /* Reset the tag to 0xff.*/
> + ptr = set_tag(ptr, KASAN_TAG_KERNEL);
> +
> + /* This access shouldn't trigger a KASAN report. */
> + *ptr = 0;
> +
> + /* Recover the pointer tag and free. */
> + ptr = set_tag(ptr, tag);
> + kfree(ptr);
> +}
> +
> +/* Check that there are no match-all memory tags for tag-based modes. */
> +static void match_all_mem_tag(struct kunit *test)
> +{
> + char *ptr;
> + int tag;
> +
> + if (IS_ENABLED(CONFIG_KASAN_GENERIC)) {
> + kunit_info(test, "skipping, CONFIG_KASAN_SW/HW_TAGS required");
> + return;
> + }
> +
> + ptr = kmalloc(128, GFP_KERNEL);
> + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
> + KUNIT_EXPECT_NE(test, (u8)get_tag(ptr), (u8)KASAN_TAG_KERNEL);
> +
> + /* For each possible tag value not matching the pointer tag. */
> + for (tag = KASAN_TAG_MIN; tag <= KASAN_TAG_KERNEL; tag++) {
> + if (tag == get_tag(ptr))
> + continue;
> +
> + /* Mark the first memory granule with the chosen memory tag. */
> + kasan_poison(ptr, KASAN_GRANULE_SIZE, (u8)tag);
> +
> + /* This access must cause a KASAN report. */
> + KUNIT_EXPECT_KASAN_FAIL(test, *ptr = 0);
> + }
> +
> + /* Recover the memory tag and free. */
> + kasan_poison(ptr, KASAN_GRANULE_SIZE, get_tag(ptr));
> + kfree(ptr);
> +}
> +
> static struct kunit_case kasan_kunit_test_cases[] = {
> KUNIT_CASE(kmalloc_oob_right),
> KUNIT_CASE(kmalloc_oob_left),
> @@ -829,6 +919,9 @@ static struct kunit_case kasan_kunit_test_cases[] = {
> KUNIT_CASE(kasan_bitops_tags),
> KUNIT_CASE(kmalloc_double_kzfree),
> KUNIT_CASE(vmalloc_oob),
> + KUNIT_CASE(match_all_not_assigned),
> + KUNIT_CASE(match_all_ptr_tag),
> + KUNIT_CASE(match_all_mem_tag),
> {}
> };
>
> diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
> index 3b38baddec47..c3fb9bf241d3 100644
> --- a/mm/kasan/kasan.h
> +++ b/mm/kasan/kasan.h
> @@ -36,6 +36,12 @@ extern bool kasan_flag_panic __ro_after_init;
> #define KASAN_TAG_INVALID 0xFE /* inaccessible memory tag */
> #define KASAN_TAG_MAX 0xFD /* maximum value for random tags */
>
> +#ifdef CONFIG_KASAN_HW_TAGS
> +#define KASAN_TAG_MIN 0xF0 /* mimimum value for random tags */
> +#else
> +#define KASAN_TAG_MIN 0x00 /* mimimum value for random tags */
> +#endif
> +
> #ifdef CONFIG_KASAN_GENERIC
> #define KASAN_FREE_PAGE 0xFF /* page was freed */
> #define KASAN_PAGE_REDZONE 0xFE /* redzone for kmalloc_large allocations */
> --
> 2.29.2.729.g45daf8777d-goog
>
next prev parent reply other threads:[~2021-01-12 13:17 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-05 18:27 [PATCH 00/11] kasan: HW_TAGS tests support and fixes Andrey Konovalov
2021-01-05 18:27 ` [PATCH 01/11] kasan: prefix exported functions with kasan_ Andrey Konovalov
2021-01-12 7:38 ` Alexander Potapenko
2021-01-12 11:19 ` Marco Elver
2021-01-05 18:27 ` [PATCH 02/11] kasan: clarify HW_TAGS impact on TBI Andrey Konovalov
2021-01-12 7:40 ` Alexander Potapenko
2021-01-12 11:38 ` Marco Elver
2021-01-05 18:27 ` [PATCH 03/11] kasan: clean up comments in tests Andrey Konovalov
2021-01-12 7:53 ` Alexander Potapenko
2021-01-12 17:55 ` Andrey Konovalov
2021-01-12 13:07 ` Marco Elver
2021-01-05 18:27 ` [PATCH 04/11] kasan: add match-all tag tests Andrey Konovalov
2021-01-12 8:04 ` Alexander Potapenko
2021-01-12 18:10 ` Andrey Konovalov
2021-01-12 13:17 ` Marco Elver [this message]
2021-01-12 18:11 ` Andrey Konovalov
2021-01-05 18:27 ` [PATCH 05/11] kasan, arm64: allow using KUnit tests with HW_TAGS mode Andrey Konovalov
2021-01-12 19:01 ` Catalin Marinas
2021-01-15 13:11 ` Andrey Konovalov
2021-01-15 15:04 ` Vincenzo Frascino
2021-01-05 18:27 ` [PATCH 06/11] kasan: rename CONFIG_TEST_KASAN_MODULE Andrey Konovalov
2021-01-12 8:09 ` Alexander Potapenko
2021-01-12 18:26 ` Andrey Konovalov
2021-01-12 13:33 ` Marco Elver
2021-01-12 18:28 ` Andrey Konovalov
2021-01-05 18:27 ` [PATCH 07/11] kasan: add compiler barriers to KUNIT_EXPECT_KASAN_FAIL Andrey Konovalov
2021-01-12 8:18 ` Alexander Potapenko
2021-01-12 19:50 ` Andrey Konovalov
2021-01-12 19:57 ` Andrey Konovalov
2021-01-12 13:34 ` Marco Elver
2021-01-05 18:27 ` [PATCH 08/11] kasan: adopt kmalloc_uaf2 test to HW_TAGS mode Andrey Konovalov
2021-01-12 8:25 ` Alexander Potapenko
2021-01-12 20:04 ` Andrey Konovalov
2021-01-12 13:39 ` Marco Elver
2021-01-12 20:05 ` Andrey Konovalov
2021-01-05 18:27 ` [PATCH 09/11] kasan: fix memory corruption in kasan_bitops_tags test Andrey Konovalov
2021-01-12 8:30 ` Alexander Potapenko
2021-01-12 20:06 ` Andrey Konovalov
2021-01-13 12:30 ` Alexander Potapenko
2021-01-12 13:55 ` Marco Elver
2021-01-05 18:27 ` [PATCH 10/11] kasan: fix bug detection via ksize for HW_TAGS mode Andrey Konovalov
2021-01-05 21:04 ` kernel test robot
2021-01-06 0:09 ` kernel test robot
2021-01-07 0:02 ` Andrew Morton
2021-01-07 1:59 ` Andrey Konovalov
2021-01-12 14:32 ` Marco Elver
2021-01-12 21:16 ` Andrey Konovalov
2021-01-12 22:54 ` Marco Elver
2021-01-05 18:27 ` [PATCH 11/11] kasan: add proper page allocator tests Andrey Konovalov
2021-01-12 8:57 ` Alexander Potapenko
2021-01-12 14:34 ` Marco Elver
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