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a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=An8QbssU3Paiod4E1kUAdvkgOfXtx5Y6R0zbziTz4iI=; b=jZnQ/vSFclBkzn1FVPFWsznGHOc7V6E9lPgEfj/n2zZIJ0x6b/1KjDTU/xH8Zwq4xF kSVOhDs4ym2Nvh3H/w5GHySt24HX1oO82bQodVAcDOwQEk7Qlj4VLwUURYcyg4w6Idcb 8zlUXMF9hqcXWSml4SR6Ps7vcTgLKoRPD5D1JYF4Ndl1ZKLIW9uYgVh6dJ4lsdKsAx9G 95b+WNQSVw/ABQ1149YCeiq/gr/aOGGFdER7ZvY3scQX/NW/cAyoq+NeLwfi2AX+xMhp 52wFmNlOhK7NJ8NFEe1qWLqsNo9+8N4lytHutPMSi1slPrw8wiSfbWE4mQBTuufVG4H3 Sqsg== X-Gm-Message-State: AOAM530hKWGdtgCZs1lTNn/Ey/49Uf+hgICCWP7xZGsSl+fart9GoSV4 1U+3gIC6n0gMVN6iYCDsHiZTTQrJr2LQELrk X-Google-Smtp-Source: ABdhPJyHKp/wtdv/7GBZwhEP0RQ9LzEgR2YxKDNd406EN/bdf9yI/02kXsTGoRQ44kcYA/LIsLz2ttRK02+QMqPG X-Received: from andreyknvl3.muc.corp.google.com ([2a00:79e0:15:13:7220:84ff:fe09:7e9d]) (user=andreyknvl job=sendgmr) by 2002:a17:906:3949:: with SMTP id g9mr6032701eje.493.1610653006118; Thu, 14 Jan 2021 11:36:46 -0800 (PST) Date: Thu, 14 Jan 2021 20:36:21 +0100 In-Reply-To: Message-Id: <5153dafd6498a9183cfedaf267a2953defb6578e.1610652890.git.andreyknvl@google.com> Mime-Version: 1.0 References: X-Mailer: git-send-email 2.30.0.284.gd98b1dd5eaa7-goog Subject: [PATCH v3 05/15] kasan: add match-all tag tests From: Andrey Konovalov To: Andrew Morton , Catalin Marinas , Vincenzo Frascino , Dmitry Vyukov , Alexander Potapenko , Marco Elver X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210114_143649_808641_5D6C662B X-CRM114-Status: GOOD ( 18.84 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Branislav Rankov , Andrey Konovalov , Kevin Brodsky , Will Deacon , linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, Andrey Ryabinin , Peter Collingbourne , Evgenii Stepanov Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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. Link: https://linux-review.googlesource.com/id/I78f1375efafa162b37f3abcb2c5bc2f3955dfd8e Reviewed-by: Marco Elver Signed-off-by: Andrey Konovalov Reviewed-by: Alexander Potapenko --- lib/test_kasan.c | 92 ++++++++++++++++++++++++++++++++++++++++++++++++ mm/kasan/kasan.h | 6 ++++ 2 files changed, 98 insertions(+) diff --git a/lib/test_kasan.c b/lib/test_kasan.c index 714ea27fcc3e..c344fe506ffc 100644 --- a/lib/test_kasan.c +++ b/lib/test_kasan.c @@ -13,6 +13,7 @@ #include #include #include +#include #include #include #include @@ -754,6 +755,94 @@ static void vmalloc_oob(struct kunit *test) vfree(area); } +/* + * Check that the assigned pointer tag falls within the [KASAN_TAG_MIN, + * KASAN_TAG_KERNEL) range (note: excluding the match-all tag) for tag-based + * modes. + */ +static void match_all_not_assigned(struct kunit *test) +{ + char *ptr; + struct page *pages; + int i, size, order; + + KASAN_TEST_NEEDS_CONFIG_OFF(test, CONFIG_KASAN_GENERIC); + + for (i = 0; i < 256; i++) { + size = (get_random_int() % 1024) + 1; + ptr = kmalloc(size, GFP_KERNEL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); + KUNIT_EXPECT_GE(test, (u8)get_tag(ptr), (u8)KASAN_TAG_MIN); + KUNIT_EXPECT_LT(test, (u8)get_tag(ptr), (u8)KASAN_TAG_KERNEL); + kfree(ptr); + } + + for (i = 0; i < 256; i++) { + order = (get_random_int() % 4) + 1; + pages = alloc_pages(GFP_KERNEL, order); + ptr = page_address(pages); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); + KUNIT_EXPECT_GE(test, (u8)get_tag(ptr), (u8)KASAN_TAG_MIN); + KUNIT_EXPECT_LT(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; + + KASAN_TEST_NEEDS_CONFIG_OFF(test, CONFIG_KASAN_GENERIC); + + 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; + + KASAN_TEST_NEEDS_CONFIG_OFF(test, CONFIG_KASAN_GENERIC); + + 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), @@ -793,6 +882,9 @@ 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 */