From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-23.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_IN_DEF_DKIM_WL autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 94F5DC433DB for ; Wed, 13 Jan 2021 16:28:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 499B523370 for ; Wed, 13 Jan 2021 16:28:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727395AbhAMQ1v (ORCPT ); Wed, 13 Jan 2021 11:27:51 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34762 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727272AbhAMQ1v (ORCPT ); Wed, 13 Jan 2021 11:27:51 -0500 Received: from mail-ot1-x329.google.com (mail-ot1-x329.google.com [IPv6:2607:f8b0:4864:20::329]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E4F71C061575 for ; Wed, 13 Jan 2021 08:27:10 -0800 (PST) Received: by mail-ot1-x329.google.com with SMTP id d8so2431871otq.6 for ; Wed, 13 Jan 2021 08:27:10 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=ToZseukMUfS4/Mno4fjs/e3BlupSLArbp20G4eoQPpc=; b=k902rbsbnxoc+Bj5N0U5Acwa809QXnhgEHkNURHH3wpV0km+RTurtwNORXWGgNzMhD oODhyAMjS70nopnlr2Uxp6jRWJaFmu2fj84kolLW2SFhwDlCMky3rqIht5Ea7DBHL2Z0 oVhG7ZDhy+W6GcQujNmDd9BbTbBiKcQurznSA636KA+VdMGOjbTnY0aQAEqYX1AaCgUG sCFy3z6u7aWY09M8BcMvMHovX59JbFjCUCP+sqOQirQCBX1qTJlnJ1Z4xTb4czvxMoE2 R8loMXO6IAkNWPyWwNYdifcUIO//KEIlNpUXHlkvXpozxPoozPLzRZI+fiPClmWYT/Xm ihGg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=ToZseukMUfS4/Mno4fjs/e3BlupSLArbp20G4eoQPpc=; b=Vf4kWff/dt60llyk14u12+5cSAuCg8WR7FWEjfbcyrTGmrvoPUXFoEO1LTyiw5MbGl dejikjK2ycxSNmHe2+EdKAn/StiVko9uWmBrM8fbEjhQAAOKeCKM6Vzkv4nu2uV1MeSx oniSQNhiQhaOQzqyKUGUq5V+mA3M8z9smCgoMz8Q8SDRzBXaYxtbW0jOVjCFtv/xs6VX vYKL6V/OSsRscdJO3b4sLfwVr9wZPMn3b3zOdzaHgJrC/VgF2QPs7MzJX51Ov0WL/JtJ 3EMUmgIQdf86aLoylFPWo6Dk/9GCUC1Jc8/4YMBrmyfONZoqRhc9Zt/8javSwxZCV3kP 9/bg== X-Gm-Message-State: AOAM53157erm5u/QnI9+lZFy2efzTXe0Om1QFhL7/1EfPnjVH4yRBQqo Ah5hVx8XdgceIieAbAls1lHMcO7Y4VSL1dkQ+Jzg2Q== X-Google-Smtp-Source: ABdhPJw0Qd7K/zT8zJ06tvDTzutjwuFCqmusr6CvuuRdVbsyHJZR2KOJ/cChg024Rs9ADuW9aH8veLV6EytfRwXLSao= X-Received: by 2002:a05:6830:2413:: with SMTP id j19mr1826937ots.251.1610555230134; Wed, 13 Jan 2021 08:27:10 -0800 (PST) MIME-Version: 1.0 References: <351f554b6e4c4c0581d15d7b70cbbacf238c887f.1610554432.git.andreyknvl@google.com> In-Reply-To: <351f554b6e4c4c0581d15d7b70cbbacf238c887f.1610554432.git.andreyknvl@google.com> From: Marco Elver Date: Wed, 13 Jan 2021 17:26:58 +0100 Message-ID: Subject: Re: [PATCH v2 05/14] kasan: add match-all tag tests To: Andrey Konovalov Cc: Catalin Marinas , Vincenzo Frascino , Dmitry Vyukov , Alexander Potapenko , Andrew Morton , Will Deacon , Andrey Ryabinin , Peter Collingbourne , Evgenii Stepanov , Branislav Rankov , Kevin Brodsky , kasan-dev , Linux ARM , Linux Memory Management List , LKML Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 13 Jan 2021 at 17:21, 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. > > Link: https://linux-review.googlesource.com/id/I78f1375efafa162b37f3abcb2c5bc2f3955dfd8e > Signed-off-by: Andrey Konovalov Reviewed-by: Marco Elver > --- > 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..f5470bed50b6 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; > + 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; > + 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 */ > -- > 2.30.0.284.gd98b1dd5eaa7-goog >