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=ham 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 934D6C433DB for ; Wed, 13 Jan 2021 16:31:43 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 2BBBE2339D for ; Wed, 13 Jan 2021 16:31:43 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2BBBE2339D Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id A19EB6B0162; Wed, 13 Jan 2021 11:31:42 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 9C95B6B0164; Wed, 13 Jan 2021 11:31:42 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 8B98D6B0165; Wed, 13 Jan 2021 11:31:42 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0051.hostedemail.com [216.40.44.51]) by kanga.kvack.org (Postfix) with ESMTP id 722CC6B0162 for ; Wed, 13 Jan 2021 11:31:42 -0500 (EST) Received: from smtpin18.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 36B06180AD837 for ; Wed, 13 Jan 2021 16:31:42 +0000 (UTC) X-FDA: 77701292844.18.doll12_08122ae2751f Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin18.hostedemail.com (Postfix) with ESMTP id 94743100ED0E4 for ; Wed, 13 Jan 2021 16:31:35 +0000 (UTC) X-HE-Tag: doll12_08122ae2751f X-Filterd-Recvd-Size: 5153 Received: from mail-oo1-f50.google.com (mail-oo1-f50.google.com [209.85.161.50]) by imf46.hostedemail.com (Postfix) with ESMTP for ; Wed, 13 Jan 2021 16:31:34 +0000 (UTC) Received: by mail-oo1-f50.google.com with SMTP id s19so664767oos.2 for ; Wed, 13 Jan 2021 08:31:34 -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=5O0XZaro4xKRzF3tZMIIKYZ6A4RiPSbA4A/IZtlADzQ=; b=lzTuCstBMF+4HZDKsJ2s+dATMMBlbJN4oiCZrltzT7iPCeTLlE7+oAba5DNQXeTy0H qnKfdwCvwwJcYXRKpllziNLCQtKD41I5lhVoPGowMm/CG46eJ+BwQOB6Yo6sHWaXoL64 Zttlt6SxFpqtcQTZ2Wlt8mDNiTU8bVQfvuTim1f6Yd6x+ZYZLOgkUfwCxdhCuQaqqiHe zqQU4ViWaQkwZtWNZxM7l4jNac4w4bHWKcQ3M4w7CXgj860cWMXp7y3S8E7/Tv2ElzbY bj5MG0hUvolK/49TUScOj0jqyd2RQAeMaGPKv1Pah9wue2u7bYsy8mIGs02PPCQKFlyd uAog== 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=5O0XZaro4xKRzF3tZMIIKYZ6A4RiPSbA4A/IZtlADzQ=; b=uJ+dH8zlI98OIbPmmtw3hnTAHOnRct2Y4zoLdZQD+YgW4Q6PtEJ0tLYI+5NvvtJkEQ xn6EdCE8TfYNjd3egSWPPeZUzzdDJ/gI2Uj4NkCXZ/pQCyLUOeCxCECASDjo499m71j5 T+ObR5BehAuiXlJ/PaYdbnAyIgfkZ/C3N+FsKKQiICpDLrRk6jOzFF6Ty2eRUq9N6DqF F7yLvwcQ2SbPaSabUpMigMHe/aVNm+Ajr5hMdf1KGCIg/4u9vnt51d3LwDWK+RtnGRKF woDIgRaUBYUwxusnPN+1xtkeIR35sjX/OVmQccqzI3nREUXn0UrvqPnCNCwVpXzEFsF0 8dzA== X-Gm-Message-State: AOAM5326vWXrzqcmKnzdAYDMCxaiQwJEQak2po41JiX3tuqXGFjaV7fx oOe7j8+lzmtq+uf6mOwOpr7xbjfbTfjF4QFgHhPmCA== X-Google-Smtp-Source: ABdhPJxMHdtWXMdBmVhNTyaR2Hfpgf6YY2QydFrNCbzcFdY/EBICBgCHdnSsfezkhLCPbsegKv261UfVBkRIZ4EGaIs= X-Received: by 2002:a4a:a11a:: with SMTP id i26mr1812321ool.54.1610555494097; Wed, 13 Jan 2021 08:31:34 -0800 (PST) MIME-Version: 1.0 References: <1b884616c85091d6d173f7c1a8647d25424f1e7e.1610554432.git.andreyknvl@google.com> In-Reply-To: <1b884616c85091d6d173f7c1a8647d25424f1e7e.1610554432.git.andreyknvl@google.com> From: Marco Elver Date: Wed, 13 Jan 2021 17:31:22 +0100 Message-ID: Subject: Re: [PATCH v2 09/14] kasan: adapt kmalloc_uaf2 test to HW_TAGS mode 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" X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, 13 Jan 2021 at 17:22, Andrey Konovalov wrote: > > In the kmalloc_uaf2() test, the pointers to the two allocated memory > blocks might happen to be the same, and the test will fail. With the > software tag-based mode, the probability of the that is 1/254, so it's > hard to observe the failure. For the hardware tag-based mode though, > the probablity is 1/14, which is quite noticable. > > Allow up to 16 attempts at generating different tags for the tag-based > modes. > > Link: https://linux-review.googlesource.com/id/Ibfa458ef2804ff465d8eb07434a300bf36388d55 > Signed-off-by: Andrey Konovalov Reviewed-by: Marco Elver > --- > lib/test_kasan.c | 11 +++++++++++ > 1 file changed, 11 insertions(+) > > diff --git a/lib/test_kasan.c b/lib/test_kasan.c > index 283feda9882a..a1a35d75ee1e 100644 > --- a/lib/test_kasan.c > +++ b/lib/test_kasan.c > @@ -382,7 +382,9 @@ static void kmalloc_uaf2(struct kunit *test) > { > char *ptr1, *ptr2; > size_t size = 43; > + int counter = 0; > > +again: > ptr1 = kmalloc(size, GFP_KERNEL); > KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr1); > > @@ -391,6 +393,15 @@ static void kmalloc_uaf2(struct kunit *test) > ptr2 = kmalloc(size, GFP_KERNEL); > KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr2); > > + /* > + * For tag-based KASAN ptr1 and ptr2 tags might happen to be the same. > + * Allow up to 16 attempts at generating different tags. > + */ > + if (!IS_ENABLED(CONFIG_KASAN_GENERIC) && ptr1 == ptr2 && counter++ < 16) { > + kfree(ptr2); > + goto again; > + } > + > KUNIT_EXPECT_KASAN_FAIL(test, ptr1[40] = 'x'); > KUNIT_EXPECT_PTR_NE(test, ptr1, ptr2); > > -- > 2.30.0.284.gd98b1dd5eaa7-goog >