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 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 64719C32771 for ; Sat, 24 Sep 2022 08:15:39 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 8E18110E518; Sat, 24 Sep 2022 08:15:35 +0000 (UTC) Received: from mail-lj1-x22e.google.com (mail-lj1-x22e.google.com [IPv6:2a00:1450:4864:20::22e]) by gabe.freedesktop.org (Postfix) with ESMTPS id 7092010E518 for ; Sat, 24 Sep 2022 08:15:31 +0000 (UTC) Received: by mail-lj1-x22e.google.com with SMTP id b24so2322535ljk.6 for ; Sat, 24 Sep 2022 01:15:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date; bh=nQomz4ut+7sjfQrrU1jIFAnyWatFfjECi53D3yczEIE=; b=KI9bvqb1+pvOBd4LUHBVRiy4ZY0slRCTRZZlpbG/wkf5BfzAwgC4tzlqpiFF6oyV8H D7v79qgnbhBTO6d2uDyYHRhhdOOhBfa6EEXzsR1OAGK0jLsPlfD7cA9BCk+dEYTkPA3D wWtwWaAoPO0/uTRDdef7+H6/fPQ584Q/+VF22lUeYetTvqY4NLRzWkfcrMuUKAwvI8Ur HORX0nTGI2VWAa2VLCpjSTjWJtDJGVfm/4NoDwUwRQY3sCzLDgDtibX9udsLmyhZz/Ab UsteBe0vnTvVHno/YLL9xbDupvnLo0yMlhWvaVPU8HJaxwp4Vvg2Oz/Cql9apCVP7xpg yn0g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date; bh=nQomz4ut+7sjfQrrU1jIFAnyWatFfjECi53D3yczEIE=; b=2iXHbmHq5XUgCzNCWxlTZv1RYhvZnwK0WzJWzNfpekZnYMkM6S3bJuRy0B1CxHYPCW y9fmiXRFiG+3sLqG8MJvWOb5oNqCcb1KzWBbPTR5pRF9a8hXcIGRXRuoy+j5sdh/ujXA +07rZhSLKkx21uG7lbmNWSUuzeq9cMQStVVgQlGfxLjlSzVA8LiFRdTeAoPFNrHQTHPT vLZPw1nVPZKlyzhmUhD56U9soVKeShgwFCuog/47YXSliPPmAc/dMpJC6zTX2S9jL6J9 eSST+W1Udas7pKcAvEn+BP8a1KQWgz/zxv528YrnRBaenkUuy7pDIr8NY+H4uQBla0r8 Tv+w== X-Gm-Message-State: ACrzQf2lXI1ezU+RmeuQI7SnkP3bjac3+NSx2EDm0rlKZyp4EG4MKjfv lbz+pE0aD59uRxQHVUSDelikd4HHmtVrvSuDpLArzah/BwRIvQ== X-Google-Smtp-Source: AMsMyM51jSACu0ueivCRHFSALnMRIGDYekDLNBr6hGK18mYNepOD+DBZDwtrPTKiiVk4AIl/66dQQBc8ZJ/gjsu15yk= X-Received: by 2002:a2e:be8d:0:b0:26c:f4b:47a0 with SMTP id a13-20020a2ebe8d000000b0026c0f4b47a0mr4030821ljr.92.1664007329396; Sat, 24 Sep 2022 01:15:29 -0700 (PDT) MIME-Version: 1.0 References: <20220923202822.2667581-1-keescook@chromium.org> <20220923202822.2667581-15-keescook@chromium.org> In-Reply-To: <20220923202822.2667581-15-keescook@chromium.org> From: Dmitry Vyukov Date: Sat, 24 Sep 2022 10:15:18 +0200 Message-ID: Subject: Re: [PATCH v2 14/16] kasan: Remove ksize()-related tests To: Kees Cook Content-Type: text/plain; charset="UTF-8" X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: llvm@lists.linux.dev, dri-devel@lists.freedesktop.org, "Ruhl, Michael J" , Eric Dumazet , Andrey Ryabinin , Alexander Potapenko , linux-hardening@vger.kernel.org, Hyeonggon Yoo <42.hyeyoo@gmail.com>, Christoph Lameter , Vincenzo Frascino , Sumit Semwal , dev@openvswitch.org, x86@kernel.org, Jesse Brandeburg , kasan-dev@googlegroups.com, intel-wired-lan@lists.osuosl.org, David Rientjes , Miguel Ojeda , Jakub Kicinski , Paolo Abeni , linux-media@vger.kernel.org, Marco Elver , Josef Bacik , linaro-mm-sig@lists.linaro.org, Yonghong Song , David Sterba , Andrew Morton , Vlastimil Babka , Andrey Konovalov , Alex Elder , linux-mm@kvack.org, Greg Kroah-Hartman , Nick Desaulniers , linux-kernel@vger.kernel.org, =?UTF-8?Q?Christian_K=C3=B6nig?= , Pekka Enberg , Daniel Micay , netdev@vger.kernel.org, linux-fsdevel@vger.kernel.org, Joonsoo Kim , "David S. Miller" , linux-btrfs@vger.kernel.org Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Fri, 23 Sept 2022 at 22:28, Kees Cook wrote: > > In preparation for no longer unpoisoning in ksize(), remove the behavioral > self-tests for ksize(). > > Cc: Andrey Ryabinin > Cc: Alexander Potapenko > Cc: Andrey Konovalov > Cc: Dmitry Vyukov > Cc: Vincenzo Frascino > Cc: Andrew Morton > Cc: kasan-dev@googlegroups.com > Cc: linux-mm@kvack.org > Signed-off-by: Kees Cook > --- > lib/test_kasan.c | 42 ------------------------------------------ > mm/kasan/shadow.c | 4 +--- > 2 files changed, 1 insertion(+), 45 deletions(-) > > diff --git a/lib/test_kasan.c b/lib/test_kasan.c > index 58c1b01ccfe2..bdd0ced8f8d7 100644 > --- a/lib/test_kasan.c > +++ b/lib/test_kasan.c > @@ -753,46 +753,6 @@ static void kasan_global_oob_left(struct kunit *test) > KUNIT_EXPECT_KASAN_FAIL(test, *(volatile char *)p); > } > > -/* Check that ksize() makes the whole object accessible. */ > -static void ksize_unpoisons_memory(struct kunit *test) > -{ > - char *ptr; > - size_t size = 123, real_size; > - > - ptr = kmalloc(size, GFP_KERNEL); > - KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); > - real_size = ksize(ptr); > - > - OPTIMIZER_HIDE_VAR(ptr); > - > - /* This access shouldn't trigger a KASAN report. */ > - ptr[size] = 'x'; I would rather keep the tests and update to the new behavior. We had bugs in ksize, we need test coverage. I assume ptr[size] access must now produce an error even after ksize. > - /* This one must. */ > - KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)ptr)[real_size]); > - > - kfree(ptr); > -} > - > -/* > - * Check that a use-after-free is detected by ksize() and via normal accesses > - * after it. > - */ > -static void ksize_uaf(struct kunit *test) > -{ > - char *ptr; > - int size = 128 - KASAN_GRANULE_SIZE; > - > - ptr = kmalloc(size, GFP_KERNEL); > - KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); > - kfree(ptr); > - > - OPTIMIZER_HIDE_VAR(ptr); > - KUNIT_EXPECT_KASAN_FAIL(test, ksize(ptr)); This is still a bug that should be detected, right? Calling ksize on a freed pointer is a bug. > - KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)ptr)[0]); > - KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)ptr)[size]); > -} > - > static void kasan_stack_oob(struct kunit *test) > { > char stack_array[10]; > @@ -1392,8 +1352,6 @@ static struct kunit_case kasan_kunit_test_cases[] = { > KUNIT_CASE(kasan_stack_oob), > KUNIT_CASE(kasan_alloca_oob_left), > KUNIT_CASE(kasan_alloca_oob_right), > - KUNIT_CASE(ksize_unpoisons_memory), > - KUNIT_CASE(ksize_uaf), > KUNIT_CASE(kmem_cache_double_free), > KUNIT_CASE(kmem_cache_invalid_free), > KUNIT_CASE(kmem_cache_double_destroy), > diff --git a/mm/kasan/shadow.c b/mm/kasan/shadow.c > index 0e3648b603a6..0895c73e9b69 100644 > --- a/mm/kasan/shadow.c > +++ b/mm/kasan/shadow.c > @@ -124,9 +124,7 @@ void kasan_unpoison(const void *addr, size_t size, bool init) > addr = kasan_reset_tag(addr); > > /* > - * Skip KFENCE memory if called explicitly outside of sl*b. Also note > - * that calls to ksize(), where size is not a multiple of machine-word > - * size, would otherwise poison the invalid portion of the word. > + * Skip KFENCE memory if called explicitly outside of sl*b. > */ > if (is_kfence_address(addr)) > return; > -- > 2.34.1