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=-9.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS 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 810E9C433DF for ; Mon, 17 Aug 2020 18:28:58 +0000 (UTC) Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.kernel.org (Postfix) with SMTP id B95732053B for ; Mon, 17 Aug 2020 18:28:57 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B95732053B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=xmission.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kernel-hardening-return-19647-kernel-hardening=archiver.kernel.org@lists.openwall.com Received: (qmail 13893 invoked by uid 550); 17 Aug 2020 18:28:43 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Received: (qmail 13821 invoked from network); 17 Aug 2020 18:28:42 -0000 From: ebiederm@xmission.com (Eric W. Biederman) To: Alexander Popov Cc: Kees Cook , Jann Horn , Will Deacon , Andrey Ryabinin , Alexander Potapenko , Dmitry Vyukov , Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Andrew Morton , Masahiro Yamada , Masami Hiramatsu , Steven Rostedt , Peter Zijlstra , Krzysztof Kozlowski , Patrick Bellasi , David Howells , Johannes Weiner , Laura Abbott , Arnd Bergmann , Greg Kroah-Hartman , kasan-dev@googlegroups.com, linux-mm@kvack.org, kernel-hardening@lists.openwall.com, linux-kernel@vger.kernel.org, notify@kernel.org, Kexec Mailing List References: <20200813151922.1093791-1-alex.popov@linux.com> <20200813151922.1093791-3-alex.popov@linux.com> Date: Mon, 17 Aug 2020 13:24:37 -0500 In-Reply-To: <20200813151922.1093791-3-alex.popov@linux.com> (Alexander Popov's message of "Thu, 13 Aug 2020 18:19:22 +0300") Message-ID: <87zh6t9llm.fsf@x220.int.ebiederm.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-XM-SPF: eid=1k7jrj-0003E9-5O;;;mid=<87zh6t9llm.fsf@x220.int.ebiederm.org>;;;hst=in02.mta.xmission.com;;;ip=68.227.160.95;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX1+IYzzebB5ZnTtqYaH62lkbTUMdTHJJuM0= X-SA-Exim-Connect-IP: 68.227.160.95 X-SA-Exim-Mail-From: ebiederm@xmission.com Subject: Re: [PATCH RFC 2/2] lkdtm: Add heap spraying test X-SA-Exim-Version: 4.2.1 (built Thu, 05 May 2016 13:38:54 -0600) X-SA-Exim-Scanned: Yes (on in02.mta.xmission.com) Alexander Popov writes: > Add a simple test for CONFIG_SLAB_QUARANTINE. > > It performs heap spraying that aims to reallocate the recently freed heap > object. This technique is used for exploiting use-after-free > vulnerabilities in the kernel code. > > This test shows that CONFIG_SLAB_QUARANTINE breaks heap spraying > exploitation technique. > > Signed-off-by: Alexander Popov Why put this test in the linux kernel dump test module? I have no problem with tests, and I may be wrong but this does not look like you are testing to see if heap corruption triggers a crash dump. Which is what the rest of the tests in lkdtm are about. Seeing if the test triggers successfully triggers a crash dump. Eric > --- > drivers/misc/lkdtm/core.c | 1 + > drivers/misc/lkdtm/heap.c | 40 ++++++++++++++++++++++++++++++++++++++ > drivers/misc/lkdtm/lkdtm.h | 1 + > 3 files changed, 42 insertions(+) > > diff --git a/drivers/misc/lkdtm/core.c b/drivers/misc/lkdtm/core.c > index a5e344df9166..78b7669c35eb 100644 > --- a/drivers/misc/lkdtm/core.c > +++ b/drivers/misc/lkdtm/core.c > @@ -126,6 +126,7 @@ static const struct crashtype crashtypes[] = { > CRASHTYPE(SLAB_FREE_DOUBLE), > CRASHTYPE(SLAB_FREE_CROSS), > CRASHTYPE(SLAB_FREE_PAGE), > + CRASHTYPE(HEAP_SPRAY), > CRASHTYPE(SOFTLOCKUP), > CRASHTYPE(HARDLOCKUP), > CRASHTYPE(SPINLOCKUP), > diff --git a/drivers/misc/lkdtm/heap.c b/drivers/misc/lkdtm/heap.c > index 1323bc16f113..a72a241e314a 100644 > --- a/drivers/misc/lkdtm/heap.c > +++ b/drivers/misc/lkdtm/heap.c > @@ -205,6 +205,46 @@ static void ctor_a(void *region) > static void ctor_b(void *region) > { } > > +#define HEAP_SPRAY_SIZE 128 > + > +void lkdtm_HEAP_SPRAY(void) > +{ > + int *addr; > + int *spray_addrs[HEAP_SPRAY_SIZE] = { 0 }; > + unsigned long i = 0; > + > + addr = kmem_cache_alloc(a_cache, GFP_KERNEL); > + if (!addr) { > + pr_info("Unable to allocate memory in lkdtm-heap-a cache\n"); > + return; > + } > + > + *addr = 0x31337; > + kmem_cache_free(a_cache, addr); > + > + pr_info("Performing heap spraying...\n"); > + for (i = 0; i < HEAP_SPRAY_SIZE; i++) { > + spray_addrs[i] = kmem_cache_alloc(a_cache, GFP_KERNEL); > + *spray_addrs[i] = 0x31337; > + pr_info("attempt %lu: spray alloc addr %p vs freed addr %p\n", > + i, spray_addrs[i], addr); > + if (spray_addrs[i] == addr) { > + pr_info("freed addr is reallocated!\n"); > + break; > + } > + } > + > + if (i < HEAP_SPRAY_SIZE) > + pr_info("FAIL! Heap spraying succeed :(\n"); > + else > + pr_info("OK! Heap spraying hasn't succeed :)\n"); > + > + for (i = 0; i < HEAP_SPRAY_SIZE; i++) { > + if (spray_addrs[i]) > + kmem_cache_free(a_cache, spray_addrs[i]); > + } > +} > + > void __init lkdtm_heap_init(void) > { > double_free_cache = kmem_cache_create("lkdtm-heap-double_free", > diff --git a/drivers/misc/lkdtm/lkdtm.h b/drivers/misc/lkdtm/lkdtm.h > index 8878538b2c13..dfafb4ae6f3a 100644 > --- a/drivers/misc/lkdtm/lkdtm.h > +++ b/drivers/misc/lkdtm/lkdtm.h > @@ -45,6 +45,7 @@ void lkdtm_READ_BUDDY_AFTER_FREE(void); > void lkdtm_SLAB_FREE_DOUBLE(void); > void lkdtm_SLAB_FREE_CROSS(void); > void lkdtm_SLAB_FREE_PAGE(void); > +void lkdtm_HEAP_SPRAY(void); > > /* lkdtm_perms.c */ > void __init lkdtm_perms_init(void);