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=-8.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 C36E2C3A59B for ; Fri, 30 Aug 2019 15:21:43 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 935A820659 for ; Fri, 30 Aug 2019 15:21:43 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="gqOQVpub" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 935A820659 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date: Message-ID:From:References:To:Subject:Reply-To:Content-ID:Content-Description :Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=UHSr73CjVTwku7S3PpbHEbsJQDcZ+KUXl+WRpkCZOek=; b=gqOQVpub64/HoU qzuIo4WWCmaO7Z90C+Bww/yomzPbPX9DFf8u1CJwZ35gT/RzE4cKeYsFQqstuofnRFBMjjjo+YgMG EaW77hypabblcVBgp1V29zrH2R8aX6ZDEVUf0lfmCN54x+Ct6pytv18jTGeP7wKRAkSezVZKIQoyM WM5EVfsR5/NvqIay+cC25mk5EoYlGpD2eqdmMm4COcgXkbr+IfUXjKyC02Da2+eL8V/Ktg251gCIn dHfdcsNWWC89SPSlqUZ1QCUTfFL/KEe3W/QAyAFPwCYN8PZo9pDURpc84adAkZbQU7SbPEfWeL1Ji ewKyatl3BFC0tlO9Pmvg==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1i3iiW-0002j2-2J; Fri, 30 Aug 2019 15:21:36 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1i3iiS-0002iZ-L7 for linux-arm-kernel@lists.infradead.org; Fri, 30 Aug 2019 15:21:34 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 81BA0344; Fri, 30 Aug 2019 08:21:31 -0700 (PDT) Received: from [10.1.197.50] (e120937-lin.cambridge.arm.com [10.1.197.50]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id CD0E43F703; Fri, 30 Aug 2019 08:21:30 -0700 (PDT) Subject: Re: [PATCH v3 10/11] kselftest: arm64: fake_sigreturn_bad_size To: Dave Martin References: <20190802170300.20662-1-cristian.marussi@arm.com> <20190802170300.20662-11-cristian.marussi@arm.com> <20190813162646.GH10425@arm.com> From: Cristian Marussi Message-ID: <599bc78e-718d-0475-0ab0-79e1277e55ab@arm.com> Date: Fri, 30 Aug 2019 16:21:29 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <20190813162646.GH10425@arm.com> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190830_082132_785228_3896EA80 X-CRM114-Status: GOOD ( 18.51 ) 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: andreyknvl@google.com, shuah@kernel.org, linux-arm-kernel@lists.infradead.org, linux-kselftest@vger.kernel.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 13/08/2019 17:26, Dave Martin wrote: > On Fri, Aug 02, 2019 at 06:02:59PM +0100, Cristian Marussi wrote: >> Added a simple fake_sigreturn testcase which builds a ucontext_t > > Add Ok > >> with a badly sized header that causes a overrun in the __reserved >> area and place it onto the stack. Expects a SIGSEGV on test PASS. >> >> Signed-off-by: Cristian Marussi >> --- >> .../arm64/signal/testcases/.gitignore | 1 + >> .../testcases/fake_sigreturn_bad_size.c | 85 +++++++++++++++++++ >> 2 files changed, 86 insertions(+) >> create mode 100644 tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_bad_size.c >> >> diff --git a/tools/testing/selftests/arm64/signal/testcases/.gitignore b/tools/testing/selftests/arm64/signal/testcases/.gitignore >> index 94f9baaf638c..3408e0f5ba98 100644 >> --- a/tools/testing/selftests/arm64/signal/testcases/.gitignore >> +++ b/tools/testing/selftests/arm64/signal/testcases/.gitignore >> @@ -8,3 +8,4 @@ fake_sigreturn_bad_magic >> fake_sigreturn_bad_size_for_magic0 >> fake_sigreturn_missing_fpsimd >> fake_sigreturn_duplicated_fpsimd >> +fake_sigreturn_bad_size >> diff --git a/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_bad_size.c b/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_bad_size.c >> new file mode 100644 >> index 000000000000..1467fb534d8b >> --- /dev/null >> +++ b/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_bad_size.c >> @@ -0,0 +1,85 @@ >> +/* SPDX-License-Identifier: GPL-2.0 */ >> +/* Copyright (C) 2019 ARM Limited */ >> + > > signal.h? > Ok >> +#include >> +#include >> + >> +#include "test_signals_utils.h" >> +#include "testcases.h" >> + >> +struct fake_sigframe sf; >> + >> +#define MIN_SZ_ALIGN 16 >> + >> +static int fake_sigreturn_bad_size_run(struct tdescr *td, >> + siginfo_t *si, ucontext_t *uc) >> +{ >> + size_t resv_sz, need_sz, offset; >> + struct _aarch64_ctx *shead = GET_SF_RESV_HEAD(sf), *head; >> + >> + /* just to fill the ucontext_t with something real */ >> + if (!get_current_context(td, &sf.uc)) >> + return 1; >> + >> + resv_sz = GET_SF_RESV_SIZE(sf); >> + /* >> + * find the terminator, preserving existing headers >> + * and verify amount of spare room in __reserved area. >> + */ >> + head = get_terminator(shead, resv_sz, &offset); >> + /* >> + * try stripping extra_context header when low on space: >> + * we need at least for the bad sized esr_context. > > double space > ok. >> + */ >> + need_sz = HDR_SZ + sizeof(struct esr_context); >> + if (head && resv_sz - offset < need_sz) { >> + fprintf(stderr, "Low on space:%zd. Discarding extra_context.\n", >> + resv_sz - offset); >> + head = get_header(shead, EXTRA_MAGIC, resv_sz, &offset); >> + } >> + /* just give up and timeout if still not enough space */ >> + if (head && resv_sz - offset >= need_sz) { >> + fprintf(stderr, "Mangling template header. Spare space:%zd\n", >> + resv_sz - offset); >> + /* >> + * Use an esr_context to build a fake header with a >> + * size greater then the free __reserved area minus HDR_SZ; >> + * using ESR_MAGIC here since it is not checked for size nor >> + * is limited to one instance. >> + * >> + * At first inject an additional normal esr_context >> + */ >> + head->magic = ESR_MAGIC; >> + head->size = sizeof(struct esr_context); >> + /* and terminate properly */ >> + write_terminator_record(GET_RESV_NEXT_HEAD(head)); >> + ASSERT_GOOD_CONTEXT(&sf.uc); >> + >> + /* >> + * now mess with fake esr_context size: leaving less space than >> + * neededwhile keeping size value 16-aligned >> + * >> + * It must trigger a SEGV from Kernel on: >> + * >> + * resv_sz - offset < sizeof(*head) >> + */ >> + /* at first set the maximum good 16-aligned size */ >> + head->size = (resv_sz - offset - need_sz + MIN_SZ_ALIGN) & ~0xfUL; >> + /* plus a bit more of 16-aligned sized stuff */ >> + head->size += MIN_SZ_ALIGN; >> + /* and terminate properly */ >> + write_terminator_record(GET_RESV_NEXT_HEAD(head)); >> + ASSERT_BAD_CONTEXT(&sf.uc); >> + fake_sigreturn(&sf, sizeof(sf), 16); >> + } >> + >> + return 1; >> +} > I'll convert to use new helper get_starting_head() to make space in __reserved. > [...] > > Otherwise looks reasonable. > > Cheers > ---Dave Cheers Cristian > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel