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 77DE8C32750 for ; Tue, 13 Aug 2019 16:29:32 +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 49C8D20840 for ; Tue, 13 Aug 2019 16:29:32 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="lRYb/C6p" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 49C8D20840 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:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=KK9r8yeGcMRBOzIdp9Y/lS5brRxjbe0HuEJDb4yhnZE=; b=lRYb/C6pmd+LxI BxdVAemdPQUvowJlX3waDzvxhJ/+NfPIq/NZRs4R3ctbHOOKapdqobkPYI4MCHs0SSOtKLwKMSdoH hl3e5LbH+9C/Mk0ISkjf56CaaNo1EefxMimb7z88brwg2zwx0p5btoRiP8tq1RemEuY7AzVDOr7hf iwLOzA+HADYN4ijs3Jo3ARtI7NLWd9mNZJMCSe/AlaMfOVYlllhmKLYCVboNe1O8BqSqLldzudCXj R+RxWbBhtoude5D/TuSu4w6V82i4ZaoxzkALyXlhHmOfJtQe6DgDt/9yI/F+Chn4iVksgSOxGAkH4 ZkI71s2z6ggsvmIlXbhQ==; 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 1hxZfv-0001Db-Qh; Tue, 13 Aug 2019 16:29:31 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1hxZdJ-0006XN-Mn for linux-arm-kernel@lists.infradead.org; Tue, 13 Aug 2019 16:26:54 +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 0A5D6337; Tue, 13 Aug 2019 09:26:49 -0700 (PDT) Received: from arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 3D2423F706; Tue, 13 Aug 2019 09:26:48 -0700 (PDT) Date: Tue, 13 Aug 2019 17:26:46 +0100 From: Dave Martin To: Cristian Marussi Subject: Re: [PATCH v3 10/11] kselftest: arm64: fake_sigreturn_bad_size Message-ID: <20190813162646.GH10425@arm.com> References: <20190802170300.20662-1-cristian.marussi@arm.com> <20190802170300.20662-11-cristian.marussi@arm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20190802170300.20662-11-cristian.marussi@arm.com> User-Agent: Mutt/1.5.23 (2014-03-12) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190813_092649_870289_2123C09B X-CRM114-Status: GOOD ( 20.68 ) 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 Fri, Aug 02, 2019 at 06:02:59PM +0100, Cristian Marussi wrote: > Added a simple fake_sigreturn testcase which builds a ucontext_t Add > 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? > +#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 > + */ > + 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; > +} [...] Otherwise looks reasonable. Cheers ---Dave _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel