From patchwork Fri Aug 30 16:42:47 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Cristian Marussi X-Patchwork-Id: 11124373 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id BFA5318B7 for ; Fri, 30 Aug 2019 16:43:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A67902173E for ; Fri, 30 Aug 2019 16:43:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728441AbfH3Qnq (ORCPT ); Fri, 30 Aug 2019 12:43:46 -0400 Received: from foss.arm.com ([217.140.110.172]:35024 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728428AbfH3Qnp (ORCPT ); Fri, 30 Aug 2019 12:43:45 -0400 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 5CA631576; Fri, 30 Aug 2019 09:43:45 -0700 (PDT) Received: from e120937-lin.cambridge.arm.com (e120937-lin.cambridge.arm.com [10.1.197.50]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 750A13F718; Fri, 30 Aug 2019 09:43:44 -0700 (PDT) From: Cristian Marussi To: linux-kselftest@vger.kernel.org, linux-arm-kernel@lists.infradead.org, shuah@kernel.org Cc: andreyknvl@google.com, dave.martin@arm.com, amit.kachhap@arm.com Subject: [PATCH v4 10/11] kselftest: arm64: fake_sigreturn_bad_size Date: Fri, 30 Aug 2019 17:42:47 +0100 Message-Id: <20190830164248.16238-11-cristian.marussi@arm.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190830164248.16238-1-cristian.marussi@arm.com> References: <20190830164248.16238-1-cristian.marussi@arm.com> Sender: linux-kselftest-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org Add a simple fake_sigreturn testcase which builds a ucontext_t 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 --- v3 --> v4 - fix commit - missing include - using new get_starting_head() helper - added test description --- .../testcases/fake_sigreturn_bad_size.c | 77 +++++++++++++++++++ 1 file changed, 77 insertions(+) create mode 100644 tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_bad_size.c 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..b1156afdb691 --- /dev/null +++ b/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_bad_size.c @@ -0,0 +1,77 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2019 ARM Limited + * + * Place a fake sigframe on the stack including a bad record overflowing + * the __reserved space: on sigreturn Kernel must spot this attempt and + * the test case is expected to be terminated via SEGV. + */ + +#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); + /* at least HDR_SZ + bad sized esr_context needed */ + need_sz = HDR_SZ + sizeof(struct esr_context); + head = get_starting_head(shead, need_sz, resv_sz, &offset); + if (head) { + /* + * 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 + * needed while 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), 0); + } + + return 1; +} + +struct tdescr tde = { + .name = "FAKE_SIGRETURN_BAD_SIZE", + .descr = "Triggers a sigreturn with a overrun __reserved area", + .sig_ok = SIGSEGV, + .timeout = 3, + .run = fake_sigreturn_bad_size_run, +};