From patchwork Wed Dec 1 19:23:10 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Reinette Chatre X-Patchwork-Id: 12650857 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 44C5AC433FE for ; Wed, 1 Dec 2021 19:23:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245127AbhLAT1F (ORCPT ); Wed, 1 Dec 2021 14:27:05 -0500 Received: from mga05.intel.com ([192.55.52.43]:21702 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244564AbhLAT1F (ORCPT ); Wed, 1 Dec 2021 14:27:05 -0500 X-IronPort-AV: E=McAfee;i="6200,9189,10185"; a="322784104" X-IronPort-AV: E=Sophos;i="5.87,279,1631602800"; d="scan'208";a="322784104" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Dec 2021 11:23:43 -0800 X-IronPort-AV: E=Sophos;i="5.87,279,1631602800"; d="scan'208";a="500380470" Received: from rchatre-ws.ostc.intel.com ([10.54.69.144]) by orsmga007-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Dec 2021 11:23:42 -0800 From: Reinette Chatre To: dave.hansen@linux.intel.com, jarkko@kernel.org, tglx@linutronix.de, bp@alien8.de, luto@kernel.org, mingo@redhat.com, linux-sgx@vger.kernel.org, x86@kernel.org Cc: seanjc@google.com, kai.huang@intel.com, cathy.zhang@intel.com, cedric.xing@intel.com, haitao.huang@intel.com, mark.shanahan@intel.com, hpa@zytor.com, linux-kernel@vger.kernel.org Subject: [PATCH 12/25] selftests/sgx: Add test for TCS page permission changes Date: Wed, 1 Dec 2021 11:23:10 -0800 Message-Id: X-Mailer: git-send-email 2.25.1 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-sgx@vger.kernel.org Kernel should not allow permission changes on TCS pages. Add test to confirm this behavior. Signed-off-by: Reinette Chatre --- tools/testing/selftests/sgx/main.c | 70 ++++++++++++++++++++++++++++++ 1 file changed, 70 insertions(+) diff --git a/tools/testing/selftests/sgx/main.c b/tools/testing/selftests/sgx/main.c index dbd071ba03fe..c7c50d05e246 100644 --- a/tools/testing/selftests/sgx/main.c +++ b/tools/testing/selftests/sgx/main.c @@ -120,6 +120,24 @@ static Elf64_Sym *vdso_symtab_get(struct vdso_symtab *symtab, const char *name) return NULL; } +/* + * Return the offset in the enclave where the TCS segment can be found. + * The first RW segment loaded is the TCS. + */ +static off_t encl_get_tcs_offset(struct encl *encl) +{ + int i; + + for (i = 0; i < encl->nr_segments; i++) { + struct encl_segment *seg = &encl->segment_tbl[i]; + + if (i == 0 && seg->prot == (PROT_READ | PROT_WRITE)) + return seg->offset; + } + + return -1; +} + /* * Return the offset in the enclave where the data segment can be found. * The first RW segment loaded is the TCS, skip that to get info on the @@ -567,6 +585,58 @@ TEST_F(enclave, pte_permissions) EXPECT_EQ(self->run.exception_addr, 0); } +/* + * Modifying permissions of TCS page should not be possible. + */ +TEST_F(enclave, tcs_permissions) +{ + struct sgx_page_modp ioc; + int ret, errno_save; + + ASSERT_TRUE(setup_test_encl(ENCL_HEAP_SIZE_DEFAULT, &self->encl, _metadata)); + + memset(&self->run, 0, sizeof(self->run)); + self->run.tcs = self->encl.encl_base; + + memset(&ioc, 0, sizeof(ioc)); + + /* + * Ensure kernel supports needed ioctl and system supports needed + * commands. + */ + + ret = ioctl(self->encl.fd, SGX_IOC_PAGE_MODP, &ioc); + + if (ret == -1) { + if (errno == ENOTTY) + SKIP(return, "Kernel does not support test SGX_IOC_PAGE_MODP ioctl"); + else if (errno == ENODEV) + SKIP(return, "System does not support SGX2"); + } + + /* + * Invalid parameters were provided during sanity check, + * expect command to fail. + */ + EXPECT_EQ(ret, -1); + + /* + * Attempt to make TCS page read-only. This is not allowed and + * should be prevented by OS. + */ + ioc.offset = encl_get_tcs_offset(&self->encl); + ioc.length = PAGE_SIZE; + ioc.prot = PROT_READ; + + ret = ioctl(self->encl.fd, SGX_IOC_PAGE_MODP, &ioc); + errno_save = ret == -1 ? errno : 0; + + EXPECT_EQ(ret, -1); + EXPECT_EQ(errno_save, EINVAL); + EXPECT_EQ(ioc.result, 0); + EXPECT_EQ(ioc.count, 0); +} + /* * Enclave page permission test. *