From patchwork Mon Apr 4 16:49:30 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Reinette Chatre X-Patchwork-Id: 12800769 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 E205FC47094 for ; Mon, 4 Apr 2022 21:23:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1376969AbiDDVZM (ORCPT ); Mon, 4 Apr 2022 17:25:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46688 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1379274AbiDDQvz (ORCPT ); Mon, 4 Apr 2022 12:51:55 -0400 Received: from mga07.intel.com (mga07.intel.com [134.134.136.100]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1646E338AA; Mon, 4 Apr 2022 09:49:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1649090999; x=1680626999; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=RLenEGRyRkGnPHbe+3ya/9vd5y8mNvmWzZIkUE5GP2Q=; b=f1FeONCAXxzEiJa96ibH89WK2aQsPFEN83B9PBTKwtG2AHqAtbQoMqSb hJYvEYM7FsVX+TmnLaSqQ/mkwQDegJZLkYjKVofPMlnaHFjZ1nzXtay3v A+1fnuR4vG1n3mIWe9eE1+vQYw9wkXd4zNyb3W4jXFIQw7QVtXflX/24E IGZ4fTCz19oLBmWeCwwVt+etTE93sUDf4vRX4ZcZyHZxE0YqDpJmxDGwn vPJ9h4RoFFzXNTNXLFvkFL7HdCfIiiKuS/+RZDkxruu9+4jEQxdmYZuMI mUbcXJJ5a+NKQE2dOnboNs3/TPVyE7EiWVy09xS6wd6IjnYn0eOYqqpU9 w==; X-IronPort-AV: E=McAfee;i="6200,9189,10307"; a="323734056" X-IronPort-AV: E=Sophos;i="5.90,234,1643702400"; d="scan'208";a="323734056" Received: from orsmga002.jf.intel.com ([10.7.209.21]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Apr 2022 09:49:51 -0700 X-IronPort-AV: E=Sophos;i="5.90,234,1643702400"; d="scan'208";a="523105214" Received: from rchatre-ws.ostc.intel.com ([10.54.69.144]) by orsmga002-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Apr 2022 09:49:50 -0700 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 V3 22/30] selftests/sgx: Add test for TCS page permission changes Date: Mon, 4 Apr 2022 09:49:30 -0700 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 --- Changes since V2: - Update to use new struct name struct sgx_enclave_restrict_perm -> struct sgx_enclave_restrict_permissions. (Jarkko) Changes since V1: - Adapt test to the kernel interface changes: the ioctl() name change and providing entire secinfo as parameter. - Rewrite error path to reduce line lengths. tools/testing/selftests/sgx/main.c | 74 ++++++++++++++++++++++++++++++ 1 file changed, 74 insertions(+) diff --git a/tools/testing/selftests/sgx/main.c b/tools/testing/selftests/sgx/main.c index 0e0bd1c4d702..59573c1128c8 100644 --- a/tools/testing/selftests/sgx/main.c +++ b/tools/testing/selftests/sgx/main.c @@ -121,6 +121,24 @@ 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 +585,62 @@ 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_enclave_restrict_permissions ioc; + struct sgx_secinfo secinfo; + 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)); + memset(&secinfo, 0, sizeof(secinfo)); + + /* + * Ensure kernel supports needed ioctl() and system supports needed + * commands. + */ + + ret = ioctl(self->encl.fd, SGX_IOC_ENCLAVE_RESTRICT_PERMISSIONS, &ioc); + errno_save = ret == -1 ? errno : 0; + + /* + * Invalid parameters were provided during sanity check, + * expect command to fail. + */ + ASSERT_EQ(ret, -1); + + /* ret == -1 */ + if (errno_save == ENOTTY) + SKIP(return, + "Kernel does not support SGX_IOC_ENCLAVE_RESTRICT_PERMISSIONS ioctl()"); + else if (errno_save == ENODEV) + SKIP(return, "System does not support SGX2"); + + /* + * Attempt to make TCS page read-only. This is not allowed and + * should be prevented by the kernel. + */ + secinfo.flags = PROT_READ; + ioc.offset = encl_get_tcs_offset(&self->encl); + ioc.length = PAGE_SIZE; + ioc.secinfo = (unsigned long)&secinfo; + + ret = ioctl(self->encl.fd, SGX_IOC_ENCLAVE_RESTRICT_PERMISSIONS, &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. *