From patchwork Wed Dec 1 19:23:20 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Reinette Chatre X-Patchwork-Id: 12650901 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 4359DC433EF for ; Wed, 1 Dec 2021 19:24:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1352665AbhLAT11 (ORCPT ); Wed, 1 Dec 2021 14:27:27 -0500 Received: from mga04.intel.com ([192.55.52.120]:46904 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1352710AbhLAT1R (ORCPT ); Wed, 1 Dec 2021 14:27:17 -0500 X-IronPort-AV: E=McAfee;i="6200,9189,10185"; a="235267937" X-IronPort-AV: E=Sophos;i="5.87,279,1631602800"; d="scan'208";a="235267937" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Dec 2021 11:23:44 -0800 X-IronPort-AV: E=Sophos;i="5.87,279,1631602800"; d="scan'208";a="500380504" 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 22/25] selftests/sgx: Test invalid access to removed enclave page Date: Wed, 1 Dec 2021 11:23:20 -0800 Message-Id: <88af581809b945b1774c32186bcb0190d3d462e9.1638381245.git.reinette.chatre@intel.com> 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 Removing a page from an initialized enclave involves three steps: (1) the user requests changing the page type to SGX_PAGE_TYPE_TRIM via the SGX_IOC_PAGE_MODT ioctl, (2) on success the ENCLU[EACCEPT] instruction is run from within the enclave to accept the page removal, (3) the user initiates the actual removal of the page via the SGX_IOC_PAGE_REMOVE ioctl. Test two possible invalid accesses during the page removal flow: * Test the behavior when a request to remove the page by changing its type to SGX_PAGE_TYPE_TRIM completes successfully but instead of executing ENCLU[EACCEPT] from within the enclave the enclave attempts to read from the page. Even though the page is accessible from the page table entries its type is SGX_PAGE_TYPE_TRIM and thus not accessible according to SGX. The expected behavior is a page fault with the SGX flag set in the error code. * Test the behavior when the page type is changed successfully and ENCLU[EACCEPT] was run from within the enclave. The final ioctl, SGX_IOC_PAGE_REMOVE, is omitted and replaced with an attempt to access the page. Even though the page is accessible from the page table entries its type is SGX_PAGE_TYPE_TRIM and thus not accessible according to SGX. The expected behavior is a page fault with the SGX flag set in the error code. Signed-off-by: Reinette Chatre --- tools/testing/selftests/sgx/main.c | 243 +++++++++++++++++++++++++++++ 1 file changed, 243 insertions(+) diff --git a/tools/testing/selftests/sgx/main.c b/tools/testing/selftests/sgx/main.c index f71f943099fb..3bee8fa557fd 100644 --- a/tools/testing/selftests/sgx/main.c +++ b/tools/testing/selftests/sgx/main.c @@ -1606,4 +1606,247 @@ TEST_F(enclave, remove_added_page_no_eaccept) EXPECT_EQ(remove_ioc.count, 0); } +/* + * Request enclave page removal but instead of correctly following with + * EACCEPT a read attempt to page is made from within the enclave. + */ +TEST_F(enclave, remove_added_page_invalid_access) +{ + struct encl_op_get_from_addr get_addr_op; + struct encl_op_put_to_addr put_addr_op; + unsigned long data_start; + struct sgx_page_modt 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; + + /* + * Hardware (SGX2) and OS support is needed for this test. Start + * with check that test has a chance of succeeding. + */ + memset(&ioc, 0, sizeof(ioc)); + ret = ioctl(self->encl.fd, SGX_IOC_PAGE_MODT, &ioc); + + if (ret == -1) { + if (errno == ENOTTY) + SKIP(return, "Kernel does not support test SGX_IOC_PAGE_MODT 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); + + /* + * Page that will be removed is the second data page in the .data + * segment. This forms part of the local encl_buffer within the + * enclave. + */ + data_start = self->encl.encl_base + + encl_get_data_offset(&self->encl) + PAGE_SIZE; + + /* + * Sanity check that page at @data_start is writable before + * removing it. + * + * Start by writing MAGIC to test page. + */ + put_addr_op.value = MAGIC; + put_addr_op.addr = data_start; + put_addr_op.header.type = ENCL_OP_PUT_TO_ADDRESS; + + EXPECT_EQ(ENCL_CALL(&put_addr_op, &self->run, true), 0); + + EXPECT_EEXIT(&self->run); + EXPECT_EQ(self->run.exception_vector, 0); + EXPECT_EQ(self->run.exception_error_code, 0); + EXPECT_EQ(self->run.exception_addr, 0); + + /* + * Read memory that was just written to, confirming that data + * previously written (MAGIC) is present. Only change two test + * parameters, rest are same as previous test. + */ + get_addr_op.value = 0; + get_addr_op.addr = data_start; + get_addr_op.header.type = ENCL_OP_GET_FROM_ADDRESS; + + EXPECT_EQ(ENCL_CALL(&get_addr_op, &self->run, true), 0); + + EXPECT_EQ(get_addr_op.value, MAGIC); + EXPECT_EEXIT(&self->run); + EXPECT_EQ(self->run.exception_vector, 0); + EXPECT_EQ(self->run.exception_error_code, 0); + EXPECT_EQ(self->run.exception_addr, 0); + + /* Start page removal by requesting change of page type to PT_TRIM */ + memset(&ioc, 0, sizeof(ioc)); + + ioc.offset = encl_get_data_offset(&self->encl) + PAGE_SIZE; + ioc.length = PAGE_SIZE; + ioc.type = SGX_PAGE_TYPE_TRIM; + + ret = ioctl(self->encl.fd, SGX_IOC_PAGE_MODT, &ioc); + errno_save = ret == -1 ? errno : 0; + + EXPECT_EQ(ret, 0); + EXPECT_EQ(errno_save, 0); + EXPECT_EQ(ioc.result, 0); + EXPECT_EQ(ioc.count, 4096); + + /* + * Read from page that was just removed. + */ + get_addr_op.value = 0; + + EXPECT_EQ(ENCL_CALL(&get_addr_op, &self->run, true), 0); + + /* + * From OS perspective the page is present but according to SGX the + * page should not be accessible so a #PF with SGX bit set is + * expected. + */ + + EXPECT_EQ(self->run.function, ERESUME); + EXPECT_EQ(self->run.exception_vector, 14); + EXPECT_EQ(self->run.exception_error_code, 0x8005); + EXPECT_EQ(self->run.exception_addr, data_start); +} + +/* + * Request enclave page removal and correctly follow with + * EACCEPT but do not follow with removal ioctl but instead a read attempt + * to removed page is made from within the enclave. + */ +TEST_F(enclave, remove_added_page_invalid_access_after_eaccept) +{ + struct encl_op_get_from_addr get_addr_op; + struct encl_op_put_to_addr put_addr_op; + struct encl_op_eaccept eaccept_op; + unsigned long data_start; + struct sgx_page_modt 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; + + /* + * Hardware (SGX2) and OS support is needed for this test. Start + * with check that test has a chance of succeeding. + */ + memset(&ioc, 0, sizeof(ioc)); + ret = ioctl(self->encl.fd, SGX_IOC_PAGE_MODT, &ioc); + + if (ret == -1) { + if (errno == ENOTTY) + SKIP(return, "Kernel does not support test SGX_IOC_PAGE_MODT 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); + + /* + * Page that will be removed is the second data page in the .data + * segment. This forms part of the local encl_buffer within the + * enclave. + */ + data_start = self->encl.encl_base + + encl_get_data_offset(&self->encl) + PAGE_SIZE; + + /* + * Sanity check that page at @data_start is writable before + * removing it. + * + * Start by writing MAGIC to test page. + */ + put_addr_op.value = MAGIC; + put_addr_op.addr = data_start; + put_addr_op.header.type = ENCL_OP_PUT_TO_ADDRESS; + + EXPECT_EQ(ENCL_CALL(&put_addr_op, &self->run, true), 0); + + EXPECT_EEXIT(&self->run); + EXPECT_EQ(self->run.exception_vector, 0); + EXPECT_EQ(self->run.exception_error_code, 0); + EXPECT_EQ(self->run.exception_addr, 0); + + /* + * Read memory that was just written to, confirming that data + * previously written (MAGIC) is present. Only change two test + * parameters, rest are same as previous test. + */ + get_addr_op.value = 0; + get_addr_op.addr = data_start; + get_addr_op.header.type = ENCL_OP_GET_FROM_ADDRESS; + + EXPECT_EQ(ENCL_CALL(&get_addr_op, &self->run, true), 0); + + EXPECT_EQ(get_addr_op.value, MAGIC); + EXPECT_EEXIT(&self->run); + EXPECT_EQ(self->run.exception_vector, 0); + EXPECT_EQ(self->run.exception_error_code, 0); + EXPECT_EQ(self->run.exception_addr, 0); + + /* Start page removal by requesting change of page type to PT_TRIM */ + memset(&ioc, 0, sizeof(ioc)); + + ioc.offset = encl_get_data_offset(&self->encl) + PAGE_SIZE; + ioc.length = PAGE_SIZE; + ioc.type = SGX_PAGE_TYPE_TRIM; + + ret = ioctl(self->encl.fd, SGX_IOC_PAGE_MODT, &ioc); + errno_save = ret == -1 ? errno : 0; + + EXPECT_EQ(ret, 0); + EXPECT_EQ(errno_save, 0); + EXPECT_EQ(ioc.result, 0); + EXPECT_EQ(ioc.count, 4096); + + eaccept_op.epc_addr = (unsigned long)data_start; + eaccept_op.ret = 0; + eaccept_op.flags = SGX_SECINFO_TRIM | SGX_SECINFO_MODIFIED; + eaccept_op.header.type = ENCL_OP_EACCEPT; + + EXPECT_EQ(ENCL_CALL(&eaccept_op, &self->run, true), 0); + + EXPECT_EEXIT(&self->run); + EXPECT_EQ(self->run.exception_vector, 0); + EXPECT_EQ(self->run.exception_error_code, 0); + EXPECT_EQ(self->run.exception_addr, 0); + EXPECT_EQ(eaccept_op.ret, 0); + + /* Skip ioctl to remove page */ + + /* + * Read from page that was just removed. + */ + get_addr_op.value = 0; + + EXPECT_EQ(ENCL_CALL(&get_addr_op, &self->run, true), 0); + + /* + * From OS perspective the page is present but according to SGX the + * page should not be accessible so a #PF with SGX bit set is + * expected. + */ + + EXPECT_EQ(self->run.function, ERESUME); + EXPECT_EQ(self->run.exception_vector, 14); + EXPECT_EQ(self->run.exception_error_code, 0x8005); + EXPECT_EQ(self->run.exception_addr, data_start); +} + TEST_HARNESS_MAIN