From patchwork Fri Mar 4 09:35:10 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jarkko Sakkinen X-Patchwork-Id: 12768830 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 0B083C4167B for ; Fri, 4 Mar 2022 09:37:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239075AbiCDJii (ORCPT ); Fri, 4 Mar 2022 04:38:38 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53950 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239426AbiCDJiJ (ORCPT ); Fri, 4 Mar 2022 04:38:09 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9B863198D34; Fri, 4 Mar 2022 01:37:00 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 57149B827BA; Fri, 4 Mar 2022 09:36:59 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id BDAC1C340E9; Fri, 4 Mar 2022 09:36:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1646386618; bh=Lz/rYuzi5eg/KbwEMeUWk0lPaFgp/JfWvLR1ugCb1u8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ADPQIIzPgR/VVYVR80TeGtzjmuXp3nSCOfr862rIX5NRbGSCA/OXoGJGz16iC1mLF fYp4VbvZUJ3+d5HJEy90eJsI2dn+XDiGe6PkY5Sd4vxv1VMswsZfmufJlJXGWnw7pH P7S0ycPFlMy1lUR489WeIPMIvsPYrVKheHXA2KvO4Do2+f3E9nILiiYc5r2N45MQ+r TvLiXLWY7SMzSN+y/ZzvCmsvUh2yCt0n0wk1mGhp7R/MxTXo2nZln2cEJIoamU0+mZ 21offXAhnvvC/vSxiQW8AG+F72l1YYEU32z9PQflzIfMZ4hRW11rKNLeeMn4XLuUXf gVIMSvGM1Aw3w== From: Jarkko Sakkinen To: linux-sgx@vger.kernel.org Cc: Nathaniel McCallum , Reinette Chatre , Jarkko Sakkinen , Dave Hansen , Shuah Khan , linux-kselftest@vger.kernel.org (open list:KERNEL SELFTEST FRAMEWORK), linux-kernel@vger.kernel.org (open list) Subject: [RFC PATCH v2.1 16/30] selftests/sgx: Add test for TCS page permission changes Date: Fri, 4 Mar 2022 11:35:10 +0200 Message-Id: <20220304093524.397485-16-jarkko@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220304093524.397485-1-jarkko@kernel.org> References: <20220304093524.397485-1-jarkko@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-sgx@vger.kernel.org From: Reinette Chatre 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 | 74 ++++++++++++++++++++++++++++++ 1 file changed, 74 insertions(+) diff --git a/tools/testing/selftests/sgx/main.c b/tools/testing/selftests/sgx/main.c index aec3355d2ace..ea5f2e064687 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_perm 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. *