From patchwork Mon Jul 27 22:30:41 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Petr Vorel X-Patchwork-Id: 11687747 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 97895138A for ; Mon, 27 Jul 2020 22:30:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8922020809 for ; Mon, 27 Jul 2020 22:30:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727091AbgG0Way (ORCPT ); Mon, 27 Jul 2020 18:30:54 -0400 Received: from mx2.suse.de ([195.135.220.15]:40016 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727095AbgG0Way (ORCPT ); Mon, 27 Jul 2020 18:30:54 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 9CF7FB5DA; Mon, 27 Jul 2020 22:31:02 +0000 (UTC) From: Petr Vorel To: ltp@lists.linux.it Cc: Lachlan Sneff , Lakshmi Ramasubramanian , Mimi Zohar , balajib@linux.microsoft.com, linux-integrity@vger.kernel.org, Petr Vorel , Mimi Zohar Subject: [PATCH v5 4/4] IMA: Add test for kexec cmdline measurement Date: Tue, 28 Jul 2020 00:30:41 +0200 Message-Id: <20200727223041.13110-5-pvorel@suse.cz> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200727223041.13110-1-pvorel@suse.cz> References: <20200727223041.13110-1-pvorel@suse.cz> MIME-Version: 1.0 Sender: linux-integrity-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org From: Lachlan Sneff IMA policy can be set to measure the command line passed in the kexec system call. Add a testcase that verifies that the IMA subsystem correctly measure the cmdline specified during a kexec. Reviewed-by: Petr Vorel Reviewed-by: Mimi Zohar Signed-off-by: Lachlan Sneff [ pvorel: improved setup, various LTP API cleanup ] Signed-off-by: Petr Vorel --- Changes v4->v5: * added kexec.policy, please check it (for lazy people, I still plan some automatic mechanism for loading policies on CONFIG_IMA_WRITE_POLICY) * rewritten checks in setup: - simplify secure boot bootctl verification - try dmesg when bootctl not available - check on failure also ^appraise.*func=KEXEC_KERNEL_CHECK policy - improve logic for func=KEXEC_CMDLINE check (instead of requiring policy to be readable check only when readable, otherwise TWARN, ...) - TWARN on failures in setup => TWARN is kind of error as it exit with non-zero, but these cases are failures thus don't hide them) * added cleanup commit (adding helpers) * various LTP API cleanup: - added setup into separate function - reuse test code with kexec_test() Kind regards, Petr runtest/ima | 1 + .../kernel/security/integrity/ima/README.md | 8 ++ .../integrity/ima/datafiles/kexec.policy | 1 + .../security/integrity/ima/tests/ima_kexec.sh | 111 ++++++++++++++++++ 4 files changed, 121 insertions(+) create mode 100644 testcases/kernel/security/integrity/ima/datafiles/kexec.policy create mode 100755 testcases/kernel/security/integrity/ima/tests/ima_kexec.sh diff --git a/runtest/ima b/runtest/ima index 309d47420..5f4b4a7a1 100644 --- a/runtest/ima +++ b/runtest/ima @@ -4,4 +4,5 @@ ima_policy ima_policy.sh ima_tpm ima_tpm.sh ima_violations ima_violations.sh ima_keys ima_keys.sh +ima_kexec ima_kexec.sh evm_overlay evm_overlay.sh diff --git a/testcases/kernel/security/integrity/ima/README.md b/testcases/kernel/security/integrity/ima/README.md index 732cd912f..d4644ba39 100644 --- a/testcases/kernel/security/integrity/ima/README.md +++ b/testcases/kernel/security/integrity/ima/README.md @@ -36,6 +36,14 @@ CONFIG_SYSTEM_TRUSTED_KEYS="/etc/keys/ima-local-ca.pem" Test also requires loaded policy with `func=KEY_CHECK`, see example in `keycheck.policy`. +### IMA kexec test + +`ima_kexec.sh` requires loaded policy which contains `measure func=KEXEC_CMDLINE`, +see example in `kexec.policy`. + +The test attempts to kexec the existing running kernel image. +To kexec a different kernel image export `IMA_KEXEC_IMAGE=`. + ## EVM tests `evm_overlay.sh` requires a builtin IMA appraise tcb policy (e.g. `ima_policy=appraise_tcb` diff --git a/testcases/kernel/security/integrity/ima/datafiles/kexec.policy b/testcases/kernel/security/integrity/ima/datafiles/kexec.policy new file mode 100644 index 000000000..58d66369e --- /dev/null +++ b/testcases/kernel/security/integrity/ima/datafiles/kexec.policy @@ -0,0 +1 @@ +measure func=KEXEC_CMDLINE diff --git a/testcases/kernel/security/integrity/ima/tests/ima_kexec.sh b/testcases/kernel/security/integrity/ima/tests/ima_kexec.sh new file mode 100755 index 000000000..fbad9b425 --- /dev/null +++ b/testcases/kernel/security/integrity/ima/tests/ima_kexec.sh @@ -0,0 +1,111 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0-or-later +# Copyright (c) 2020 Microsoft Corporation +# Copyright (c) 2020 Petr Vorel +# Author: Lachlan Sneff +# +# Verify that kexec cmdline is measured correctly. +# Test attempts to kexec the existing running kernel image. +# To kexec a different kernel image export IMA_KEXEC_IMAGE=. + +TST_NEEDS_CMDS="grep kexec sed" +TST_CNT=2 +TST_NEEDS_DEVICE=1 +TST_SETUP="setup" + +. ima_setup.sh + +IMA_KEXEC_IMAGE="${IMA_KEXEC_IMAGE:-/boot/vmlinuz-$(uname -r)}" + +measure() +{ + local cmdline="$1" + local algorithm digest expected_digest found + + printf "$cmdline" > file1 + grep "kexec-cmdline" $ASCII_MEASUREMENTS > file2 + + while read found + do + algorithm=$(echo "$found" | cut -d' ' -f4 | cut -d':' -f1) + digest=$(echo "$found" | cut -d' ' -f4 | cut -d':' -f2) + + expected_digest=$(compute_digest $algorithm file1) + + if [ "$digest" = "$expected_digest" ]; then + return 0 + fi + done < file2 + + return 1 +} + +setup() +{ + local cmdline="$(sed 's/BOOT_IMAGE=[^ ]* //' /proc/cmdline)" + local res=TBROK + local sb_enabled + + if [ ! -f "$IMA_KEXEC_IMAGE" ]; then + tst_brk TCONF "kernel image not found, specify path in \$IMA_KEXEC_IMAGE" + fi + + if check_policy_readable; then + require_ima_policy_content '^measure.*func=KEXEC_CMDLINE' + res=TFAIL + fi + + tst_res TINFO "loading kernel $IMA_KEXEC_IMAGE, cmdline: $cmdline" + if kexec -s -l $IMA_KEXEC_IMAGE --reuse-cmdline 2>err; then + ROD kexec -su + if ! measure "$cmdline"; then + if [ "$res" = TBROK ]; then + tst_res TWARN "policy not readable, it might not contain required measure func=KEXEC_CMDLINE" + fi + tst_brk $res "unable to find a correct entry for --reuse-cmdline" + fi + return + fi + + if tst_cmd_available bootctl; then + if bootctl status 2>/dev/null | grep -qi 'Secure Boot: enabled'; then + sb_enabled=1 + fi + elif tst_cmd_available dmesg; then + if dmesg | grep -qi 'Secure boot enabled'; then + sb_enabled=1 + fi + fi + if [ "$sb_enabled" ]; then + tst_res TWARN "secure boot is enabled, kernel image may not be signed" + fi + + if check_ima_policy_content '^appraise.*func=KEXEC_KERNEL_CHECK'; then + tst_res TWARN "'func=KEXEC_KERNEL_CHECK' appraise policy loaded, kernel image may not be signed" + fi + + tst_brk TBROK "kexec failed: $(cat err)" +} + +kexec_test() +{ + local cmdline="$1" + local param="$2" + + EXPECT_PASS_BRK kexec -s -l $IMA_KEXEC_IMAGE $param=$cmdline + ROD kexec -su + if ! measure "$cmdline"; then + tst_brk TFAIL "unable to find a correct entry for $param=$cmdline" + fi + tst_res TPASS "kexec cmdline for $param=$cmdline was measured correctly" +} + +test() +{ + case $1 in + 1) kexec_test 'foo' '--append';; + 2) kexec_test 'bar' '--command-line';; + esac +} + +tst_run