From patchwork Wed Mar 2 11:14:03 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Roberto Sassu X-Patchwork-Id: 12765801 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 0567EC3527A for ; Wed, 2 Mar 2022 11:18:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241326AbiCBLTC (ORCPT ); Wed, 2 Mar 2022 06:19:02 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51584 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241739AbiCBLSf (ORCPT ); Wed, 2 Mar 2022 06:18:35 -0500 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 21FDFC4B7B; Wed, 2 Mar 2022 03:16:05 -0800 (PST) Received: from fraeml714-chm.china.huawei.com (unknown [172.18.147.200]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4K7s2l3lsFz67xDf; Wed, 2 Mar 2022 19:14:39 +0800 (CST) Received: from roberto-ThinkStation-P620.huawei.com (10.204.63.22) by fraeml714-chm.china.huawei.com (10.206.15.33) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.21; Wed, 2 Mar 2022 12:15:51 +0100 From: Roberto Sassu To: , , , , , , , , CC: , , , , , , Roberto Sassu Subject: [PATCH v3 8/9] selftests/bpf: Add test for bpf_lsm_kernel_read_file() Date: Wed, 2 Mar 2022 12:14:03 +0100 Message-ID: <20220302111404.193900-9-roberto.sassu@huawei.com> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20220302111404.193900-1-roberto.sassu@huawei.com> References: <20220302111404.193900-1-roberto.sassu@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.204.63.22] X-ClientProxiedBy: lhreml751-chm.china.huawei.com (10.201.108.201) To fraeml714-chm.china.huawei.com (10.206.15.33) X-CFilter-Loop: Reflected Precedence: bulk List-ID: Test the ability of bpf_lsm_kernel_read_file() to call the sleepable functions bpf_ima_inode_hash() or bpf_ima_file_hash() to obtain a measurement of a loaded IMA policy. Signed-off-by: Roberto Sassu --- tools/testing/selftests/bpf/ima_setup.sh | 13 ++++++++++++- .../selftests/bpf/prog_tests/test_ima.c | 19 +++++++++++++++++++ tools/testing/selftests/bpf/progs/ima.c | 18 ++++++++++++++++++ 3 files changed, 49 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/bpf/ima_setup.sh b/tools/testing/selftests/bpf/ima_setup.sh index a3de1cd43ba0..8ecead4ccad0 100755 --- a/tools/testing/selftests/bpf/ima_setup.sh +++ b/tools/testing/selftests/bpf/ima_setup.sh @@ -12,7 +12,7 @@ LOG_FILE="$(mktemp /tmp/ima_setup.XXXX.log)" usage() { - echo "Usage: $0 " + echo "Usage: $0 " exit 1 } @@ -51,6 +51,7 @@ setup() ensure_mount_securityfs echo "measure func=BPRM_CHECK fsuuid=${mount_uuid}" > ${IMA_POLICY_FILE} + echo "measure func=BPRM_CHECK fsuuid=${mount_uuid}" > ${mount_dir}/policy_test } cleanup() { @@ -95,6 +96,14 @@ restore_bin() truncate -s -4 "${copied_bin_path}" } +load_policy() +{ + local tmp_dir="$1" + local mount_dir="${tmp_dir}/mnt" + + echo ${mount_dir}/policy_test > ${IMA_POLICY_FILE} 2> /dev/null +} + catch() { local exit_code="$1" @@ -127,6 +136,8 @@ main() modify_bin "${tmp_dir}" elif [[ "${action}" == "restore-bin" ]]; then restore_bin "${tmp_dir}" + elif [[ "${action}" == "load-policy" ]]; then + load_policy "${tmp_dir}" else echo "Unknown action: ${action}" exit 1 diff --git a/tools/testing/selftests/bpf/prog_tests/test_ima.c b/tools/testing/selftests/bpf/prog_tests/test_ima.c index a0cfba0b4273..b13a141c4220 100644 --- a/tools/testing/selftests/bpf/prog_tests/test_ima.c +++ b/tools/testing/selftests/bpf/prog_tests/test_ima.c @@ -58,6 +58,7 @@ static void test_init(struct ima__bss *bss) bss->use_ima_file_hash = false; bss->enable_bprm_creds_for_exec = false; + bss->enable_kernel_read_file = false; } void test_test_ima(void) @@ -181,6 +182,24 @@ void test_test_ima(void) if (CHECK(err, "restore-bin #3", "err = %d\n", err)) goto close_clean; + /* + * Test #5 + * - Goal: obtain a sample from the kernel_read_file hook + * - Expected result: 2 samples (./ima_setup.sh, policy_test) + */ + test_init(skel->bss); + skel->bss->use_ima_file_hash = true; + skel->bss->enable_kernel_read_file = true; + err = _run_measured_process(measured_dir, &skel->bss->monitored_pid, + "load-policy"); + if (CHECK(err, "run_measured_process #5", "err = %d\n", err)) + goto close_clean; + + err = ring_buffer__consume(ringbuf); + ASSERT_EQ(err, 2, "num_samples_or_err"); + ASSERT_NEQ(ima_hash_from_bpf[0], 0, "ima_hash"); + ASSERT_NEQ(ima_hash_from_bpf[1], 0, "ima_hash"); + close_clean: snprintf(cmd, sizeof(cmd), "./ima_setup.sh cleanup %s", measured_dir); err = system(cmd); diff --git a/tools/testing/selftests/bpf/progs/ima.c b/tools/testing/selftests/bpf/progs/ima.c index 9633e5f2453d..e3ce943c5c3d 100644 --- a/tools/testing/selftests/bpf/progs/ima.c +++ b/tools/testing/selftests/bpf/progs/ima.c @@ -20,6 +20,7 @@ char _license[] SEC("license") = "GPL"; bool use_ima_file_hash; bool enable_bprm_creds_for_exec; +bool enable_kernel_read_file; static void ima_test_common(struct file *file) { @@ -65,3 +66,20 @@ int BPF_PROG(bprm_creds_for_exec, struct linux_binprm *bprm) ima_test_common(bprm->file); return 0; } + +SEC("lsm.s/kernel_read_file") +int BPF_PROG(kernel_read_file, struct file *file, enum kernel_read_file_id id, + bool contents) +{ + if (!enable_kernel_read_file) + return 0; + + if (!contents) + return 0; + + if (id != READING_POLICY) + return 0; + + ima_test_common(file); + return 0; +}