From patchwork Mon Mar 10 22:17:12 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Blaise Boscaccy X-Patchwork-Id: 14010788 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 87EC71E885C; Mon, 10 Mar 2025 22:18:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=13.77.154.182 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741645095; cv=none; b=dvN75p9OpC7cFdaJ61JD5TursvMB3qnfIZkSWg50fYkJ9PPpyIasudR5PO2FW6KBZKDug+QGTjDtGtzR35U2AxGvFZW9r9xj2z5w2XSfgW9/GiDDXFWTceoA9CnY2gMMZrXj+X8AZrF/cLZHe/sH7+elLM8xvE56LfBwKlpHD9g= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741645095; c=relaxed/simple; bh=SN3qRmp2VsH+hfZzbschHT13b+7JeCD/f0E1AXv3ATw=; h=From:To:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=XRmXWkpN+t/7fenzISf4SkQ9TZ2QluzufrKMFxdDaJyPiqmUsK8FA2nalhR5sfDc9hm7/gNkYjc5L80KDfnmA6+g+HaxyahrON5lnRonNmz3FCvyGPgu7b3C3Lx7tecvOg/XSRnlhf/IACIpHYfNkWqcx4XsBWJdHkbv6LEnxNY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com; spf=pass smtp.mailfrom=linux.microsoft.com; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b=dK52eV9D; arc=none smtp.client-ip=13.77.154.182 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="dK52eV9D" Received: from narnia.corp.microsoft.com (unknown [167.220.2.28]) by linux.microsoft.com (Postfix) with ESMTPSA id D5CFA2111421; Mon, 10 Mar 2025 15:18:04 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com D5CFA2111421 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1741645093; bh=MrftlxeEFs9Mx0mFvTjVrigQo9uOdYagfaYRGPfbOKw=; h=From:To:Subject:Date:In-Reply-To:References:From; b=dK52eV9DWfe7TBQSD7aqqx8TJ30fFtxC/Cmv6vrVTtwBqYqmdavIqpSd9K0LTuivJ 7D9vi8zuASSTi2F18Tnt42dmGnxWiCQfxCTgiTG02a7GmX19VRaYtaSpv5AIP/JLLB noz0r8BvFIMi2SP4NQJwHbHYSS4TSJ5KiGQBJmJw= From: Blaise Boscaccy To: Paul Moore , James Morris , "Serge E. Hallyn" , Alexei Starovoitov , Daniel Borkmann , John Fastabend , Andrii Nakryiko , Martin KaFai Lau , Eduard Zingerman , Song Liu , Yonghong Song , KP Singh , Stanislav Fomichev , Hao Luo , Jiri Olsa , Stephen Smalley , Ondrej Mosnacek , Mykola Lysenko , Shuah Khan , Blaise Boscaccy , Kumar Kartikeya Dwivedi , Matt Bobrowski , Xu Kuohai , linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, bpf@vger.kernel.org, selinux@vger.kernel.org, linux-kselftest@vger.kernel.org Subject: [PATCH v7 bpf-next 2/2] selftests/bpf: Add a kernel flag test for LSM bpf hook Date: Mon, 10 Mar 2025 15:17:12 -0700 Message-ID: <20250310221737.821889-3-bboscaccy@linux.microsoft.com> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250310221737.821889-1-bboscaccy@linux.microsoft.com> References: <20250310221737.821889-1-bboscaccy@linux.microsoft.com> Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 This test exercises the kernel flag added to security_bpf by effectively blocking light-skeletons from loading while allowing normal skeletons to function as-is. Since this should work with any arbitrary BPF program, an existing program from LSKELS_EXTRA was used as a test payload. Signed-off-by: Blaise Boscaccy Acked-by: Song Liu --- .../selftests/bpf/prog_tests/kernel_flag.c | 43 +++++++++++++++++++ .../selftests/bpf/progs/test_kernel_flag.c | 28 ++++++++++++ 2 files changed, 71 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/kernel_flag.c create mode 100644 tools/testing/selftests/bpf/progs/test_kernel_flag.c diff --git a/tools/testing/selftests/bpf/prog_tests/kernel_flag.c b/tools/testing/selftests/bpf/prog_tests/kernel_flag.c new file mode 100644 index 0000000000000..a133354ac9bc2 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/kernel_flag.c @@ -0,0 +1,43 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2025 Microsoft */ +#include +#include "kfunc_call_test.skel.h" +#include "kfunc_call_test.lskel.h" +#include "test_kernel_flag.skel.h" + +void test_kernel_flag(void) +{ + struct test_kernel_flag *lsm_skel; + struct kfunc_call_test *skel = NULL; + struct kfunc_call_test_lskel *lskel = NULL; + int ret; + + lsm_skel = test_kernel_flag__open_and_load(); + if (!ASSERT_OK_PTR(lsm_skel, "lsm_skel")) + return; + + lsm_skel->bss->monitored_tid = gettid(); + + ret = test_kernel_flag__attach(lsm_skel); + if (!ASSERT_OK(ret, "test_kernel_flag__attach")) + goto close_prog; + + /* Test with skel. This should pass the gatekeeper */ + skel = kfunc_call_test__open_and_load(); + if (!ASSERT_OK_PTR(skel, "skel")) + goto close_prog; + + /* Test with lskel. This should fail due to blocking kernel-based bpf() invocations */ + lskel = kfunc_call_test_lskel__open_and_load(); + if (!ASSERT_ERR_PTR(lskel, "lskel")) + goto close_prog; + +close_prog: + if (skel) + kfunc_call_test__destroy(skel); + if (lskel) + kfunc_call_test_lskel__destroy(lskel); + + lsm_skel->bss->monitored_tid = 0; + test_kernel_flag__destroy(lsm_skel); +} diff --git a/tools/testing/selftests/bpf/progs/test_kernel_flag.c b/tools/testing/selftests/bpf/progs/test_kernel_flag.c new file mode 100644 index 0000000000000..b45fab3be3528 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_kernel_flag.c @@ -0,0 +1,28 @@ +// SPDX-License-Identifier: GPL-2.0 + +/* + * Copyright (C) 2025 Microsoft Corporation + * + * Author: Blaise Boscaccy + */ + +#include "vmlinux.h" +#include +#include +#include + +char _license[] SEC("license") = "GPL"; + +__u32 monitored_tid; + +SEC("lsm.s/bpf") +int BPF_PROG(bpf, int cmd, union bpf_attr *attr, unsigned int size, bool kernel) +{ + __u32 tid; + + tid = bpf_get_current_pid_tgid() & 0xFFFFFFFF; + if (!kernel || tid != monitored_tid) + return 0; + else + return -EINVAL; +}