From patchwork Fri Mar 7 21:36:39 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Blaise Boscaccy X-Patchwork-Id: 14007166 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 5C02525A2DA; Fri, 7 Mar 2025 21:37:32 +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=1741383453; cv=none; b=reUuiMuvVIfaiz83k7YN6RMCgGYplTgfymwHtv21sPlpw4c8b+B7b8MIvpHvje1SJago7YsybZRusmoOpeiwau8paRkd1Fxe8vFH+aKvT8eaMjtZwT2vAbVU+2bQvjXS75VTxUAvH3eHX9iQXCpJFGMMHaYxCcIehEBBu/1XvFg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741383453; c=relaxed/simple; bh=O8PVKvYuLZFZ1hbzG93ZiIe9NX0YGjQDGVDwdAB9GMo=; h=From:To:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=HC0za8zIg9XHSjS/dS3pEahJrszSGr7VViZoe9g1g7Ob2nJitlFAIVk+lRvpKB7eL7PwAKzG9INbBUduDmBQJZCpIDDllPGBHxpvScdd0riJUFvb0lRRfzVAIafTTDNSSzSGRiJr9amBfITSLBTTu1MtQ1cZvPmQcWsmWMl17ZM= 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=LJQ414ln; 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="LJQ414ln" Received: from narnia.corp.microsoft.com (unknown [167.220.2.28]) by linux.microsoft.com (Postfix) with ESMTPSA id 4D24D2038F3B; Fri, 7 Mar 2025 13:37:25 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 4D24D2038F3B DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1741383452; bh=0AvrEDwUkbov0d3x+aDqvdBfQQy6YYXE98sXwLkrjtY=; h=From:To:Subject:Date:In-Reply-To:References:From; b=LJQ414lnYZARo0aMTvwWc2kATbCTSu9aBj+s12srL5KQV7K4/s1xNr7xZ7lZAxUZC /ZfonVXkRcx4s+GRK80VkNXdblRxFqXCY0LrZg2w8zmUse6H++oMz/0gRQOubxrMjj z+8aafN0C+ToqqXYxvl29Rxo31xl/WQIkTU3nx9I= 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 v5 bpf-next 2/2] selftests/bpf: Add a kernel flag test for LSM bpf hook Date: Fri, 7 Mar 2025 13:36:39 -0800 Message-ID: <20250307213651.3065714-3-bboscaccy@linux.microsoft.com> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250307213651.3065714-1-bboscaccy@linux.microsoft.com> References: <20250307213651.3065714-1-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 --- .../selftests/bpf/prog_tests/kernel_flag.c | 43 +++++++++++++++++++ .../selftests/bpf/progs/test_kernel_flag.c | 32 ++++++++++++++ 2 files changed, 75 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..479ad5de3737e --- /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; + + ret = test_kernel_flag__attach(lsm_skel); + if (!ASSERT_OK(ret, "test_kernel_flag__attach")) + goto close_prog; + + lsm_skel->bss->monitored_pid = getpid(); + + /* 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_pid = 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..1e0320a1d2f6b --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_kernel_flag.c @@ -0,0 +1,32 @@ +// 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_pid; + +SEC("lsm.s/bpf") +int BPF_PROG(bpf, int cmd, union bpf_attr *attr, unsigned int size, bool kernel) +{ + __u32 pid; + + pid = bpf_get_current_pid_tgid() >> 32; + + if (pid != monitored_pid) + return 0; + + if (kernel) + return -EINVAL; + else + return 0; +}