From patchwork Tue Aug 6 23:09:04 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Song Liu X-Patchwork-Id: 13755420 X-Patchwork-Delegate: bpf@iogearbox.net Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CDAE518D644; Tue, 6 Aug 2024 23:09:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722985772; cv=none; b=GuGq8QRi2kX6J2ifVcXqj6OFyYLYiZ1DqX5P7L5kNyorpKq0CMMkc337jXEEzPQiFKeWExGGshDhIVpCo3xossTtiEycWIBJ34NXVpOvx8AktnMeHrPflHsre2yiSvTkpyPYHjmVJ/M1RVx1H3pTpDhpgZeHkHdLuw4tUh1LCvA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722985772; c=relaxed/simple; bh=0/MubfKnoLPYreR2kgF8sk51n7kV6GHO/DNAiZifwVk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=VwsJbcdl9SQcfXzfNalmq9E0dYaAt7RYNKfZdbEauqWnL9jmK4g7WfyUzySVgiHZdTch8IlT4escGwKUopAufdivePNMB8nbuutlVDWaEPeXqSuAkp1uGKaIdjGvrGSjejXvZ0wrp4CPEBA73SRRkZjeJFOg1F8O0GmER2aABIc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=jgW+kgdD; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="jgW+kgdD" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CF356C32786; Tue, 6 Aug 2024 23:09:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1722985772; bh=0/MubfKnoLPYreR2kgF8sk51n7kV6GHO/DNAiZifwVk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jgW+kgdDhLoZ7Kne03x5GEE93NEKXaOg/ynpypt1cfgCe8mi3saO5FG35KqYTM6Sp LOLfZE1ez9a7EjkcVPoHE+LukV4C+eN9RQHSTtStfsSK8bFypLMgmuQ6tCPAKAuWUb BHx2SvifR1kzwHoQNBTz1FY2mZWf8t6SIQz6QDDlIHX+VLJtV5bSaNM5poT0vcGGjr xLMh2jVpLRny4W9Y07nz1/NVL29vZPOWjCrCofkK3YZ2OcaNqY0WuuMeVnE9CAMy3b zDVisNuRkmGc1nunxoNnUvmihEpoX2jg17vlJve6XTerhlOYrRjR4Lf4lzEdH6/sto O1/Z3YW1J0asw== From: Song Liu To: bpf@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Cc: kernel-team@meta.com, andrii@kernel.org, eddyz87@gmail.com, ast@kernel.org, daniel@iogearbox.net, martin.lau@linux.dev, viro@zeniv.linux.org.uk, brauner@kernel.org, jack@suse.cz, kpsingh@kernel.org, liamwisehart@meta.com, lltang@meta.com, shankaran@meta.com, Song Liu Subject: [PATCH v4 bpf-next 3/3] selftests/bpf: Add tests for bpf_get_dentry_xattr Date: Tue, 6 Aug 2024 16:09:04 -0700 Message-ID: <20240806230904.71194-4-song@kernel.org> X-Mailer: git-send-email 2.43.5 In-Reply-To: <20240806230904.71194-1-song@kernel.org> References: <20240806230904.71194-1-song@kernel.org> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: bpf@iogearbox.net Add test for bpf_get_dentry_xattr on hook security_inode_getxattr. Verify that the kfunc can read the xattr. Also test failing getxattr from user space by returning non-zero from the LSM bpf program. Acked-by: Christian Brauner Signed-off-by: Song Liu --- tools/testing/selftests/bpf/bpf_kfuncs.h | 9 +++++ .../selftests/bpf/prog_tests/fs_kfuncs.c | 9 ++++- .../selftests/bpf/progs/test_get_xattr.c | 37 ++++++++++++++++--- 3 files changed, 49 insertions(+), 6 deletions(-) diff --git a/tools/testing/selftests/bpf/bpf_kfuncs.h b/tools/testing/selftests/bpf/bpf_kfuncs.h index 3b6675ab4086..efed458a3c0a 100644 --- a/tools/testing/selftests/bpf/bpf_kfuncs.h +++ b/tools/testing/selftests/bpf/bpf_kfuncs.h @@ -78,4 +78,13 @@ extern int bpf_verify_pkcs7_signature(struct bpf_dynptr *data_ptr, extern bool bpf_session_is_return(void) __ksym __weak; extern __u64 *bpf_session_cookie(void) __ksym __weak; + +struct dentry; +/* Description + * Returns xattr of a dentry + * Returns__bpf_kfunc + * Error code + */ +extern int bpf_get_dentry_xattr(struct dentry *dentry, const char *name, + struct bpf_dynptr *value_ptr) __ksym __weak; #endif diff --git a/tools/testing/selftests/bpf/prog_tests/fs_kfuncs.c b/tools/testing/selftests/bpf/prog_tests/fs_kfuncs.c index 37056ba73847..5a0b51157451 100644 --- a/tools/testing/selftests/bpf/prog_tests/fs_kfuncs.c +++ b/tools/testing/selftests/bpf/prog_tests/fs_kfuncs.c @@ -16,6 +16,7 @@ static void test_xattr(void) { struct test_get_xattr *skel = NULL; int fd = -1, err; + int v[32]; fd = open(testfile, O_CREAT | O_RDONLY, 0644); if (!ASSERT_GE(fd, 0, "create_file")) @@ -50,7 +51,13 @@ static void test_xattr(void) if (!ASSERT_GE(fd, 0, "open_file")) goto out; - ASSERT_EQ(skel->bss->found_xattr, 1, "found_xattr"); + ASSERT_EQ(skel->bss->found_xattr_from_file, 1, "found_xattr_from_file"); + + /* Trigger security_inode_getxattr */ + err = getxattr(testfile, "user.kfuncs", v, sizeof(v)); + ASSERT_EQ(err, -1, "getxattr_return"); + ASSERT_EQ(errno, EINVAL, "getxattr_errno"); + ASSERT_EQ(skel->bss->found_xattr_from_dentry, 1, "found_xattr_from_dentry"); out: close(fd); diff --git a/tools/testing/selftests/bpf/progs/test_get_xattr.c b/tools/testing/selftests/bpf/progs/test_get_xattr.c index 7eb2a4e5a3e5..66e737720f7c 100644 --- a/tools/testing/selftests/bpf/progs/test_get_xattr.c +++ b/tools/testing/selftests/bpf/progs/test_get_xattr.c @@ -2,6 +2,7 @@ /* Copyright (c) 2023 Meta Platforms, Inc. and affiliates. */ #include "vmlinux.h" +#include #include #include #include "bpf_kfuncs.h" @@ -9,10 +10,12 @@ char _license[] SEC("license") = "GPL"; __u32 monitored_pid; -__u32 found_xattr; +__u32 found_xattr_from_file; +__u32 found_xattr_from_dentry; static const char expected_value[] = "hello"; -char value[32]; +char value1[32]; +char value2[32]; SEC("lsm.s/file_open") int BPF_PROG(test_file_open, struct file *f) @@ -25,13 +28,37 @@ int BPF_PROG(test_file_open, struct file *f) if (pid != monitored_pid) return 0; - bpf_dynptr_from_mem(value, sizeof(value), 0, &value_ptr); + bpf_dynptr_from_mem(value1, sizeof(value1), 0, &value_ptr); ret = bpf_get_file_xattr(f, "user.kfuncs", &value_ptr); if (ret != sizeof(expected_value)) return 0; - if (bpf_strncmp(value, ret, expected_value)) + if (bpf_strncmp(value1, ret, expected_value)) return 0; - found_xattr = 1; + found_xattr_from_file = 1; return 0; } + +SEC("lsm.s/inode_getxattr") +int BPF_PROG(test_inode_getxattr, struct dentry *dentry, char *name) +{ + struct bpf_dynptr value_ptr; + __u32 pid; + int ret; + + pid = bpf_get_current_pid_tgid() >> 32; + if (pid != monitored_pid) + return 0; + + bpf_dynptr_from_mem(value2, sizeof(value2), 0, &value_ptr); + + ret = bpf_get_dentry_xattr(dentry, "user.kfuncs", &value_ptr); + if (ret != sizeof(expected_value)) + return 0; + if (bpf_strncmp(value2, ret, expected_value)) + return 0; + found_xattr_from_dentry = 1; + + /* return non-zero to fail getxattr from user space */ + return -EINVAL; +}