From nobody Thu Oct 9 20:24:11 2025 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 EC10828BAB3; Tue, 17 Jun 2025 06:11:43 +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=1750140704; cv=none; b=Qlzia7KEsULgz6UE5jAJpOEq5GQBfqjf1Xp4xSDpHKdKz6KljrjLli9DZqZEIQxVgj07Pfu3HfQAosRFLUK4E/0rABXU5G0Vwd90+DwrT0pJpizF73wYfowk9xcWQUqBeOjcBJFy+Rg+dGmsnRSUIz3TzdyTQQ1RLqBA0g75Wlw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750140704; c=relaxed/simple; bh=9F10qO9Msdgz89bnpZRuwO8YiDXQDw7GfTMJBW3OmZE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=PSF2sjB2qCuhQcIcWKGms4vd1RLAO8Pe5zZLwonkKbSHdc586PQYgVjd2VDpHN9oyUJAFVoPnDfc9z7SKGR0A5Pe3Wifu6tzuSeDBuO6D7BtwtDI3LxhrTTyRc7p0SJM/0rKEuWCVRAXoEq+Of+P1p5qF0NBUZrm3DK4MLgklAo= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Mn6udA3y; 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="Mn6udA3y" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1571DC4CEE3; Tue, 17 Jun 2025 06:11:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1750140703; bh=9F10qO9Msdgz89bnpZRuwO8YiDXQDw7GfTMJBW3OmZE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Mn6udA3yB79z8yC8ygoRrxMRO8mWkizhYEKHHaL8t+nI1J7ZKscNDnnAB93/9mN+b OZxD6CUDlPTnQy5Unjl9+5Jyx0RQU4AilFBBleS3Nn4mT0kYKpZXyCWfAIz4GhK4Rq 3i1JVJei50XA/OwfM6UxXcG2sZKuKn1E2ImoWduSZxXXaK03vIhZDx7kK8v38yoqUs fXD0RdbH4LVWSpVxBRC2BmAol5Ab+Toj5eZxnJyvn77/IXayMj1L34QxKjniJn/zdw 51w/DnVPBrC/nwJwzjmhyR2IxuUPBciW/KGs5GGMnQKindt4bJiGE/sRhAO9SvL32y Vrep7EVsxfDMg== From: Song Liu To: bpf@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-security-module@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, mattbobrowski@google.com, m@maowtm.org, neil@brown.name, Song Liu Subject: [PATCH v5 bpf-next 4/5] selftests/bpf: Add tests for bpf path iterator Date: Mon, 16 Jun 2025 23:11:15 -0700 Message-ID: <20250617061116.3681325-5-song@kernel.org> X-Mailer: git-send-email 2.47.1 In-Reply-To: <20250617061116.3681325-1-song@kernel.org> References: <20250617061116.3681325-1-song@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Add tests for bpf path iterator, including test cases similar to real workload (call bpf_path_d_path and bpf_get_dentry_xattr), and test cases where the verifier rejects invalid use of the iterator. Signed-off-by: Song Liu --- .../testing/selftests/bpf/bpf_experimental.h | 6 + .../selftests/bpf/prog_tests/path_iter.c | 12 ++ tools/testing/selftests/bpf/progs/path_iter.c | 145 ++++++++++++++++++ 3 files changed, 163 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/path_iter.c create mode 100644 tools/testing/selftests/bpf/progs/path_iter.c diff --git a/tools/testing/selftests/bpf/bpf_experimental.h b/tools/testing= /selftests/bpf/bpf_experimental.h index 5e512a1d09d1..cbb759b473df 100644 --- a/tools/testing/selftests/bpf/bpf_experimental.h +++ b/tools/testing/selftests/bpf/bpf_experimental.h @@ -596,4 +596,10 @@ extern int bpf_iter_dmabuf_new(struct bpf_iter_dmabuf = *it) __weak __ksym; extern struct dma_buf *bpf_iter_dmabuf_next(struct bpf_iter_dmabuf *it) __= weak __ksym; extern void bpf_iter_dmabuf_destroy(struct bpf_iter_dmabuf *it) __weak __k= sym; =20 +struct bpf_iter_path; +extern int bpf_iter_path_new(struct bpf_iter_path *it, struct path *start, + __u64 flags) __weak __ksym; +extern struct path *bpf_iter_path_next(struct bpf_iter_path *it) __weak __= ksym; +extern void bpf_iter_path_destroy(struct bpf_iter_path *it) __weak __ksym; + #endif diff --git a/tools/testing/selftests/bpf/prog_tests/path_iter.c b/tools/tes= ting/selftests/bpf/prog_tests/path_iter.c new file mode 100644 index 000000000000..3c99c24fbd96 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/path_iter.c @@ -0,0 +1,12 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2025 Meta Platforms, Inc. and affiliates. */ + +#include +#include +#include +#include "path_iter.skel.h" + +void test_path_iter(void) +{ + RUN_TESTS(path_iter); +} diff --git a/tools/testing/selftests/bpf/progs/path_iter.c b/tools/testing/= selftests/bpf/progs/path_iter.c new file mode 100644 index 000000000000..74d0f4e19ffa --- /dev/null +++ b/tools/testing/selftests/bpf/progs/path_iter.c @@ -0,0 +1,145 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2025 Meta Platforms, Inc. and affiliates. */ + +#include "vmlinux.h" +#include +#include +#include "bpf_misc.h" +#include "bpf_experimental.h" + +char _license[] SEC("license") =3D "GPL"; + +char path_name[256]; +char xattr_val[64]; + +static __always_inline void access_path_dentry(struct path *p) +{ + struct bpf_dynptr ptr; + struct dentry *dentry; + + if (!p) + return; + + bpf_dynptr_from_mem(xattr_val, sizeof(xattr_val), 0, &ptr); + bpf_path_d_path(p, path_name, sizeof(path_name)); + + dentry =3D p->dentry; + if (dentry) + bpf_get_dentry_xattr(dentry, "user.xattr", &ptr); +} + +SEC("lsm.s/file_open") +__success +int BPF_PROG(open_code, struct file *f) +{ + struct bpf_iter_path path_it; + struct path *p; + int ret; + + ret =3D bpf_iter_path_new(&path_it, &f->f_path, 0); + if (ret) { + bpf_iter_path_destroy(&path_it); + return 0; + } + + p =3D bpf_iter_path_next(&path_it); + access_path_dentry(p); + bpf_iter_path_destroy(&path_it); + + return 0; +} + +SEC("lsm.s/file_open") +__success +int BPF_PROG(for_each, struct file *f) +{ + struct path *p; + + bpf_for_each(path, p, &f->f_path, 0) + access_path_dentry(p); + + return 0; +} + +SEC("lsm.s/file_open") +__failure __msg("Unreleased reference") +int BPF_PROG(missing_destroy, struct file *f) +{ + struct bpf_iter_path path_it; + + bpf_iter_path_new(&path_it, &f->f_path, 0); + + return 0; +} + +SEC("lsm.s/file_open") +__failure __msg("expected an initialized iter_path") +int BPF_PROG(missing_new, struct file *f) +{ + struct bpf_iter_path path_it; + + bpf_iter_path_destroy(&path_it); + return 0; +} + +SEC("lsm.s/file_open") +__failure __msg("expected uninitialized iter_path") +int BPF_PROG(new_twice, struct file *f) +{ + struct bpf_iter_path path_it; + + bpf_iter_path_new(&path_it, &f->f_path, 0); + bpf_iter_path_new(&path_it, &f->f_path, 0); + bpf_iter_path_destroy(&path_it); + return 0; +} + +SEC("lsm.s/file_open") +__failure __msg("expected an initialized iter_path") +int BPF_PROG(destroy_twice, struct file *f) +{ + struct bpf_iter_path path_it; + + bpf_iter_path_new(&path_it, &f->f_path, 0); + bpf_iter_path_destroy(&path_it); + bpf_iter_path_destroy(&path_it); + return 0; +} + +SEC("lsm.s/file_open") +__success +int BPF_PROG(reuse_path_iter, struct file *f) +{ + struct bpf_iter_path path_it; + + bpf_iter_path_new(&path_it, &f->f_path, 0); + bpf_iter_path_destroy(&path_it); + bpf_iter_path_new(&path_it, &f->f_path, 0); + bpf_iter_path_destroy(&path_it); + return 0; +} + +SEC("lsm.s/file_open") +__failure __msg("invalid read from stack off") +int BPF_PROG(invalid_read_path_iter, struct file *f) +{ + struct bpf_iter_path path_it; + struct bpf_iter_path path_it_2; + + + bpf_iter_path_new(&path_it, &f->f_path, 0); + path_it_2 =3D path_it; + bpf_iter_path_destroy(&path_it_2); + return 0; +} + +SEC("lsm.s/sb_alloc_security") +__failure __msg("must be referenced or trusted") +int BPF_PROG(untrusted_path, struct super_block *sb) +{ + struct bpf_iter_path path_it; + + bpf_iter_path_new(&path_it, &sb->s_bdev_file->f_path, 0); + bpf_iter_path_destroy(&path_it); + return 0; +} --=20 2.47.1