From patchwork Tue Oct 4 13:17:50 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Roberto Sassu X-Patchwork-Id: 12998298 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 57A47C433F5 for ; Tue, 4 Oct 2022 13:19:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230297AbiJDNTr (ORCPT ); Tue, 4 Oct 2022 09:19:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53102 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230135AbiJDNTZ (ORCPT ); Tue, 4 Oct 2022 09:19:25 -0400 Received: from frasgout12.his.huawei.com (frasgout12.his.huawei.com [14.137.139.154]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A5B454F66F; Tue, 4 Oct 2022 06:19:11 -0700 (PDT) Received: from mail02.huawei.com (unknown [172.18.147.229]) by frasgout12.his.huawei.com (SkyGuard) with ESMTP id 4MhdT333Ygz9v7Gg; Tue, 4 Oct 2022 21:14:15 +0800 (CST) Received: from huaweicloud.com (unknown [10.204.63.22]) by APP2 (Coremail) with SMTP id GxC2BwA3ZV+JMjxj8ZGaAA--.6154S8; Tue, 04 Oct 2022 14:18:52 +0100 (CET) From: Roberto Sassu To: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, martin.lau@linux.dev, song@kernel.org, yhs@fb.com, john.fastabend@gmail.com, kpsingh@kernel.org, sdf@google.com, haoluo@google.com, jolsa@kernel.org, mykolal@fb.com, shuah@kernel.org Cc: bpf@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, Roberto Sassu Subject: [RESEND][PATCH 6/6] selftests/bpf: Add tests for _opts variants of bpf_*_get_fd_by_id() Date: Tue, 4 Oct 2022 15:17:50 +0200 Message-Id: <20221004131750.2306251-7-roberto.sassu@huaweicloud.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20221004131750.2306251-1-roberto.sassu@huaweicloud.com> References: <20221004131750.2306251-1-roberto.sassu@huaweicloud.com> MIME-Version: 1.0 X-CM-TRANSID: GxC2BwA3ZV+JMjxj8ZGaAA--.6154S8 X-Coremail-Antispam: 1UD129KBjvJXoW3XF4rJF43GFW8ur47tw45trb_yoWxXr17pa 93Gr1YkryFqr4093sxJF45Wr48KFW8X34Ut397WFy5Zr18XFn7Ww1xGF13tF9xurZ5Gws3 Z3y3try8GrW7ua7anT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUBvb4IE77IF4wAFF20E14v26rWj6s0DM7CY07I20VC2zVCF04k2 6cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28IrcIa0xkI8VA2jI8067AKxVWUAV Cq3wA2048vs2IY020Ec7CjxVAFwI0_Xr0E3s1l8cAvFVAK0II2c7xJM28CjxkF64kEwVA0 rcxSw2x7M28EF7xvwVC0I7IYx2IY67AKxVWUCVW8JwA2z4x0Y4vE2Ix0cI8IcVCY1x0267 AKxVW8Jr0_Cr1UM28EF7xvwVC2z280aVAFwI0_Gr0_Cr1l84ACjcxK6I8E87Iv6xkF7I0E 14v26r4UJVWxJr1le2I262IYc4CY6c8Ij28IcVAaY2xG8wAqx4xG64xvF2IEw4CE5I8CrV C2j2WlYx0E2Ix0cI8IcVAFwI0_Jr0_Jr4lYx0Ex4A2jsIE14v26r1j6r4UMcvjeVCFs4IE 7xkEbVWUJVW8JwACjcxG0xvY0x0EwIxGrwACI402YVCY1x02628vn2kIc2xKxwCF04k20x vY0x0EwIxGrwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E14v26r1j6r18MI8I 3I0E7480Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_GFv_WrylIxkGc2Ij64vIr41lIx AIcVC0I7IYx2IY67AKxVWUCVW8JwCI42IY6xIIjxv20xvEc7CjxVAFwI0_Gr1j6F4UJwCI 42IY6xAIw20EY4v20xvaj40_Jr0_JF4lIxAIcVC2z280aVAFwI0_Gr0_Cr1lIxAIcVC2z2 80aVCY1x0267AKxVW8Jr0_Cr1UYxBIdaVFxhVjvjDU0xZFpf9x07UZo7tUUUUU= X-CM-SenderInfo: purev21wro2thvvxqx5xdzvxpfor3voofrz/1tbiAQAPBF1jj4PQKgAAsC X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org From: Roberto Sassu Introduce the data_input map, write-protected with a small eBPF program implementing the lsm/bpf_map hook. Then, ensure that bpf_map_get_fd_by_id() and bpf_map_get_fd_by_id_opts() with NULL opts don't succeed due to requesting read-write access to the write-protected map. Also, ensure that bpf_map_get_fd_by_id_opts() with open_flags in opts set to BPF_F_RDONLY instead succeeds. After obtaining a read-only fd, ensure that only map lookup succeeds and not update. Ensure that update works only with the read-write fd obtained at program loading time, when the write protection was not yet enabled. Finally, ensure that the other _opts variants of bpf_*_get_fd_by_id() don't work if the BPF_F_RDONLY flag is set in opts (due to the kernel not handling the open_flags member of bpf_attr). Signed-off-by: Roberto Sassu --- tools/testing/selftests/bpf/DENYLIST.s390x | 1 + .../bpf/prog_tests/libbpf_get_fd_opts.c | 88 +++++++++++++++++++ .../bpf/progs/test_libbpf_get_fd_opts.c | 36 ++++++++ 3 files changed, 125 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/libbpf_get_fd_opts.c create mode 100644 tools/testing/selftests/bpf/progs/test_libbpf_get_fd_opts.c diff --git a/tools/testing/selftests/bpf/DENYLIST.s390x b/tools/testing/selftests/bpf/DENYLIST.s390x index 17e074eb42b8..780a9b2090ad 100644 --- a/tools/testing/selftests/bpf/DENYLIST.s390x +++ b/tools/testing/selftests/bpf/DENYLIST.s390x @@ -75,3 +75,4 @@ user_ringbuf # failed to find kernel BTF type ID of lookup_key # JIT does not support calling kernel function (kfunc) verify_pkcs7_sig # JIT does not support calling kernel function (kfunc) kfunc_dynptr_param # JIT does not support calling kernel function (kfunc) +libbpf_get_fd_opts # failed to attach: ERROR: strerror_r(-524)=22 (trampoline) diff --git a/tools/testing/selftests/bpf/prog_tests/libbpf_get_fd_opts.c b/tools/testing/selftests/bpf/prog_tests/libbpf_get_fd_opts.c new file mode 100644 index 000000000000..2d4ba8f80d55 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/libbpf_get_fd_opts.c @@ -0,0 +1,88 @@ +// SPDX-License-Identifier: GPL-2.0 + +/* + * Copyright (C) 2022 Huawei Technologies Duesseldorf GmbH + * + * Author: Roberto Sassu + */ + +#include + +#include "test_libbpf_get_fd_opts.skel.h" + +void test_libbpf_get_fd_opts(void) +{ + struct test_libbpf_get_fd_opts *skel; + struct bpf_map_info info_m = { 0 }; + __u32 len = sizeof(info_m), value; + struct bpf_map *map; + int ret, zero = 0, fd = -1; + + DECLARE_LIBBPF_OPTS(bpf_get_fd_opts, fd_opts_rdonly, + .open_flags = BPF_F_RDONLY, + ); + + skel = test_libbpf_get_fd_opts__open_and_load(); + if (!ASSERT_OK_PTR(skel, "test_libbpf_get_fd_opts__open_and_load")) + return; + + ret = test_libbpf_get_fd_opts__attach(skel); + if (!ASSERT_OK(ret, "test_libbpf_get_fd_opts__attach")) + goto close_prog; + + map = bpf_object__find_map_by_name(skel->obj, "data_input"); + if (!ASSERT_OK_PTR(map, "bpf_object__find_map_by_name")) + goto close_prog; + + ret = bpf_obj_get_info_by_fd(bpf_map__fd(map), &info_m, &len); + if (!ASSERT_OK(ret, "bpf_obj_get_info_by_fd")) + goto close_prog; + + fd = bpf_map_get_fd_by_id(info_m.id); + if (!ASSERT_LT(fd, 0, "bpf_map_get_fd_by_id")) + goto close_prog; + + fd = bpf_map_get_fd_by_id_opts(info_m.id, NULL); + if (!ASSERT_LT(fd, 0, "bpf_map_get_fd_by_id_opts")) + goto close_prog; + + fd = bpf_map_get_fd_by_id_opts(info_m.id, &fd_opts_rdonly); + if (!ASSERT_GE(fd, 0, "bpf_map_get_fd_by_id_opts")) + goto close_prog; + + /* Map lookup should work with read-only fd. */ + ret = bpf_map_lookup_elem(fd, &zero, &value); + if (!ASSERT_OK(ret, "bpf_map_lookup_elem")) + goto close_prog; + + if (!ASSERT_EQ(value, 0, "map value mismatch")) + goto close_prog; + + /* Map update should not work with read-only fd. */ + ret = bpf_map_update_elem(fd, &zero, &len, BPF_ANY); + if (!ASSERT_LT(ret, 0, "bpf_map_update_elem")) + goto close_prog; + + /* Map update should work with read-write fd. */ + ret = bpf_map_update_elem(bpf_map__fd(map), &zero, &len, BPF_ANY); + if (!ASSERT_OK(ret, "bpf_map_update_elem")) + goto close_prog; + + /* Prog get fd with opts set should not work (no kernel support). */ + ret = bpf_prog_get_fd_by_id_opts(0, &fd_opts_rdonly); + if (!ASSERT_EQ(ret, -EINVAL, "bpf_prog_get_fd_by_id_opts")) + goto close_prog; + + /* Link get fd with opts set should not work (no kernel support). */ + ret = bpf_link_get_fd_by_id_opts(0, &fd_opts_rdonly); + if (!ASSERT_EQ(ret, -EINVAL, "bpf_link_get_fd_by_id_opts")) + goto close_prog; + + /* BTF get fd with opts set should not work (no kernel support). */ + ret = bpf_btf_get_fd_by_id_opts(0, &fd_opts_rdonly); + ASSERT_EQ(ret, -EINVAL, "bpf_btf_get_fd_by_id_opts"); + +close_prog: + close(fd); + test_libbpf_get_fd_opts__destroy(skel); +} diff --git a/tools/testing/selftests/bpf/progs/test_libbpf_get_fd_opts.c b/tools/testing/selftests/bpf/progs/test_libbpf_get_fd_opts.c new file mode 100644 index 000000000000..f5ac5f3e8919 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_libbpf_get_fd_opts.c @@ -0,0 +1,36 @@ +// SPDX-License-Identifier: GPL-2.0 + +/* + * Copyright (C) 2022 Huawei Technologies Duesseldorf GmbH + * + * Author: Roberto Sassu + */ + +#include "vmlinux.h" +#include +#include +#include + +/* From include/linux/mm.h. */ +#define FMODE_WRITE 0x2 + +struct { + __uint(type, BPF_MAP_TYPE_ARRAY); + __uint(max_entries, 1); + __type(key, __u32); + __type(value, __u32); +} data_input SEC(".maps"); + +char _license[] SEC("license") = "GPL"; + +SEC("lsm/bpf_map") +int BPF_PROG(check_access, struct bpf_map *map, fmode_t fmode) +{ + if (map != (struct bpf_map *)&data_input) + return 0; + + if (fmode & FMODE_WRITE) + return -EACCES; + + return 0; +}