From patchwork Mon Aug 14 14:33:40 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yafang Shao X-Patchwork-Id: 13352987 X-Patchwork-Delegate: bpf@iogearbox.net Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (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 197FBBA34 for ; Mon, 14 Aug 2023 14:33:57 +0000 (UTC) Received: from mail-pj1-x1031.google.com (mail-pj1-x1031.google.com [IPv6:2607:f8b0:4864:20::1031]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4CB31E4 for ; Mon, 14 Aug 2023 07:33:56 -0700 (PDT) Received: by mail-pj1-x1031.google.com with SMTP id 98e67ed59e1d1-26b51d4c985so588636a91.3 for ; Mon, 14 Aug 2023 07:33:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1692023636; x=1692628436; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=kfmfYuK3h1PWtmYdohsUHU5+4gvI6M0fjo7fbdpTz7I=; b=g2uYCkqZpoTD4jcO2bcD0TQiKJnOLI4CZBurFbLB916Cn8tq1Xfi3aPZR1CSlT2FcK Mt2+IsalXWiNgfqLoJ2UsKIgDfuXPXm1kXsKlRIQimN9e2k4gU1XRzSW/qaDKlrDwxsG 4mNpsckTMjZPZEwjtXVuXdMa1Gpy3A4C3IPbFSx6GKBDpx/1bTmiIqzDAKG89OBIhgV0 bxUCy0T0LLiYzA6tyC52iMNr4GZIijoHS/ZSz0lxUv3TDXjbor1nG+IA3khAQNTZTk4M PgN2ZZt0XWCvNpRk93L/PoGHz3ar93jI3yuJQXuGWbU+xzPjUn5z2SlbQEXPnotrrfqq /GQA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1692023636; x=1692628436; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=kfmfYuK3h1PWtmYdohsUHU5+4gvI6M0fjo7fbdpTz7I=; b=Am7VLVB5zzWuIGWY6ydHa90dNomETVLBkljhUjrfy5z38AXBOm51j+1HBt8dL85kBI jJFx+vc4EO+MudD7Uypo2sbQudjAd/CQcvhIjq3zyLVvhFLp6nH1sQ0/SERDNjPltH2J dh4tOODKyLHf3cdEJVXdH0yyuUydjAH3u+5gLWqy7U50r7MhiJtq2LH/iW1H68FZqPUW rf1w4alupxTnPhLqyUgnlGwcmfhzJeSPmK1Bf+yP5qcWfAvRPfbMzH8fhyRHnFRVLsfj CLhusFsKvTIF3TNKxK3hrBMaWwdWLVHgtNPG1AM8A2ba0K8N2ne6kfAuhv4j0rVr2LKN niAA== X-Gm-Message-State: AOJu0YwEFnsiE6+D5FNz2s68GmeAFk/R9w5WseyGmjkizZeGDFSLlyBh /BYNmFNUP8WgLtfLFnxV8u4= X-Google-Smtp-Source: AGHT+IFpHhdkMyFLONbLvcR5AqtEfQgR7VeOhXl8SxCE1FqouAwF8UlvWOwMhF4SBfSFc0svxQ/8Kg== X-Received: by 2002:a17:90a:760c:b0:263:f7ce:335e with SMTP id s12-20020a17090a760c00b00263f7ce335emr6785987pjk.43.1692023635590; Mon, 14 Aug 2023 07:33:55 -0700 (PDT) Received: from vultr.guest ([149.28.193.116]) by smtp.gmail.com with ESMTPSA id 19-20020a17090a031300b002677739860fsm8640390pje.34.2023.08.14.07.33.54 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 14 Aug 2023 07:33:55 -0700 (PDT) From: Yafang Shao To: ast@kernel.org, daniel@iogearbox.net, john.fastabend@gmail.com, andrii@kernel.org, martin.lau@linux.dev, song@kernel.org, yonghong.song@linux.dev, kpsingh@kernel.org, sdf@google.com, haoluo@google.com, jolsa@kernel.org Cc: bpf@vger.kernel.org, Yafang Shao Subject: [RFC PATCH bpf-next 1/2] bpf: Add bpf_current_capable kfunc Date: Mon, 14 Aug 2023 14:33:40 +0000 Message-Id: <20230814143341.3767-2-laoar.shao@gmail.com> X-Mailer: git-send-email 2.39.3 In-Reply-To: <20230814143341.3767-1-laoar.shao@gmail.com> References: <20230814143341.3767-1-laoar.shao@gmail.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FREEMAIL_FROM, RCVD_IN_DNSWL_BLOCKED,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net X-Patchwork-Delegate: bpf@iogearbox.net X-Patchwork-State: RFC Add a new bpf_current_capable kfunc to check whether the current task has a specific capability. In our use case, we will use it in a lsm bpf program to help identify if the user operation is permitted. Signed-off-by: Yafang Shao --- kernel/bpf/helpers.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index eb91cae..bbee7ea 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -2429,6 +2429,11 @@ __bpf_kfunc void bpf_rcu_read_unlock(void) rcu_read_unlock(); } +__bpf_kfunc bool bpf_current_capable(int cap) +{ + return has_capability(current, cap); +} + __diag_pop(); BTF_SET8_START(generic_btf_ids) @@ -2456,6 +2461,7 @@ __bpf_kfunc void bpf_rcu_read_unlock(void) BTF_ID_FLAGS(func, bpf_task_under_cgroup, KF_RCU) #endif BTF_ID_FLAGS(func, bpf_task_from_pid, KF_ACQUIRE | KF_RET_NULL) +BTF_ID_FLAGS(func, bpf_current_capable, KF_RCU) BTF_SET8_END(generic_btf_ids) static const struct btf_kfunc_id_set generic_kfunc_set = { From patchwork Mon Aug 14 14:33:41 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yafang Shao X-Patchwork-Id: 13352988 X-Patchwork-Delegate: bpf@iogearbox.net Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (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 AEB7DBA34 for ; Mon, 14 Aug 2023 14:33:58 +0000 (UTC) Received: from mail-pl1-x62f.google.com (mail-pl1-x62f.google.com [IPv6:2607:f8b0:4864:20::62f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A3ABAE4 for ; Mon, 14 Aug 2023 07:33:57 -0700 (PDT) Received: by mail-pl1-x62f.google.com with SMTP id d9443c01a7336-1bdb7b0c8afso15579645ad.3 for ; Mon, 14 Aug 2023 07:33:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1692023637; x=1692628437; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=Vv4yUrMyWBhLHqAH2ovg1Sj3+silqXptyM0b5G7vsNI=; b=kGUe+mJFGFg9aC/s8merWTnWNun1P0VmxQ/LRkfNSvUQ0uUuDuEolcDXuqcHeWfziC D8rrmnR6x7jeoTyVP1H0orcQdmDU3ZnFBeu7KfabJKFghZQyCtg94EQn0KAmjAaJYsJe EiX6QNpT/+4GNyfD5gATADfzcJbwLICnYbgUuxmsTT8WrsTFvYOoOVx7F3r89bjL9EXZ IfY27oXcYjsYYzNqkxaMI1U8Z6/pH87jn/rQDJKKvbC6gHMJvI47e49fSlPc80t4hwGC mRlk12kdux/nO/5hJjh6+4QUtC967+exEfxSWE5QOllttf3MrKsWh0uzXMObRtF/Iz/R 4KPg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1692023637; x=1692628437; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=Vv4yUrMyWBhLHqAH2ovg1Sj3+silqXptyM0b5G7vsNI=; b=Kt4D132tBMCKKjrYjP4lyMplaqHHsa2NIpWBLoF7I5FoaffKM7g+zaHSDcN3kR9HKx 8WOA+ZTffRAHdxOqUhonCmYFxqV1sCgUWk6L1Bw69tI3wHl9IKiCF7AtMYgugTl3JsVb FaB6E+UWVCfXjeRv1TVZPaeJpg3/x1yi/B0COWfk7zycXnOw31WOUSN5t6Q6VX0qz1Ok QM/STxKBTOgUb+PjlSl1IUrdpys2TdrrZjO0ep6NVUetBJekz+8rWZzidPmEtUIpyXqr s2aGEE3FSUUtRrVcYfad8ePxCK3ar7YCz7aM5weucGjw55Ze2PKEvFqzofeIXfs37LBt gEUQ== X-Gm-Message-State: AOJu0YwwR2OHwmFJUo0Hs1ePUhWpAy1N8ngioDhel0PepnajjWc1MYDo b6jJ1iYJtVe43q8+3XEdGrvXa0rjgbZh0s6+ X-Google-Smtp-Source: AGHT+IH7dsJH26H/nkFXa68jzmQQIpzL3bo9qMkvtmk9p2dGcKieaMc1ZD8WOQj8ic0AzNh0KMx/CQ== X-Received: by 2002:a17:90a:9ee:b0:267:c21f:ce0d with SMTP id 101-20020a17090a09ee00b00267c21fce0dmr6655310pjo.27.1692023636965; Mon, 14 Aug 2023 07:33:56 -0700 (PDT) Received: from vultr.guest ([149.28.193.116]) by smtp.gmail.com with ESMTPSA id 19-20020a17090a031300b002677739860fsm8640390pje.34.2023.08.14.07.33.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 14 Aug 2023 07:33:56 -0700 (PDT) From: Yafang Shao To: ast@kernel.org, daniel@iogearbox.net, john.fastabend@gmail.com, andrii@kernel.org, martin.lau@linux.dev, song@kernel.org, yonghong.song@linux.dev, kpsingh@kernel.org, sdf@google.com, haoluo@google.com, jolsa@kernel.org Cc: bpf@vger.kernel.org, Yafang Shao Subject: [RFC PATCH bpf-next 2/2] selftests/bpf: Add selftest for bpf_current_capable Date: Mon, 14 Aug 2023 14:33:41 +0000 Message-Id: <20230814143341.3767-3-laoar.shao@gmail.com> X-Mailer: git-send-email 2.39.3 In-Reply-To: <20230814143341.3767-1-laoar.shao@gmail.com> References: <20230814143341.3767-1-laoar.shao@gmail.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FREEMAIL_FROM, RCVD_IN_DNSWL_BLOCKED,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net X-Patchwork-Delegate: bpf@iogearbox.net X-Patchwork-State: RFC Add testcase for the newly added bpf_current_capable. The result: $ tools/testing/selftests/bpf/test_progs --name=bpf_current_cap #13 bpf_current_cap:OK Summary: 1/0 PASSED, 0 SKIPPED, 0 FAILED Signed-off-by: Yafang Shao --- .../selftests/bpf/prog_tests/bpf_current_cap.c | 80 ++++++++++++++++++++++ .../selftests/bpf/progs/test_bpf_current_cap.c | 37 ++++++++++ 2 files changed, 117 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/bpf_current_cap.c create mode 100644 tools/testing/selftests/bpf/progs/test_bpf_current_cap.c diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_current_cap.c b/tools/testing/selftests/bpf/prog_tests/bpf_current_cap.c new file mode 100644 index 0000000..6952908 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/bpf_current_cap.c @@ -0,0 +1,80 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (C) 2023 Yafang Shao */ + +#include +#include +#include +#include "cap_helpers.h" +#include "test_bpf_current_cap.skel.h" + +void serial_test_bpf_current_cap(void) +{ + struct test_bpf_current_cap *skel; + struct perf_event_attr attr = {}; + int pfd, link_fd, err; + __u64 caps = 0; + + skel = test_bpf_current_cap__open_and_load(); + if (!ASSERT_OK_PTR(skel, "skel_open")) + return; + + attr.size = sizeof(attr); + attr.type = PERF_TYPE_SOFTWARE; + attr.config = PERF_COUNT_SW_CPU_CLOCK; + attr.freq = 1; + attr.sample_freq = 1000; + pfd = syscall(__NR_perf_event_open, &attr, -1, 0, -1, PERF_FLAG_FD_CLOEXEC); + if (!ASSERT_GE(pfd, 0, "perf_event_open")) + goto cleanup; + + /* In case CAP_BPF and CAP_PERFMON is not set */ + err = cap_enable_effective(1ULL << CAP_BPF | 1ULL << CAP_PERFMON, &caps); + if (!ASSERT_OK(err, "set_cap_bpf_perfmon")) + goto close_perf; + + err = cap_disable_effective(1ULL << CAP_SYS_ADMIN, NULL); + if (!ASSERT_OK(err, "disable_cap_sys_admin")) + goto restore_cap; + + link_fd = bpf_link_create(bpf_program__fd(skel->progs.perf_event_run), pfd, + BPF_PERF_EVENT, NULL); + if (!ASSERT_GE(link_fd, 0, "link_create_without_lsm")) + goto restore_cap; + close(link_fd); + ASSERT_EQ(skel->bss->cap_sys_admin, false, "cap_sys_admin_init_value"); + ASSERT_EQ(skel->bss->cap_bpf, false, "cap_bpf_init_value"); + ASSERT_EQ(skel->bss->cap_perfmon, false, "cap_perfmon_init_value"); + + skel->links.lsm_run = bpf_program__attach_lsm(skel->progs.lsm_run); + if (!ASSERT_OK_PTR(skel->links.lsm_run, "lsm_attach")) + goto restore_cap; + + link_fd = bpf_link_create(bpf_program__fd(skel->progs.perf_event_run), pfd, + BPF_PERF_EVENT, NULL); + if (!ASSERT_LE(link_fd, 0, "link_create_without_sys_admin")) + goto restore_cap; + ASSERT_EQ(skel->bss->cap_sys_admin, false, "cap_sys_admin_disable"); + ASSERT_EQ(skel->bss->cap_bpf, true, "cap_bpf_enable"); + ASSERT_EQ(skel->bss->cap_perfmon, true, "cap_perfmon_enable"); + + err = cap_enable_effective(1ULL << CAP_SYS_ADMIN, NULL); + if (!ASSERT_OK(err, "enable_cap_sys_admin")) + goto restore_cap; + + link_fd = bpf_link_create(bpf_program__fd(skel->progs.perf_event_run), pfd, + BPF_PERF_EVENT, NULL); + if (!ASSERT_GE(link_fd, 0, "link_create_with_sys_admin")) + goto restore_cap; + close(link_fd); + ASSERT_EQ(skel->bss->cap_sys_admin, true, "cap_sys_admin_enable"); + ASSERT_EQ(skel->bss->cap_bpf, true, "cap_bpf_enable"); + ASSERT_EQ(skel->bss->cap_perfmon, true, "cap_perfmon_enable"); + +restore_cap: + if (caps) + cap_enable_effective(caps, NULL); +close_perf: + close(pfd); +cleanup: + test_bpf_current_cap__destroy(skel); +} diff --git a/tools/testing/selftests/bpf/progs/test_bpf_current_cap.c b/tools/testing/selftests/bpf/progs/test_bpf_current_cap.c new file mode 100644 index 0000000..6dd97a1 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_bpf_current_cap.c @@ -0,0 +1,37 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (C) 2023 Yafang Shao */ + +#include "vmlinux.h" +#include +#include + +#define CAP_SYS_ADMIN 21 +#define CAP_PERFMON 38 +#define CAP_BPF 39 + +extern bool bpf_current_capable(int cap) __ksym; +bool cap_sys_admin, cap_bpf, cap_perfmon; + +int link_create_audit(union bpf_attr *attr) +{ + cap_bpf = bpf_current_capable(CAP_BPF); + cap_perfmon = bpf_current_capable(CAP_PERFMON); + cap_sys_admin = bpf_current_capable(CAP_SYS_ADMIN); + return cap_sys_admin ? 0 : -1; +} + +SEC("lsm/bpf") +int BPF_PROG(lsm_run, int cmd, union bpf_attr *attr, unsigned int size) +{ + if (cmd != BPF_LINK_CREATE) + return 0; + return link_create_audit(attr); +} + +SEC("perf_event") +int BPF_PROG(perf_event_run) +{ + return 0; +} + +char _license[] SEC("license") = "GPL";