From patchwork Sun Jul 14 17:51:23 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Amery Hung X-Patchwork-Id: 13732775 X-Patchwork-Delegate: bpf@iogearbox.net Received: from mail-qt1-f177.google.com (mail-qt1-f177.google.com [209.85.160.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3FB9013C8E8; Sun, 14 Jul 2024 17:51:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.160.177 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720979497; cv=none; b=VR/ooQI1g+hCsDqg4v1nhmnljUUea6TSeEyYdOivc5VVzpB8nkyI3Q3UFpZxbUfrOkhy2hpRue2d3ETygZo1PQUpIfzNyLQftXyqS1S0hK0ZpR2+YqKZydWk6YlA1J9+YsYgkIqc7J48IXI1GAIZiO3b3CsaVewS15olz7iZQV0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720979497; c=relaxed/simple; bh=SV59NoCDZEsIWoEZ8m1wiLRmxwg4eOSsNAwhBb54M7o=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=Uv0kMHX40hgq5wWGgQ9D3cqqE2gQJ58ypquB6ZzyGEEeXF5rwUrxSDhqsYvuH5inbDMIpEa/ML/hcB/MwlafxgiDN7DCHXYA4y7s+ik6GyE0143F9kFEeyYyqNxOpoLBH5DB8kHGVIvgZVXXPIaYRZHNLQMb3dpeNhisbkVDrcY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=UG3pESic; arc=none smtp.client-ip=209.85.160.177 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="UG3pESic" Received: by mail-qt1-f177.google.com with SMTP id d75a77b69052e-447d97f98d3so19562081cf.2; Sun, 14 Jul 2024 10:51:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1720979494; x=1721584294; darn=vger.kernel.org; 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=HtImcwPeg2GxCBruL+KDWulfN186/oe5ccglZIuiGmQ=; b=UG3pESics827TxdSh6HEhEoEeToSmCb3kA3P0oOvJTJpZ7wp+b+IVT7oUYwTyL6y2J 3vHT6HuzPYIPfrUA/NKGVGG1UoYFXgNccD7ECe0AJJHPXmcK6J6q5Mdxi+XPCAxyfg7q 9SSw/rIkNnRInt1Uf17Y4VcxNRL0LkZfQ/xx7bQGvSOuyZdlPe5VV9J9tPnaJQTQm79V ThCEToLMPN6J0KMu/yE19Xl04Cpyz89Qg2Ysj5i/sqoD1L3aVRP31uUtTFM2u7P40rG/ bjdcQ2JlqfKawB/i7HQWlW+UJPy/whBKfGEZ9e1d/s5au3aTDxwgAgZqE+42J1B420Nx Hcqg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1720979494; x=1721584294; 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=HtImcwPeg2GxCBruL+KDWulfN186/oe5ccglZIuiGmQ=; b=uYCEwt34QyrhRkim/coKviOtSmf3dsp1seYnLhvK5HWtqQO9rZKPuSl/CjKd1Yb4pt BJOt+efO6VZeEtoqMqFwwHenhtzpGzSzc0wf/01xDLB/ikfnrau79Saaurtaq6Chede4 fBNYb238NqKv0F3qgqFLeq/nQ387NhwNaSTb+S2EesdXSJM8QNNstBnAtWQs+V4j2IPu 9J1jwTj3T4iv8+oBlH2nIxP7rh0c/LH+1hIRhsVoHaQP4LviU9QdY055K01h4CnLRWXc S1W6wQXZByKa0nSpce7E8I67I/rs6HdNQNr9OeWbequks7nmNDR1DEpWeqkza598tnhv xr3A== X-Gm-Message-State: AOJu0YzQ68nK43UZfU78AIWiy9pu1oPrMIT+rsc5l4uyjjULZWERhrVl xMg6s/26Ih5N4u5yIPVxDY5dzTR/yW8d5ylFn6GZVrrNJj9WI1CIPSaO7g== X-Google-Smtp-Source: AGHT+IHlHI1THSfFh2F1K9EqvKpO8OA2UwpG5hWJuPi4BFcCR0tJl5Y+MnR2fnrM9nw+Nqbu4aqT5w== X-Received: by 2002:a05:622a:15d3:b0:447:e51b:60c0 with SMTP id d75a77b69052e-447fa825dd8mr219483131cf.12.1720979493953; Sun, 14 Jul 2024 10:51:33 -0700 (PDT) Received: from n36-183-057.byted.org ([147.160.184.91]) by smtp.gmail.com with ESMTPSA id d75a77b69052e-44f5b7e1e38sm17010481cf.25.2024.07.14.10.51.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 14 Jul 2024 10:51:33 -0700 (PDT) From: Amery Hung X-Google-Original-From: Amery Hung To: netdev@vger.kernel.org Cc: bpf@vger.kernel.org, yangpeihao@sjtu.edu.cn, daniel@iogearbox.net, andrii@kernel.org, alexei.starovoitov@gmail.com, martin.lau@kernel.org, sinquersw@gmail.com, toke@redhat.com, jhs@mojatatu.com, jiri@resnulli.us, sdf@google.com, xiyou.wangcong@gmail.com, yepeilin.cs@gmail.com, ameryhung@gmail.com Subject: [RFC PATCH v9 04/11] selftests/bpf: Test returning referenced kptr from struct_ops programs Date: Sun, 14 Jul 2024 17:51:23 +0000 Message-Id: <20240714175130.4051012-5-amery.hung@bytedance.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20240714175130.4051012-1-amery.hung@bytedance.com> References: <20240714175130.4051012-1-amery.hung@bytedance.com> 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 X-Patchwork-State: RFC Test struct_ops programs returning referenced kptr. When the return type of a struct_ops operator is pointer to struct, the verifier should only allow programs that return a scalar NULL or a non-local kptr with the correct type in its unmodified form. Signed-off-by: Amery Hung --- .../selftests/bpf/bpf_testmod/bpf_testmod.c | 8 ++ .../selftests/bpf/bpf_testmod/bpf_testmod.h | 4 + .../prog_tests/test_struct_ops_kptr_return.c | 87 +++++++++++++++++++ .../bpf/progs/struct_ops_kptr_return.c | 29 +++++++ ...uct_ops_kptr_return_fail__invalid_scalar.c | 24 +++++ .../struct_ops_kptr_return_fail__local_kptr.c | 30 +++++++ ...uct_ops_kptr_return_fail__nonzero_offset.c | 23 +++++ .../struct_ops_kptr_return_fail__wrong_type.c | 28 ++++++ 8 files changed, 233 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/test_struct_ops_kptr_return.c create mode 100644 tools/testing/selftests/bpf/progs/struct_ops_kptr_return.c create mode 100644 tools/testing/selftests/bpf/progs/struct_ops_kptr_return_fail__invalid_scalar.c create mode 100644 tools/testing/selftests/bpf/progs/struct_ops_kptr_return_fail__local_kptr.c create mode 100644 tools/testing/selftests/bpf/progs/struct_ops_kptr_return_fail__nonzero_offset.c create mode 100644 tools/testing/selftests/bpf/progs/struct_ops_kptr_return_fail__wrong_type.c diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c index 316a4c3d3a88..c90bb3a5e86a 100644 --- a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c +++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c @@ -922,11 +922,19 @@ static int bpf_testmod_ops__test_refcounted(int dummy, return 0; } +static struct task_struct * +bpf_testmod_ops__test_return_ref_kptr(int dummy, struct task_struct *task__ref, + struct cgroup *cgrp) +{ + return NULL; +} + static struct bpf_testmod_ops __bpf_testmod_ops = { .test_1 = bpf_testmod_test_1, .test_2 = bpf_testmod_test_2, .test_maybe_null = bpf_testmod_ops__test_maybe_null, .test_refcounted = bpf_testmod_ops__test_refcounted, + .test_return_ref_kptr = bpf_testmod_ops__test_return_ref_kptr, }; struct bpf_struct_ops bpf_bpf_testmod_ops = { diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.h b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.h index bfef5f382d01..2289ecd38401 100644 --- a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.h +++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.h @@ -6,6 +6,7 @@ #include struct task_struct; +struct cgroup; struct bpf_testmod_test_read_ctx { char *buf; @@ -37,6 +38,9 @@ struct bpf_testmod_ops { int (*test_maybe_null)(int dummy, struct task_struct *task); /* Used to test ref_acquired arguments. */ int (*test_refcounted)(int dummy, struct task_struct *task); + /* Used to test returning referenced kptr. */ + struct task_struct *(*test_return_ref_kptr)(int dummy, struct task_struct *task, + struct cgroup *cgrp); /* The following fields are used to test shadow copies. */ char onebyte; diff --git a/tools/testing/selftests/bpf/prog_tests/test_struct_ops_kptr_return.c b/tools/testing/selftests/bpf/prog_tests/test_struct_ops_kptr_return.c new file mode 100644 index 000000000000..bc2fac39215a --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/test_struct_ops_kptr_return.c @@ -0,0 +1,87 @@ +#include + +#include "struct_ops_kptr_return.skel.h" +#include "struct_ops_kptr_return_fail__wrong_type.skel.h" +#include "struct_ops_kptr_return_fail__invalid_scalar.skel.h" +#include "struct_ops_kptr_return_fail__nonzero_offset.skel.h" +#include "struct_ops_kptr_return_fail__local_kptr.skel.h" + +/* Test that the verifier accepts a program that acquires a referenced + * kptr and releases the reference through return + */ +static void kptr_return(void) +{ + struct struct_ops_kptr_return *skel; + + skel = struct_ops_kptr_return__open_and_load(); + if (!ASSERT_OK_PTR(skel, "struct_ops_module_open_and_load")) + return; + + struct_ops_kptr_return__destroy(skel); +} + +/* Test that the verifier rejects a program that returns a kptr of the + * wrong type + */ +static void kptr_return_fail__wrong_type(void) +{ + struct struct_ops_kptr_return_fail__wrong_type *skel; + + skel = struct_ops_kptr_return_fail__wrong_type__open_and_load(); + if (ASSERT_ERR_PTR(skel, "struct_ops_module_fail__wrong_type__open_and_load")) + return; + + struct_ops_kptr_return_fail__wrong_type__destroy(skel); +} + +/* Test that the verifier rejects a program that returns a non-null scalar */ +static void kptr_return_fail__invalid_scalar(void) +{ + struct struct_ops_kptr_return_fail__invalid_scalar *skel; + + skel = struct_ops_kptr_return_fail__invalid_scalar__open_and_load(); + if (ASSERT_ERR_PTR(skel, "struct_ops_module_fail__invalid_scalar__open_and_load")) + return; + + struct_ops_kptr_return_fail__invalid_scalar__destroy(skel); +} + +/* Test that the verifier rejects a program that returns kptr with non-zero offset */ +static void kptr_return_fail__nonzero_offset(void) +{ + struct struct_ops_kptr_return_fail__nonzero_offset *skel; + + skel = struct_ops_kptr_return_fail__nonzero_offset__open_and_load(); + if (ASSERT_ERR_PTR(skel, "struct_ops_module_fail__nonzero_offset__open_and_load")) + return; + + struct_ops_kptr_return_fail__nonzero_offset__destroy(skel); +} + +/* Test that the verifier rejects a program that returns local kptr */ +static void kptr_return_fail__local_kptr(void) +{ + struct struct_ops_kptr_return_fail__local_kptr *skel; + + skel = struct_ops_kptr_return_fail__local_kptr__open_and_load(); + if (ASSERT_ERR_PTR(skel, "struct_ops_module_fail__local_kptr__open_and_load")) + return; + + struct_ops_kptr_return_fail__local_kptr__destroy(skel); +} + +void test_struct_ops_kptr_return(void) +{ + if (test__start_subtest("kptr_return")) + kptr_return(); + if (test__start_subtest("kptr_return_fail__wrong_type")) + kptr_return_fail__wrong_type(); + if (test__start_subtest("kptr_return_fail__invalid_scalar")) + kptr_return_fail__invalid_scalar(); + if (test__start_subtest("kptr_return_fail__nonzero_offset")) + kptr_return_fail__nonzero_offset(); + if (test__start_subtest("kptr_return_fail__local_kptr")) + kptr_return_fail__local_kptr(); +} + + diff --git a/tools/testing/selftests/bpf/progs/struct_ops_kptr_return.c b/tools/testing/selftests/bpf/progs/struct_ops_kptr_return.c new file mode 100644 index 000000000000..29b7719cd4c9 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/struct_ops_kptr_return.c @@ -0,0 +1,29 @@ +#include +#include +#include "../bpf_testmod/bpf_testmod.h" + +char _license[] SEC("license") = "GPL"; + +void bpf_task_release(struct task_struct *p) __ksym; + +/* This test struct_ops BPF programs returning referenced kptr. The verifier should + * allow a referenced kptr or a NULL pointer to be returned. A referenced kptr to task + * here is acquried automatically as the task argument is tagged with "__ref". + */ +SEC("struct_ops/test_return_ref_kptr") +struct task_struct *BPF_PROG(test_return_ref_kptr, int dummy, + struct task_struct *task, struct cgroup *cgrp) +{ + if (dummy % 2) { + bpf_task_release(task); + return NULL; + } + return task; +} + +SEC(".struct_ops.link") +struct bpf_testmod_ops testmod_kptr_return = { + .test_return_ref_kptr = (void *)test_return_ref_kptr, +}; + + diff --git a/tools/testing/selftests/bpf/progs/struct_ops_kptr_return_fail__invalid_scalar.c b/tools/testing/selftests/bpf/progs/struct_ops_kptr_return_fail__invalid_scalar.c new file mode 100644 index 000000000000..d67982ba8224 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/struct_ops_kptr_return_fail__invalid_scalar.c @@ -0,0 +1,24 @@ +#include +#include +#include "../bpf_testmod/bpf_testmod.h" + +char _license[] SEC("license") = "GPL"; + +struct cgroup *bpf_cgroup_acquire(struct cgroup *p) __ksym; +void bpf_task_release(struct task_struct *p) __ksym; + +/* This test struct_ops BPF programs returning referenced kptr. The verifier should + * reject programs returning a non-zero scalar value. + */ +SEC("struct_ops/test_return_ref_kptr") +struct task_struct *BPF_PROG(test_return_ref_kptr, int dummy, + struct task_struct *task, struct cgroup *cgrp) +{ + bpf_task_release(task); + return (struct task_struct *)1; +} + +SEC(".struct_ops.link") +struct bpf_testmod_ops testmod_kptr_return = { + .test_return_ref_kptr = (void *)test_return_ref_kptr, +}; diff --git a/tools/testing/selftests/bpf/progs/struct_ops_kptr_return_fail__local_kptr.c b/tools/testing/selftests/bpf/progs/struct_ops_kptr_return_fail__local_kptr.c new file mode 100644 index 000000000000..9a4247432539 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/struct_ops_kptr_return_fail__local_kptr.c @@ -0,0 +1,30 @@ +#include +#include +#include "../bpf_testmod/bpf_testmod.h" +#include "bpf_experimental.h" + +char _license[] SEC("license") = "GPL"; + +struct cgroup *bpf_cgroup_acquire(struct cgroup *p) __ksym; +void bpf_task_release(struct task_struct *p) __ksym; + +/* This test struct_ops BPF programs returning referenced kptr. The verifier should + * reject programs returning a local kptr. + */ +SEC("struct_ops/test_return_ref_kptr") +struct task_struct *BPF_PROG(test_return_ref_kptr, int dummy, + struct task_struct *task, struct cgroup *cgrp) +{ + struct task_struct *t; + + t = bpf_obj_new(typeof(*task)); + if (!t) + return task; + + return t; +} + +SEC(".struct_ops.link") +struct bpf_testmod_ops testmod_kptr_return = { + .test_return_ref_kptr = (void *)test_return_ref_kptr, +}; diff --git a/tools/testing/selftests/bpf/progs/struct_ops_kptr_return_fail__nonzero_offset.c b/tools/testing/selftests/bpf/progs/struct_ops_kptr_return_fail__nonzero_offset.c new file mode 100644 index 000000000000..5bb0b4029d11 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/struct_ops_kptr_return_fail__nonzero_offset.c @@ -0,0 +1,23 @@ +#include +#include +#include "../bpf_testmod/bpf_testmod.h" + +char _license[] SEC("license") = "GPL"; + +struct cgroup *bpf_cgroup_acquire(struct cgroup *p) __ksym; +void bpf_task_release(struct task_struct *p) __ksym; + +/* This test struct_ops BPF programs returning referenced kptr. The verifier should + * reject programs returning a modified referenced kptr. + */ +SEC("struct_ops/test_return_ref_kptr") +struct task_struct *BPF_PROG(test_return_ref_kptr, int dummy, + struct task_struct *task, struct cgroup *cgrp) +{ + return (struct task_struct *)&task->jobctl; +} + +SEC(".struct_ops.link") +struct bpf_testmod_ops testmod_kptr_return = { + .test_return_ref_kptr = (void *)test_return_ref_kptr, +}; diff --git a/tools/testing/selftests/bpf/progs/struct_ops_kptr_return_fail__wrong_type.c b/tools/testing/selftests/bpf/progs/struct_ops_kptr_return_fail__wrong_type.c new file mode 100644 index 000000000000..32365cb7af49 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/struct_ops_kptr_return_fail__wrong_type.c @@ -0,0 +1,28 @@ +#include +#include +#include "../bpf_testmod/bpf_testmod.h" + +char _license[] SEC("license") = "GPL"; + +struct cgroup *bpf_cgroup_acquire(struct cgroup *p) __ksym; +void bpf_task_release(struct task_struct *p) __ksym; + +/* This test struct_ops BPF programs returning referenced kptr. The verifier should + * reject programs returning a referenced kptr of the wrong type. + */ +SEC("struct_ops/test_return_ref_kptr") +struct task_struct *BPF_PROG(test_return_ref_kptr, int dummy, + struct task_struct *task, struct cgroup *cgrp) +{ + struct task_struct *ret; + + ret = (struct task_struct *)bpf_cgroup_acquire(cgrp); + bpf_task_release(task); + + return ret; +} + +SEC(".struct_ops.link") +struct bpf_testmod_ops testmod_kptr_return = { + .test_return_ref_kptr = (void *)test_return_ref_kptr, +};