[RFC,v8,04/20] selftests/bpf: Test returning kptr from struct_ops programs

Message ID	20240510192412.3297104-5-amery.hung@bytedance.com (mailing list archive)
State	RFC
Delegated to:	BPF
Headers	show Received: from mail-yw1-f170.google.com (mail-yw1-f170.google.com [209.85.128.170]) (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 60FBD495F0; Fri, 10 May 2024 19:24:17 +0000 (UTC) From: Amery Hung <ameryhung@gmail.com> To: netdev@vger.kernel.org Cc: bpf@vger.kernel.org, yangpeihao@sjtu.edu.cn, daniel@iogearbox.net, andrii@kernel.org, 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 v8 04/20] selftests/bpf: Test returning kptr from struct_ops programs Date: Fri, 10 May 2024 19:23:56 +0000 Message-Id: <20240510192412.3297104-5-amery.hung@bytedance.com> In-Reply-To: <20240510192412.3297104-1-amery.hung@bytedance.com> References: <20240510192412.3297104-1-amery.hung@bytedance.com> Precedence: bulk MIME-Version: 1.0 Content-Transfer-Encoding: 8bit
Series	bpf qdisc \| expand [RFC,v8,00/20] bpf qdisc [RFC,v8,01/20] bpf: Support passing referenced kptr to struct_ops programs [RFC,v8,02/20] selftests/bpf: Test referenced kptr arguments of struct_ops programs [RFC,v8,03/20] bpf: Allow struct_ops prog to return referenced kptr [RFC,v8,04/20] selftests/bpf: Test returning kptr from struct_ops programs [RFC,v8,05/20] bpf: Generate btf_struct_metas for kernel BTF [RFC,v8,06/20] bpf: Recognize kernel types as graph values [RFC,v8,07/20] bpf: Allow adding kernel objects to collections [RFC,v8,08/20] selftests/bpf: Test adding kernel object to bpf graph [RFC,v8,09/20] bpf: Find special BTF fields in union [RFC,v8,10/20] bpf: Introduce exclusive-ownership list and rbtree nodes [RFC,v8,11/20] bpf: Allow adding exclusive nodes to bpf list and rbtree [RFC,v8,12/20] selftests/bpf: Modify linked_list tests to work with macro-ified removes [RFC,v8,13/20] bpf: net_sched: Support implementation of Qdisc_ops in bpf [RFC,v8,14/20] bpf: net_sched: Add bpf qdisc kfuncs [RFC,v8,15/20] bpf: net_sched: Allow more optional methods in Qdisc_ops [RFC,v8,16/20] libbpf: Support creating and destroying qdisc [RFC,v8,17/20] selftests: Add a basic fifo qdisc test [RFC,v8,18/20] selftests: Add a bpf fq qdisc to selftest [RFC,v8,19/20] selftests: Add a bpf netem qdisc to selftest [RFC,v8,20/20] selftests: Add a prio bpf qdisc

Context	Check	Description
netdev/tree_selection	success	Guessing tree name failed - patch did not apply, async

diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c index 64dcab25b539..097a8d1c2ef8 100644 --- a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c +++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c @@ -600,11 +600,19 @@ static int bpf_testmod_ops__test_ref_acquire(int dummy, return 0; } +static struct task_struct * +bpf_testmod_ops__test_kptr_return(int dummy, struct task_struct *task__ref_acquired, + 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_ref_acquire = bpf_testmod_ops__test_ref_acquire, + .test_kptr_return = bpf_testmod_ops__test_kptr_return, }; 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 a0233990fb0e..6d24e1307b64 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 <linux/types.h> 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_ref_acquire)(int dummy, struct task_struct *task); + /* Used to test returning kptr. */ + struct task_struct *(*test_kptr_return)(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 <test_progs.h> + +#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..34933a88e1f9 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/struct_ops_kptr_return.c @@ -0,0 +1,24 @@ +#include <vmlinux.h> +#include <bpf/bpf_tracing.h> +#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 (acquired with "ref_acquired") to be leaked through return. + */ +SEC("struct_ops/test_kptr_return") +struct task_struct *BPF_PROG(test_kptr_return, int dummy, + struct task_struct *task, struct cgroup *cgrp) +{ + return task; +} + +SEC(".struct_ops.link") +struct bpf_testmod_ops testmod_kptr_return = { + .test_kptr_return = (void *)test_kptr_return, +}; + + 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..d479e3377496 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/struct_ops_kptr_return_fail__invalid_scalar.c @@ -0,0 +1,24 @@ +#include <vmlinux.h> +#include <bpf/bpf_tracing.h> +#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_kptr_return") +struct task_struct *BPF_PROG(test_kptr_return, 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_kptr_return = (void *)test_kptr_return, +}; 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..9266987798ca --- /dev/null +++ b/tools/testing/selftests/bpf/progs/struct_ops_kptr_return_fail__local_kptr.c @@ -0,0 +1,30 @@ +#include <vmlinux.h> +#include <bpf/bpf_tracing.h> +#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_kptr_return") +struct task_struct *BPF_PROG(test_kptr_return, 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_kptr_return = (void *)test_kptr_return, +}; 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..1a369e9839f3 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/struct_ops_kptr_return_fail__nonzero_offset.c @@ -0,0 +1,23 @@ +#include <vmlinux.h> +#include <bpf/bpf_tracing.h> +#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_kptr_return") +struct task_struct *BPF_PROG(test_kptr_return, 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_kptr_return = (void *)test_kptr_return, +}; 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..4128ea0b77f1 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/struct_ops_kptr_return_fail__wrong_type.c @@ -0,0 +1,28 @@ +#include <vmlinux.h> +#include <bpf/bpf_tracing.h> +#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_kptr_return") +struct task_struct *BPF_PROG(test_kptr_return, 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_kptr_return = (void *)test_kptr_return, +};

[RFC,v8,04/20] selftests/bpf: Test returning kptr from struct_ops programs

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