From: Feng Zhou zhoufeng.zf@bytedance.com
test_progs: Tests new kfunc bpf_task_under_cgroup().
The bpf program saves the pid which call the getuid syscall within a given cgroup to the remote_pid, which is convenient for the user-mode program to verify the test correctness.
The user-mode program creates its own mount namespace, and mounts the cgroupsv2 hierarchy in there, call the getuid syscall, then check if remote_pid and local_pid are equal.
Signed-off-by: Feng Zhou zhoufeng.zf@bytedance.com --- .../bpf/prog_tests/task_under_cgroup.c | 46 +++++++++++++++++++ .../selftests/bpf/progs/cgrp_kfunc_common.h | 1 + .../bpf/progs/test_task_under_cgroup.c | 40 ++++++++++++++++ 3 files changed, 87 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/task_under_cgroup.c create mode 100644 tools/testing/selftests/bpf/progs/test_task_under_cgroup.c
diff --git a/tools/testing/selftests/bpf/prog_tests/task_under_cgroup.c b/tools/testing/selftests/bpf/prog_tests/task_under_cgroup.c new file mode 100644 index 000000000000..bd3deb469938 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/task_under_cgroup.c @@ -0,0 +1,46 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2023 Bytedance */ + +#include <test_progs.h> +#include <cgroup_helpers.h> +#include "test_task_under_cgroup.skel.h" + +#define FOO "/foo" + +void test_task_under_cgroup(void) +{ + struct test_task_under_cgroup *skel; + int ret, foo = -1; + + foo = test__join_cgroup(FOO); + if (!ASSERT_OK(foo < 0, "cgroup_join_foo")) + return; + + skel = test_task_under_cgroup__open(); + if (!ASSERT_OK_PTR(skel, "test_task_under_cgroup__open")) + goto cleanup; + + skel->rodata->local_pid = getpid(); + skel->rodata->cgid = get_cgroup_id(FOO); + + ret = test_task_under_cgroup__load(skel); + if (!ASSERT_OK(ret, "test_task_under_cgroup__load")) + goto cleanup; + + ret = test_task_under_cgroup__attach(skel); + if (!ASSERT_OK(ret, "test_task_under_cgroup__attach")) + goto cleanup; + + syscall(__NR_getuid); + + test_task_under_cgroup__detach(skel); + + ASSERT_EQ(skel->bss->remote_pid, skel->rodata->local_pid, + "test task_under_cgroup"); + +cleanup: + if (foo) + close(foo); + + test_task_under_cgroup__destroy(skel); +} diff --git a/tools/testing/selftests/bpf/progs/cgrp_kfunc_common.h b/tools/testing/selftests/bpf/progs/cgrp_kfunc_common.h index 22914a70db54..41b3ea231698 100644 --- a/tools/testing/selftests/bpf/progs/cgrp_kfunc_common.h +++ b/tools/testing/selftests/bpf/progs/cgrp_kfunc_common.h @@ -26,6 +26,7 @@ struct cgroup *bpf_cgroup_ancestor(struct cgroup *cgrp, int level) __ksym; struct cgroup *bpf_cgroup_from_id(u64 cgid) __ksym; void bpf_rcu_read_lock(void) __ksym; void bpf_rcu_read_unlock(void) __ksym; +int bpf_task_under_cgroup(struct cgroup *cgrp, struct task_struct *task) __ksym;
static inline struct __cgrps_kfunc_map_value *cgrps_kfunc_map_value_lookup(struct cgroup *cgrp) { diff --git a/tools/testing/selftests/bpf/progs/test_task_under_cgroup.c b/tools/testing/selftests/bpf/progs/test_task_under_cgroup.c new file mode 100644 index 000000000000..e2740f9b029d --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_task_under_cgroup.c @@ -0,0 +1,40 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2023 Bytedance */ + +#include <vmlinux.h> +#include <asm/unistd.h> +#include <bpf/bpf_tracing.h> +#include <bpf/bpf_helpers.h> + +#include "cgrp_kfunc_common.h" + +const volatile int local_pid; +const volatile long cgid; +int remote_pid; + +SEC("tp_btf/sys_enter") +int BPF_PROG(sysenter, struct pt_regs *regs, long id) +{ + struct cgroup *cgrp; + + if (id != __NR_getuid) + return 0; + + if (local_pid != (bpf_get_current_pid_tgid() >> 32)) + return 0; + + cgrp = bpf_cgroup_from_id(cgid); + if (!cgrp) + return 0; + + if (!bpf_task_under_cgroup(cgrp, bpf_get_current_task_btf())) + goto out; + + remote_pid = local_pid; + +out: + bpf_cgroup_release(cgrp); + return 0; +} + +char _license[] SEC("license") = "GPL";