From: Feng Zhou zhoufeng.zf@bytedance.com
test_progs: Tests new ebpf helpers bpf_task_under_cgroup.
The bpf program saves the pid which call the getuid syscall within a given cgroup to a map 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 | 49 +++++++++++++++++++ .../bpf/progs/test_task_under_cgroup.c | 31 ++++++++++++ 2 files changed, 80 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..4dd704b11a95 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/task_under_cgroup.c @@ -0,0 +1,49 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2023 Bytedance */ + +#include <test_progs.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, idx = 0; + + skel = test_task_under_cgroup__open(); + if (!ASSERT_OK_PTR(skel, "test_task_under_cgroup__open")) + return; + + skel->rodata->local_pid = getpid(); + + 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; + + foo = test__join_cgroup(FOO); + if (!ASSERT_OK(foo < 0, "cgroup_join_foo")) + goto cleanup; + + ret = bpf_map_update_elem(bpf_map__fd(skel->maps.cgroup_map), &idx, + &foo, BPF_ANY); + if (!ASSERT_OK(ret < 0, "cgroup_map update")) + 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/test_task_under_cgroup.c b/tools/testing/selftests/bpf/progs/test_task_under_cgroup.c new file mode 100644 index 000000000000..0f3d53f636de --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_task_under_cgroup.c @@ -0,0 +1,31 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2023 Bytedance */ + +#include "vmlinux.h" +#include <bpf/bpf_helpers.h> + +const volatile int local_pid; +int remote_pid; + +struct { + __uint(type, BPF_MAP_TYPE_CGROUP_ARRAY); + __uint(max_entries, 1); + __type(key, __u32); + __type(value, __u32); +} cgroup_map SEC(".maps"); + +SEC("tp/syscalls/sys_enter_getuid") +int sysenter_getuid(const void *ctx) +{ + if (local_pid != (bpf_get_current_pid_tgid() >> 32)) + return 0; + + if (!bpf_task_under_cgroup(&cgroup_map, bpf_get_current_task_btf(), 0)) + return 0; + + remote_pid = local_pid; + + return 0; +} + +char _license[] SEC("license") = "GPL";