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// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2023 Bytedance */
#include <vmlinux.h>
#include <bpf/bpf_tracing.h>
#include <bpf/bpf_helpers.h>
#include "bpf_misc.h"
struct cgroup *bpf_cgroup_from_id(u64 cgid) __ksym;
long bpf_task_under_cgroup(struct task_struct *task, struct cgroup *ancestor) __ksym;
void bpf_cgroup_release(struct cgroup *p) __ksym;
struct task_struct *bpf_task_acquire(struct task_struct *p) __ksym;
void bpf_task_release(struct task_struct *p) __ksym;
const volatile int local_pid;
const volatile __u64 cgid;
int remote_pid;
SEC("tp_btf/task_newtask")
int BPF_PROG(tp_btf_run, struct task_struct *task, u64 clone_flags)
{
struct cgroup *cgrp = NULL;
struct task_struct *acquired;
if (local_pid != (bpf_get_current_pid_tgid() >> 32))
return 0;
acquired = bpf_task_acquire(task);
if (!acquired)
return 0;
if (local_pid == acquired->tgid)
goto out;
cgrp = bpf_cgroup_from_id(cgid);
if (!cgrp)
goto out;
if (bpf_task_under_cgroup(acquired, cgrp))
remote_pid = acquired->tgid;
out:
if (cgrp)
bpf_cgroup_release(cgrp);
bpf_task_release(acquired);
return 0;
}
SEC("lsm.s/bpf")
int BPF_PROG(lsm_run, int cmd, union bpf_attr *attr, unsigned int size, bool kernel)
{
struct cgroup *cgrp = NULL;
struct task_struct *task;
int ret = 0;
task = bpf_get_current_task_btf();
if (local_pid != task->pid)
return 0;
if (cmd != BPF_LINK_CREATE)
return 0;
/* 1 is the root cgroup */
cgrp = bpf_cgroup_from_id(1);
if (!cgrp)
goto out;
if (!bpf_task_under_cgroup(task, cgrp))
ret = -1;
bpf_cgroup_release(cgrp);
out:
return ret;
}
char _license[] SEC("license") = "GPL";
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