// SPDX-License-Identifier: GPL-2.0

/*
 * Copyright 2020 Google LLC.
 */

#include "vmlinux.h"
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_tracing.h>
#include  <errno.h>

struct {
	__uint(type, BPF_MAP_TYPE_ARRAY);
	__uint(max_entries, 1);
	__type(key, __u32);
	__type(value, __u64);
} array SEC(".maps");

struct {
	__uint(type, BPF_MAP_TYPE_HASH);
	__uint(max_entries, 1);
	__type(key, __u32);
	__type(value, __u64);
} hash SEC(".maps");

struct {
	__uint(type, BPF_MAP_TYPE_LRU_HASH);
	__uint(max_entries, 1);
	__type(key, __u32);
	__type(value, __u64);
} lru_hash SEC(".maps");

char _license[] SEC("license") = "GPL";

int monitored_pid = 0;
int mprotect_count = 0;
int bprm_count = 0;

SEC("lsm/file_mprotect")
int BPF_PROG(test_int_hook, struct vm_area_struct *vma,
	     unsigned long reqprot, unsigned long prot, int ret)
{
	if (ret != 0)
		return ret;

	__u32 pid = bpf_get_current_pid_tgid() >> 32;
	int is_stack = 0;

	is_stack = (vma->vm_start <= vma->vm_mm->start_stack &&
		    vma->vm_end >= vma->vm_mm->start_stack);

	if (is_stack && monitored_pid == pid) {
		mprotect_count++;
		ret = -EPERM;
	}

	return ret;
}

SEC("lsm.s/bprm_committed_creds")
int BPF_PROG(test_void_hook, struct linux_binprm *bprm)
{
	__u32 pid = bpf_get_current_pid_tgid() >> 32;
	char args[64];
	__u32 key = 0;
	__u64 *value;

	if (monitored_pid == pid)
		bprm_count++;

	bpf_copy_from_user(args, sizeof(args), (void *)bprm->vma->vm_mm->arg_start);
	bpf_copy_from_user(args, sizeof(args), (void *)bprm->mm->arg_start);

	value = bpf_map_lookup_elem(&array, &key);
	if (value)
		*value = 0;
	value = bpf_map_lookup_elem(&hash, &key);
	if (value)
		*value = 0;
	value = bpf_map_lookup_elem(&lru_hash, &key);
	if (value)
		*value = 0;

	return 0;
}
SEC("lsm/task_free") /* lsm/ is ok, lsm.s/ fails */
int BPF_PROG(test_task_free, struct task_struct *task)
{
	return 0;
}

int copy_test = 0;

SEC("fentry.s/__x64_sys_setdomainname")
int BPF_PROG(test_sys_setdomainname, struct pt_regs *regs)
{
	void *ptr = (void *)PT_REGS_PARM1(regs);
	int len = PT_REGS_PARM2(regs);
	int buf = 0;
	long ret;

	ret = bpf_copy_from_user(&buf, sizeof(buf), ptr);
	if (len == -2 && ret == 0 && buf == 1234)
		copy_test++;
	if (len == -3 && ret == -EFAULT)
		copy_test++;
	if (len == -4 && ret == -EFAULT)
		copy_test++;
	return 0;
}