// SPDX-License-Identifier: GPL-2.0

/*
 * Copyright 2020 Google LLC.
 */

#include "vmlinux.h"
#include <errno.h>
#include <bpf/bpf_core_read.h>
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_tracing.h>
#include "bpf_misc.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");

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

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

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

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

struct outer_arr {
        __uint(type, BPF_MAP_TYPE_ARRAY_OF_MAPS);
        __uint(max_entries, 1);
        __uint(key_size, sizeof(int));
        __uint(value_size, sizeof(int));
        __array(values, struct inner_map);
} outer_arr SEC(".maps") = {
        .values = { [0] = &inner_map },
};

struct outer_hash {
        __uint(type, BPF_MAP_TYPE_HASH_OF_MAPS);
        __uint(max_entries, 1);
        __uint(key_size, sizeof(int));
        __array(values, struct inner_map);
} outer_hash SEC(".maps") = {
        .values = { [0] = &inner_map },
};

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)
{
        struct mm_struct *mm = vma->vm_mm;

        if (ret != 0 || !mm)
                return ret;

        __s32 pid = bpf_get_current_pid_tgid() >> 32;
        int is_stack = 0;

        is_stack = (vma->vm_start <= mm->start_stack &&
                    vma->vm_end >= 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;
        struct inner_map *inner_map;
        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;
        value = bpf_map_lookup_elem(&percpu_array, &key);
        if (value)
                *value = 0;
        value = bpf_map_lookup_elem(&percpu_hash, &key);
        if (value)
                *value = 0;
        value = bpf_map_lookup_elem(&lru_percpu_hash, &key);
        if (value)
                *value = 0;
        inner_map = bpf_map_lookup_elem(&outer_arr, &key);
        if (inner_map) {
                value = bpf_map_lookup_elem(inner_map, &key);
                if (value)
                        *value = 0;
        }
        inner_map = bpf_map_lookup_elem(&outer_hash, &key);
        if (inner_map) {
                value = bpf_map_lookup_elem(inner_map, &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/" SYS_PREFIX "sys_setdomainname")
int BPF_PROG(test_sys_setdomainname, struct pt_regs *regs)
{
        void *ptr = (void *)PT_REGS_PARM1_SYSCALL(regs);
        int len = PT_REGS_PARM2_SYSCALL(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;
}