1// SPDX-License-Identifier: GPL-2.0
 2/* Copyright (c) 2021 Facebook */
 3#include "vmlinux.h"
 4#include <bpf/bpf_helpers.h>
 5#include <bpf/bpf_tracing.h>
 6
 7char _license[] SEC("license") = "GPL";
 8
 9struct callback_ctx {
10	int dummy;
11};
12
13#define VM_EXEC		0x00000004
14#define DNAME_INLINE_LEN 32
15
16pid_t target_pid = 0;
17char d_iname[DNAME_INLINE_LEN] = {0};
18__u32 found_vm_exec = 0;
19__u64 addr = 0;
20int find_zero_ret = -1;
21int find_addr_ret = -1;
22
23static long check_vma(struct task_struct *task, struct vm_area_struct *vma,
24		      struct callback_ctx *data)
25{
26	if (vma->vm_file)
27		bpf_probe_read_kernel_str(d_iname, DNAME_INLINE_LEN - 1,
28					  vma->vm_file->f_path.dentry->d_iname);
29
30	/* check for VM_EXEC */
31	if (vma->vm_flags & VM_EXEC)
32		found_vm_exec = 1;
33
34	return 0;
35}
36
37SEC("raw_tp/sys_enter")
38int handle_getpid(void)
39{
40	struct task_struct *task = bpf_get_current_task_btf();
41	struct callback_ctx data = {};
42
43	if (task->pid != target_pid)
44		return 0;
45
46	find_addr_ret = bpf_find_vma(task, addr, check_vma, &data, 0);
47
48	/* this should return -ENOENT */
49	find_zero_ret = bpf_find_vma(task, 0, check_vma, &data, 0);
50	return 0;
51}
52
53SEC("perf_event")
54int handle_pe(void)
55{
56	struct task_struct *task = bpf_get_current_task_btf();
57	struct callback_ctx data = {};
58
59	if (task->pid != target_pid)
60		return 0;
61
62	find_addr_ret = bpf_find_vma(task, addr, check_vma, &data, 0);
63
64	/* In NMI, this should return -EBUSY, as the previous call is using
65	 * the irq_work.
66	 */
67	find_zero_ret = bpf_find_vma(task, 0, check_vma, &data, 0);
68	return 0;
69}