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
7 char _license[] SEC("license") = "GPL";
8
9 struct callback_ctx {
10 int dummy;
11 };
12
13 #define VM_EXEC 0x00000004
14 #define DNAME_INLINE_LEN 32
15
16 pid_t target_pid = 0;
17 char d_iname[DNAME_INLINE_LEN] = {0};
18 __u32 found_vm_exec = 0;
19 __u64 addr = 0;
20 int find_zero_ret = -1;
21 int find_addr_ret = -1;
22
23 static 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
37 SEC("raw_tp/sys_enter")
38 int 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
53 SEC("perf_event")
54 int 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 }
70
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