1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */ |
3 | |
4 | #include <linux/bpf.h> |
5 | #include <bpf/bpf_helpers.h> |
6 | #include <bpf/bpf_core_read.h> |
7 | |
8 | struct task_struct___bad { |
9 | int pid; |
10 | int fake_field; |
11 | void *fake_field_subprog; |
12 | } __attribute__((preserve_access_index)); |
13 | |
14 | SEC("?raw_tp/sys_enter" ) |
15 | int bad_relo(const void *ctx) |
16 | { |
17 | static struct task_struct___bad *t; |
18 | |
19 | return bpf_core_field_size(t->fake_field); |
20 | } |
21 | |
22 | static __noinline int bad_subprog(void) |
23 | { |
24 | static struct task_struct___bad *t; |
25 | |
26 | /* ugliness below is a field offset relocation */ |
27 | return (void *)&t->fake_field_subprog - (void *)t; |
28 | } |
29 | |
30 | SEC("?raw_tp/sys_enter" ) |
31 | int bad_relo_subprog(const void *ctx) |
32 | { |
33 | static struct task_struct___bad *t; |
34 | |
35 | return bad_subprog() + bpf_core_field_size(t->pid); |
36 | } |
37 | |
38 | struct { |
39 | __uint(type, BPF_MAP_TYPE_ARRAY); |
40 | __uint(max_entries, 1); |
41 | __type(key, int); |
42 | __type(value, int); |
43 | } existing_map SEC(".maps" ); |
44 | |
45 | struct { |
46 | __uint(type, BPF_MAP_TYPE_ARRAY); |
47 | __uint(max_entries, 1); |
48 | __type(key, int); |
49 | __type(value, int); |
50 | } missing_map SEC(".maps" ); |
51 | |
52 | SEC("?raw_tp/sys_enter" ) |
53 | int use_missing_map(const void *ctx) |
54 | { |
55 | int zero = 0, *value; |
56 | |
57 | value = bpf_map_lookup_elem(&existing_map, &zero); |
58 | |
59 | value = bpf_map_lookup_elem(&missing_map, &zero); |
60 | |
61 | return value != NULL; |
62 | } |
63 | |
64 | extern int bpf_nonexistent_kfunc(void) __ksym __weak; |
65 | |
66 | SEC("?raw_tp/sys_enter" ) |
67 | int use_missing_kfunc(const void *ctx) |
68 | { |
69 | bpf_nonexistent_kfunc(); |
70 | |
71 | return 0; |
72 | } |
73 | |
74 | char _license[] SEC("license" ) = "GPL" ; |
75 | |