1 | // SPDX-License-Identifier: GPL-2.0 |
2 | |
3 | /* |
4 | * Copyright (C) 2022 Huawei Technologies Duesseldorf GmbH |
5 | * |
6 | * Author: Roberto Sassu <roberto.sassu@huawei.com> |
7 | */ |
8 | |
9 | #include "vmlinux.h" |
10 | #include <errno.h> |
11 | #include <bpf/bpf_helpers.h> |
12 | #include <bpf/bpf_tracing.h> |
13 | |
14 | char _license[] SEC("license" ) = "GPL" ; |
15 | |
16 | __u32 monitored_pid; |
17 | __u32 key_serial; |
18 | __u32 key_id; |
19 | __u64 flags; |
20 | |
21 | extern struct bpf_key *bpf_lookup_user_key(__u32 serial, __u64 flags) __ksym; |
22 | extern struct bpf_key *bpf_lookup_system_key(__u64 id) __ksym; |
23 | extern void bpf_key_put(struct bpf_key *key) __ksym; |
24 | |
25 | SEC("lsm.s/bpf" ) |
26 | int BPF_PROG(bpf, int cmd, union bpf_attr *attr, unsigned int size) |
27 | { |
28 | struct bpf_key *bkey; |
29 | __u32 pid; |
30 | |
31 | pid = bpf_get_current_pid_tgid() >> 32; |
32 | if (pid != monitored_pid) |
33 | return 0; |
34 | |
35 | if (key_serial) |
36 | bkey = bpf_lookup_user_key(key_serial, flags); |
37 | else |
38 | bkey = bpf_lookup_system_key(key_id); |
39 | |
40 | if (!bkey) |
41 | return -ENOENT; |
42 | |
43 | bpf_key_put(bkey); |
44 | |
45 | return 0; |
46 | } |
47 | |