1 /*
2 * Copyright (C) 2018-2023 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #pragma once
18
19 #include <linux/bpf.h>
20
21 #include <fstream>
22
23 namespace android {
24 namespace bpf {
25
26 // Bpf programs may specify per-program & per-map selinux_context and pin_subdir.
27 //
28 // The BpfLoader needs to convert these bpf.o specified strings into an enum
29 // for internal use (to check that valid values were specified for the specific
30 // location of the bpf.o file).
31 //
32 // It also needs to map selinux_context's into pin_subdir's.
33 // This is because of how selinux_context is actually implemented via pin+rename.
34 //
35 // Thus 'domain' enumerates all selinux_context's/pin_subdir's that the BpfLoader
36 // is aware of. Thus there currently needs to be a 1:1 mapping between the two.
37 //
38 enum class domain : int {
39 unrecognized = -1, // invalid for this version of the bpfloader
40 unspecified = 0, // means just use the default for that specific pin location
41 tethering, // (S+) fs_bpf_tethering /sys/fs/bpf/tethering
42 net_private, // (T+) fs_bpf_net_private /sys/fs/bpf/net_private
43 net_shared, // (T+) fs_bpf_net_shared /sys/fs/bpf/net_shared
44 netd_readonly, // (T+) fs_bpf_netd_readonly /sys/fs/bpf/netd_readonly
45 netd_shared, // (T+) fs_bpf_netd_shared /sys/fs/bpf/netd_shared
46 };
47
48 // Note: this does not include domain::unrecognized, but does include domain::unspecified
49 static constexpr domain AllDomains[] = {
50 domain::unspecified,
51 domain::tethering,
52 domain::net_private,
53 domain::net_shared,
54 domain::netd_readonly,
55 domain::netd_shared,
56 };
57
unrecognized(domain d)58 static constexpr bool unrecognized(domain d) {
59 return d == domain::unrecognized;
60 }
61
62 // Note: this doesn't handle unrecognized, handle it first.
specified(domain d)63 static constexpr bool specified(domain d) {
64 return d != domain::unspecified;
65 }
66
67 struct Location {
68 const char* const dir = "";
69 const char* const prefix = "";
70 };
71
72 // BPF loader implementation. Loads an eBPF ELF object
73 int loadProg(const char* elfPath, bool* isCritical, const unsigned int bpfloader_ver,
74 const Location &location = {});
75
76 // Exposed for testing
77 unsigned int readSectionUint(const char* name, std::ifstream& elfFile, unsigned int defVal);
78
79 // Returns the build type string (from ro.build.type).
80 const std::string& getBuildType();
81
82 // The following functions classify the 3 Android build types.
isEng()83 inline bool isEng() {
84 return getBuildType() == "eng";
85 }
isUser()86 inline bool isUser() {
87 return getBuildType() == "user";
88 }
isUserdebug()89 inline bool isUserdebug() {
90 return getBuildType() == "userdebug";
91 }
92
93 } // namespace bpf
94 } // namespace android
95