1 /*
2 * Copyright (C) 2020 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 #include "linkerconfig/apex.h"
17
18 #include <algorithm>
19 #include <cstring>
20 #include <regex>
21 #include <set>
22 #include <string>
23 #include <string_view>
24 #include <vector>
25
26 #include <android-base/file.h>
27 #include <android-base/result.h>
28 #include <android-base/strings.h>
29 #include <apexutil.h>
30 #include <unistd.h>
31
32 #include "linkerconfig/configparser.h"
33 #include "linkerconfig/environment.h"
34 #include "linkerconfig/log.h"
35 #include "linkerconfig/stringutil.h"
36
37 // include after log.h to avoid macro redefinition error
38 #include "com_android_apex.h"
39
40 using android::base::ErrnoError;
41 using android::base::Error;
42 using android::base::ReadFileToString;
43 using android::base::Result;
44 using android::base::StartsWith;
45
46 namespace {
PathExists(const std::string & path)47 bool PathExists(const std::string& path) {
48 return access(path.c_str(), F_OK) == 0;
49 }
50
ReadPublicLibraries(const std::string & filepath)51 Result<std::set<std::string>> ReadPublicLibraries(const std::string& filepath) {
52 std::string file_content;
53 if (!android::base::ReadFileToString(filepath, &file_content)) {
54 return ErrnoError();
55 }
56 std::vector<std::string> lines = android::base::Split(file_content, "\n");
57 std::set<std::string> sonames;
58 for (auto& line : lines) {
59 auto trimmed_line = android::base::Trim(line);
60 if (trimmed_line[0] == '#' || trimmed_line.empty()) {
61 continue;
62 }
63 std::vector<std::string> tokens = android::base::Split(trimmed_line, " ");
64 if (tokens.size() < 1 || tokens.size() > 3) {
65 return Errorf("Malformed line \"{}\"", line);
66 }
67 sonames.insert(tokens[0]);
68 }
69 return sonames;
70 }
71
Intersect(const std::vector<std::string> & as,const std::set<std::string> & bs)72 std::vector<std::string> Intersect(const std::vector<std::string>& as,
73 const std::set<std::string>& bs) {
74 std::vector<std::string> intersect;
75 std::copy_if(as.begin(),
76 as.end(),
77 std::back_inserter(intersect),
78 [&bs](const auto& a) { return bs.find(a) != bs.end(); });
79 return intersect;
80 }
81
IsValidForPath(const uint_fast8_t c)82 bool IsValidForPath(const uint_fast8_t c) {
83 if (c >= 'a' && c <= 'z') return true;
84 if (c >= 'A' && c <= 'Z') return true;
85 if (c >= '0' && c <= '9') return true;
86 if (c == '-' || c == '_' || c == '.') return true;
87 return false;
88 }
89
VerifyPath(const std::string & path)90 Result<void> VerifyPath(const std::string& path) {
91 const size_t length = path.length();
92 constexpr char lib_dir[] = "${LIB}";
93 constexpr size_t lib_dir_len = (sizeof lib_dir) - 1;
94 const std::string_view path_view(path);
95
96 if (length == 0) {
97 return Error() << "Empty path is not allowed";
98 }
99
100 for (size_t i = 0; i < length; i++) {
101 uint_fast8_t current_char = path[i];
102 if (current_char == '/') {
103 i++;
104 if (i >= length) {
105 return {};
106 } else if (path[i] == '/') {
107 return Error() << "'/' should not appear twice in " << path;
108 } else if (i + lib_dir_len <= length &&
109 path_view.substr(i, lib_dir_len) == lib_dir) {
110 i += lib_dir_len - 1;
111 } else {
112 for (; i < length; i++) {
113 current_char = path[i];
114 if (current_char == '/') {
115 i--;
116 break;
117 }
118
119 if (!IsValidForPath(current_char)) {
120 return Error() << "Invalid char '" << current_char << "' in "
121 << path;
122 }
123 }
124 }
125 } else {
126 return Error() << "Invalid char '" << current_char << "' in " << path
127 << " at " << i;
128 }
129 }
130
131 return {};
132 }
133 } // namespace
134
135 namespace android {
136 namespace linkerconfig {
137 namespace modules {
138
ScanActiveApexes(const std::string & root)139 Result<std::map<std::string, ApexInfo>> ScanActiveApexes(const std::string& root) {
140 std::map<std::string, ApexInfo> apexes;
141 const auto apex_root = root + apex::kApexRoot;
142 for (const auto& [path, manifest] : apex::GetActivePackages(apex_root)) {
143 bool has_bin = PathExists(path + "/bin");
144 bool has_lib = PathExists(path + "/lib") || PathExists(path + "/lib64");
145 bool has_shared_lib = manifest.requiresharedapexlibs().size() != 0;
146
147 std::vector<std::string> permitted_paths;
148 bool visible = false;
149
150 std::string linker_config_path = path + "/etc/linker.config.pb";
151 if (PathExists(linker_config_path)) {
152 auto linker_config = ParseLinkerConfig(linker_config_path);
153
154 if (linker_config.ok()) {
155 permitted_paths = {linker_config->permittedpaths().begin(),
156 linker_config->permittedpaths().end()};
157 for (const std::string& path : permitted_paths) {
158 Result<void> verify_permitted_path = VerifyPath(path);
159 if (!verify_permitted_path.ok()) {
160 return Error() << "Failed to validate path from APEX linker config"
161 << linker_config_path << " : "
162 << verify_permitted_path.error();
163 }
164 }
165 visible = linker_config->visible();
166 } else {
167 return Error() << "Failed to read APEX linker config : "
168 << linker_config.error();
169 }
170 }
171
172 ApexInfo info(manifest.name(),
173 TrimPrefix(path, root),
174 {manifest.providenativelibs().begin(),
175 manifest.providenativelibs().end()},
176 {manifest.requirenativelibs().begin(),
177 manifest.requirenativelibs().end()},
178 {manifest.jnilibs().begin(), manifest.jnilibs().end()},
179 std::move(permitted_paths),
180 has_bin,
181 has_lib,
182 visible,
183 has_shared_lib);
184 apexes.emplace(manifest.name(), std::move(info));
185 }
186
187 if (!apexes.empty()) {
188 const std::string info_list_file = apex_root + "/apex-info-list.xml";
189 auto info_list =
190 com::android::apex::readApexInfoList(info_list_file.c_str());
191 if (info_list.has_value()) {
192 for (const auto& info : info_list->getApexInfo()) {
193 apexes[info.getModuleName()].original_path =
194 info.getPreinstalledModulePath();
195 }
196 } else {
197 return ErrnoError() << "Can't read " << info_list_file;
198 }
199
200 const std::string public_libraries_file =
201 root + "/system/etc/public.libraries.txt";
202 auto public_libraries = ReadPublicLibraries(public_libraries_file);
203 if (public_libraries.ok()) {
204 for (auto& [name, apex] : apexes) {
205 // Only system apexes can provide public libraries.
206 if (!apex.InSystem()) {
207 continue;
208 }
209 apex.public_libs = Intersect(apex.provide_libs, *public_libraries);
210 }
211 } else {
212 // Do not fail when public.libraries.txt is missing for minimal Android
213 // environment with no ART.
214 LOG(WARNING) << "Can't read " << public_libraries_file << ": "
215 << public_libraries.error();
216 }
217 }
218
219 return apexes;
220 }
221
InSystem() const222 bool ApexInfo::InSystem() const {
223 return StartsWith(original_path, "/system/apex/") ||
224 StartsWith(original_path, "/system_ext/apex/") ||
225 (!IsProductVndkVersionDefined() &&
226 StartsWith(original_path, "/product/apex/"));
227 }
228
InProduct() const229 bool ApexInfo::InProduct() const {
230 return IsProductVndkVersionDefined() &&
231 StartsWith(original_path, "/product/apex/");
232 }
233
InVendor() const234 bool ApexInfo::InVendor() const {
235 return StartsWith(original_path, "/vendor/apex/") ||
236 StartsWith(original_path, "/odm/apex/");
237 }
238
239 } // namespace modules
240 } // namespace linkerconfig
241 } // namespace android