1 /*
2 * Copyright (C) 2015 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 #define LOG_TAG "cmd"
18
19 #include <utils/Log.h>
20 #include <binder/Parcel.h>
21 #include <binder/ProcessState.h>
22 #include <binder/IResultReceiver.h>
23 #include <binder/IServiceManager.h>
24 #include <binder/IShellCallback.h>
25 #include <binder/TextOutput.h>
26 #include <utils/Condition.h>
27 #include <utils/Mutex.h>
28 #include <utils/Vector.h>
29
30 #include <getopt.h>
31 #include <stdlib.h>
32 #include <stdio.h>
33 #include <string.h>
34 #include <unistd.h>
35 #include <fcntl.h>
36 #include <sys/time.h>
37 #include <errno.h>
38 #include <memory>
39
40 #include "selinux/selinux.h"
41 #include "selinux/android.h"
42
43 #include "cmd.h"
44
45 #define DEBUG 0
46
47 using namespace android;
48
sort_func(const String16 * lhs,const String16 * rhs)49 static int sort_func(const String16* lhs, const String16* rhs)
50 {
51 return lhs->compare(*rhs);
52 }
53
54 struct SecurityContext_Delete {
operator ()SecurityContext_Delete55 void operator()(security_context_t p) const {
56 freecon(p);
57 }
58 };
59 typedef std::unique_ptr<char[], SecurityContext_Delete> Unique_SecurityContext;
60
61 class MyShellCallback : public BnShellCallback
62 {
63 public:
64 TextOutput& mErrorLog;
65 bool mActive = true;
66
MyShellCallback(TextOutput & errorLog)67 MyShellCallback(TextOutput& errorLog) : mErrorLog(errorLog) {}
68
openFile(const String16 & path,const String16 & seLinuxContext,const String16 & mode)69 virtual int openFile(const String16& path, const String16& seLinuxContext,
70 const String16& mode) {
71 String8 path8(path);
72 char cwd[256];
73 getcwd(cwd, 256);
74 String8 fullPath(cwd);
75 fullPath.appendPath(path8);
76 if (!mActive) {
77 mErrorLog << "Open attempt after active for: " << fullPath << endl;
78 return -EPERM;
79 }
80 #if DEBUG
81 ALOGD("openFile: %s, full=%s", path8.string(), fullPath.string());
82 #endif
83 int flags = 0;
84 bool checkRead = false;
85 bool checkWrite = false;
86 if (mode == u"w") {
87 flags = O_WRONLY|O_CREAT|O_TRUNC;
88 checkWrite = true;
89 } else if (mode == u"w+") {
90 flags = O_RDWR|O_CREAT|O_TRUNC;
91 checkRead = checkWrite = true;
92 } else if (mode == u"r") {
93 flags = O_RDONLY;
94 checkRead = true;
95 } else if (mode == u"r+") {
96 flags = O_RDWR;
97 checkRead = checkWrite = true;
98 } else {
99 mErrorLog << "Invalid mode requested: " << mode.string() << endl;
100 return -EINVAL;
101 }
102 int fd = open(fullPath.string(), flags, S_IRWXU|S_IRWXG);
103 #if DEBUG
104 ALOGD("openFile: fd=%d", fd);
105 #endif
106 if (fd < 0) {
107 return fd;
108 }
109 if (is_selinux_enabled() && seLinuxContext.size() > 0) {
110 String8 seLinuxContext8(seLinuxContext);
111 security_context_t tmp = nullptr;
112 getfilecon(fullPath.string(), &tmp);
113 Unique_SecurityContext context(tmp);
114 if (checkWrite) {
115 int accessGranted = selinux_check_access(seLinuxContext8.string(), context.get(),
116 "file", "write", nullptr);
117 if (accessGranted != 0) {
118 #if DEBUG
119 ALOGD("openFile: failed selinux write check!");
120 #endif
121 close(fd);
122 mErrorLog << "System server has no access to write file context " << context.get() << " (from path " << fullPath.string() << ", context " << seLinuxContext8.string() << ")" << endl;
123 return -EPERM;
124 }
125 }
126 if (checkRead) {
127 int accessGranted = selinux_check_access(seLinuxContext8.string(), context.get(),
128 "file", "read", nullptr);
129 if (accessGranted != 0) {
130 #if DEBUG
131 ALOGD("openFile: failed selinux read check!");
132 #endif
133 close(fd);
134 mErrorLog << "System server has no access to read file context " << context.get() << " (from path " << fullPath.string() << ", context " << seLinuxContext8.string() << ")" << endl;
135 return -EPERM;
136 }
137 }
138 }
139 return fd;
140 }
141 };
142
143 class MyResultReceiver : public BnResultReceiver
144 {
145 public:
146 Mutex mMutex;
147 Condition mCondition;
148 bool mHaveResult = false;
149 int32_t mResult = 0;
150
send(int32_t resultCode)151 virtual void send(int32_t resultCode) {
152 AutoMutex _l(mMutex);
153 mResult = resultCode;
154 mHaveResult = true;
155 mCondition.signal();
156 }
157
waitForResult()158 int32_t waitForResult() {
159 AutoMutex _l(mMutex);
160 while (!mHaveResult) {
161 mCondition.wait(mMutex);
162 }
163 return mResult;
164 }
165 };
166
cmdMain(const std::vector<std::string_view> & argv,TextOutput & outputLog,TextOutput & errorLog,int in,int out,int err,RunMode runMode)167 int cmdMain(const std::vector<std::string_view>& argv, TextOutput& outputLog, TextOutput& errorLog,
168 int in, int out, int err, RunMode runMode) {
169 sp<ProcessState> proc = ProcessState::self();
170 proc->startThreadPool();
171
172 #if DEBUG
173 ALOGD("cmd: starting");
174 #endif
175 sp<IServiceManager> sm = defaultServiceManager();
176 if (runMode == RunMode::kStandalone) {
177 fflush(stdout);
178 }
179 if (sm == nullptr) {
180 ALOGW("Unable to get default service manager!");
181 errorLog << "cmd: Unable to get default service manager!" << endl;
182 return 20;
183 }
184
185 int argc = argv.size();
186
187 if (argc == 0) {
188 errorLog << "cmd: No service specified; use -l to list all services" << endl;
189 return 20;
190 }
191
192 if ((argc == 1) && (argv[0] == "-l")) {
193 Vector<String16> services = sm->listServices();
194 services.sort(sort_func);
195 outputLog << "Currently running services:" << endl;
196
197 for (size_t i=0; i<services.size(); i++) {
198 sp<IBinder> service = sm->checkService(services[i]);
199 if (service != nullptr) {
200 outputLog << " " << services[i] << endl;
201 }
202 }
203 return 0;
204 }
205
206 const auto cmd = argv[0];
207
208 Vector<String16> args;
209 String16 serviceName = String16(cmd.data(), cmd.size());
210 for (int i = 1; i < argc; i++) {
211 args.add(String16(argv[i].data(), argv[i].size()));
212 }
213 sp<IBinder> service = sm->checkService(serviceName);
214 if (service == nullptr) {
215 if (runMode == RunMode::kStandalone) {
216 ALOGW("Can't find service %.*s", static_cast<int>(cmd.size()), cmd.data());
217 }
218 errorLog << "cmd: Can't find service: " << cmd << endl;
219 return 20;
220 }
221
222 sp<MyShellCallback> cb = new MyShellCallback(errorLog);
223 sp<MyResultReceiver> result = new MyResultReceiver();
224
225 #if DEBUG
226 ALOGD("cmd: Invoking %s in=%d, out=%d, err=%d", cmd, in, out, err);
227 #endif
228
229 // TODO: block until a result is returned to MyResultReceiver.
230 status_t error = IBinder::shellCommand(service, in, out, err, args, cb, result);
231 if (error < 0) {
232 const char* errstr;
233 switch (error) {
234 case BAD_TYPE: errstr = "Bad type"; break;
235 case FAILED_TRANSACTION: errstr = "Failed transaction"; break;
236 case FDS_NOT_ALLOWED: errstr = "File descriptors not allowed"; break;
237 case UNEXPECTED_NULL: errstr = "Unexpected null"; break;
238 default: errstr = strerror(-error); break;
239 }
240 if (runMode == RunMode::kStandalone) {
241 ALOGW("Failure calling service %.*s: %s (%d)", static_cast<int>(cmd.size()), cmd.data(),
242 errstr, -error);
243 }
244 outputLog << "cmd: Failure calling service " << cmd << ": " << errstr << " (" << (-error)
245 << ")" << endl;
246 return error;
247 }
248
249 cb->mActive = false;
250 status_t res = result->waitForResult();
251 #if DEBUG
252 ALOGD("result=%d", (int)res);
253 #endif
254 return res;
255 }
256