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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  
17  #include "incremental.h"
18  
19  #include "incremental_utils.h"
20  
21  #include <android-base/file.h>
22  #include <android-base/stringprintf.h>
23  #include <openssl/base64.h>
24  
25  #include "adb_client.h"
26  #include "adb_utils.h"
27  #include "commandline.h"
28  #include "sysdeps.h"
29  
30  using namespace std::literals;
31  
32  namespace incremental {
33  
34  using android::base::StringPrintf;
35  
36  // Read, verify and return the signature bytes. Keeping fd at the position of start of verity tree.
read_signature(Size file_size,std::string signature_file,bool silent)37  static std::pair<unique_fd, std::vector<char>> read_signature(Size file_size,
38                                                                std::string signature_file,
39                                                                bool silent) {
40      signature_file += IDSIG;
41  
42      struct stat st;
43      if (stat(signature_file.c_str(), &st)) {
44          if (!silent) {
45              fprintf(stderr, "Failed to stat signature file %s. Abort.\n", signature_file.c_str());
46          }
47          return {};
48      }
49  
50      unique_fd fd(adb_open(signature_file.c_str(), O_RDONLY));
51      if (fd < 0) {
52          if (!silent) {
53              fprintf(stderr, "Failed to open signature file: %s. Abort.\n", signature_file.c_str());
54          }
55          return {};
56      }
57  
58      auto [signature, tree_size] = read_id_sig_headers(fd);
59      if (auto expected = verity_tree_size_for_file(file_size); tree_size != expected) {
60          if (!silent) {
61              fprintf(stderr,
62                      "Verity tree size mismatch in signature file: %s [was %lld, expected %lld].\n",
63                      signature_file.c_str(), (long long)tree_size, (long long)expected);
64          }
65          return {};
66      }
67  
68      return {std::move(fd), std::move(signature)};
69  }
70  
71  // Base64-encode signature bytes. Keeping fd at the position of start of verity tree.
read_and_encode_signature(Size file_size,std::string signature_file,bool silent)72  static std::pair<unique_fd, std::string> read_and_encode_signature(Size file_size,
73                                                                     std::string signature_file,
74                                                                     bool silent) {
75      auto [fd, signature] = read_signature(file_size, std::move(signature_file), silent);
76      if (!fd.ok()) {
77          return {};
78      }
79  
80      size_t base64_len = 0;
81      if (!EVP_EncodedLength(&base64_len, signature.size())) {
82          if (!silent) {
83              fprintf(stderr, "Fail to estimate base64 encoded length. Abort.\n");
84          }
85          return {};
86      }
87      std::string encoded_signature(base64_len, '\0');
88      encoded_signature.resize(EVP_EncodeBlock((uint8_t*)encoded_signature.data(),
89                                               (const uint8_t*)signature.data(), signature.size()));
90  
91      return {std::move(fd), std::move(encoded_signature)};
92  }
93  
94  // Send install-incremental to the device along with properly configured file descriptors in
95  // streaming format. Once connection established, send all fs-verity tree bytes.
start_install(const Files & files,const Args & passthrough_args,bool silent)96  static unique_fd start_install(const Files& files, const Args& passthrough_args, bool silent) {
97      std::vector<std::string> command_args{"package", "install-incremental"};
98      command_args.insert(command_args.end(), passthrough_args.begin(), passthrough_args.end());
99  
100      for (int i = 0, size = files.size(); i < size; ++i) {
101          const auto& file = files[i];
102  
103          struct stat st;
104          if (stat(file.c_str(), &st)) {
105              if (!silent) {
106                  fprintf(stderr, "Failed to stat input file %s. Abort.\n", file.c_str());
107              }
108              return {};
109          }
110  
111          auto [signature_fd, signature] = read_and_encode_signature(st.st_size, file, silent);
112          if (!signature_fd.ok()) {
113              return {};
114          }
115  
116          auto file_desc = StringPrintf("%s:%lld:%d:%s:1", android::base::Basename(file).c_str(),
117                                        (long long)st.st_size, i, signature.c_str());
118          command_args.push_back(std::move(file_desc));
119      }
120  
121      std::string error;
122      auto connection_fd = unique_fd(send_abb_exec_command(command_args, &error));
123      if (connection_fd < 0) {
124          if (!silent) {
125              fprintf(stderr, "Failed to run: %s, error: %s\n",
126                      android::base::Join(command_args, " ").c_str(), error.c_str());
127          }
128          return {};
129      }
130  
131      return connection_fd;
132  }
133  
can_install(const Files & files)134  bool can_install(const Files& files) {
135      for (const auto& file : files) {
136          struct stat st;
137          if (stat(file.c_str(), &st)) {
138              return false;
139          }
140  
141          auto [fd, _] = read_signature(st.st_size, file, true);
142          if (!fd.ok()) {
143              return false;
144          }
145      }
146      return true;
147  }
148  
install(const Files & files,const Args & passthrough_args,bool silent)149  std::optional<Process> install(const Files& files, const Args& passthrough_args, bool silent) {
150      auto connection_fd = start_install(files, passthrough_args, silent);
151      if (connection_fd < 0) {
152          if (!silent) {
153              fprintf(stderr, "adb: failed to initiate installation on device.\n");
154          }
155          return {};
156      }
157  
158      std::string adb_path = android::base::GetExecutablePath();
159  
160      auto osh = adb_get_os_handle(connection_fd.get());
161  #ifdef _WIN32
162      auto fd_param = std::to_string(reinterpret_cast<intptr_t>(osh));
163  #else /* !_WIN32 a.k.a. Unix */
164      auto fd_param = std::to_string(osh);
165  #endif
166  
167      // pipe for child process to write output
168      int print_fds[2];
169      if (adb_socketpair(print_fds) != 0) {
170          if (!silent) {
171              fprintf(stderr, "Failed to create socket pair for child to print to parent\n");
172          }
173          return {};
174      }
175      auto [pipe_read_fd, pipe_write_fd] = print_fds;
176      auto pipe_write_fd_param = std::to_string(intptr_t(adb_get_os_handle(pipe_write_fd)));
177      close_on_exec(pipe_read_fd);
178  
179      std::vector<std::string> args(std::move(files));
180      args.insert(args.begin(), {"inc-server", fd_param, pipe_write_fd_param});
181      auto child =
182              adb_launch_process(adb_path, std::move(args), {connection_fd.get(), pipe_write_fd});
183      if (!child) {
184          if (!silent) {
185              fprintf(stderr, "adb: failed to fork: %s\n", strerror(errno));
186          }
187          return {};
188      }
189  
190      adb_close(pipe_write_fd);
191  
192      auto killOnExit = [](Process* p) { p->kill(); };
193      std::unique_ptr<Process, decltype(killOnExit)> serverKiller(&child, killOnExit);
194  
195      Result result = wait_for_installation(pipe_read_fd);
196      adb_close(pipe_read_fd);
197  
198      if (result == Result::Success) {
199          // adb client exits now but inc-server can continue
200          serverKiller.release();
201      }
202      return child;
203  }
204  
wait_for_installation(int read_fd)205  Result wait_for_installation(int read_fd) {
206      static constexpr int maxMessageSize = 256;
207      std::vector<char> child_stdout(CHUNK_SIZE);
208      int bytes_read;
209      int buf_size = 0;
210      // TODO(b/150865433): optimize child's output parsing
211      while ((bytes_read = adb_read(read_fd, child_stdout.data() + buf_size,
212                                    child_stdout.size() - buf_size)) > 0) {
213          // print to parent's stdout
214          fprintf(stdout, "%.*s", bytes_read, child_stdout.data() + buf_size);
215  
216          buf_size += bytes_read;
217          const std::string_view stdout_str(child_stdout.data(), buf_size);
218          // wait till installation either succeeds or fails
219          if (stdout_str.find("Success") != std::string::npos) {
220              return Result::Success;
221          }
222          // on failure, wait for full message
223          static constexpr auto failure_msg_head = "Failure ["sv;
224          if (const auto begin_itr = stdout_str.find(failure_msg_head);
225              begin_itr != std::string::npos) {
226              if (buf_size >= maxMessageSize) {
227                  return Result::Failure;
228              }
229              const auto end_itr = stdout_str.rfind("]");
230              if (end_itr != std::string::npos && end_itr >= begin_itr + failure_msg_head.size()) {
231                  return Result::Failure;
232              }
233          }
234          child_stdout.resize(buf_size + CHUNK_SIZE);
235      }
236      return Result::None;
237  }
238  
239  }  // namespace incremental
240