apt-pkg/contrib/gpgv.cc

   1 // -*- mode: cpp; mode: fold -*-
   2 // Include Files                                                        /*{{{*/
   3 #include<config.h>
   4
   5 #include <errno.h>
   6 #include <stdio.h>
   7 #include <string.h>
   8 #include <stdlib.h>
   9 #include <fcntl.h>
  10 #include <sys/stat.h>
  11 #include <sys/types.h>
  12 #include <sys/wait.h>
  13 #include <unistd.h>
  14
  15 #include<apt-pkg/configuration.h>
  16 #include<apt-pkg/error.h>
  17 #include<apt-pkg/strutl.h>
  18 #include<apt-pkg/fileutl.h>
  19 #include<apt-pkg/gpgv.h>
  20
  21 #include <apti18n.h>
  22                                                                         /*}}}*/
  23 static char * GenerateTemporaryFileTemplate(const char *basename)       /*{{{*/
  24 {
  25    std::string out;
  26    std::string tmpdir = GetTempDir();
  27    strprintf(out,  "%s/%s.XXXXXX", tmpdir.c_str(), basename);
  28    return strdup(out.c_str());
  29 }
  30                                                                         /*}}}*/
  31 // ExecGPGV - returns the command needed for verify                     /*{{{*/
  32 // ---------------------------------------------------------------------
  33 /* Generating the commandline for calling gpgv is somehow complicated as
  34    we need to add multiple keyrings and user supplied options.
  35    Also, as gpgv has no options to enforce a certain reduced style of
  36    clear-signed files (=the complete content of the file is signed and
  37    the content isn't encoded) we do a divide and conquer approach here
  38    and split up the clear-signed file in message and signature for gpgv
  39 */
  40 void ExecGPGV(std::string const &File, std::string const &FileGPG,
  41              int const &statusfd, int fd[2])
  42 {
  43    #define EINTERNAL 111
  44    std::string const gpgvpath = _config->Find("Dir::Bin::gpg", "/usr/bin/gpgv");
  45    // FIXME: remove support for deprecated APT::GPGV setting
  46    std::string const trustedFile = _config->Find("APT::GPGV::TrustedKeyring", _config->FindFile("Dir::Etc::Trusted"));
  47    std::string const trustedPath = _config->FindDir("Dir::Etc::TrustedParts");
  48
  49    bool const Debug = _config->FindB("Debug::Acquire::gpgv", false);
  50
  51    if (Debug == true)
  52    {
  53       std::clog << "gpgv path: " << gpgvpath << std::endl;
  54       std::clog << "Keyring file: " << trustedFile << std::endl;
  55       std::clog << "Keyring path: " << trustedPath << std::endl;
  56    }
  57
  58    std::vector<std::string> keyrings;
  59    if (DirectoryExists(trustedPath))
  60      keyrings = GetListOfFilesInDir(trustedPath, "gpg", false, true);
  61    if (RealFileExists(trustedFile) == true)
  62      keyrings.push_back(trustedFile);
  63
  64    std::vector<const char *> Args;
  65    Args.reserve(30);
  66
  67    if (keyrings.empty() == true)
  68    {
  69       // TRANSLATOR: %s is the trusted keyring parts directory
  70       ioprintf(std::cerr, _("No keyring installed in %s."),
  71             _config->FindDir("Dir::Etc::TrustedParts").c_str());
  72       exit(EINTERNAL);
  73    }
  74
  75    Args.push_back(gpgvpath.c_str());
  76    Args.push_back("--ignore-time-conflict");
  77
  78    char statusfdstr[10];
  79    if (statusfd != -1)
  80    {
  81       Args.push_back("--status-fd");
  82       snprintf(statusfdstr, sizeof(statusfdstr), "%i", statusfd);
  83       Args.push_back(statusfdstr);
  84    }
  85
  86    for (std::vector<std::string>::const_iterator K = keyrings.begin();
  87         K != keyrings.end(); ++K)
  88    {
  89       Args.push_back("--keyring");
  90       Args.push_back(K->c_str());
  91    }
  92
  93    Configuration::Item const *Opts;
  94    Opts = _config->Tree("Acquire::gpgv::Options");
  95    if (Opts != 0)
  96    {
  97       Opts = Opts->Child;
  98       for (; Opts != 0; Opts = Opts->Next)
  99       {
 100          if (Opts->Value.empty() == true)
 101             continue;
 102          Args.push_back(Opts->Value.c_str());
 103       }
 104    }
 105
 106    enum  { DETACHED, CLEARSIGNED } releaseSignature = (FileGPG != File) ? DETACHED : CLEARSIGNED;
 107    std::vector<std::string> dataHeader;
 108    char * sig = NULL;
 109    char * data = NULL;
 110
 111    if (releaseSignature == DETACHED)
 112    {
 113       Args.push_back(FileGPG.c_str());
 114       Args.push_back(File.c_str());
 115    }
 116    else // clear-signed file
 117    {
 118       sig = GenerateTemporaryFileTemplate("apt.sig");
 119       data = GenerateTemporaryFileTemplate("apt.data");
 120       if (sig == NULL || data == NULL)
 121       {
 122          ioprintf(std::cerr, "Couldn't create tempfile names for splitting up %s", File.c_str());
 123          exit(EINTERNAL);
 124       }
 125
 126       int const sigFd = mkstemp(sig);
 127       int const dataFd = mkstemp(data);
 128       if (sigFd == -1 || dataFd == -1)
 129       {
 130          if (dataFd != -1)
 131             unlink(sig);
 132          if (sigFd != -1)
 133             unlink(data);
 134          ioprintf(std::cerr, "Couldn't create tempfiles for splitting up %s", File.c_str());
 135          exit(EINTERNAL);
 136       }
 137
 138       FileFd signature;
 139       signature.OpenDescriptor(sigFd, FileFd::WriteOnly, true);
 140       FileFd message;
 141       message.OpenDescriptor(dataFd, FileFd::WriteOnly, true);
 142
 143       if (signature.Failed() == true || message.Failed() == true ||
 144             SplitClearSignedFile(File, &message, &dataHeader, &signature) == false)
 145       {
 146          if (dataFd != -1)
 147             unlink(sig);
 148          if (sigFd != -1)
 149             unlink(data);
 150          ioprintf(std::cerr, "Splitting up %s into data and signature failed", File.c_str());
 151          exit(112);
 152       }
 153       Args.push_back(sig);
 154       Args.push_back(data);
 155    }
 156
 157    Args.push_back(NULL);
 158
 159    if (Debug == true)
 160    {
 161       std::clog << "Preparing to exec: " << gpgvpath;
 162       for (std::vector<const char *>::const_iterator a = Args.begin(); *a != NULL; ++a)
 163          std::clog << " " << *a;
 164       std::clog << std::endl;
 165    }
 166
 167    if (statusfd != -1)
 168    {
 169       int const nullfd = open("/dev/null", O_RDONLY);
 170       close(fd[0]);
 171       // Redirect output to /dev/null; we read from the status fd
 172       if (statusfd != STDOUT_FILENO)
 173          dup2(nullfd, STDOUT_FILENO);
 174       if (statusfd != STDERR_FILENO)
 175          dup2(nullfd, STDERR_FILENO);
 176       // Redirect the pipe to the status fd (3)
 177       dup2(fd[1], statusfd);
 178
 179       putenv((char *)"LANG=");
 180       putenv((char *)"LC_ALL=");
 181       putenv((char *)"LC_MESSAGES=");
 182    }
 183
 184    if (releaseSignature == DETACHED)
 185    {
 186       execvp(gpgvpath.c_str(), (char **) &Args[0]);
 187       ioprintf(std::cerr, "Couldn't execute %s to check %s", Args[0], File.c_str());
 188       exit(EINTERNAL);
 189    }
 190    else
 191    {
 192 //#define UNLINK_EXIT(X) exit(X)
 193 #define UNLINK_EXIT(X) unlink(sig);unlink(data);exit(X)
 194
 195       // for clear-signed files we have created tempfiles we have to clean up
 196       // and we do an additional check, so fork yet another time …
 197       pid_t pid = ExecFork();
 198       if(pid < 0) {
 199          ioprintf(std::cerr, "Fork failed for %s to check %s", Args[0], File.c_str());
 200          UNLINK_EXIT(EINTERNAL);
 201       }
 202       if(pid == 0)
 203       {
 204          if (statusfd != -1)
 205             dup2(fd[1], statusfd);
 206          execvp(gpgvpath.c_str(), (char **) &Args[0]);
 207          ioprintf(std::cerr, "Couldn't execute %s to check %s", Args[0], File.c_str());
 208          UNLINK_EXIT(EINTERNAL);
 209       }
 210
 211       // Wait and collect the error code - taken from WaitPid as we need the exact Status
 212       int Status;
 213       while (waitpid(pid,&Status,0) != pid)
 214       {
 215          if (errno == EINTR)
 216             continue;
 217          ioprintf(std::cerr, _("Waited for %s but it wasn't there"), "gpgv");
 218          UNLINK_EXIT(EINTERNAL);
 219       }
 220 #undef UNLINK_EXIT
 221       // we don't need the files any longer
 222       unlink(sig);
 223       unlink(data);
 224       free(sig);
 225       free(data);
 226
 227       // check if it exit'ed normally …
 228       if (WIFEXITED(Status) == false)
 229       {
 230          ioprintf(std::cerr, _("Sub-process %s exited unexpectedly"), "gpgv");
 231          exit(EINTERNAL);
 232       }
 233
 234       // … and with a good exit code
 235       if (WEXITSTATUS(Status) != 0)
 236       {
 237          ioprintf(std::cerr, _("Sub-process %s returned an error code (%u)"), "gpgv", WEXITSTATUS(Status));
 238          exit(WEXITSTATUS(Status));
 239       }
 240
 241       // everything fine
 242       exit(0);
 243    }
 244    exit(EINTERNAL); // unreachable safe-guard
 245 }
 246                                                                         /*}}}*/
 247 // SplitClearSignedFile - split message into data/signature             /*{{{*/
 248 bool SplitClearSignedFile(std::string const &InFile, FileFd * const ContentFile,
 249       std::vector<std::string> * const ContentHeader, FileFd * const SignatureFile)
 250 {
 251    FILE *in = fopen(InFile.c_str(), "r");
 252    if (in == NULL)
 253       return _error->Errno("fopen", "can not open %s", InFile.c_str());
 254
 255    bool found_message_start = false;
 256    bool found_message_end = false;
 257    bool skip_until_empty_line = false;
 258    bool found_signature = false;
 259    bool first_line = true;
 260
 261    char *buf = NULL;
 262    size_t buf_size = 0;
 263    ssize_t line_len = 0;
 264    while ((line_len = getline(&buf, &buf_size, in)) != -1)
 265    {
 266       _strrstrip(buf);
 267       if (found_message_start == false)
 268       {
 269          if (strcmp(buf, "-----BEGIN PGP SIGNED MESSAGE-----") == 0)
 270          {
 271             found_message_start = true;
 272             skip_until_empty_line = true;
 273          }
 274       }
 275       else if (skip_until_empty_line == true)
 276       {
 277          if (strlen(buf) == 0)
 278             skip_until_empty_line = false;
 279          // save "Hash" Armor Headers, others aren't allowed
 280          else if (ContentHeader != NULL && strncmp(buf, "Hash: ", strlen("Hash: ")) == 0)
 281             ContentHeader->push_back(buf);
 282       }
 283       else if (found_signature == false)
 284       {
 285          if (strcmp(buf, "-----BEGIN PGP SIGNATURE-----") == 0)
 286          {
 287             found_signature = true;
 288             found_message_end = true;
 289             if (SignatureFile != NULL)
 290             {
 291                SignatureFile->Write(buf, strlen(buf));
 292                SignatureFile->Write("\n", 1);
 293             }
 294          }
 295          else if (found_message_end == false) // we are in the message block
 296          {
 297             // we don't have any fields which need dash-escaped,
 298             // but implementations are free to encode all lines …
 299             char const * dashfree = buf;
 300             if (strncmp(dashfree, "- ", 2) == 0)
 301                dashfree += 2;
 302             if(first_line == true) // first line does not need a newline
 303                first_line = false;
 304             else if (ContentFile != NULL)
 305                ContentFile->Write("\n", 1);
 306             else
 307                continue;
 308             if (ContentFile != NULL)
 309                ContentFile->Write(dashfree, strlen(dashfree));
 310          }
 311       }
 312       else if (found_signature == true)
 313       {
 314          if (SignatureFile != NULL)
 315          {
 316             SignatureFile->Write(buf, strlen(buf));
 317             SignatureFile->Write("\n", 1);
 318          }
 319          if (strcmp(buf, "-----END PGP SIGNATURE-----") == 0)
 320             found_signature = false; // look for other signatures
 321       }
 322       // all the rest is whitespace, unsigned garbage or additional message blocks we ignore
 323    }
 324    fclose(in);
 325
 326    if (found_signature == true)
 327       return _error->Error("Signature in file %s wasn't closed", InFile.c_str());
 328
 329    // if we haven't found any of them, this an unsigned file,
 330    // so don't generate an error, but splitting was unsuccessful none-the-less
 331    if (first_line == true && found_message_start == false && found_message_end == false)
 332       return false;
 333    // otherwise one missing indicates a syntax error
 334    else if (first_line == true || found_message_start == false || found_message_end == false)
 335      return _error->Error("Splitting of file %s failed as it doesn't contain all expected parts %i %i %i", InFile.c_str(), first_line, found_message_start, found_message_end);
 336
 337    return true;
 338 }
 339                                                                         /*}}}*/
 340 bool OpenMaybeClearSignedFile(std::string const &ClearSignedFileName, FileFd &MessageFile) /*{{{*/
 341 {
 342    char * const message = GenerateTemporaryFileTemplate("fileutl.message");
 343    int const messageFd = mkstemp(message);
 344    if (messageFd == -1)
 345    {
 346       free(message);
 347       return _error->Errno("mkstemp", "Couldn't create temporary file to work with %s", ClearSignedFileName.c_str());
 348    }
 349    // we have the fd, thats enough for us
 350    unlink(message);
 351    free(message);
 352
 353    MessageFile.OpenDescriptor(messageFd, FileFd::ReadWrite, true);
 354    if (MessageFile.Failed() == true)
 355       return _error->Error("Couldn't open temporary file to work with %s", ClearSignedFileName.c_str());
 356
 357    _error->PushToStack();
 358    bool const splitDone = SplitClearSignedFile(ClearSignedFileName.c_str(), &MessageFile, NULL, NULL);
 359    bool const errorDone = _error->PendingError();
 360    _error->MergeWithStack();
 361    if (splitDone == false)
 362    {
 363       MessageFile.Close();
 364
 365       if (errorDone == true)
 366          return false;
 367
 368       // we deal with an unsigned file
 369       MessageFile.Open(ClearSignedFileName, FileFd::ReadOnly);
 370    }
 371    else // clear-signed
 372    {
 373       if (MessageFile.Seek(0) == false)
 374          return _error->Errno("lseek", "Unable to seek back in message for file %s", ClearSignedFileName.c_str());
 375    }
 376
 377    return MessageFile.Failed() == false;
 378 }
 379                                                                         /*}}}*/