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
  14 #include<apt-pkg/configuration.h>
  15 #include<apt-pkg/error.h>
  16 #include<apt-pkg/strutl.h>
  17 #include<apt-pkg/fileutl.h>
  18 #include<apt-pkg/gpgv.h>
  19
  20 #include <apti18n.h>
  21                                                                         /*}}}*/
  22 char * GenerateTemporaryFileTemplate(const char *basename)              /*{{{*/
  23 {
  24    const char *tmpdir = getenv("TMPDIR");
  25 #ifdef P_tmpdir
  26    if (!tmpdir)
  27       tmpdir = P_tmpdir;
  28 #endif
  29    if (!tmpdir)
  30       tmpdir = "/tmp";
  31
  32    std::string out;
  33    strprintf(out,  "%s/%s.XXXXXX", tmpdir, basename);
  34    return strdup(out.c_str());
  35 }
  36                                                                         /*}}}*/
  37 // ExecGPGV - returns the command needed for verify                     /*{{{*/
  38 // ---------------------------------------------------------------------
  39 /* Generating the commandline for calling gpgv is somehow complicated as
  40    we need to add multiple keyrings and user supplied options.
  41    Also, as gpgv has no options to enforce a certain reduced style of
  42    clear-signed files (=the complete content of the file is signed and
  43    the content isn't encoded) we do a divide and conquer approach here
  44 */
  45 void ExecGPGV(std::string const &File, std::string const &FileGPG,
  46              int const &statusfd, int fd[2])
  47 {
  48    #define EINTERNAL 111
  49    std::string const gpgvpath = _config->Find("Dir::Bin::gpg", "/usr/bin/gpgv");
  50    // FIXME: remove support for deprecated APT::GPGV setting
  51    std::string const trustedFile = _config->Find("APT::GPGV::TrustedKeyring", _config->FindFile("Dir::Etc::Trusted"));
  52    std::string const trustedPath = _config->FindDir("Dir::Etc::TrustedParts");
  53
  54    bool const Debug = _config->FindB("Debug::Acquire::gpgv", false);
  55
  56    if (Debug == true)
  57    {
  58       std::clog << "gpgv path: " << gpgvpath << std::endl;
  59       std::clog << "Keyring file: " << trustedFile << std::endl;
  60       std::clog << "Keyring path: " << trustedPath << std::endl;
  61    }
  62
  63    std::vector<std::string> keyrings;
  64    if (DirectoryExists(trustedPath))
  65      keyrings = GetListOfFilesInDir(trustedPath, "gpg", false, true);
  66    if (RealFileExists(trustedFile) == true)
  67      keyrings.push_back(trustedFile);
  68
  69    std::vector<const char *> Args;
  70    Args.reserve(30);
  71
  72    if (keyrings.empty() == true)
  73    {
  74       // TRANSLATOR: %s is the trusted keyring parts directory
  75       ioprintf(std::cerr, _("No keyring installed in %s."),
  76             _config->FindDir("Dir::Etc::TrustedParts").c_str());
  77       exit(EINTERNAL);
  78    }
  79
  80    Args.push_back(gpgvpath.c_str());
  81    Args.push_back("--ignore-time-conflict");
  82
  83    char statusfdstr[10];
  84    if (statusfd != -1)
  85    {
  86       Args.push_back("--status-fd");
  87       snprintf(statusfdstr, sizeof(statusfdstr), "%i", statusfd);
  88       Args.push_back(statusfdstr);
  89    }
  90
  91    for (std::vector<std::string>::const_iterator K = keyrings.begin();
  92         K != keyrings.end(); ++K)
  93    {
  94       Args.push_back("--keyring");
  95       Args.push_back(K->c_str());
  96    }
  97
  98    Configuration::Item const *Opts;
  99    Opts = _config->Tree("Acquire::gpgv::Options");
 100    if (Opts != 0)
 101    {
 102       Opts = Opts->Child;
 103       for (; Opts != 0; Opts = Opts->Next)
 104       {
 105          if (Opts->Value.empty() == true)
 106             continue;
 107          Args.push_back(Opts->Value.c_str());
 108       }
 109    }
 110
 111    int sigFd = -1;
 112    int dataFd = -1;
 113    std::vector<std::string> dataHeader;
 114    char * sig = NULL;
 115    char * data = NULL;
 116
 117    // file with detached signature
 118    if (FileGPG != File)
 119    {
 120       Args.push_back(FileGPG.c_str());
 121       Args.push_back(File.c_str());
 122    }
 123    else // clear-signed file
 124    {
 125       sig = GenerateTemporaryFileTemplate("apt.sig");
 126       data = GenerateTemporaryFileTemplate("apt.data");
 127       if (sig == NULL || data == NULL)
 128       {
 129          ioprintf(std::cerr, "Couldn't create tempfiles for splitting up %s", File.c_str());
 130          exit(EINTERNAL);
 131       }
 132
 133       sigFd = mkstemp(sig);
 134       dataFd = mkstemp(data);
 135       int const duppedSigFd = dup(sigFd);
 136       int const duppedDataFd = dup(dataFd);
 137
 138       if (dataFd == -1 || sigFd == -1 || duppedDataFd == -1 || duppedSigFd == -1 ||
 139             SplitClearSignedFile(File, duppedDataFd, &dataHeader, duppedSigFd) == false)
 140       {
 141          if (dataFd != -1)
 142             unlink(sig);
 143          if (sigFd != -1)
 144             unlink(data);
 145          ioprintf(std::cerr, "Splitting up %s into data and signature failed", File.c_str());
 146          exit(EINTERNAL);
 147       }
 148       lseek(dataFd, 0, SEEK_SET);
 149       lseek(sigFd, 0, SEEK_SET);
 150       Args.push_back(sig);
 151       Args.push_back(data);
 152    }
 153
 154    Args.push_back(NULL);
 155
 156    if (Debug == true)
 157    {
 158       std::clog << "Preparing to exec: " << gpgvpath;
 159       for (std::vector<const char *>::const_iterator a = Args.begin(); *a != NULL; ++a)
 160          std::clog << " " << *a;
 161       std::clog << std::endl;
 162    }
 163
 164    if (statusfd != -1)
 165    {
 166       int const nullfd = open("/dev/null", O_RDONLY);
 167       close(fd[0]);
 168       // Redirect output to /dev/null; we read from the status fd
 169       if (statusfd != STDOUT_FILENO)
 170          dup2(nullfd, STDOUT_FILENO);
 171       if (statusfd != STDERR_FILENO)
 172          dup2(nullfd, STDERR_FILENO);
 173       // Redirect the pipe to the status fd (3)
 174       dup2(fd[1], statusfd);
 175
 176       putenv((char *)"LANG=");
 177       putenv((char *)"LC_ALL=");
 178       putenv((char *)"LC_MESSAGES=");
 179    }
 180
 181    if (FileGPG != File)
 182    {
 183       execvp(gpgvpath.c_str(), (char **) &Args[0]);
 184       ioprintf(std::cerr, "Couldn't execute %s to check %s", Args[0], File.c_str());
 185       exit(EINTERNAL);
 186    }
 187    else
 188    {
 189 //#define UNLINK_EXIT(X) exit(X)
 190 #define UNLINK_EXIT(X) unlink(sig);unlink(data);exit(X)
 191
 192       // for clear-signed files we have created tempfiles we have to clean up
 193       // and we do an additional check, so fork yet another time …
 194       pid_t pid = ExecFork();
 195       if(pid < 0) {
 196          ioprintf(std::cerr, "Fork failed for %s to check %s", Args[0], File.c_str());
 197          UNLINK_EXIT(EINTERNAL);
 198       }
 199       if(pid == 0)
 200       {
 201          if (statusfd != -1)
 202             dup2(fd[1], statusfd);
 203          execvp(gpgvpath.c_str(), (char **) &Args[0]);
 204          ioprintf(std::cerr, "Couldn't execute %s to check %s", Args[0], File.c_str());
 205          UNLINK_EXIT(EINTERNAL);
 206       }
 207
 208       // Wait and collect the error code - taken from WaitPid as we need the exact Status
 209       int Status;
 210       while (waitpid(pid,&Status,0) != pid)
 211       {
 212          if (errno == EINTR)
 213             continue;
 214          ioprintf(std::cerr, _("Waited for %s but it wasn't there"), "gpgv");
 215          UNLINK_EXIT(EINTERNAL);
 216       }
 217 #undef UNLINK_EXIT
 218       // we don't need the files any longer as we have the filedescriptors still open
 219       unlink(sig);
 220       unlink(data);
 221       free(sig);
 222       free(data);
 223
 224       // check if it exit'ed normally …
 225       if (WIFEXITED(Status) == false)
 226       {
 227          ioprintf(std::cerr, _("Sub-process %s exited unexpectedly"), "gpgv");
 228          exit(EINTERNAL);
 229       }
 230
 231       // … and with a good exit code
 232       if (WEXITSTATUS(Status) != 0)
 233       {
 234          ioprintf(std::cerr, _("Sub-process %s returned an error code (%u)"), "gpgv", WEXITSTATUS(Status));
 235          exit(WEXITSTATUS(Status));
 236       }
 237
 238       /* looks like its fine. Our caller will check the status fd,
 239          but we construct a good-known clear-signed file without garbage
 240          and other non-sense. In a perfect world, we get the same file,
 241          but empty lines, trailing whitespaces and stuff makes it inperfect … */
 242       if (RecombineToClearSignedFile(File, dataFd, dataHeader, sigFd) == false)
 243       {
 244          _error->DumpErrors(std::cerr);
 245          exit(EINTERNAL);
 246       }
 247
 248       // everything fine, we have a clean file now!
 249       exit(0);
 250    }
 251    exit(EINTERNAL); // unreachable safe-guard
 252 }
 253                                                                         /*}}}*/
 254 // RecombineToClearSignedFile - combine data/signature to message       /*{{{*/
 255 bool RecombineToClearSignedFile(std::string const &OutFile, int const ContentFile,
 256       std::vector<std::string> const &ContentHeader, int const SignatureFile)
 257 {
 258    FILE *clean_file = fopen(OutFile.c_str(), "w");
 259    fputs("-----BEGIN PGP SIGNED MESSAGE-----\n", clean_file);
 260    for (std::vector<std::string>::const_iterator h = ContentHeader.begin(); h != ContentHeader.end(); ++h)
 261       fprintf(clean_file, "%s\n", h->c_str());
 262    fputs("\n", clean_file);
 263
 264    FILE *data_file = fdopen(ContentFile, "r");
 265    FILE *sig_file = fdopen(SignatureFile, "r");
 266    if (data_file == NULL || sig_file == NULL)
 267    {
 268       fclose(clean_file);
 269       return _error->Error("Couldn't open splitfiles to recombine them into %s", OutFile.c_str());
 270    }
 271    char *buf = NULL;
 272    size_t buf_size = 0;
 273    while (getline(&buf, &buf_size, data_file) != -1)
 274       fputs(buf, clean_file);
 275    fclose(data_file);
 276    fputs("\n", clean_file);
 277    while (getline(&buf, &buf_size, sig_file) != -1)
 278       fputs(buf, clean_file);
 279    fclose(sig_file);
 280    fclose(clean_file);
 281    return true;
 282 }
 283                                                                         /*}}}*/
 284 // SplitClearSignedFile - split message into data/signature             /*{{{*/
 285 bool SplitClearSignedFile(std::string const &InFile, int const ContentFile,
 286       std::vector<std::string> * const ContentHeader, int const SignatureFile)
 287 {
 288    FILE *in = fopen(InFile.c_str(), "r");
 289    if (in == NULL)
 290       return _error->Errno("fopen", "can not open %s", InFile.c_str());
 291
 292    FILE *out_content = NULL;
 293    FILE *out_signature = NULL;
 294    if (ContentFile != -1)
 295    {
 296       out_content = fdopen(ContentFile, "w");
 297       if (out_content == NULL)
 298       {
 299          fclose(in);
 300          return _error->Errno("fdopen", "Failed to open file to write content to from %s", InFile.c_str());
 301       }
 302    }
 303    if (SignatureFile != -1)
 304    {
 305       out_signature = fdopen(SignatureFile, "w");
 306       if (out_signature == NULL)
 307       {
 308          fclose(in);
 309          if (out_content != NULL)
 310             fclose(out_content);
 311          return _error->Errno("fdopen", "Failed to open file to write signature to from %s", InFile.c_str());
 312       }
 313    }
 314
 315    bool found_message_start = false;
 316    bool found_message_end = false;
 317    bool skip_until_empty_line = false;
 318    bool found_signature = false;
 319    bool first_line = true;
 320
 321    char *buf = NULL;
 322    size_t buf_size = 0;
 323    while (getline(&buf, &buf_size, in) != -1)
 324    {
 325       _strrstrip(buf);
 326       if (found_message_start == false)
 327       {
 328          if (strcmp(buf, "-----BEGIN PGP SIGNED MESSAGE-----") == 0)
 329          {
 330             found_message_start = true;
 331             skip_until_empty_line = true;
 332          }
 333       }
 334       else if (skip_until_empty_line == true)
 335       {
 336          if (strlen(buf) == 0)
 337             skip_until_empty_line = false;
 338          // save "Hash" Armor Headers, others aren't allowed
 339          else if (ContentHeader != NULL && strncmp(buf, "Hash: ", strlen("Hash: ")) == 0)
 340             ContentHeader->push_back(buf);
 341       }
 342       else if (found_signature == false)
 343       {
 344          if (strcmp(buf, "-----BEGIN PGP SIGNATURE-----") == 0)
 345          {
 346             found_signature = true;
 347             found_message_end = true;
 348             if (out_signature != NULL)
 349                fprintf(out_signature, "%s\n", buf);
 350          }
 351          else if (found_message_end == false)
 352          {
 353             // we are in the message block
 354             if(first_line == true) // first line does not need a newline
 355             {
 356                if (out_content != NULL)
 357                   fprintf(out_content, "%s", buf);
 358                first_line = false;
 359             }
 360             else if (out_content != NULL)
 361                fprintf(out_content, "\n%s", buf);
 362          }
 363       }
 364       else if (found_signature == true)
 365       {
 366          if (out_signature != NULL)
 367             fprintf(out_signature, "%s\n", buf);
 368          if (strcmp(buf, "-----END PGP SIGNATURE-----") == 0)
 369             found_signature = false; // look for other signatures
 370       }
 371       // all the rest is whitespace, unsigned garbage or additional message blocks we ignore
 372    }
 373    if (out_content != NULL)
 374       fclose(out_content);
 375    if (out_signature != NULL)
 376       fclose(out_signature);
 377    fclose(in);
 378
 379    return true;
 380 }