methods/gpgv.cc

   1 #include <apt-pkg/error.h>
   2 #include <apt-pkg/acquire-method.h>
   3 #include <apt-pkg/strutl.h>
   4 #include <apti18n.h>
   5
   6 #include <sys/stat.h>
   7 #include <unistd.h>
   8 #include <utime.h>
   9 #include <stdio.h>
  10 #include <fcntl.h>
  11 #include <errno.h>
  12 #include <sys/wait.h>
  13 #include <iostream>
  14 #include <sstream>
  15
  16 #define GNUPGPREFIX "[GNUPG:]"
  17 #define GNUPGBADSIG "[GNUPG:] BADSIG"
  18 #define GNUPGNOPUBKEY "[GNUPG:] NO_PUBKEY"
  19 #define GNUPGVALIDSIG "[GNUPG:] VALIDSIG"
  20 #define GNUPGNODATA "[GNUPG:] NODATA"
  21
  22 class GPGVMethod : public pkgAcqMethod
  23 {
  24    private:
  25    string VerifyGetSigners(const char *file, const char *outfile,
  26                                 vector<string> &GoodSigners, vector<string> &BadSigners,
  27                                 vector<string> &NoPubKeySigners);
  28
  29    protected:
  30    virtual bool Fetch(FetchItem *Itm);
  31
  32    public:
  33
  34    GPGVMethod() : pkgAcqMethod("1.0",SingleInstance | SendConfig) {};
  35 };
  36
  37 string GPGVMethod::VerifyGetSigners(const char *file, const char *outfile,
  38                                          vector<string> &GoodSigners,
  39                                          vector<string> &BadSigners,
  40                                          vector<string> &NoPubKeySigners)
  41 {
  42    // setup a (empty) stringstream for formating the return value
  43    std::stringstream ret;
  44    ret.str("");
  45
  46    if (_config->FindB("Debug::Acquire::gpgv", false))
  47    {
  48       std::cerr << "inside VerifyGetSigners" << std::endl;
  49    }
  50    pid_t pid;
  51    int fd[2];
  52    FILE *pipein;
  53    int status;
  54    struct stat buff;
  55    string gpgvpath = _config->Find("Dir::Bin::gpg", "/usr/bin/gpgv");
  56    string pubringpath = _config->Find("APT::GPGV::TrustedKeyring", "/etc/apt/trusted.gpg");
  57    if (_config->FindB("Debug::Acquire::gpgv", false))
  58    {
  59       std::cerr << "gpgv path: " << gpgvpath << std::endl;
  60       std::cerr << "Keyring path: " << pubringpath << std::endl;
  61    }
  62
  63    if (stat(pubringpath.c_str(), &buff) != 0)
  64    {
  65       ioprintf(ret, _("Couldn't access keyring: '%s'"), strerror(errno));
  66       return ret.str();
  67    }
  68    if (pipe(fd) < 0)
  69    {
  70       return "Couldn't create pipe";
  71    }
  72
  73    pid = fork();
  74    if (pid < 0)
  75    {
  76       return string("Couldn't spawn new process") + strerror(errno);
  77    }
  78    else if (pid == 0)
  79    {
  80       const char *Args[400];
  81       unsigned int i = 0;
  82
  83       Args[i++] = gpgvpath.c_str();
  84       Args[i++] = "--status-fd";
  85       Args[i++] = "3";
  86       Args[i++] = "--ignore-time-conflict";
  87       Args[i++] = "--keyring";
  88       Args[i++] = pubringpath.c_str();
  89
  90       Configuration::Item const *Opts;
  91       Opts = _config->Tree("Acquire::gpgv::Options");
  92       if (Opts != 0)
  93       {
  94          Opts = Opts->Child;
  95          for (; Opts != 0; Opts = Opts->Next)
  96          {
  97             if (Opts->Value.empty() == true)
  98                continue;
  99             Args[i++] = Opts->Value.c_str();
 100             if(i >= 395) {
 101                std::cerr << _("E: Argument list from Acquire::gpgv::Options too long. Exiting.") << std::endl;
 102                exit(111);
 103             }
 104          }
 105       }
 106       Args[i++] = file;
 107       Args[i++] = outfile;
 108       Args[i++] = NULL;
 109
 110       if (_config->FindB("Debug::Acquire::gpgv", false))
 111       {
 112          std::cerr << "Preparing to exec: " << gpgvpath;
 113          for(unsigned int j=0;Args[j] != NULL; j++)
 114             std::cerr << " " << Args[j];
 115          std::cerr << std::endl;
 116       }
 117       int nullfd = open("/dev/null", O_RDONLY);
 118       close(fd[0]);
 119       // Redirect output to /dev/null; we read from the status fd
 120       dup2(nullfd, STDOUT_FILENO);
 121       dup2(nullfd, STDERR_FILENO);
 122       // Redirect the pipe to the status fd (3)
 123       dup2(fd[1], 3);
 124
 125       putenv((char *)"LANG=");
 126       putenv((char *)"LC_ALL=");
 127       putenv((char *)"LC_MESSAGES=");
 128       execvp(gpgvpath.c_str(), (char **)Args);
 129
 130       exit(111);
 131    }
 132    close(fd[1]);
 133
 134    pipein = fdopen(fd[0], "r");
 135
 136    // Loop over the output of gpgv, and check the signatures.
 137    size_t buffersize = 64;
 138    char *buffer = (char *) malloc(buffersize);
 139    size_t bufferoff = 0;
 140    while (1)
 141    {
 142       int c;
 143
 144       // Read a line.  Sigh.
 145       while ((c = getc(pipein)) != EOF && c != '\n')
 146       {
 147          if (bufferoff == buffersize)
 148             buffer = (char *) realloc(buffer, buffersize *= 2);
 149          *(buffer+bufferoff) = c;
 150          bufferoff++;
 151       }
 152       if (bufferoff == 0 && c == EOF)
 153          break;
 154       *(buffer+bufferoff) = '\0';
 155       bufferoff = 0;
 156       if (_config->FindB("Debug::Acquire::gpgv", false))
 157          std::cerr << "Read: " << buffer << std::endl;
 158
 159       // Push the data into three separate vectors, which
 160       // we later concatenate.  They're kept separate so
 161       // if we improve the apt method communication stuff later
 162       // it will be better.
 163       if (strncmp(buffer, GNUPGBADSIG, sizeof(GNUPGBADSIG)-1) == 0)
 164       {
 165          if (_config->FindB("Debug::Acquire::gpgv", false))
 166             std::cerr << "Got BADSIG! " << std::endl;
 167          BadSigners.push_back(string(buffer+sizeof(GNUPGPREFIX)));
 168       }
 169
 170       if (strncmp(buffer, GNUPGNOPUBKEY, sizeof(GNUPGNOPUBKEY)-1) == 0)
 171       {
 172          if (_config->FindB("Debug::Acquire::gpgv", false))
 173             std::cerr << "Got NO_PUBKEY " << std::endl;
 174          NoPubKeySigners.push_back(string(buffer+sizeof(GNUPGPREFIX)));
 175       }
 176       if (strncmp(buffer, GNUPGNODATA, sizeof(GNUPGBADSIG)-1) == 0)
 177       {
 178          if (_config->FindB("Debug::Acquire::gpgv", false))
 179             std::cerr << "Got NODATA! " << std::endl;
 180          BadSigners.push_back(string(buffer+sizeof(GNUPGPREFIX)));
 181       }
 182       if (strncmp(buffer, GNUPGVALIDSIG, sizeof(GNUPGVALIDSIG)-1) == 0)
 183       {
 184          char *sig = buffer + sizeof(GNUPGPREFIX);
 185          char *p = sig + sizeof("VALIDSIG");
 186          while (*p && isxdigit(*p))
 187             p++;
 188          *p = 0;
 189          if (_config->FindB("Debug::Acquire::gpgv", false))
 190             std::cerr << "Got VALIDSIG, key ID:" << sig << std::endl;
 191          GoodSigners.push_back(string(sig));
 192       }
 193    }
 194    fclose(pipein);
 195
 196    waitpid(pid, &status, 0);
 197    if (_config->FindB("Debug::Acquire::gpgv", false))
 198    {
 199       std::cerr << "gpgv exited\n";
 200    }
 201
 202    if (WEXITSTATUS(status) == 0)
 203    {
 204       if (GoodSigners.empty())
 205          return _("Internal error: Good signature, but could not determine key fingerprint?!");
 206       return "";
 207    }
 208    else if (WEXITSTATUS(status) == 1)
 209    {
 210       return _("At least one invalid signature was encountered.");
 211    }
 212    else if (WEXITSTATUS(status) == 111)
 213    {
 214       ioprintf(ret, _("Could not execute '%s' to verify signature (is gnupg installed?)"), gpgvpath.c_str());
 215       return ret.str();
 216    }
 217    else
 218    {
 219       return _("Unknown error executing gpgv");
 220    }
 221 }
 222
 223 bool GPGVMethod::Fetch(FetchItem *Itm)
 224 {
 225    URI Get = Itm->Uri;
 226    string Path = Get.Host + Get.Path; // To account for relative paths
 227    string keyID;
 228    vector<string> GoodSigners;
 229    vector<string> BadSigners;
 230    vector<string> NoPubKeySigners;
 231
 232    FetchResult Res;
 233    Res.Filename = Itm->DestFile;
 234    URIStart(Res);
 235
 236    // Run gpgv on file, extract contents and get the key ID of the signer
 237    string msg = VerifyGetSigners(Path.c_str(), Itm->DestFile.c_str(),
 238                               GoodSigners, BadSigners, NoPubKeySigners);
 239    if (GoodSigners.empty() || !BadSigners.empty() || !NoPubKeySigners.empty())
 240    {
 241       string errmsg;
 242       // In this case, something bad probably happened, so we just go
 243       // with what the other method gave us for an error message.
 244       if (BadSigners.empty() && NoPubKeySigners.empty())
 245          errmsg = msg;
 246       else
 247       {
 248          if (!BadSigners.empty())
 249          {
 250             errmsg += _("The following signatures were invalid:\n");
 251             for (vector<string>::iterator I = BadSigners.begin();
 252                  I != BadSigners.end(); I++)
 253                errmsg += (*I + "\n");
 254          }
 255          if (!NoPubKeySigners.empty())
 256          {
 257              errmsg += _("The following signatures couldn't be verified because the public key is not available:\n");
 258             for (vector<string>::iterator I = NoPubKeySigners.begin();
 259                  I != NoPubKeySigners.end(); I++)
 260                errmsg += (*I + "\n");
 261          }
 262       }
 263       // this is only fatal if we have no good sigs or if we have at
 264       // least one bad signature. good signatures and NoPubKey signatures
 265       // happen easily when a file is signed with multiple signatures
 266       if(GoodSigners.empty() or !BadSigners.empty())
 267          return _error->Error(errmsg.c_str());
 268    }
 269
 270    // Just pass the raw output up, because passing it as a real data
 271    // structure is too difficult with the method stuff.  We keep it
 272    // as three separate vectors for future extensibility.
 273    Res.GPGVOutput = GoodSigners;
 274    Res.GPGVOutput.insert(Res.GPGVOutput.end(),BadSigners.begin(),BadSigners.end());
 275    Res.GPGVOutput.insert(Res.GPGVOutput.end(),NoPubKeySigners.begin(),NoPubKeySigners.end());
 276    URIDone(Res);
 277
 278    if (_config->FindB("Debug::Acquire::gpgv", false))
 279    {
 280       std::cerr << "gpgv succeeded\n";
 281    }
 282
 283    return true;
 284 }
 285
 286
 287 int main()
 288 {
 289    setlocale(LC_ALL, "");
 290
 291    GPGVMethod Mth;
 292
 293    return Mth.Run();
 294 }