methods/gpgv.cc

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