methods/gpgv.cc

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