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    {
  75       _error->PushToStack();
  76       bool const success = ExecGPGV(outfile, file, 3, fd);
  77       if (success == false)
  78       {
  79          string errmsg;
  80          _error->PopMessage(errmsg);
  81          _error->RevertToStack();
  82          return errmsg;
  83       }
  84       _error->RevertToStack();
  85       exit(111);
  86    }
  87    close(fd[1]);
  88
  89    FILE *pipein = fdopen(fd[0], "r");
  90
  91    // Loop over the output of gpgv, and check the signatures.
  92    size_t buffersize = 64;
  93    char *buffer = (char *) malloc(buffersize);
  94    size_t bufferoff = 0;
  95    while (1)
  96    {
  97       int c;
  98
  99       // Read a line.  Sigh.
 100       while ((c = getc(pipein)) != EOF && c != '\n')
 101       {
 102          if (bufferoff == buffersize)
 103          {
 104             char* newBuffer = (char *) realloc(buffer, buffersize *= 2);
 105             if (newBuffer == NULL)
 106             {
 107                free(buffer);
 108                return "Couldn't allocate a buffer big enough for reading";
 109             }
 110             buffer = newBuffer;
 111          }
 112          *(buffer+bufferoff) = c;
 113          bufferoff++;
 114       }
 115       if (bufferoff == 0 && c == EOF)
 116          break;
 117       *(buffer+bufferoff) = '\0';
 118       bufferoff = 0;
 119       if (Debug == true)
 120          std::clog << "Read: " << buffer << std::endl;
 121
 122       // Push the data into three separate vectors, which
 123       // we later concatenate.  They're kept separate so
 124       // if we improve the apt method communication stuff later
 125       // it will be better.
 126       if (strncmp(buffer, GNUPGBADSIG, sizeof(GNUPGBADSIG)-1) == 0)
 127       {
 128          if (Debug == true)
 129             std::clog << "Got BADSIG! " << std::endl;
 130          BadSigners.push_back(string(buffer+sizeof(GNUPGPREFIX)));
 131       }
 132
 133       if (strncmp(buffer, GNUPGNOPUBKEY, sizeof(GNUPGNOPUBKEY)-1) == 0)
 134       {
 135          if (Debug == true)
 136             std::clog << "Got NO_PUBKEY " << std::endl;
 137          NoPubKeySigners.push_back(string(buffer+sizeof(GNUPGPREFIX)));
 138       }
 139       if (strncmp(buffer, GNUPGNODATA, sizeof(GNUPGBADSIG)-1) == 0)
 140       {
 141          if (Debug == true)
 142             std::clog << "Got NODATA! " << std::endl;
 143          BadSigners.push_back(string(buffer+sizeof(GNUPGPREFIX)));
 144       }
 145       if (strncmp(buffer, GNUPGKEYEXPIRED, sizeof(GNUPGKEYEXPIRED)-1) == 0)
 146       {
 147          if (Debug == true)
 148             std::clog << "Got KEYEXPIRED! " << std::endl;
 149          WorthlessSigners.push_back(string(buffer+sizeof(GNUPGPREFIX)));
 150       }
 151       if (strncmp(buffer, GNUPGREVKEYSIG, sizeof(GNUPGREVKEYSIG)-1) == 0)
 152       {
 153          if (Debug == true)
 154             std::clog << "Got REVKEYSIG! " << std::endl;
 155          WorthlessSigners.push_back(string(buffer+sizeof(GNUPGPREFIX)));
 156       }
 157       if (strncmp(buffer, GNUPGGOODSIG, sizeof(GNUPGGOODSIG)-1) == 0)
 158       {
 159          char *sig = buffer + sizeof(GNUPGPREFIX);
 160          char *p = sig + sizeof("GOODSIG");
 161          while (*p && isxdigit(*p))
 162             p++;
 163          *p = 0;
 164          if (Debug == true)
 165             std::clog << "Got GOODSIG, key ID:" << sig << std::endl;
 166          GoodSigners.push_back(string(sig));
 167       }
 168    }
 169    fclose(pipein);
 170
 171    int status;
 172    waitpid(pid, &status, 0);
 173    if (Debug == true)
 174    {
 175       std::clog << "gpgv exited\n";
 176    }
 177
 178    if (WEXITSTATUS(status) == 0)
 179    {
 180       if (GoodSigners.empty())
 181          return _("Internal error: Good signature, but could not determine key fingerprint?!");
 182       return "";
 183    }
 184    else if (WEXITSTATUS(status) == 1)
 185    {
 186       return _("At least one invalid signature was encountered.");
 187    }
 188    else if (WEXITSTATUS(status) == 111)
 189    {
 190       ioprintf(ret, _("Could not execute 'gpgv' to verify signature (is gpgv installed?)"));
 191       return ret.str();
 192    }
 193    else
 194    {
 195       return _("Unknown error executing gpgv");
 196    }
 197 }
 198
 199 bool GPGVMethod::Fetch(FetchItem *Itm)
 200 {
 201    URI Get = Itm->Uri;
 202    string Path = Get.Host + Get.Path; // To account for relative paths
 203    string keyID;
 204    vector<string> GoodSigners;
 205    vector<string> BadSigners;
 206    // a worthless signature is a expired or revoked one
 207    vector<string> WorthlessSigners;
 208    vector<string> NoPubKeySigners;
 209
 210    FetchResult Res;
 211    Res.Filename = Itm->DestFile;
 212    URIStart(Res);
 213
 214    // Run gpgv on file, extract contents and get the key ID of the signer
 215    string msg = VerifyGetSigners(Path.c_str(), Itm->DestFile.c_str(),
 216                                  GoodSigners, BadSigners, WorthlessSigners,
 217                                  NoPubKeySigners);
 218    if (GoodSigners.empty() || !BadSigners.empty() || !NoPubKeySigners.empty())
 219    {
 220       string errmsg;
 221       // In this case, something bad probably happened, so we just go
 222       // with what the other method gave us for an error message.
 223       if (BadSigners.empty() && WorthlessSigners.empty() && NoPubKeySigners.empty())
 224          errmsg = msg;
 225       else
 226       {
 227          if (!BadSigners.empty())
 228          {
 229             errmsg += _("The following signatures were invalid:\n");
 230             for (vector<string>::iterator I = BadSigners.begin();
 231                  I != BadSigners.end(); ++I)
 232                errmsg += (*I + "\n");
 233          }
 234          if (!WorthlessSigners.empty())
 235          {
 236             errmsg += _("The following signatures were invalid:\n");
 237             for (vector<string>::iterator I = WorthlessSigners.begin();
 238                  I != WorthlessSigners.end(); ++I)
 239                errmsg += (*I + "\n");
 240          }
 241          if (!NoPubKeySigners.empty())
 242          {
 243              errmsg += _("The following signatures couldn't be verified because the public key is not available:\n");
 244             for (vector<string>::iterator I = NoPubKeySigners.begin();
 245                  I != NoPubKeySigners.end(); ++I)
 246                errmsg += (*I + "\n");
 247          }
 248       }
 249       // this is only fatal if we have no good sigs or if we have at
 250       // least one bad signature. good signatures and NoPubKey signatures
 251       // happen easily when a file is signed with multiple signatures
 252       if(GoodSigners.empty() or !BadSigners.empty())
 253          return _error->Error("%s", errmsg.c_str());
 254    }
 255
 256    // Just pass the raw output up, because passing it as a real data
 257    // structure is too difficult with the method stuff.  We keep it
 258    // as three separate vectors for future extensibility.
 259    Res.GPGVOutput = GoodSigners;
 260    Res.GPGVOutput.insert(Res.GPGVOutput.end(),BadSigners.begin(),BadSigners.end());
 261    Res.GPGVOutput.insert(Res.GPGVOutput.end(),NoPubKeySigners.begin(),NoPubKeySigners.end());
 262    URIDone(Res);
 263
 264    if (_config->FindB("Debug::Acquire::gpgv", false))
 265    {
 266       std::clog << "gpgv succeeded\n";
 267    }
 268
 269    return true;
 270 }
 271
 272
 273 int main()
 274 {
 275    setlocale(LC_ALL, "");
 276
 277    GPGVMethod Mth;
 278
 279    return Mth.Run();
 280 }