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 <apti18n.h>
   6
   7 #include <utime.h>
   8 #include <stdio.h>
   9 #include <fcntl.h>
  10 #include <errno.h>
  11 #include <sys/wait.h>
  12 #include <iostream>
  13 #include <sstream>
  14
  15 #define GNUPGPREFIX "[GNUPG:]"
  16 #define GNUPGBADSIG "[GNUPG:] BADSIG"
  17 #define GNUPGNOPUBKEY "[GNUPG:] NO_PUBKEY"
  18 #define GNUPGVALIDSIG "[GNUPG:] VALIDSIG"
  19 #define GNUPGGOODSIG "[GNUPG:] GOODSIG"
  20 #define GNUPGKEYEXPIRED "[GNUPG:] KEYEXPIRED"
  21 #define GNUPGREVKEYSIG "[GNUPG:] REVKEYSIG"
  22 #define GNUPGNODATA "[GNUPG:] NODATA"
  23
  24 class GPGVMethod : public pkgAcqMethod
  25 {
  26    private:
  27    string VerifyGetSigners(const char *file, const char *outfile,
  28                                 vector<string> &GoodSigners,
  29                                 vector<string> &BadSigners,
  30                                 vector<string> &WorthlessSigners,
  31                                 vector<string> &NoPubKeySigners);
  32
  33    protected:
  34    virtual bool Fetch(FetchItem *Itm);
  35
  36    public:
  37
  38    GPGVMethod() : pkgAcqMethod("1.0",SingleInstance | SendConfig) {};
  39 };
  40
  41 string GPGVMethod::VerifyGetSigners(const char *file, const char *outfile,
  42                                          vector<string> &GoodSigners,
  43                                          vector<string> &BadSigners,
  44                                          vector<string> &WorthlessSigners,
  45                                          vector<string> &NoPubKeySigners)
  46 {
  47    bool const Debug = _config->FindB("Debug::Acquire::gpgv", false);
  48    // setup a (empty) stringstream for formating the return value
  49    std::stringstream ret;
  50    ret.str("");
  51
  52    if (Debug == true)
  53       std::clog << "inside VerifyGetSigners" << std::endl;
  54
  55    pid_t pid;
  56    int fd[2];
  57    FILE *pipein;
  58    int status;
  59    string const gpgvpath = _config->Find("Dir::Bin::gpg", "/usr/bin/gpgv");
  60    // FIXME: remove support for deprecated APT::GPGV setting
  61    string const trustedFile = _config->FindFile("Dir::Etc::Trusted",
  62                         _config->Find("APT::GPGV::TrustedKeyring", "/etc/apt/trusted.gpg").c_str());
  63    string const trustedPath = _config->FindDir("Dir::Etc::TrustedParts", "/etc/apt/trusted.gpg.d");
  64    if (Debug == true)
  65    {
  66       std::clog << "gpgv path: " << gpgvpath << std::endl;
  67       std::clog << "Keyring file: " << trustedFile << std::endl;
  68       std::clog << "Keyring path: " << trustedPath << std::endl;
  69    }
  70
  71    vector<string> keyrings = GetListOfFilesInDir(trustedPath, "gpg", false);
  72    if (FileExists(trustedFile) == true)
  73       keyrings.push_back(trustedFile);
  74
  75    if (keyrings.empty() == true)
  76    {
  77       // TRANSLATOR: %s is the trusted keyring parts directory
  78       ioprintf(ret, _("No keyring installed in %s."), trustedPath.c_str());
  79       return ret.str();
  80    }
  81
  82    if (pipe(fd) < 0)
  83       return "Couldn't create pipe";
  84
  85    pid = fork();
  86    if (pid < 0)
  87       return string("Couldn't spawn new process") + strerror(errno);
  88    else if (pid == 0)
  89    {
  90       const char *Args[400];
  91       unsigned int i = 0;
  92
  93       Args[i++] = gpgvpath.c_str();
  94       Args[i++] = "--status-fd";
  95       Args[i++] = "3";
  96       Args[i++] = "--ignore-time-conflict";
  97       for (vector<string>::const_iterator K = keyrings.begin();
  98            K != keyrings.end(); ++K)
  99       {
 100          Args[i++] = "--keyring";
 101          Args[i++] = K->c_str();
 102          // check overflow (minus a bit of extra space at the end)
 103          if(i >= sizeof(Args)/sizeof(char*)-5) {
 104             std::clog << _("E: Too many keyrings should be passed to gpgv. Exiting.") << std::endl;
 105             exit(111);
 106          }
 107       }
 108
 109       Configuration::Item const *Opts;
 110       Opts = _config->Tree("Acquire::gpgv::Options");
 111       if (Opts != 0)
 112       {
 113          Opts = Opts->Child;
 114          for (; Opts != 0; Opts = Opts->Next)
 115          {
 116             if (Opts->Value.empty() == true)
 117                continue;
 118             Args[i++] = Opts->Value.c_str();
 119             // check overflow (minus a bit of extra space at the end)
 120             if(i >= sizeof(Args)/sizeof(char*)-5) {
 121                std::clog << _("E: Argument list from Acquire::gpgv::Options too long. Exiting.") << std::endl;
 122                exit(111);
 123             }
 124          }
 125       }
 126       Args[i++] = file;
 127       Args[i++] = outfile;
 128       Args[i++] = NULL;
 129
 130       if (Debug == true)
 131       {
 132          std::clog << "Preparing to exec: " << gpgvpath;
 133          for(unsigned int j=0;Args[j] != NULL; j++)
 134             std::clog << " " << Args[j];
 135          std::clog << std::endl;
 136       }
 137       int const nullfd = open("/dev/null", O_RDONLY);
 138       close(fd[0]);
 139       // Redirect output to /dev/null; we read from the status fd
 140       dup2(nullfd, STDOUT_FILENO);
 141       dup2(nullfd, STDERR_FILENO);
 142       // Redirect the pipe to the status fd (3)
 143       dup2(fd[1], 3);
 144
 145       putenv((char *)"LANG=");
 146       putenv((char *)"LC_ALL=");
 147       putenv((char *)"LC_MESSAGES=");
 148       execvp(gpgvpath.c_str(), (char **)Args);
 149
 150       exit(111);
 151    }
 152    close(fd[1]);
 153
 154    pipein = fdopen(fd[0], "r");
 155
 156    // Loop over the output of gpgv, and check the signatures.
 157    size_t buffersize = 64;
 158    char *buffer = (char *) malloc(buffersize);
 159    size_t bufferoff = 0;
 160    while (1)
 161    {
 162       int c;
 163
 164       // Read a line.  Sigh.
 165       while ((c = getc(pipein)) != EOF && c != '\n')
 166       {
 167          if (bufferoff == buffersize)
 168             buffer = (char *) realloc(buffer, buffersize *= 2);
 169          *(buffer+bufferoff) = c;
 170          bufferoff++;
 171       }
 172       if (bufferoff == 0 && c == EOF)
 173          break;
 174       *(buffer+bufferoff) = '\0';
 175       bufferoff = 0;
 176       if (Debug == true)
 177          std::clog << "Read: " << buffer << std::endl;
 178
 179       // Push the data into three separate vectors, which
 180       // we later concatenate.  They're kept separate so
 181       // if we improve the apt method communication stuff later
 182       // it will be better.
 183       if (strncmp(buffer, GNUPGBADSIG, sizeof(GNUPGBADSIG)-1) == 0)
 184       {
 185          if (Debug == true)
 186             std::clog << "Got BADSIG! " << std::endl;
 187          BadSigners.push_back(string(buffer+sizeof(GNUPGPREFIX)));
 188       }
 189
 190       if (strncmp(buffer, GNUPGNOPUBKEY, sizeof(GNUPGNOPUBKEY)-1) == 0)
 191       {
 192          if (Debug == true)
 193             std::clog << "Got NO_PUBKEY " << std::endl;
 194          NoPubKeySigners.push_back(string(buffer+sizeof(GNUPGPREFIX)));
 195       }
 196       if (strncmp(buffer, GNUPGNODATA, sizeof(GNUPGBADSIG)-1) == 0)
 197       {
 198          if (Debug == true)
 199             std::clog << "Got NODATA! " << std::endl;
 200          BadSigners.push_back(string(buffer+sizeof(GNUPGPREFIX)));
 201       }
 202       if (strncmp(buffer, GNUPGKEYEXPIRED, sizeof(GNUPGKEYEXPIRED)-1) == 0)
 203       {
 204          if (Debug == true)
 205             std::clog << "Got KEYEXPIRED! " << std::endl;
 206          WorthlessSigners.push_back(string(buffer+sizeof(GNUPGPREFIX)));
 207       }
 208       if (strncmp(buffer, GNUPGREVKEYSIG, sizeof(GNUPGREVKEYSIG)-1) == 0)
 209       {
 210          if (Debug == true)
 211             std::clog << "Got REVKEYSIG! " << std::endl;
 212          WorthlessSigners.push_back(string(buffer+sizeof(GNUPGPREFIX)));
 213       }
 214       if (strncmp(buffer, GNUPGGOODSIG, sizeof(GNUPGGOODSIG)-1) == 0)
 215       {
 216          char *sig = buffer + sizeof(GNUPGPREFIX);
 217          char *p = sig + sizeof("GOODSIG");
 218          while (*p && isxdigit(*p))
 219             p++;
 220          *p = 0;
 221          if (Debug == true)
 222             std::clog << "Got GOODSIG, key ID:" << sig << std::endl;
 223          GoodSigners.push_back(string(sig));
 224       }
 225    }
 226    fclose(pipein);
 227
 228    waitpid(pid, &status, 0);
 229    if (Debug == true)
 230    {
 231       std::clog << "gpgv exited\n";
 232    }
 233
 234    if (WEXITSTATUS(status) == 0)
 235    {
 236       if (GoodSigners.empty())
 237          return _("Internal error: Good signature, but could not determine key fingerprint?!");
 238       return "";
 239    }
 240    else if (WEXITSTATUS(status) == 1)
 241    {
 242       return _("At least one invalid signature was encountered.");
 243    }
 244    else if (WEXITSTATUS(status) == 111)
 245    {
 246       ioprintf(ret, _("Could not execute '%s' to verify signature (is gpgv installed?)"), gpgvpath.c_str());
 247       return ret.str();
 248    }
 249    else
 250    {
 251       return _("Unknown error executing gpgv");
 252    }
 253 }
 254
 255 bool GPGVMethod::Fetch(FetchItem *Itm)
 256 {
 257    URI Get = Itm->Uri;
 258    string Path = Get.Host + Get.Path; // To account for relative paths
 259    string keyID;
 260    vector<string> GoodSigners;
 261    vector<string> BadSigners;
 262    // a worthless signature is a expired or revoked one
 263    vector<string> WorthlessSigners;
 264    vector<string> NoPubKeySigners;
 265
 266    FetchResult Res;
 267    Res.Filename = Itm->DestFile;
 268    URIStart(Res);
 269
 270    // Run gpgv on file, extract contents and get the key ID of the signer
 271    string msg = VerifyGetSigners(Path.c_str(), Itm->DestFile.c_str(),
 272                                  GoodSigners, BadSigners, WorthlessSigners,
 273                                  NoPubKeySigners);
 274    if (GoodSigners.empty() || !BadSigners.empty() || !NoPubKeySigners.empty())
 275    {
 276       string errmsg;
 277       // In this case, something bad probably happened, so we just go
 278       // with what the other method gave us for an error message.
 279       if (BadSigners.empty() && WorthlessSigners.empty() && NoPubKeySigners.empty())
 280          errmsg = msg;
 281       else
 282       {
 283          if (!BadSigners.empty())
 284          {
 285             errmsg += _("The following signatures were invalid:\n");
 286             for (vector<string>::iterator I = BadSigners.begin();
 287                  I != BadSigners.end(); I++)
 288                errmsg += (*I + "\n");
 289          }
 290          if (!WorthlessSigners.empty())
 291          {
 292             errmsg += _("The following signatures were invalid:\n");
 293             for (vector<string>::iterator I = WorthlessSigners.begin();
 294                  I != WorthlessSigners.end(); I++)
 295                errmsg += (*I + "\n");
 296          }
 297          if (!NoPubKeySigners.empty())
 298          {
 299              errmsg += _("The following signatures couldn't be verified because the public key is not available:\n");
 300             for (vector<string>::iterator I = NoPubKeySigners.begin();
 301                  I != NoPubKeySigners.end(); I++)
 302                errmsg += (*I + "\n");
 303          }
 304       }
 305       // this is only fatal if we have no good sigs or if we have at
 306       // least one bad signature. good signatures and NoPubKey signatures
 307       // happen easily when a file is signed with multiple signatures
 308       if(GoodSigners.empty() or !BadSigners.empty())
 309          return _error->Error("%s", errmsg.c_str());
 310    }
 311
 312    // Just pass the raw output up, because passing it as a real data
 313    // structure is too difficult with the method stuff.  We keep it
 314    // as three separate vectors for future extensibility.
 315    Res.GPGVOutput = GoodSigners;
 316    Res.GPGVOutput.insert(Res.GPGVOutput.end(),BadSigners.begin(),BadSigners.end());
 317    Res.GPGVOutput.insert(Res.GPGVOutput.end(),NoPubKeySigners.begin(),NoPubKeySigners.end());
 318    URIDone(Res);
 319
 320    if (_config->FindB("Debug::Acquire::gpgv", false))
 321    {
 322       std::clog << "gpgv succeeded\n";
 323    }
 324
 325    return true;
 326 }
 327
 328
 329 int main()
 330 {
 331    setlocale(LC_ALL, "");
 332
 333    GPGVMethod Mth;
 334
 335    return Mth.Run();
 336 }