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 GNUPGGOODSIG "[GNUPG:] GOODSIG"
  21 #define GNUPGKEYEXPIRED "[GNUPG:] KEYEXPIRED"
  22 #define GNUPGREVKEYSIG "[GNUPG:] REVKEYSIG"
  23 #define GNUPGNODATA "[GNUPG:] NODATA"
  24
  25 class GPGVMethod : public pkgAcqMethod
  26 {
  27    private:
  28    string VerifyGetSigners(const char *file, const char *outfile,
  29                                 vector<string> &GoodSigners,
  30                                 vector<string> &BadSigners,
  31                                 vector<string> &WorthlessSigners,
  32                                 vector<string> &NoPubKeySigners);
  33
  34    protected:
  35    virtual bool Fetch(FetchItem *Itm);
  36
  37    public:
  38
  39    GPGVMethod() : pkgAcqMethod("1.0",SingleInstance | SendConfig) {};
  40 };
  41
  42 string GPGVMethod::VerifyGetSigners(const char *file, const char *outfile,
  43                                          vector<string> &GoodSigners,
  44                                          vector<string> &BadSigners,
  45                                          vector<string> &WorthlessSigners,
  46                                          vector<string> &NoPubKeySigners)
  47 {
  48    // setup a (empty) stringstream for formating the return value
  49    std::stringstream ret;
  50    ret.str("");
  51
  52    if (_config->FindB("Debug::Acquire::gpgv", false))
  53    {
  54       std::cerr << "inside VerifyGetSigners" << std::endl;
  55    }
  56    pid_t pid;
  57    int fd[2];
  58    FILE *pipein;
  59    int status;
  60    struct stat buff;
  61    string gpgvpath = _config->Find("Dir::Bin::gpg", "/usr/bin/gpgv");
  62    string pubringpath = _config->Find("APT::GPGV::TrustedKeyring", "/etc/apt/trusted.gpg");
  63    if (_config->FindB("Debug::Acquire::gpgv", false))
  64    {
  65       std::cerr << "gpgv path: " << gpgvpath << std::endl;
  66       std::cerr << "Keyring path: " << pubringpath << std::endl;
  67    }
  68
  69    if (stat(pubringpath.c_str(), &buff) != 0)
  70    {
  71       ioprintf(ret, _("Couldn't access keyring: '%s'"), strerror(errno));
  72       return ret.str();
  73    }
  74    if (pipe(fd) < 0)
  75    {
  76       return "Couldn't create pipe";
  77    }
  78
  79    pid = fork();
  80    if (pid < 0)
  81    {
  82       return string("Couldn't spawn new process") + strerror(errno);
  83    }
  84    else if (pid == 0)
  85    {
  86       const char *Args[400];
  87       unsigned int i = 0;
  88
  89       Args[i++] = gpgvpath.c_str();
  90       Args[i++] = "--status-fd";
  91       Args[i++] = "3";
  92       Args[i++] = "--ignore-time-conflict";
  93       Args[i++] = "--keyring";
  94       Args[i++] = pubringpath.c_str();
  95
  96       Configuration::Item const *Opts;
  97       Opts = _config->Tree("Acquire::gpgv::Options");
  98       if (Opts != 0)
  99       {
 100          Opts = Opts->Child;
 101          for (; Opts != 0; Opts = Opts->Next)
 102          {
 103             if (Opts->Value.empty() == true)
 104                continue;
 105             Args[i++] = Opts->Value.c_str();
 106             if(i >= 395) {
 107                std::cerr << _("E: Argument list from Acquire::gpgv::Options too long. Exiting.") << std::endl;
 108                exit(111);
 109             }
 110          }
 111       }
 112       Args[i++] = file;
 113       Args[i++] = outfile;
 114       Args[i++] = NULL;
 115
 116       if (_config->FindB("Debug::Acquire::gpgv", false))
 117       {
 118          std::cerr << "Preparing to exec: " << gpgvpath;
 119          for(unsigned int j=0;Args[j] != NULL; j++)
 120             std::cerr << " " << Args[j];
 121          std::cerr << std::endl;
 122       }
 123       int nullfd = open("/dev/null", O_RDONLY);
 124       close(fd[0]);
 125       // Redirect output to /dev/null; we read from the status fd
 126       dup2(nullfd, STDOUT_FILENO);
 127       dup2(nullfd, STDERR_FILENO);
 128       // Redirect the pipe to the status fd (3)
 129       dup2(fd[1], 3);
 130
 131       putenv((char *)"LANG=");
 132       putenv((char *)"LC_ALL=");
 133       putenv((char *)"LC_MESSAGES=");
 134       execvp(gpgvpath.c_str(), (char **)Args);
 135
 136       exit(111);
 137    }
 138    close(fd[1]);
 139
 140    pipein = fdopen(fd[0], "r");
 141
 142    // Loop over the output of gpgv, and check the signatures.
 143    size_t buffersize = 64;
 144    char *buffer = (char *) malloc(buffersize);
 145    size_t bufferoff = 0;
 146    while (1)
 147    {
 148       int c;
 149
 150       // Read a line.  Sigh.
 151       while ((c = getc(pipein)) != EOF && c != '\n')
 152       {
 153          if (bufferoff == buffersize)
 154             buffer = (char *) realloc(buffer, buffersize *= 2);
 155          *(buffer+bufferoff) = c;
 156          bufferoff++;
 157       }
 158       if (bufferoff == 0 && c == EOF)
 159          break;
 160       *(buffer+bufferoff) = '\0';
 161       bufferoff = 0;
 162       if (_config->FindB("Debug::Acquire::gpgv", false))
 163          std::cerr << "Read: " << buffer << std::endl;
 164
 165       // Push the data into three separate vectors, which
 166       // we later concatenate.  They're kept separate so
 167       // if we improve the apt method communication stuff later
 168       // it will be better.
 169       if (strncmp(buffer, GNUPGBADSIG, sizeof(GNUPGBADSIG)-1) == 0)
 170       {
 171          if (_config->FindB("Debug::Acquire::gpgv", false))
 172             std::cerr << "Got BADSIG! " << std::endl;
 173          BadSigners.push_back(string(buffer+sizeof(GNUPGPREFIX)));
 174       }
 175
 176       if (strncmp(buffer, GNUPGNOPUBKEY, sizeof(GNUPGNOPUBKEY)-1) == 0)
 177       {
 178          if (_config->FindB("Debug::Acquire::gpgv", false))
 179             std::cerr << "Got NO_PUBKEY " << std::endl;
 180          NoPubKeySigners.push_back(string(buffer+sizeof(GNUPGPREFIX)));
 181       }
 182       if (strncmp(buffer, GNUPGNODATA, sizeof(GNUPGBADSIG)-1) == 0)
 183       {
 184          if (_config->FindB("Debug::Acquire::gpgv", false))
 185             std::cerr << "Got NODATA! " << std::endl;
 186          BadSigners.push_back(string(buffer+sizeof(GNUPGPREFIX)));
 187       }
 188       if (strncmp(buffer, GNUPGKEYEXPIRED, sizeof(GNUPGKEYEXPIRED)-1) == 0)
 189       {
 190          if (_config->FindB("Debug::Acquire::gpgv", false))
 191             std::cerr << "Got KEYEXPIRED! " << std::endl;
 192          WorthlessSigners.push_back(string(buffer+sizeof(GNUPGPREFIX)));
 193       }
 194       if (strncmp(buffer, GNUPGREVKEYSIG, sizeof(GNUPGREVKEYSIG)-1) == 0)
 195       {
 196          if (_config->FindB("Debug::Acquire::gpgv", false))
 197             std::cerr << "Got REVKEYSIG! " << std::endl;
 198          WorthlessSigners.push_back(string(buffer+sizeof(GNUPGPREFIX)));
 199       }
 200       if (strncmp(buffer, GNUPGGOODSIG, sizeof(GNUPGGOODSIG)-1) == 0)
 201       {
 202          char *sig = buffer + sizeof(GNUPGPREFIX);
 203          char *p = sig + sizeof("GOODSIG");
 204          while (*p && isxdigit(*p))
 205             p++;
 206          *p = 0;
 207          if (_config->FindB("Debug::Acquire::gpgv", false))
 208             std::cerr << "Got GOODSIG, key ID:" << sig << std::endl;
 209          GoodSigners.push_back(string(sig));
 210       }
 211    }
 212    fclose(pipein);
 213
 214    waitpid(pid, &status, 0);
 215    if (_config->FindB("Debug::Acquire::gpgv", false))
 216    {
 217       std::cerr << "gpgv exited\n";
 218    }
 219
 220    if (WEXITSTATUS(status) == 0)
 221    {
 222       if (GoodSigners.empty())
 223          return _("Internal error: Good signature, but could not determine key fingerprint?!");
 224       return "";
 225    }
 226    else if (WEXITSTATUS(status) == 1)
 227    {
 228       return _("At least one invalid signature was encountered.");
 229    }
 230    else if (WEXITSTATUS(status) == 111)
 231    {
 232       ioprintf(ret, _("Could not execute '%s' to verify signature (is gpgv installed?)"), gpgvpath.c_str());
 233       return ret.str();
 234    }
 235    else
 236    {
 237       return _("Unknown error executing gpgv");
 238    }
 239 }
 240
 241 bool GPGVMethod::Fetch(FetchItem *Itm)
 242 {
 243    URI Get = Itm->Uri;
 244    string Path = Get.Host + Get.Path; // To account for relative paths
 245    string keyID;
 246    vector<string> GoodSigners;
 247    vector<string> BadSigners;
 248    // a worthless signature is a expired or revoked one
 249    vector<string> WorthlessSigners;
 250    vector<string> NoPubKeySigners;
 251
 252    FetchResult Res;
 253    Res.Filename = Itm->DestFile;
 254    URIStart(Res);
 255
 256    // Run gpgv on file, extract contents and get the key ID of the signer
 257    string msg = VerifyGetSigners(Path.c_str(), Itm->DestFile.c_str(),
 258                                  GoodSigners, BadSigners, WorthlessSigners,
 259                                  NoPubKeySigners);
 260    if (GoodSigners.empty() || !BadSigners.empty() || !NoPubKeySigners.empty())
 261    {
 262       string errmsg;
 263       // In this case, something bad probably happened, so we just go
 264       // with what the other method gave us for an error message.
 265       if (BadSigners.empty() && WorthlessSigners.empty() && NoPubKeySigners.empty())
 266          errmsg = msg;
 267       else
 268       {
 269          if (!BadSigners.empty())
 270          {
 271             errmsg += _("The following signatures were invalid:\n");
 272             for (vector<string>::iterator I = BadSigners.begin();
 273                  I != BadSigners.end(); I++)
 274                errmsg += (*I + "\n");
 275          }
 276          if (!WorthlessSigners.empty())
 277          {
 278             errmsg += _("The following signatures were invalid:\n");
 279             for (vector<string>::iterator I = WorthlessSigners.begin();
 280                  I != WorthlessSigners.end(); I++)
 281                errmsg += (*I + "\n");
 282          }
 283          if (!NoPubKeySigners.empty())
 284          {
 285              errmsg += _("The following signatures couldn't be verified because the public key is not available:\n");
 286             for (vector<string>::iterator I = NoPubKeySigners.begin();
 287                  I != NoPubKeySigners.end(); I++)
 288                errmsg += (*I + "\n");
 289          }
 290       }
 291       // this is only fatal if we have no good sigs or if we have at
 292       // least one bad signature. good signatures and NoPubKey signatures
 293       // happen easily when a file is signed with multiple signatures
 294       if(GoodSigners.empty() or !BadSigners.empty())
 295          return _error->Error("%s", errmsg.c_str());
 296    }
 297
 298    // Just pass the raw output up, because passing it as a real data
 299    // structure is too difficult with the method stuff.  We keep it
 300    // as three separate vectors for future extensibility.
 301    Res.GPGVOutput = GoodSigners;
 302    Res.GPGVOutput.insert(Res.GPGVOutput.end(),BadSigners.begin(),BadSigners.end());
 303    Res.GPGVOutput.insert(Res.GPGVOutput.end(),NoPubKeySigners.begin(),NoPubKeySigners.end());
 304    URIDone(Res);
 305
 306    if (_config->FindB("Debug::Acquire::gpgv", false))
 307    {
 308       std::cerr << "gpgv succeeded\n";
 309    }
 310
 311    return true;
 312 }
 313
 314
 315 int main()
 316 {
 317    setlocale(LC_ALL, "");
 318
 319    GPGVMethod Mth;
 320
 321    return Mth.Run();
 322 }