methods/gpgv.cc

   1 #include <config.h>
   2
   3 #include <apt-pkg/acquire-method.h>
   4 #include <apt-pkg/configuration.h>
   5 #include <apt-pkg/error.h>
   6 #include <apt-pkg/gpgv.h>
   7 #include <apt-pkg/strutl.h>
   8 #include <apt-pkg/fileutl.h>
   9
  10 #include <ctype.h>
  11 #include <errno.h>
  12 #include <stddef.h>
  13 #include <stdio.h>
  14 #include <stdlib.h>
  15 #include <string.h>
  16 #include <sys/wait.h>
  17 #include <unistd.h>
  18 #include <iostream>
  19 #include <string>
  20 #include <vector>
  21
  22 #include <apti18n.h>
  23
  24 using std::string;
  25 using std::vector;
  26
  27 #define GNUPGPREFIX "[GNUPG:]"
  28 #define GNUPGBADSIG "[GNUPG:] BADSIG"
  29 #define GNUPGNOPUBKEY "[GNUPG:] NO_PUBKEY"
  30 #define GNUPGVALIDSIG "[GNUPG:] VALIDSIG"
  31 #define GNUPGGOODSIG "[GNUPG:] GOODSIG"
  32 #define GNUPGKEYEXPIRED "[GNUPG:] KEYEXPIRED"
  33 #define GNUPGREVKEYSIG "[GNUPG:] REVKEYSIG"
  34 #define GNUPGNODATA "[GNUPG:] NODATA"
  35
  36 class GPGVMethod : public pkgAcqMethod
  37 {
  38    private:
  39    string VerifyGetSigners(const char *file, const char *outfile,
  40                                 vector<string> &GoodSigners,
  41                                 vector<string> &BadSigners,
  42                                 vector<string> &WorthlessSigners,
  43                                 vector<string> &NoPubKeySigners);
  44
  45    protected:
  46    virtual bool Fetch(FetchItem *Itm);
  47
  48    public:
  49
  50    GPGVMethod() : pkgAcqMethod("1.0",SingleInstance | SendConfig) {};
  51 };
  52
  53 string GPGVMethod::VerifyGetSigners(const char *file, const char *outfile,
  54                                          vector<string> &GoodSigners,
  55                                          vector<string> &BadSigners,
  56                                          vector<string> &WorthlessSigners,
  57                                          vector<string> &NoPubKeySigners)
  58 {
  59    bool const Debug = _config->FindB("Debug::Acquire::gpgv", false);
  60
  61    if (Debug == true)
  62       std::clog << "inside VerifyGetSigners" << std::endl;
  63
  64    int fd[2];
  65
  66    if (pipe(fd) < 0)
  67       return "Couldn't create pipe";
  68
  69    pid_t pid = fork();
  70    if (pid < 0)
  71       return string("Couldn't spawn new process") + strerror(errno);
  72    else if (pid == 0)
  73       ExecGPGV(outfile, file, 3, fd);
  74    close(fd[1]);
  75
  76    FILE *pipein = fdopen(fd[0], "r");
  77
  78    // Loop over the output of gpgv, and check the signatures.
  79    size_t buffersize = 64;
  80    char *buffer = (char *) malloc(buffersize);
  81    size_t bufferoff = 0;
  82    while (1)
  83    {
  84       int c;
  85
  86       // Read a line.  Sigh.
  87       while ((c = getc(pipein)) != EOF && c != '\n')
  88       {
  89          if (bufferoff == buffersize)
  90          {
  91             char* newBuffer = (char *) realloc(buffer, buffersize *= 2);
  92             if (newBuffer == NULL)
  93             {
  94                free(buffer);
  95                return "Couldn't allocate a buffer big enough for reading";
  96             }
  97             buffer = newBuffer;
  98          }
  99          *(buffer+bufferoff) = c;
 100          bufferoff++;
 101       }
 102       if (bufferoff == 0 && c == EOF)
 103          break;
 104       *(buffer+bufferoff) = '\0';
 105       bufferoff = 0;
 106       if (Debug == true)
 107          std::clog << "Read: " << buffer << std::endl;
 108
 109       // Push the data into three separate vectors, which
 110       // we later concatenate.  They're kept separate so
 111       // if we improve the apt method communication stuff later
 112       // it will be better.
 113       if (strncmp(buffer, GNUPGBADSIG, sizeof(GNUPGBADSIG)-1) == 0)
 114       {
 115          if (Debug == true)
 116             std::clog << "Got BADSIG! " << std::endl;
 117          BadSigners.push_back(string(buffer+sizeof(GNUPGPREFIX)));
 118       }
 119
 120       if (strncmp(buffer, GNUPGNOPUBKEY, sizeof(GNUPGNOPUBKEY)-1) == 0)
 121       {
 122          if (Debug == true)
 123             std::clog << "Got NO_PUBKEY " << std::endl;
 124          NoPubKeySigners.push_back(string(buffer+sizeof(GNUPGPREFIX)));
 125       }
 126       if (strncmp(buffer, GNUPGNODATA, sizeof(GNUPGBADSIG)-1) == 0)
 127       {
 128          if (Debug == true)
 129             std::clog << "Got NODATA! " << std::endl;
 130          BadSigners.push_back(string(buffer+sizeof(GNUPGPREFIX)));
 131       }
 132       if (strncmp(buffer, GNUPGKEYEXPIRED, sizeof(GNUPGKEYEXPIRED)-1) == 0)
 133       {
 134          if (Debug == true)
 135             std::clog << "Got KEYEXPIRED! " << std::endl;
 136          WorthlessSigners.push_back(string(buffer+sizeof(GNUPGPREFIX)));
 137       }
 138       if (strncmp(buffer, GNUPGREVKEYSIG, sizeof(GNUPGREVKEYSIG)-1) == 0)
 139       {
 140          if (Debug == true)
 141             std::clog << "Got REVKEYSIG! " << std::endl;
 142          WorthlessSigners.push_back(string(buffer+sizeof(GNUPGPREFIX)));
 143       }
 144       if (strncmp(buffer, GNUPGGOODSIG, sizeof(GNUPGGOODSIG)-1) == 0)
 145       {
 146          char *sig = buffer + sizeof(GNUPGPREFIX);
 147          char *p = sig + sizeof("GOODSIG");
 148          while (*p && isxdigit(*p))
 149             p++;
 150          *p = 0;
 151          if (Debug == true)
 152             std::clog << "Got GOODSIG, key ID:" << sig << std::endl;
 153          GoodSigners.push_back(string(sig));
 154       }
 155    }
 156    fclose(pipein);
 157    free(buffer);
 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       return _("At least one invalid signature was encountered.");
 174    else if (WEXITSTATUS(status) == 111)
 175       return _("Could not execute 'gpgv' to verify signature (is gpgv installed?)");
 176    else if (WEXITSTATUS(status) == 112)
 177    {
 178       // acquire system checks for "NODATA" to generate GPG errors (the others are only warnings)
 179       std::string errmsg;
 180       //TRANSLATORS: %s is a single techy word like 'NODATA'
 181       strprintf(errmsg, _("Clearsigned file isn't valid, got '%s' (does the network require authentication?)"), "NODATA");
 182       return errmsg;
 183    }
 184    else
 185       return _("Unknown error executing gpgv");
 186 }
 187
 188 bool GPGVMethod::Fetch(FetchItem *Itm)
 189 {
 190    URI Get = Itm->Uri;
 191    string Path = Get.Host + Get.Path; // To account for relative paths
 192    string keyID;
 193    vector<string> GoodSigners;
 194    vector<string> BadSigners;
 195    // a worthless signature is a expired or revoked one
 196    vector<string> WorthlessSigners;
 197    vector<string> NoPubKeySigners;
 198
 199    FetchResult Res;
 200    Res.Filename = Itm->DestFile;
 201    URIStart(Res);
 202
 203    // Run gpgv on file, extract contents and get the key ID of the signer
 204    string msg = VerifyGetSigners(Path.c_str(), Itm->DestFile.c_str(),
 205                                  GoodSigners, BadSigners, WorthlessSigners,
 206                                  NoPubKeySigners);
 207    if (GoodSigners.empty() || !BadSigners.empty() || !NoPubKeySigners.empty())
 208    {
 209       string errmsg;
 210       // In this case, something bad probably happened, so we just go
 211       // with what the other method gave us for an error message.
 212       if (BadSigners.empty() && WorthlessSigners.empty() && NoPubKeySigners.empty())
 213          errmsg = msg;
 214       else
 215       {
 216          if (!BadSigners.empty())
 217          {
 218             errmsg += _("The following signatures were invalid:\n");
 219             for (vector<string>::iterator I = BadSigners.begin();
 220                  I != BadSigners.end(); ++I)
 221                errmsg += (*I + "\n");
 222          }
 223          if (!WorthlessSigners.empty())
 224          {
 225             errmsg += _("The following signatures were invalid:\n");
 226             for (vector<string>::iterator I = WorthlessSigners.begin();
 227                  I != WorthlessSigners.end(); ++I)
 228                errmsg += (*I + "\n");
 229          }
 230          if (!NoPubKeySigners.empty())
 231          {
 232              errmsg += _("The following signatures couldn't be verified because the public key is not available:\n");
 233             for (vector<string>::iterator I = NoPubKeySigners.begin();
 234                  I != NoPubKeySigners.end(); ++I)
 235                errmsg += (*I + "\n");
 236          }
 237       }
 238       // this is only fatal if we have no good sigs or if we have at
 239       // least one bad signature. good signatures and NoPubKey signatures
 240       // happen easily when a file is signed with multiple signatures
 241       if(GoodSigners.empty() or !BadSigners.empty())
 242          return _error->Error("%s", errmsg.c_str());
 243    }
 244
 245    // Just pass the raw output up, because passing it as a real data
 246    // structure is too difficult with the method stuff.  We keep it
 247    // as three separate vectors for future extensibility.
 248    Res.GPGVOutput = GoodSigners;
 249    Res.GPGVOutput.insert(Res.GPGVOutput.end(),BadSigners.begin(),BadSigners.end());
 250    Res.GPGVOutput.insert(Res.GPGVOutput.end(),NoPubKeySigners.begin(),NoPubKeySigners.end());
 251    URIDone(Res);
 252
 253    if (_config->FindB("Debug::Acquire::gpgv", false))
 254    {
 255       std::clog << "gpgv succeeded\n";
 256    }
 257
 258    return true;
 259 }
 260
 261
 262 int main()
 263 {
 264    setlocale(LC_ALL, "");
 265
 266    GPGVMethod Mth;
 267
 268    Mth.DropPrivsOrDie();
 269
 270    return Mth.Run();
 271 }