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    virtual bool Configuration(string Message);
  48    public:
  49
  50    GPGVMethod() : pkgAcqMethod("1.0",SingleInstance | SendConfig) {};
  51 };
  52
  53 bool GPGVMethod::Configuration(string Message)
  54 {
  55    if (pkgAcqMethod::Configuration(Message) == false)
  56       return false;
  57
  58    DropPrivsOrDie();
  59
  60    return true;
  61 }
  62
  63 string GPGVMethod::VerifyGetSigners(const char *file, const char *outfile,
  64                                          vector<string> &GoodSigners,
  65                                          vector<string> &BadSigners,
  66                                          vector<string> &WorthlessSigners,
  67                                          vector<string> &NoPubKeySigners)
  68 {
  69    bool const Debug = _config->FindB("Debug::Acquire::gpgv", false);
  70
  71    if (Debug == true)
  72       std::clog << "inside VerifyGetSigners" << std::endl;
  73
  74    int fd[2];
  75
  76    if (pipe(fd) < 0)
  77       return "Couldn't create pipe";
  78
  79    pid_t pid = fork();
  80    if (pid < 0)
  81       return string("Couldn't spawn new process") + strerror(errno);
  82    else if (pid == 0)
  83       ExecGPGV(outfile, file, 3, fd);
  84    close(fd[1]);
  85
  86    FILE *pipein = fdopen(fd[0], "r");
  87
  88    // Loop over the output of apt-key (which really is gnupg), and check the signatures.
  89    size_t buffersize = 0;
  90    char *buffer = NULL;
  91    while (1)
  92    {
  93       if (getline(&buffer, &buffersize, pipein) == -1)
  94          break;
  95       if (Debug == true)
  96          std::clog << "Read: " << buffer << std::endl;
  97
  98       // Push the data into three separate vectors, which
  99       // we later concatenate.  They're kept separate so
 100       // if we improve the apt method communication stuff later
 101       // it will be better.
 102       if (strncmp(buffer, GNUPGBADSIG, sizeof(GNUPGBADSIG)-1) == 0)
 103       {
 104          if (Debug == true)
 105             std::clog << "Got BADSIG! " << std::endl;
 106          BadSigners.push_back(string(buffer+sizeof(GNUPGPREFIX)));
 107       }
 108
 109       if (strncmp(buffer, GNUPGNOPUBKEY, sizeof(GNUPGNOPUBKEY)-1) == 0)
 110       {
 111          if (Debug == true)
 112             std::clog << "Got NO_PUBKEY " << std::endl;
 113          NoPubKeySigners.push_back(string(buffer+sizeof(GNUPGPREFIX)));
 114       }
 115       if (strncmp(buffer, GNUPGNODATA, sizeof(GNUPGBADSIG)-1) == 0)
 116       {
 117          if (Debug == true)
 118             std::clog << "Got NODATA! " << std::endl;
 119          BadSigners.push_back(string(buffer+sizeof(GNUPGPREFIX)));
 120       }
 121       if (strncmp(buffer, GNUPGKEYEXPIRED, sizeof(GNUPGKEYEXPIRED)-1) == 0)
 122       {
 123          if (Debug == true)
 124             std::clog << "Got KEYEXPIRED! " << std::endl;
 125          WorthlessSigners.push_back(string(buffer+sizeof(GNUPGPREFIX)));
 126       }
 127       if (strncmp(buffer, GNUPGREVKEYSIG, sizeof(GNUPGREVKEYSIG)-1) == 0)
 128       {
 129          if (Debug == true)
 130             std::clog << "Got REVKEYSIG! " << std::endl;
 131          WorthlessSigners.push_back(string(buffer+sizeof(GNUPGPREFIX)));
 132       }
 133       if (strncmp(buffer, GNUPGGOODSIG, sizeof(GNUPGGOODSIG)-1) == 0)
 134       {
 135          char *sig = buffer + sizeof(GNUPGPREFIX);
 136          char *p = sig + sizeof("GOODSIG");
 137          while (*p && isxdigit(*p))
 138             p++;
 139          *p = 0;
 140          if (Debug == true)
 141             std::clog << "Got GOODSIG, key ID:" << sig << std::endl;
 142          GoodSigners.push_back(string(sig));
 143       }
 144    }
 145    fclose(pipein);
 146    free(buffer);
 147
 148    int status;
 149    waitpid(pid, &status, 0);
 150    if (Debug == true)
 151    {
 152       ioprintf(std::clog, "gpgv exited with status %i\n", WEXITSTATUS(status));
 153    }
 154
 155    if (WEXITSTATUS(status) == 0)
 156    {
 157       if (GoodSigners.empty())
 158          return _("Internal error: Good signature, but could not determine key fingerprint?!");
 159       return "";
 160    }
 161    else if (WEXITSTATUS(status) == 1)
 162       return _("At least one invalid signature was encountered.");
 163    else if (WEXITSTATUS(status) == 111)
 164       return _("Could not execute 'apt-key' to verify signature (is gnupg installed?)");
 165    else if (WEXITSTATUS(status) == 112)
 166    {
 167       // acquire system checks for "NODATA" to generate GPG errors (the others are only warnings)
 168       std::string errmsg;
 169       //TRANSLATORS: %s is a single techy word like 'NODATA'
 170       strprintf(errmsg, _("Clearsigned file isn't valid, got '%s' (does the network require authentication?)"), "NODATA");
 171       return errmsg;
 172    }
 173    else
 174       return _("Unknown error executing apt-key");
 175 }
 176
 177 bool GPGVMethod::Fetch(FetchItem *Itm)
 178 {
 179    URI Get = Itm->Uri;
 180    string Path = Get.Host + Get.Path; // To account for relative paths
 181    string keyID;
 182    vector<string> GoodSigners;
 183    vector<string> BadSigners;
 184    // a worthless signature is a expired or revoked one
 185    vector<string> WorthlessSigners;
 186    vector<string> NoPubKeySigners;
 187
 188    FetchResult Res;
 189    Res.Filename = Itm->DestFile;
 190    URIStart(Res);
 191
 192    // Run apt-key on file, extract contents and get the key ID of the signer
 193    string msg = VerifyGetSigners(Path.c_str(), Itm->DestFile.c_str(),
 194                                  GoodSigners, BadSigners, WorthlessSigners,
 195                                  NoPubKeySigners);
 196    if (GoodSigners.empty() || !BadSigners.empty() || !NoPubKeySigners.empty())
 197    {
 198       string errmsg;
 199       // In this case, something bad probably happened, so we just go
 200       // with what the other method gave us for an error message.
 201       if (BadSigners.empty() && WorthlessSigners.empty() && NoPubKeySigners.empty())
 202          errmsg = msg;
 203       else
 204       {
 205          if (!BadSigners.empty())
 206          {
 207             errmsg += _("The following signatures were invalid:\n");
 208             for (vector<string>::iterator I = BadSigners.begin();
 209                  I != BadSigners.end(); ++I)
 210                errmsg += (*I + "\n");
 211          }
 212          if (!WorthlessSigners.empty())
 213          {
 214             errmsg += _("The following signatures were invalid:\n");
 215             for (vector<string>::iterator I = WorthlessSigners.begin();
 216                  I != WorthlessSigners.end(); ++I)
 217                errmsg += (*I + "\n");
 218          }
 219          if (!NoPubKeySigners.empty())
 220          {
 221              errmsg += _("The following signatures couldn't be verified because the public key is not available:\n");
 222             for (vector<string>::iterator I = NoPubKeySigners.begin();
 223                  I != NoPubKeySigners.end(); ++I)
 224                errmsg += (*I + "\n");
 225          }
 226       }
 227       // this is only fatal if we have no good sigs or if we have at
 228       // least one bad signature. good signatures and NoPubKey signatures
 229       // happen easily when a file is signed with multiple signatures
 230       if(GoodSigners.empty() or !BadSigners.empty())
 231          return _error->Error("%s", errmsg.c_str());
 232    }
 233
 234    // Just pass the raw output up, because passing it as a real data
 235    // structure is too difficult with the method stuff.  We keep it
 236    // as three separate vectors for future extensibility.
 237    Res.GPGVOutput = GoodSigners;
 238    Res.GPGVOutput.insert(Res.GPGVOutput.end(),BadSigners.begin(),BadSigners.end());
 239    Res.GPGVOutput.insert(Res.GPGVOutput.end(),NoPubKeySigners.begin(),NoPubKeySigners.end());
 240    URIDone(Res);
 241
 242    if (_config->FindB("Debug::Acquire::gpgv", false))
 243    {
 244       std::clog << "apt-key succeeded\n";
 245    }
 246
 247    return true;
 248 }
 249
 250
 251 int main()
 252 {
 253    setlocale(LC_ALL, "");
 254
 255    GPGVMethod Mth;
 256
 257    return Mth.Run();
 258 }