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