tools/make-dns-cert.c

   1 /* make-dns-cert.c - An OpenPGP-to-DNS CERT conversion tool
   2  * Copyright (C) 2006, 2008 Free Software Foundation, Inc.
   3  *
   4  * This file is part of GnuPG.
   5  *
   6  * GnuPG is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 3 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * GnuPG is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #ifdef HAVE_CONFIG_H
  21 # include <config.h>
  22 #endif
  23
  24 #include <unistd.h>
  25 #ifdef HAVE_GETOPT_H
  26 #include <getopt.h>
  27 #endif
  28 #include <stdio.h>
  29 #include <stdlib.h>
  30 #include <string.h>
  31 #include <errno.h>
  32 #include <unistd.h>
  33 #include <sys/types.h>
  34 #include <sys/stat.h>
  35 #include <fcntl.h>
  36
  37 /* We use TYPE37 instead of CERT since not all nameservers can handle
  38    CERT yet... */
  39
  40 static int
  41 cert_key(const char *name,const char *keyfile)
  42 {
  43   int fd,ret=1,err,i;
  44   struct stat statbuf;
  45
  46   fd=open(keyfile,O_RDONLY);
  47   if(fd==-1)
  48     {
  49       fprintf(stderr,"Cannot open key file %s: %s\n",keyfile,strerror(errno));
  50       return 1;
  51     }
  52
  53   err=fstat(fd,&statbuf);
  54   if(err==-1)
  55     {
  56       fprintf(stderr,"Unable to stat key file %s: %s\n",
  57               keyfile,strerror(errno));
  58       goto fail;
  59     }
  60
  61   if(statbuf.st_size>65536)
  62     {
  63       fprintf(stderr,"Key %s too large for CERT encoding\n",keyfile);
  64       goto fail;
  65     }
  66
  67   if(statbuf.st_size>16384)
  68     fprintf(stderr,"Warning: key file %s is larger than the default"
  69             " GnuPG max-cert-size\n",keyfile);
  70
  71   printf("%s\tTYPE37\t\\# %u 0003 0000 00 ",
  72          name,(unsigned int)statbuf.st_size+5);
  73
  74   err=1;
  75   while(err!=0)
  76     {
  77       unsigned char buffer[1024];
  78
  79       do
  80         err = read (fd,buffer,1024);
  81       while (err == -1 && errno == EINTR);
  82       if(err==-1)
  83         {
  84           fprintf(stderr,"Unable to read key file %s: %s\n",
  85                   keyfile,strerror(errno));
  86           goto fail;
  87         }
  88
  89       for(i=0;i<err;i++)
  90         printf("%02X",buffer[i]);
  91     }
  92
  93   printf("\n");
  94
  95   ret=0;
  96
  97  fail:
  98   close(fd);
  99
 100   return ret;
 101 }
 102
 103 static int
 104 url_key(const char *name,const char *fpr,const char *url)
 105 {
 106   int len=6,fprlen=0;
 107
 108   if(fpr)
 109     {
 110       const char *tmp = fpr;
 111       while (*tmp)
 112         {
 113           if ((*tmp >= 'A' && *tmp <= 'F') ||
 114               (*tmp >= 'a' && *tmp <= 'f') ||
 115               (*tmp >= '0' && *tmp <= '9'))
 116             {
 117               fprlen++;
 118             }
 119           else if (*tmp != ' ' && *tmp != '\t')
 120             {
 121               fprintf(stderr,"Fingerprint must consist of only hex digits"
 122                       " and whitespace\n");
 123               return 1;
 124             }
 125
 126           tmp++;
 127         }
 128
 129       if(fprlen%2)
 130         {
 131           fprintf(stderr,"Fingerprint must be an even number of characters\n");
 132           return 1;
 133         }
 134
 135       fprlen/=2;
 136       len+=fprlen;
 137     }
 138
 139   if(url)
 140     len+=strlen(url);
 141
 142   if(!fpr && !url)
 143     {
 144       fprintf(stderr,
 145               "Cannot generate a CERT without either a fingerprint or URL\n");
 146       return 1;
 147     }
 148
 149   printf("%s\tTYPE37\t\\# %d 0006 0000 00 %02X",name,len,fprlen);
 150
 151   if(fpr)
 152     printf(" %s",fpr);
 153
 154   if(url)
 155     {
 156       const char *c;
 157       printf(" ");
 158       for(c=url;*c;c++)
 159         printf("%02X",*c);
 160     }
 161
 162   printf("\n");
 163
 164   return 0;
 165 }
 166
 167 static void
 168 usage(FILE *stream)
 169 {
 170   fprintf(stream,"make-dns-cert\n");
 171   fprintf(stream,"\t-f\tfingerprint\n");
 172   fprintf(stream,"\t-u\tURL\n");
 173   fprintf(stream,"\t-k\tkey file\n");
 174   fprintf(stream,"\t-n\tDNS name\n");
 175 }
 176
 177 int
 178 main(int argc,char *argv[])
 179 {
 180   int arg,err=1;
 181   char *fpr=NULL,*url=NULL,*keyfile=NULL,*name=NULL;
 182
 183   if(argc==1)
 184     {
 185       usage(stderr);
 186       return 1;
 187     }
 188   else if(argc>1 && strcmp(argv[1],"--version")==0)
 189     {
 190 #if defined(HAVE_CONFIG_H) && defined(VERSION)
 191       printf ("make-dns-cert (GnuPG) " VERSION "\n");
 192 #else
 193       printf ("make-dns-cert gnupg-svn%d\n", atoi (10+"$Revision$"));
 194 #endif
 195       return 0;
 196     }
 197   else if(argc>1 && strcmp(argv[1],"--help")==0)
 198     {
 199       usage(stdout);
 200       return 0;
 201     }
 202
 203   while((arg=getopt(argc,argv,"hf:u:k:n:"))!=-1)
 204     switch(arg)
 205       {
 206       default:
 207       case 'h':
 208         usage(stdout);
 209         exit(0);
 210
 211       case 'f':
 212         fpr=optarg;
 213         break;
 214
 215       case 'u':
 216         url=optarg;
 217         break;
 218
 219       case 'k':
 220         keyfile=optarg;
 221         break;
 222
 223       case 'n':
 224         name=optarg;
 225         break;
 226       }
 227
 228   if(!name)
 229     {
 230       fprintf(stderr,"No name provided\n");
 231       return 1;
 232     }
 233
 234   if(keyfile && (fpr || url))
 235     {
 236       fprintf(stderr,"Cannot generate a CERT record with both a keyfile and"
 237               " a fingerprint or URL\n");
 238       return 1;
 239     }
 240
 241   if(keyfile)
 242     err=cert_key(name,keyfile);
 243   else
 244     err=url_key(name,fpr,url);
 245
 246   return err;
 247 }