tools/make-dns-cert.c

   1 /* make-dns-cert.c - An OpenPGP-to-DNS CERT conversion tool
   2  * Copyright (C) 2006 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 2 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, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
  19  * USA.
  20  */
  21
  22 #include <config.h>
  23 #include <unistd.h>
  24 #ifdef HAVE_GETOPT_H
  25 #include <getopt.h>
  26 #endif
  27 #include <stdio.h>
  28 #include <stdlib.h>
  29 #include <string.h>
  30 #include <errno.h>
  31 #include <sys/types.h>
  32 #include <sys/stat.h>
  33 #include <fcntl.h>
  34
  35 /* We use TYPE37 instead of CERT since not all nameservers can handle
  36    CERT yet... */
  37
  38 static int
  39 cert_key(const char *name,const char *keyfile)
  40 {
  41   int fd,ret=1,err,i;
  42   struct stat statbuf;
  43
  44   fd=open(keyfile,O_RDONLY);
  45   if(fd==-1)
  46     {
  47       fprintf(stderr,"Cannot open key file %s: %s\n",keyfile,strerror(errno));
  48       return 1;
  49     }
  50
  51   err=fstat(fd,&statbuf);
  52   if(err==-1)
  53     {
  54       fprintf(stderr,"Unable to stat key file %s: %s\n",
  55               keyfile,strerror(errno));
  56       goto fail;
  57     }
  58
  59   if(statbuf.st_size>65536)
  60     {
  61       fprintf(stderr,"Key %s too large for CERT encoding\n",keyfile);
  62       goto fail;
  63     }
  64
  65   if(statbuf.st_size>16384)
  66     fprintf(stderr,"Warning: key file %s is larger than the default"
  67             " GnuPG max-cert-size\n",keyfile);
  68
  69   printf("%s\tTYPE37\t\\# %u 0003 0000 00 ",
  70          name,(unsigned int)statbuf.st_size+5);
  71
  72   err=1;
  73   while(err!=0)
  74     {
  75       unsigned char buffer[1024];
  76
  77       err=read(fd,buffer,1024);
  78       if(err==-1)
  79         {
  80           fprintf(stderr,"Unable to read key file %s: %s\n",
  81                   keyfile,strerror(errno));
  82           goto fail;
  83         }
  84
  85       for(i=0;i<err;i++)
  86         printf("%02X",buffer[i]);
  87     }
  88
  89   printf("\n");
  90
  91   ret=0;
  92
  93  fail:
  94   close(fd);
  95
  96   return ret;
  97 }
  98
  99 static int
 100 url_key(const char *name,const char *fpr,const char *url)
 101 {
 102   int len=6,fprlen=0;
 103
 104   if(fpr)
 105     {
 106       const char *tmp = fpr;
 107       while (*tmp)
 108         {
 109           if ((*tmp >= 'A' && *tmp <= 'F') ||
 110               (*tmp >= 'a' && *tmp <= 'f') ||
 111               (*tmp >= '0' && *tmp <= '9'))
 112             {
 113               fprlen++;
 114             }
 115           else if (*tmp != ' ' && *tmp != '\t')
 116             {
 117               fprintf(stderr,"Fingerprint must consist of only hex digits"
 118                       " and whitespace\n");
 119               return 1;
 120             }
 121
 122           tmp++;
 123         }
 124
 125       if(fprlen%2)
 126         {
 127           fprintf(stderr,"Fingerprint must be an even number of characters\n");
 128           return 1;
 129         }
 130
 131       fprlen/=2;
 132       len+=fprlen;
 133     }
 134
 135   if(url)
 136     len+=strlen(url);
 137
 138   if(!fpr && !url)
 139     {
 140       fprintf(stderr,
 141               "Cannot generate a CERT without either a fingerprint or URL\n");
 142       return 1;
 143     }
 144
 145   printf("%s\tTYPE37\t\\# %d 0006 0000 00 %02X",name,len,fprlen);
 146
 147   if(fpr)
 148     printf(" %s",fpr);
 149
 150   if(url)
 151     {
 152       const char *c;
 153       printf(" ");
 154       for(c=url;*c;c++)
 155         printf("%02X",*c);
 156     }
 157
 158   printf("\n");
 159
 160   return 0;
 161 }
 162
 163 static void
 164 usage(FILE *stream)
 165 {
 166   fprintf(stream,"make-dns-cert\n");
 167   fprintf(stream,"\t-f\tfingerprint\n");
 168   fprintf(stream,"\t-u\tURL\n");
 169   fprintf(stream,"\t-k\tkey file\n");
 170   fprintf(stream,"\t-n\tDNS name\n");
 171 }
 172
 173 int
 174 main(int argc,char *argv[])
 175 {
 176   int arg,err=1;
 177   char *fpr=NULL,*url=NULL,*keyfile=NULL,*name=NULL;
 178
 179   if(argc==1)
 180     {
 181       usage(stderr);
 182       return 1;
 183     }
 184   else if(argc>1 && strcmp(argv[1],"--version")==0)
 185     {
 186       printf("make-dns-cert (GnuPG) " VERSION "\n");
 187       return 0;
 188     }
 189   else if(argc>1 && strcmp(argv[1],"--help")==0)
 190     {
 191       usage(stdout);
 192       return 0;
 193     }
 194
 195   while((arg=getopt(argc,argv,"hf:u:k:n:"))!=-1)
 196     switch(arg)
 197       {
 198       default:
 199       case 'h':
 200         usage(stdout);
 201         exit(0);
 202
 203       case 'f':
 204         fpr=optarg;
 205         break;
 206
 207       case 'u':
 208         url=optarg;
 209         break;
 210
 211       case 'k':
 212         keyfile=optarg;
 213         break;
 214
 215       case 'n':
 216         name=optarg;
 217         break;
 218       }
 219
 220   if(!name)
 221     {
 222       fprintf(stderr,"No name provided\n");
 223       return 1;
 224     }
 225
 226   if(keyfile && (fpr || url))
 227     {
 228       fprintf(stderr,"Cannot generate a CERT record with both a keyfile and"
 229               " a fingerprint or URL\n");
 230       return 1;
 231     }
 232
 233   if(keyfile)
 234     err=cert_key(name,keyfile);
 235   else
 236     err=url_key(name,fpr,url);
 237
 238   return err;
 239 }