linux/lib/libfreeswan/keyblobtoid.c

   1 /*
   2  * generate printable key IDs
   3  * Copyright (C) 2002  Henry Spencer.
   4  *
   5  * This library is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU Library General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or (at your
   8  * option) any later version.  See <http://www.fsf.org/copyleft/lgpl.txt>.
   9  *
  10  * This library is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  12  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Library General Public
  13  * License for more details.
  14  *
  15  * RCSID $Id: keyblobtoid.c,v 1.1 2004/03/15 20:35:26 as Exp $
  16  */
  17 #include "internal.h"
  18 #include "freeswan.h"
  19
  20 /*
  21  - keyblobtoid - generate a printable key ID from an RFC 2537/3110 key blob
  22  * Current algorithm is just to use first nine base64 digits.
  23  */
  24 size_t
  25 keyblobtoid(src, srclen, dst, dstlen)
  26 const unsigned char *src;
  27 size_t srclen;
  28 char *dst;                      /* need not be valid if dstlen is 0 */
  29 size_t dstlen;
  30 {
  31         char buf[KEYID_BUF];
  32         size_t ret;
  33 #       define  NDIG    9
  34
  35         if (srclen < (NDIG*6 + 7)/8) {
  36                 strcpy(buf, "?len= ?");
  37                 buf[5] = '0' + srclen;
  38                 ret = 0;
  39         } else {
  40                 (void) datatot(src, srclen, 64, buf, NDIG+1);
  41                 ret = NDIG+1;
  42         }
  43
  44         if (dstlen > 0) {
  45                 if (strlen(buf)+1 > dstlen)
  46                         *(buf + dstlen - 1) = '\0';
  47                 strcpy(dst, buf);
  48         }
  49         return ret;
  50 }
  51
  52 /*
  53  - splitkeytoid - generate a printable key ID from exponent/modulus pair
  54  * Just constructs the beginnings of a key blob and calls keyblobtoid().
  55  */
  56 size_t
  57 splitkeytoid(e, elen, m, mlen, dst, dstlen)
  58 const unsigned char *e;
  59 size_t elen;
  60 const unsigned char *m;
  61 size_t mlen;
  62 char *dst;                      /* need not be valid if dstlen is 0 */
  63 size_t dstlen;
  64 {
  65         unsigned char buf[KEYID_BUF];   /* ample room */
  66         unsigned char *bufend = buf + sizeof(buf);
  67         unsigned char *p;
  68         size_t n;
  69
  70         p = buf;
  71         if (elen <= 255)
  72                 *p++ = elen;
  73         else if ((elen &~ 0xffff) == 0) {
  74                 *p++ = 0;
  75                 *p++ = (elen>>8) & 0xff;
  76                 *p++ = elen & 0xff;
  77         } else
  78                 return 0;       /* unrepresentable exponent length */
  79
  80         n = bufend - p;
  81         if (elen < n)
  82                 n = elen;
  83         memcpy(p, e, n);
  84         p += n;
  85
  86         n = bufend - p;
  87         if (n > 0) {
  88                 if (mlen < n)
  89                         n = mlen;
  90                 memcpy(p, m, n);
  91                 p += n;
  92         }
  93
  94         return keyblobtoid(buf, p - buf, dst, dstlen);
  95 }
  96
  97
  98
  99 #ifdef KEYBLOBTOID_MAIN
 100
 101 #include <stdio.h>
 102
 103 void regress();
 104
 105 int
 106 main(argc, argv)
 107 int argc;
 108 char *argv[];
 109 {
 110         typedef unsigned char uc;
 111         uc hexblob[] = "\x01\x03\x85\xf2\xd6\x76\x9b\x03\x59\xb6\x21\x52";
 112         uc hexe[] = "\x03";
 113         uc hexm[] = "\x85\xf2\xd6\x76\x9b\x03\x59\xb6\x21\x52\xef\x85";
 114         char b64nine[] = "AQOF8tZ2m";
 115         char b64six[] = "AQOF8t";
 116         char buf[100];
 117         size_t n;
 118         char *b = b64nine;
 119         size_t bl = strlen(b) + 1;
 120         int st = 0;
 121
 122         n = keyblobtoid(hexblob, strlen(hexblob), buf, sizeof(buf));
 123         if (n != bl) {
 124                 fprintf(stderr, "%s: keyblobtoid returned %d not %d\n",
 125                                                         argv[0], n, bl);
 126                 st = 1;
 127         }
 128         if (strcmp(buf, b) != 0) {
 129                 fprintf(stderr, "%s: keyblobtoid generated `%s' not `%s'\n",
 130                                                         argv[0], buf, b);
 131                 st = 1;
 132         }
 133         n = splitkeytoid(hexe, strlen(hexe), hexm, strlen(hexm), buf,
 134                                                                 sizeof(buf));
 135         if (n != bl) {
 136                 fprintf(stderr, "%s: splitkeytoid returned %d not %d\n",
 137                                                         argv[0], n, bl);
 138                 st = 1;
 139         }
 140         if (strcmp(buf, b) != 0) {
 141                 fprintf(stderr, "%s: splitkeytoid generated `%s' not `%s'\n",
 142                                                         argv[0], buf, b);
 143                 st = 1;
 144         }
 145         exit(st);
 146 }
 147
 148 #endif /* KEYBLOBTOID_MAIN */