crypto/external/bsd/heimdal/dist/lib/roken/base64.c

   1 /*      $NetBSD: base64.c,v 1.1.1.1 2011/04/13 18:15:40 elric Exp $     */
   2
   3 /*
   4  * Copyright (c) 1995-2001 Kungliga Tekniska Högskolan
   5  * (Royal Institute of Technology, Stockholm, Sweden).
   6  * All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  *
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  *
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  *
  19  * 3. Neither the name of the Institute nor the names of its contributors
  20  *    may be used to endorse or promote products derived from this software
  21  *    without specific prior written permission.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  33  * SUCH DAMAGE.
  34  */
  35
  36 #include <config.h>
  37
  38 #include <stdlib.h>
  39 #include <string.h>
  40 #include <limits.h>
  41 #include <krb5/base64.h>
  42
  43 static const char base64_chars[] =
  44     "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
  45
  46 static int
  47 pos(char c)
  48 {
  49     const char *p;
  50     for (p = base64_chars; *p; p++)
  51         if (*p == c)
  52             return p - base64_chars;
  53     return -1;
  54 }
  55
  56 ROKEN_LIB_FUNCTION int ROKEN_LIB_CALL
  57 base64_encode(const void *data, int size, char **str)
  58 {
  59     char *s, *p;
  60     int i;
  61     int c;
  62     const unsigned char *q;
  63
  64     if (size > INT_MAX/4 || size < 0) {
  65         *str = NULL;
  66         return -1;
  67     }
  68
  69     p = s = (char *) malloc(size * 4 / 3 + 4);
  70     if (p == NULL) {
  71         *str = NULL;
  72         return -1;
  73     }
  74     q = (const unsigned char *) data;
  75
  76     for (i = 0; i < size;) {
  77         c = q[i++];
  78         c *= 256;
  79         if (i < size)
  80             c += q[i];
  81         i++;
  82         c *= 256;
  83         if (i < size)
  84             c += q[i];
  85         i++;
  86         p[0] = base64_chars[(c & 0x00fc0000) >> 18];
  87         p[1] = base64_chars[(c & 0x0003f000) >> 12];
  88         p[2] = base64_chars[(c & 0x00000fc0) >> 6];
  89         p[3] = base64_chars[(c & 0x0000003f) >> 0];
  90         if (i > size)
  91             p[3] = '=';
  92         if (i > size + 1)
  93             p[2] = '=';
  94         p += 4;
  95     }
  96     *p = 0;
  97     *str = s;
  98     return (int) strlen(s);
  99 }
 100
 101 #define DECODE_ERROR 0xffffffff
 102
 103 static unsigned int
 104 token_decode(const char *token)
 105 {
 106     int i;
 107     unsigned int val = 0;
 108     int marker = 0;
 109     if (strlen(token) < 4)
 110         return DECODE_ERROR;
 111     for (i = 0; i < 4; i++) {
 112         val *= 64;
 113         if (token[i] == '=')
 114             marker++;
 115         else if (marker > 0)
 116             return DECODE_ERROR;
 117         else
 118             val += pos(token[i]);
 119     }
 120     if (marker > 2)
 121         return DECODE_ERROR;
 122     return (marker << 24) | val;
 123 }
 124
 125 ROKEN_LIB_FUNCTION int ROKEN_LIB_CALL
 126 base64_decode(const char *str, void *data)
 127 {
 128     const char *p;
 129     unsigned char *q;
 130
 131     q = data;
 132     for (p = str; *p && (*p == '=' || strchr(base64_chars, *p)); p += 4) {
 133         unsigned int val = token_decode(p);
 134         unsigned int marker = (val >> 24) & 0xff;
 135         if (val == DECODE_ERROR)
 136             return -1;
 137         *q++ = (val >> 16) & 0xff;
 138         if (marker < 2)
 139             *q++ = (val >> 8) & 0xff;
 140         if (marker < 1)
 141             *q++ = val & 0xff;
 142     }
 143     return q - (unsigned char *) data;
 144 }