src/openvpn/base64.c

   1 /*
   2  * Copyright (c) 1995-2001 Kungliga Tekniska Högskolan
   3  * (Royal Institute of Technology, Stockholm, Sweden).
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  *
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  *
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * 3. Neither the name of the Institute nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #ifdef WIN32
  35 #include "config-win32.h"
  36 #else
  37 #include "config.h"
  38 #endif
  39
  40 #include "syshead.h"
  41
  42 #ifdef ENABLE_HTTP_PROXY
  43
  44 #include "base64.h"
  45
  46 #include "memdbg.h"
  47
  48 static char base64_chars[] =
  49     "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
  50
  51 int
  52 base64_encode(const void *data, int size, char **str)
  53 {
  54     char *s, *p;
  55     int i;
  56     int c;
  57     const unsigned char *q;
  58
  59     p = s = (char *) malloc(size * 4 / 3 + 4);
  60     if (p == NULL)
  61         return -1;
  62     q = (const unsigned char *) data;
  63     i = 0;
  64     for (i = 0; i < size;) {
  65         c = q[i++];
  66         c *= 256;
  67         if (i < size)
  68             c += q[i];
  69         i++;
  70         c *= 256;
  71         if (i < size)
  72             c += q[i];
  73         i++;
  74         p[0] = base64_chars[(c & 0x00fc0000) >> 18];
  75         p[1] = base64_chars[(c & 0x0003f000) >> 12];
  76         p[2] = base64_chars[(c & 0x00000fc0) >> 6];
  77         p[3] = base64_chars[(c & 0x0000003f) >> 0];
  78         if (i > size)
  79             p[3] = '=';
  80         if (i > size + 1)
  81             p[2] = '=';
  82         p += 4;
  83     }
  84     *p = 0;
  85     *str = s;
  86     return strlen(s);
  87 }
  88
  89 #if NTLM
  90
  91 static int
  92 pos(char c)
  93 {
  94     char *p;
  95     for (p = base64_chars; *p; p++)
  96         if (*p == c)
  97             return p - base64_chars;
  98     return -1;
  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 int
 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 }
 145
 146 #endif /* NTLM */
 147
 148 #else
 149 static void dummy(void) {}
 150 #endif