contrib/wpa_supplicant-0.5.8/base64.c

   1 /*
   2  * Base64 encoding/decoding (RFC1341)
   3  * Copyright (c) 2005, Jouni Malinen <j@w1.fi>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation.
   8  *
   9  * Alternatively, this software may be distributed under the terms of BSD
  10  * license.
  11  *
  12  * See README and COPYING for more details.
  13  */
  14
  15 #include "includes.h"
  16
  17 #include "os.h"
  18 #include "base64.h"
  19
  20 static const unsigned char base64_table[65] =
  21         "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
  22
  23 /**
  24  * base64_encode - Base64 encode
  25  * @src: Data to be encoded
  26  * @len: Length of the data to be encoded
  27  * @out_len: Pointer to output length variable, or %NULL if not used
  28  * Returns: Allocated buffer of out_len bytes of encoded data,
  29  * or %NULL on failure
  30  *
  31  * Caller is responsible for freeing the returned buffer. Returned buffer is
  32  * nul terminated to make it easier to use as a C string. The nul terminator is
  33  * not included in out_len.
  34  */
  35 unsigned char * base64_encode(const unsigned char *src, size_t len,
  36                               size_t *out_len)
  37 {
  38         unsigned char *out, *pos;
  39         const unsigned char *end, *in;
  40         size_t olen;
  41         int line_len;
  42
  43         olen = len * 4 / 3 + 4; /* 3-byte blocks to 4-byte */
  44         olen += olen / 72; /* line feeds */
  45         olen++; /* nul termination */
  46         out = os_malloc(olen);
  47         if (out == NULL)
  48                 return NULL;
  49
  50         end = src + len;
  51         in = src;
  52         pos = out;
  53         line_len = 0;
  54         while (end - in >= 3) {
  55                 *pos++ = base64_table[in[0] >> 2];
  56                 *pos++ = base64_table[((in[0] & 0x03) << 4) | (in[1] >> 4)];
  57                 *pos++ = base64_table[((in[1] & 0x0f) << 2) | (in[2] >> 6)];
  58                 *pos++ = base64_table[in[2] & 0x3f];
  59                 in += 3;
  60                 line_len += 4;
  61                 if (line_len >= 72) {
  62                         *pos++ = '\n';
  63                         line_len = 0;
  64                 }
  65         }
  66
  67         if (end - in) {
  68                 *pos++ = base64_table[in[0] >> 2];
  69                 if (end - in == 1) {
  70                         *pos++ = base64_table[(in[0] & 0x03) << 4];
  71                         *pos++ = '=';
  72                 } else {
  73                         *pos++ = base64_table[((in[0] & 0x03) << 4) |
  74                                               (in[1] >> 4)];
  75                         *pos++ = base64_table[(in[1] & 0x0f) << 2];
  76                 }
  77                 *pos++ = '=';
  78                 line_len += 4;
  79         }
  80
  81         if (line_len)
  82                 *pos++ = '\n';
  83
  84         *pos = '\0';
  85         if (out_len)
  86                 *out_len = pos - out;
  87         return out;
  88 }
  89
  90
  91 /**
  92  * base64_decode - Base64 decode
  93  * @src: Data to be decoded
  94  * @len: Length of the data to be decoded
  95  * @out_len: Pointer to output length variable
  96  * Returns: Allocated buffer of out_len bytes of decoded data,
  97  * or %NULL on failure
  98  *
  99  * Caller is responsible for freeing the returned buffer.
 100  */
 101 unsigned char * base64_decode(const unsigned char *src, size_t len,
 102                               size_t *out_len)
 103 {
 104         unsigned char dtable[256], *out, *pos, in[4], block[4], tmp;
 105         size_t i, count, olen;
 106
 107         os_memset(dtable, 0x80, 256);
 108         for (i = 0; i < sizeof(base64_table) - 1; i++)
 109                 dtable[base64_table[i]] = (unsigned char) i;
 110         dtable['='] = 0;
 111
 112         count = 0;
 113         for (i = 0; i < len; i++) {
 114                 if (dtable[src[i]] != 0x80)
 115                         count++;
 116         }
 117
 118         if (count % 4)
 119                 return NULL;
 120
 121         olen = count / 4 * 3;
 122         pos = out = os_malloc(olen);
 123         if (out == NULL)
 124                 return NULL;
 125
 126         count = 0;
 127         for (i = 0; i < len; i++) {
 128                 tmp = dtable[src[i]];
 129                 if (tmp == 0x80)
 130                         continue;
 131
 132                 in[count] = src[i];
 133                 block[count] = tmp;
 134                 count++;
 135                 if (count == 4) {
 136                         *pos++ = (block[0] << 2) | (block[1] >> 4);
 137                         *pos++ = (block[1] << 4) | (block[2] >> 2);
 138                         *pos++ = (block[2] << 6) | block[3];
 139                         count = 0;
 140                 }
 141         }
 142
 143         if (pos > out) {
 144                 if (in[2] == '=')
 145                         pos -= 2;
 146                 else if (in[3] == '=')
 147                         pos--;
 148         }
 149
 150         *out_len = pos - out;
 151         return out;
 152 }
 153
 154
 155 #ifdef TEST_MAIN
 156 #include <stdio.h>
 157
 158 int main(int argc, char *argv[])
 159 {
 160         FILE *f;
 161         size_t len, elen;
 162         unsigned char *buf, *e;
 163
 164         if (argc != 4) {
 165                 printf("Usage: base64 <encode|decode> <in file> <out file>\n");
 166                 return -1;
 167         }
 168
 169         buf = os_readfile(argv[2], &len);
 170         if (buf == NULL)
 171                 return -1;
 172
 173         if (strcmp(argv[1], "encode") == 0)
 174                 e = base64_encode(buf, len, &elen);
 175         else
 176                 e = base64_decode(buf, len, &elen);
 177         if (e == NULL)
 178                 return -2;
 179         f = fopen(argv[3], "w");
 180         if (f == NULL)
 181                 return -3;
 182         fwrite(e, 1, elen, f);
 183         fclose(f);
 184         free(e);
 185
 186         return 0;
 187 }
 188 #endif /* TEST_MAIN */