Line data    Source code

       1             : /*
       2             :  * Base64 encoding/decoding (RFC1341)
       3             :  * Copyright (c) 2005-2011, Jouni Malinen <j@w1.fi>
       4             :  *
       5             :  * This software may be distributed under the terms of the BSD license.
       6             :  * See README for more details.
       7             :  */
       8             : 
       9             : #include "includes.h"
      10             : 
      11             : #include "os.h"
      12             : #include "base64.h"
      13             : 
      14             : static const unsigned char base64_table[65] =
      15             :         "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
      16             : 
      17             : /**
      18             :  * base64_encode - Base64 encode
      19             :  * @src: Data to be encoded
      20             :  * @len: Length of the data to be encoded
      21             :  * @out_len: Pointer to output length variable, or %NULL if not used
      22             :  * Returns: Allocated buffer of out_len bytes of encoded data,
      23             :  * or %NULL on failure
      24             :  *
      25             :  * Caller is responsible for freeing the returned buffer. Returned buffer is
      26             :  * nul terminated to make it easier to use as a C string. The nul terminator is
      27             :  * not included in out_len.
      28             :  */
      29          57 : unsigned char * base64_encode(const unsigned char *src, size_t len,
      30             :                               size_t *out_len)
      31             : {
      32             :         unsigned char *out, *pos;
      33             :         const unsigned char *end, *in;
      34             :         size_t olen;
      35             :         int line_len;
      36             : 
      37          57 :         olen = len * 4 / 3 + 4; /* 3-byte blocks to 4-byte */
      38          57 :         olen += olen / 72; /* line feeds */
      39          57 :         olen++; /* nul termination */
      40          57 :         if (olen < len)
      41           0 :                 return NULL; /* integer overflow */
      42          57 :         out = os_malloc(olen);
      43          57 :         if (out == NULL)
      44           0 :                 return NULL;
      45             : 
      46          57 :         end = src + len;
      47          57 :         in = src;
      48          57 :         pos = out;
      49          57 :         line_len = 0;
      50        2826 :         while (end - in >= 3) {
      51        2712 :                 *pos++ = base64_table[in[0] >> 2];
      52        2712 :                 *pos++ = base64_table[((in[0] & 0x03) << 4) | (in[1] >> 4)];
      53        2712 :                 *pos++ = base64_table[((in[1] & 0x0f) << 2) | (in[2] >> 6)];
      54        2712 :                 *pos++ = base64_table[in[2] & 0x3f];
      55        2712 :                 in += 3;
      56        2712 :                 line_len += 4;
      57        2712 :                 if (line_len >= 72) {
      58         136 :                         *pos++ = '\n';
      59         136 :                         line_len = 0;
      60             :                 }
      61             :         }
      62             : 
      63          57 :         if (end - in) {
      64          21 :                 *pos++ = base64_table[in[0] >> 2];
      65          21 :                 if (end - in == 1) {
      66           6 :                         *pos++ = base64_table[(in[0] & 0x03) << 4];
      67           6 :                         *pos++ = '=';
      68             :                 } else {
      69          30 :                         *pos++ = base64_table[((in[0] & 0x03) << 4) |
      70          15 :                                               (in[1] >> 4)];
      71          15 :                         *pos++ = base64_table[(in[1] & 0x0f) << 2];
      72             :                 }
      73          21 :                 *pos++ = '=';
      74          21 :                 line_len += 4;
      75             :         }
      76             : 
      77          57 :         if (line_len)
      78          56 :                 *pos++ = '\n';
      79             : 
      80          57 :         *pos = '\0';
      81          57 :         if (out_len)
      82          54 :                 *out_len = pos - out;
      83          57 :         return out;
      84             : }
      85             : 
      86             : 
      87             : /**
      88             :  * base64_decode - Base64 decode
      89             :  * @src: Data to be decoded
      90             :  * @len: Length of the data to be decoded
      91             :  * @out_len: Pointer to output length variable
      92             :  * Returns: Allocated buffer of out_len bytes of decoded data,
      93             :  * or %NULL on failure
      94             :  *
      95             :  * Caller is responsible for freeing the returned buffer.
      96             :  */
      97          76 : unsigned char * base64_decode(const unsigned char *src, size_t len,
      98             :                               size_t *out_len)
      99             : {
     100             :         unsigned char dtable[256], *out, *pos, block[4], tmp;
     101             :         size_t i, count, olen;
     102          76 :         int pad = 0;
     103             : 
     104          76 :         os_memset(dtable, 0x80, 256);
     105        4940 :         for (i = 0; i < sizeof(base64_table) - 1; i++)
     106        4864 :                 dtable[base64_table[i]] = (unsigned char) i;
     107          76 :         dtable['='] = 0;
     108             : 
     109          76 :         count = 0;
     110       19270 :         for (i = 0; i < len; i++) {
     111       19194 :                 if (dtable[src[i]] != 0x80)
     112       18884 :                         count++;
     113             :         }
     114             : 
     115          76 :         if (count == 0 || count % 4)
     116           0 :                 return NULL;
     117             : 
     118          76 :         olen = count / 4 * 3;
     119          76 :         pos = out = os_malloc(olen);
     120          76 :         if (out == NULL)
     121           0 :                 return NULL;
     122             : 
     123          76 :         count = 0;
     124       19227 :         for (i = 0; i < len; i++) {
     125       19173 :                 tmp = dtable[src[i]];
     126       19173 :                 if (tmp == 0x80)
     127         289 :                         continue;
     128             : 
     129       18884 :                 if (src[i] == '=')
     130          30 :                         pad++;
     131       18884 :                 block[count] = tmp;
     132       18884 :                 count++;
     133       18884 :                 if (count == 4) {
     134        4721 :                         *pos++ = (block[0] << 2) | (block[1] >> 4);
     135        4721 :                         *pos++ = (block[1] << 4) | (block[2] >> 2);
     136        4721 :                         *pos++ = (block[2] << 6) | block[3];
     137        4721 :                         count = 0;
     138        4721 :                         if (pad) {
     139          22 :                                 if (pad == 1)
     140          14 :                                         pos--;
     141           8 :                                 else if (pad == 2)
     142           8 :                                         pos -= 2;
     143             :                                 else {
     144             :                                         /* Invalid padding */
     145           0 :                                         os_free(out);
     146           0 :                                         return NULL;
     147             :                                 }
     148          22 :                                 break;
     149             :                         }
     150             :                 }
     151             :         }
     152             : 
     153          76 :         *out_len = pos - out;
     154          76 :         return out;
     155             : }