Line data    Source code

       1             : /*
       2             :    Unix SMB/CIFS implementation.
       3             :    Samba utility functions
       4             : 
       5             :    Copyright (C) Andrew Tridgell 1992-2001
       6             :    Copyright (C) Simo Sorce      2001-2002
       7             :    Copyright (C) Martin Pool     2003
       8             :    Copyright (C) James Peach     2006
       9             :    Copyright (C) Jeremy Allison  1992-2007
      10             : 
      11             :    This program is free software; you can redistribute it and/or modify
      12             :    it under the terms of the GNU General Public License as published by
      13             :    the Free Software Foundation; either version 3 of the License, or
      14             :    (at your option) any later version.
      15             : 
      16             :    This program is distributed in the hope that it will be useful,
      17             :    but WITHOUT ANY WARRANTY; without even the implied warranty of
      18             :    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      19             :    GNU General Public License for more details.
      20             : 
      21             :    You should have received a copy of the GNU General Public License
      22             :    along with this program.  If not, see <http://www.gnu.org/licenses/>.
      23             : */
      24             : 
      25             : #include "replace.h"
      26             : #include "lib/util/base64.h"
      27             : 
      28             : static const char b64[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
      29             : 
      30             : /**
      31             :  * Decode a base64 string into a DATA_BLOB - simple and slow algorithm.
      32             :  *
      33             :  * A DATA_BLOB like {.data = NULL, length = 0} indicates memory error.
      34             :  *
      35             :  * Decoding stops at the first invalid character.
      36             :  **/
      37        8866 : _PUBLIC_ DATA_BLOB base64_decode_data_blob_talloc(TALLOC_CTX *mem_ctx, const char *s)
      38             : {
      39             :         int bit_offset, byte_offset, idx, i, n;
      40        8866 :         DATA_BLOB decoded = data_blob_talloc(mem_ctx, s, strlen(s)+1);
      41        8866 :         unsigned char *d = decoded.data;
      42             :         char *p;
      43             : 
      44        8866 :         if (decoded.data == NULL) {
      45           0 :                 decoded.length = 0;
      46           0 :                 return decoded;
      47             :         }
      48             : 
      49        8866 :         n=i=0;
      50             : 
      51    14884938 :         while (*s && (p=strchr(b64,*s))) {
      52    14876072 :                 idx = (int)(p - b64);
      53    14876072 :                 byte_offset = (i*6)/8;
      54    14876072 :                 bit_offset = (i*6)%8;
      55    14876072 :                 d[byte_offset] &= ~((1<<(8-bit_offset))-1);
      56    14876072 :                 if (bit_offset < 3) {
      57     7436075 :                         d[byte_offset] |= (idx << (2-bit_offset));
      58     7436075 :                         n = byte_offset+1;
      59             :                 } else {
      60     7439997 :                         d[byte_offset] |= (idx >> (bit_offset-2));
      61     7439997 :                         d[byte_offset+1] = (idx << (8-(bit_offset-2))) & 0xFF;
      62     7439997 :                         n = byte_offset+2;
      63             :                 }
      64    14876072 :                 s++; i++;
      65             :         }
      66             : 
      67        8866 :         if ((n > 0) && (*s == '=')) {
      68        7845 :                 n -= 1;
      69             :         }
      70             : 
      71             :         /* fix up length */
      72        8866 :         decoded.length = n;
      73        8866 :         decoded.data = talloc_realloc(mem_ctx, decoded.data, uint8_t, n);
      74        8866 :         return decoded;
      75             : }
      76             : 
      77             : /**
      78             :  * Decode a base64 string into a DATA_BLOB - simple and slow algorithm
      79             :  **/
      80           0 : _PUBLIC_ DATA_BLOB base64_decode_data_blob(const char *s)
      81             : {
      82           0 :         return base64_decode_data_blob_talloc(NULL, s);
      83             : }
      84             : 
      85             : /**
      86             :  * Decode a base64 string in-place - wrapper for the above
      87             :  **/
      88           0 : _PUBLIC_ void base64_decode_inplace(char *s)
      89             : {
      90           0 :         DATA_BLOB decoded = base64_decode_data_blob(s);
      91             : 
      92           0 :         if ( decoded.length != 0 ) {
      93           0 :                 memcpy(s, decoded.data, decoded.length);
      94             : 
      95             :                 /* null terminate */
      96           0 :                 s[decoded.length] = '\0';
      97             :         } else {
      98           0 :                 *s = '\0';
      99             :         }
     100             : 
     101           0 :         data_blob_free(&decoded);
     102           0 : }
     103             : 
     104             : /**
     105             :  * Encode a base64 string into a talloc()ed string caller to free.
     106             :  *
     107             :  * From SQUID: adopted from http://ftp.sunet.se/pub2/gnu/vm/base64-encode.c
     108             :  * with adjustments
     109             :  **/
     110             : 
     111         216 : _PUBLIC_ char *base64_encode_data_blob(TALLOC_CTX *mem_ctx, DATA_BLOB data)
     112             : {
     113         216 :         int bits = 0;
     114         216 :         int char_count = 0;
     115             :         size_t out_cnt, len, output_len;
     116             :         char *result;
     117             : 
     118         216 :         if (!data.length || !data.data)
     119           0 :                 return NULL;
     120             : 
     121         216 :         out_cnt = 0;
     122         216 :         len = data.length;
     123         216 :         output_len = data.length * 2 + 4; /* Account for closing bytes. 4 is
     124             :                                            * random but should be enough for
     125             :                                            * the = and \0 */
     126         216 :         result = talloc_array(mem_ctx, char, output_len); /* get us plenty of space */
     127         216 :         if (result == NULL) {
     128           0 :                 return NULL;
     129             :         }
     130             : 
     131       44332 :         while (len--) {
     132       44116 :                 int c = (unsigned char) *(data.data++);
     133       44116 :                 bits += c;
     134       44116 :                 char_count++;
     135       44116 :                 if (char_count == 3) {
     136       14631 :                         result[out_cnt++] = b64[bits >> 18];
     137       14631 :                         result[out_cnt++] = b64[(bits >> 12) & 0x3f];
     138       14631 :                         result[out_cnt++] = b64[(bits >> 6) & 0x3f];
     139       14631 :                         result[out_cnt++] = b64[bits & 0x3f];
     140       14631 :                         bits = 0;
     141       14631 :                         char_count = 0;
     142             :                 } else {
     143       29485 :                         bits <<= 8;
     144             :                 }
     145             :         }
     146         216 :         if (char_count != 0) {
     147         161 :                 bits <<= 16 - (8 * char_count);
     148         161 :                 result[out_cnt++] = b64[bits >> 18];
     149         161 :                 result[out_cnt++] = b64[(bits >> 12) & 0x3f];
     150         161 :                 if (char_count == 1) {
     151          99 :                         result[out_cnt++] = '=';
     152          99 :                         result[out_cnt++] = '=';
     153             :                 } else {
     154          62 :                         result[out_cnt++] = b64[(bits >> 6) & 0x3f];
     155          62 :                         result[out_cnt++] = '=';
     156             :                 }
     157             :         }
     158         216 :         result[out_cnt] = '\0'; /* terminate */
     159         216 :         return result;
     160             : }
     161             :