aboutsummaryrefslogtreecommitdiffstats
path: root/contrib/libs/curl/lib/base64.c
blob: 960a1ca3ad82de75373003cf10aa3d3222dcfaf6 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
/***************************************************************************
 *                                  _   _ ____  _
 *  Project                     ___| | | |  _ \| |
 *                             / __| | | | |_) | |
 *                            | (__| |_| |  _ <| |___
 *                             \___|\___/|_| \_\_____|
 *
 * Copyright (C) 1998 - 2022, Daniel Stenberg, <daniel@haxx.se>, et al.
 *
 * This software is licensed as described in the file COPYING, which
 * you should have received as part of this distribution. The terms
 * are also available at https://curl.se/docs/copyright.html.
 *
 * You may opt to use, copy, modify, merge, publish, distribute and/or sell
 * copies of the Software, and permit persons to whom the Software is
 * furnished to do so, under the terms of the COPYING file.
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
 * KIND, either express or implied.
 *
 ***************************************************************************/

/* Base64 encoding/decoding */

#include "curl_setup.h"

#if !defined(CURL_DISABLE_HTTP_AUTH) || defined(USE_SSH) || \
  !defined(CURL_DISABLE_LDAP) || \
  !defined(CURL_DISABLE_SMTP) || \
  !defined(CURL_DISABLE_POP3) || \
  !defined(CURL_DISABLE_IMAP) || \
  !defined(CURL_DISABLE_DOH) || defined(USE_SSL)

#include "urldata.h" /* for the Curl_easy definition */
#include "warnless.h"
#include "curl_base64.h"

/* The last 3 #include files should be in this order */
#include "curl_printf.h"
#include "curl_memory.h"
#include "memdebug.h"

/* ---- Base64 Encoding/Decoding Table --- */
static const char base64[]=
  "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

/* The Base 64 encoding with an URL and filename safe alphabet, RFC 4648
   section 5 */
static const char base64url[]=
  "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_";

static size_t decodeQuantum(unsigned char *dest, const char *src)
{
  size_t padding = 0;
  const char *s, *p;
  unsigned long i, x = 0;

  for(i = 0, s = src; i < 4; i++, s++) {
    if(*s == '=') {
      x = (x << 6);
      padding++;
    }
    else {
      unsigned long v = 0;
      p = base64;

      while(*p && (*p != *s)) {
        v++;
        p++;
      }

      if(*p == *s)
        x = (x << 6) + v;
      else
        return 0;
    }
  }

  if(padding < 1)
    dest[2] = curlx_ultouc(x & 0xFFUL);

  x >>= 8;
  if(padding < 2)
    dest[1] = curlx_ultouc(x & 0xFFUL);

  x >>= 8;
  dest[0] = curlx_ultouc(x & 0xFFUL);

  return 3 - padding;
}

/*
 * Curl_base64_decode()
 *
 * Given a base64 NUL-terminated string at src, decode it and return a
 * pointer in *outptr to a newly allocated memory area holding decoded
 * data. Size of decoded data is returned in variable pointed by outlen.
 *
 * Returns CURLE_OK on success, otherwise specific error code. Function
 * output shall not be considered valid unless CURLE_OK is returned.
 *
 * When decoded data length is 0, returns NULL in *outptr.
 *
 * @unittest: 1302
 */
CURLcode Curl_base64_decode(const char *src,
                            unsigned char **outptr, size_t *outlen)
{
  size_t srclen = 0;
  size_t length = 0;
  size_t padding = 0;
  size_t i;
  size_t numQuantums;
  size_t rawlen = 0;
  unsigned char *pos;
  unsigned char *newstr;

  *outptr = NULL;
  *outlen = 0;
  srclen = strlen(src);

  /* Check the length of the input string is valid */
  if(!srclen || srclen % 4)
    return CURLE_BAD_CONTENT_ENCODING;

  /* Find the position of any = padding characters */
  while((src[length] != '=') && src[length])
    length++;

  /* A maximum of two = padding characters is allowed */
  if(src[length] == '=') {
    padding++;
    if(src[length + 1] == '=')
      padding++;
  }

  /* Check the = padding characters weren't part way through the input */
  if(length + padding != srclen)
    return CURLE_BAD_CONTENT_ENCODING;

  /* Calculate the number of quantums */
  numQuantums = srclen / 4;

  /* Calculate the size of the decoded string */
  rawlen = (numQuantums * 3) - padding;

  /* Allocate our buffer including room for a zero terminator */
  newstr = malloc(rawlen + 1);
  if(!newstr)
    return CURLE_OUT_OF_MEMORY;

  pos = newstr;

  /* Decode the quantums */
  for(i = 0; i < numQuantums; i++) {
    size_t result = decodeQuantum(pos, src);
    if(!result) {
      free(newstr);

      return CURLE_BAD_CONTENT_ENCODING;
    }

    pos += result;
    src += 4;
  }

  /* Zero terminate */
  *pos = '\0';

  /* Return the decoded data */
  *outptr = newstr;
  *outlen = rawlen;

  return CURLE_OK;
}

static CURLcode base64_encode(const char *table64,
                              const char *inputbuff, size_t insize,
                              char **outptr, size_t *outlen)
{
  unsigned char ibuf[3];
  unsigned char obuf[4];
  int i;
  int inputparts;
  char *output;
  char *base64data;
  const char *indata = inputbuff;

  *outptr = NULL;
  *outlen = 0;

  if(!insize)
    insize = strlen(indata);

#if SIZEOF_SIZE_T == 4
  if(insize > UINT_MAX/4)
    return CURLE_OUT_OF_MEMORY;
#endif

  base64data = output = malloc(insize * 4 / 3 + 4);
  if(!output)
    return CURLE_OUT_OF_MEMORY;

  while(insize > 0) {
    for(i = inputparts = 0; i < 3; i++) {
      if(insize > 0) {
        inputparts++;
        ibuf[i] = (unsigned char) *indata;
        indata++;
        insize--;
      }
      else
        ibuf[i] = 0;
    }

    obuf[0] = (unsigned char)  ((ibuf[0] & 0xFC) >> 2);
    obuf[1] = (unsigned char) (((ibuf[0] & 0x03) << 4) | \
                               ((ibuf[1] & 0xF0) >> 4));
    obuf[2] = (unsigned char) (((ibuf[1] & 0x0F) << 2) | \
                               ((ibuf[2] & 0xC0) >> 6));
    obuf[3] = (unsigned char)   (ibuf[2] & 0x3F);

    switch(inputparts) {
    case 1: /* only one byte read */
      msnprintf(output, 5, "%c%c==",
                table64[obuf[0]],
                table64[obuf[1]]);
      break;

    case 2: /* two bytes read */
      msnprintf(output, 5, "%c%c%c=",
                table64[obuf[0]],
                table64[obuf[1]],
                table64[obuf[2]]);
      break;

    default:
      msnprintf(output, 5, "%c%c%c%c",
                table64[obuf[0]],
                table64[obuf[1]],
                table64[obuf[2]],
                table64[obuf[3]]);
      break;
    }
    output += 4;
  }

  /* Zero terminate */
  *output = '\0';

  /* Return the pointer to the new data (allocated memory) */
  *outptr = base64data;

  /* Return the length of the new data */
  *outlen = output - base64data;

  return CURLE_OK;
}

/*
 * Curl_base64_encode()
 *
 * Given a pointer to an input buffer and an input size, encode it and
 * return a pointer in *outptr to a newly allocated memory area holding
 * encoded data. Size of encoded data is returned in variable pointed by
 * outlen.
 *
 * Input length of 0 indicates input buffer holds a NUL-terminated string.
 *
 * Returns CURLE_OK on success, otherwise specific error code. Function
 * output shall not be considered valid unless CURLE_OK is returned.
 *
 * When encoded data length is 0, returns NULL in *outptr.
 *
 * @unittest: 1302
 */
CURLcode Curl_base64_encode(const char *inputbuff, size_t insize,
                            char **outptr, size_t *outlen)
{
  return base64_encode(base64, inputbuff, insize, outptr, outlen);
}

/*
 * Curl_base64url_encode()
 *
 * Given a pointer to an input buffer and an input size, encode it and
 * return a pointer in *outptr to a newly allocated memory area holding
 * encoded data. Size of encoded data is returned in variable pointed by
 * outlen.
 *
 * Input length of 0 indicates input buffer holds a NUL-terminated string.
 *
 * Returns CURLE_OK on success, otherwise specific error code. Function
 * output shall not be considered valid unless CURLE_OK is returned.
 *
 * When encoded data length is 0, returns NULL in *outptr.
 *
 * @unittest: 1302
 */
CURLcode Curl_base64url_encode(const char *inputbuff, size_t insize,
                               char **outptr, size_t *outlen)
{
  return base64_encode(base64url, inputbuff, insize, outptr, outlen);
}

#endif /* no users so disabled */