2 * Modified by Kurt D. Zeilenga for inclusion into OpenLDAP
6 * Copyright (c) 1996, 1998 by Internet Software Consortium.
8 * Permission to use, copy, modify, and distribute this software for any
9 * purpose with or without fee is hereby granted, provided that the above
10 * copyright notice and this permission notice appear in all copies.
12 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
13 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
14 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
15 * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
16 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
17 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
18 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
23 * Portions Copyright (c) 1995 by International Business Machines, Inc.
25 * International Business Machines, Inc. (hereinafter called IBM) grants
26 * permission under its copyrights to use, copy, modify, and distribute this
27 * Software with or without fee, provided that the above copyright notice and
28 * all paragraphs of this notice appear in all copies, and that the name of IBM
29 * not be used in connection with the marketing of any product incorporating
30 * the Software or modifications thereof, without specific, written prior
33 * To the extent it has a right to do so, IBM grants an immunity from suit
34 * under its patents, if any, for the use, sale or manufacture of products to
35 * the extent that such products are used for performing Domain Name System
36 * dynamic updates in TCP/IP networks by means of the Software. No immunity is
37 * granted for any product per se or for any other function of any product.
39 * THE SOFTWARE IS PROVIDED "AS IS", AND IBM DISCLAIMS ALL WARRANTIES,
40 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
41 * PARTICULAR PURPOSE. IN NO EVENT SHALL IBM BE LIABLE FOR ANY SPECIAL,
42 * DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER ARISING
43 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE, EVEN
44 * IF IBM IS APPRISED OF THE POSSIBILITY OF SUCH DAMAGES.
49 #include <ac/assert.h>
50 #include <ac/stdlib.h>
52 #include <ac/string.h>
54 /* include socket.h to get sys/types.h and/or winsock2.h */
55 #include <ac/socket.h>
59 static const char Base64[] =
60 "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
61 static const char Pad64 = '=';
63 /* (From RFC1521 and draft-ietf-dnssec-secext-03.txt)
64 The following encoding technique is taken from RFC 1521 by Borenstein
65 and Freed. It is reproduced here in a slightly edited form for
68 A 65-character subset of US-ASCII is used, enabling 6 bits to be
69 represented per printable character. (The extra 65th character, "=",
70 is used to signify a special processing function.)
72 The encoding process represents 24-bit groups of input bits as output
73 strings of 4 encoded characters. Proceeding from left to right, a
74 24-bit input group is formed by concatenating 3 8-bit input groups.
75 These 24 bits are then treated as 4 concatenated 6-bit groups, each
76 of which is translated into a single digit in the base64 alphabet.
78 Each 6-bit group is used as an index into an array of 64 printable
79 characters. The character referenced by the index is placed in the
82 Table 1: The Base64 Alphabet
84 Value Encoding Value Encoding Value Encoding Value Encoding
99 14 O 31 f 48 w (pad) =
103 Special processing is performed if fewer than 24 bits are available
104 at the end of the data being encoded. A full encoding quantum is
105 always completed at the end of a quantity. When fewer than 24 input
106 bits are available in an input group, zero bits are added (on the
107 right) to form an integral number of 6-bit groups. Padding at the
108 end of the data is performed using the '=' character.
110 Since all base64 input is an integral number of octets, only the
111 -------------------------------------------------
112 following cases can arise:
114 (1) the final quantum of encoding input is an integral
115 multiple of 24 bits; here, the final unit of encoded
116 output will be an integral multiple of 4 characters
118 (2) the final quantum of encoding input is exactly 8 bits;
119 here, the final unit of encoded output will be two
120 characters followed by two "=" padding characters, or
121 (3) the final quantum of encoding input is exactly 16 bits;
122 here, the final unit of encoded output will be three
123 characters followed by one "=" padding character.
133 size_t datalength = 0;
138 while (2 < srclength) {
144 output[0] = input[0] >> 2;
145 output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4);
146 output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6);
147 output[3] = input[2] & 0x3f;
148 assert(output[0] < 64);
149 assert(output[1] < 64);
150 assert(output[2] < 64);
151 assert(output[3] < 64);
153 if (datalength + 4 > targsize)
155 target[datalength++] = Base64[output[0]];
156 target[datalength++] = Base64[output[1]];
157 target[datalength++] = Base64[output[2]];
158 target[datalength++] = Base64[output[3]];
161 /* Now we worry about padding. */
162 if (0 != srclength) {
163 /* Get what's left. */
164 input[0] = input[1] = input[2] = '\0';
165 for (i = 0; i < srclength; i++)
168 output[0] = input[0] >> 2;
169 output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4);
170 output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6);
171 assert(output[0] < 64);
172 assert(output[1] < 64);
173 assert(output[2] < 64);
175 if (datalength + 4 > targsize)
177 target[datalength++] = Base64[output[0]];
178 target[datalength++] = Base64[output[1]];
180 target[datalength++] = Pad64;
182 target[datalength++] = Base64[output[2]];
183 target[datalength++] = Pad64;
185 if (datalength >= targsize)
187 target[datalength] = '\0'; /* Returned value doesn't count \0. */
191 /* skips all whitespace anywhere.
192 converts characters, four at a time, starting at (or after)
193 src from base - 64 numbers into three 8 bit bytes in the target area.
194 it returns the number of data bytes stored at the target, or -1 on error.
203 int tarindex, state, ch;
209 while ((ch = *src++) != '\0') {
210 if (isascii(ch) && isspace(ch)) /* Skip whitespace anywhere. */
216 pos = strchr(Base64, ch);
217 if (pos == 0) /* A non-base64 character. */
223 if ((size_t)tarindex >= targsize)
225 target[tarindex] = (pos - Base64) << 2;
231 if ((size_t)tarindex + 1 >= targsize)
233 target[tarindex] |= (pos - Base64) >> 4;
234 target[tarindex+1] = ((pos - Base64) & 0x0f)
242 if ((size_t)tarindex + 1 >= targsize)
244 target[tarindex] |= (pos - Base64) >> 2;
245 target[tarindex+1] = ((pos - Base64) & 0x03)
253 if ((size_t)tarindex >= targsize)
255 target[tarindex] |= (pos - Base64);
266 * We are done decoding Base-64 chars. Let's see if we ended
267 * on a byte boundary, and/or with erroneous trailing characters.
270 if (ch == Pad64) { /* We got a pad char. */
271 ch = *src++; /* Skip it, get next. */
273 case 0: /* Invalid = in first position */
274 case 1: /* Invalid = in second position */
277 case 2: /* Valid, means one byte of info */
278 /* Skip any number of spaces. */
279 for ((void)NULL; ch != '\0'; ch = *src++)
280 if (! (isascii(ch) && isspace(ch)))
282 /* Make sure there is another trailing = sign. */
285 ch = *src++; /* Skip the = */
286 /* Fall through to "single trailing =" case. */
289 case 3: /* Valid, means two bytes of info */
291 * We know this char is an =. Is there anything but
292 * whitespace after it?
294 for ((void)NULL; ch != '\0'; ch = *src++)
295 if (! (isascii(ch) && isspace(ch)))
299 * Now make sure for cases 2 and 3 that the "extra"
300 * bits that slopped past the last full byte were
301 * zeros. If we don't check them, they become a
302 * subliminal channel.
304 if (target && target[tarindex] != 0)
309 * We ended by seeing the end of the string. Make sure we
310 * have no partial bytes lying around.