1 /* $OpenBSD: base64.c,v 1.4 2002/01/02 23:00:10 deraadt Exp $ */
4 * Copyright (c) 1996 by Internet Software Consortium.
6 * Permission to use, copy, modify, and distribute this software for any
7 * purpose with or without fee is hereby granted, provided that the above
8 * copyright notice and this permission notice appear in all copies.
10 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
11 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
12 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
13 * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
14 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
15 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
16 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
21 * Portions Copyright (c) 1995 by International Business Machines, Inc.
23 * International Business Machines, Inc. (hereinafter called IBM) grants
24 * permission under its copyrights to use, copy, modify, and distribute this
25 * Software with or without fee, provided that the above copyright notice and
26 * all paragraphs of this notice appear in all copies, and that the name of IBM
27 * not be used in connection with the marketing of any product incorporating
28 * the Software or modifications thereof, without specific, written prior
31 * To the extent it has a right to do so, IBM grants an immunity from suit
32 * under its patents, if any, for the use, sale or manufacture of products to
33 * the extent that such products are used for performing Domain Name System
34 * dynamic updates in TCP/IP networks by means of the Software. No immunity is
35 * granted for any product per se or for any other function of any product.
37 * THE SOFTWARE IS PROVIDED "AS IS", AND IBM DISCLAIMS ALL WARRANTIES,
38 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
39 * PARTICULAR PURPOSE. IN NO EVENT SHALL IBM BE LIABLE FOR ANY SPECIAL,
40 * DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER ARISING
41 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE, EVEN
42 * IF IBM IS APPRISED OF THE POSSIBILITY OF SUCH DAMAGES.
45 /* OPENBSD ORIGINAL: lib/libc/net/base64.c */
49 #if (!defined(HAVE_B64_NTOP) && !defined(HAVE___B64_NTOP)) || (!defined(HAVE_B64_PTON) && !defined(HAVE___B64_PTON))
51 #include <sys/types.h>
52 #include <sys/param.h>
53 #include <sys/socket.h>
54 #include <netinet/in.h>
55 #include <arpa/inet.h>
65 /* XXX abort illegal in library */
66 #define Assert(Cond) if (!(Cond)) abort()
68 static const char Base64[] =
69 "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
70 static const char Pad64 = '=';
72 /* (From RFC1521 and draft-ietf-dnssec-secext-03.txt)
73 The following encoding technique is taken from RFC 1521 by Borenstein
74 and Freed. It is reproduced here in a slightly edited form for
77 A 65-character subset of US-ASCII is used, enabling 6 bits to be
78 represented per printable character. (The extra 65th character, "=",
79 is used to signify a special processing function.)
81 The encoding process represents 24-bit groups of input bits as output
82 strings of 4 encoded characters. Proceeding from left to right, a
83 24-bit input group is formed by concatenating 3 8-bit input groups.
84 These 24 bits are then treated as 4 concatenated 6-bit groups, each
85 of which is translated into a single digit in the base64 alphabet.
87 Each 6-bit group is used as an index into an array of 64 printable
88 characters. The character referenced by the index is placed in the
91 Table 1: The Base64 Alphabet
93 Value Encoding Value Encoding Value Encoding Value Encoding
108 14 O 31 f 48 w (pad) =
112 Special processing is performed if fewer than 24 bits are available
113 at the end of the data being encoded. A full encoding quantum is
114 always completed at the end of a quantity. When fewer than 24 input
115 bits are available in an input group, zero bits are added (on the
116 right) to form an integral number of 6-bit groups. Padding at the
117 end of the data is performed using the '=' character.
119 Since all base64 input is an integral number of octets, only the
120 -------------------------------------------------
121 following cases can arise:
123 (1) the final quantum of encoding input is an integral
124 multiple of 24 bits; here, the final unit of encoded
125 output will be an integral multiple of 4 characters
127 (2) the final quantum of encoding input is exactly 8 bits;
128 here, the final unit of encoded output will be two
129 characters followed by two "=" padding characters, or
130 (3) the final quantum of encoding input is exactly 16 bits;
131 here, the final unit of encoded output will be three
132 characters followed by one "=" padding character.
135 #if !defined(HAVE_B64_NTOP) && !defined(HAVE___B64_NTOP)
137 b64_ntop(u_char const *src, size_t srclength, char *target, size_t targsize)
139 size_t datalength = 0;
144 while (2 < srclength) {
150 output[0] = input[0] >> 2;
151 output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4);
152 output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6);
153 output[3] = input[2] & 0x3f;
154 Assert(output[0] < 64);
155 Assert(output[1] < 64);
156 Assert(output[2] < 64);
157 Assert(output[3] < 64);
159 if (datalength + 4 > targsize)
161 target[datalength++] = Base64[output[0]];
162 target[datalength++] = Base64[output[1]];
163 target[datalength++] = Base64[output[2]];
164 target[datalength++] = Base64[output[3]];
167 /* Now we worry about padding. */
168 if (0 != srclength) {
169 /* Get what's left. */
170 input[0] = input[1] = input[2] = '\0';
171 for (i = 0; i < srclength; i++)
174 output[0] = input[0] >> 2;
175 output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4);
176 output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6);
177 Assert(output[0] < 64);
178 Assert(output[1] < 64);
179 Assert(output[2] < 64);
181 if (datalength + 4 > targsize)
183 target[datalength++] = Base64[output[0]];
184 target[datalength++] = Base64[output[1]];
186 target[datalength++] = Pad64;
188 target[datalength++] = Base64[output[2]];
189 target[datalength++] = Pad64;
191 if (datalength >= targsize)
193 target[datalength] = '\0'; /* Returned value doesn't count \0. */
196 #endif /* !defined(HAVE_B64_NTOP) && !defined(HAVE___B64_NTOP) */
198 #if !defined(HAVE_B64_PTON) && !defined(HAVE___B64_PTON)
200 /* skips all whitespace anywhere.
201 converts characters, four at a time, starting at (or after)
202 src from base - 64 numbers into three 8 bit bytes in the target area.
203 it returns the number of data bytes stored at the target, or -1 on error.
207 b64_pton(char const *src, u_char *target, size_t targsize)
209 u_int tarindex, state;
216 while ((ch = *src++) != '\0') {
217 if (isspace(ch)) /* Skip whitespace anywhere. */
223 pos = strchr(Base64, ch);
224 if (pos == 0) /* A non-base64 character. */
230 if (tarindex >= targsize)
232 target[tarindex] = (pos - Base64) << 2;
238 if (tarindex + 1 >= targsize)
240 target[tarindex] |= (pos - Base64) >> 4;
241 target[tarindex+1] = ((pos - Base64) & 0x0f)
249 if (tarindex + 1 >= targsize)
251 target[tarindex] |= (pos - Base64) >> 2;
252 target[tarindex+1] = ((pos - Base64) & 0x03)
260 if (tarindex >= targsize)
262 target[tarindex] |= (pos - Base64);
271 * We are done decoding Base-64 chars. Let's see if we ended
272 * on a byte boundary, and/or with erroneous trailing characters.
275 if (ch == Pad64) { /* We got a pad char. */
276 ch = *src++; /* Skip it, get next. */
278 case 0: /* Invalid = in first position */
279 case 1: /* Invalid = in second position */
282 case 2: /* Valid, means one byte of info */
283 /* Skip any number of spaces. */
284 for (; ch != '\0'; ch = *src++)
287 /* Make sure there is another trailing = sign. */
290 ch = *src++; /* Skip the = */
291 /* Fall through to "single trailing =" case. */
294 case 3: /* Valid, means two bytes of info */
296 * We know this char is an =. Is there anything but
297 * whitespace after it?
299 for (; ch != '\0'; ch = *src++)
304 * Now make sure for cases 2 and 3 that the "extra"
305 * bits that slopped past the last full byte were
306 * zeros. If we don't check them, they become a
307 * subliminal channel.
309 if (target && target[tarindex] != 0)
314 * We ended by seeing the end of the string. Make sure we
315 * have no partial bytes lying around.
324 #endif /* !defined(HAVE_B64_PTON) && !defined(HAVE___B64_PTON) */