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1/* $OpenBSD: base64.c,v 1.3 1997/11/08 20:46:55 deraadt Exp $ */
2
3/*
4 * Copyright (c) 1996 by Internet Software Consortium.
5 *
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.
9 *
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
17 * SOFTWARE.
18 */
19
20/*
21 * Portions Copyright (c) 1995 by International Business Machines, Inc.
22 *
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
29 * permission.
30 *
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.
36 *
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.
43 */
44
45#include "config.h"
46
47#ifndef HAVE_B64_NTOP
48
49#include <sys/types.h>
50#include <sys/param.h>
51#include <sys/socket.h>
52#include <netinet/in.h>
53#include <arpa/inet.h>
54
55#include <ctype.h>
56#include <resolv.h>
57#include <stdio.h>
58
59#include <stdlib.h>
60#include <string.h>
61
62#define Assert(Cond) if (!(Cond)) abort()
63
64static const char Base64[] =
65 "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
66static const char Pad64 = '=';
67
68/* (From RFC1521 and draft-ietf-dnssec-secext-03.txt)
69 The following encoding technique is taken from RFC 1521 by Borenstein
70 and Freed. It is reproduced here in a slightly edited form for
71 convenience.
72
73 A 65-character subset of US-ASCII is used, enabling 6 bits to be
74 represented per printable character. (The extra 65th character, "=",
75 is used to signify a special processing function.)
76
77 The encoding process represents 24-bit groups of input bits as output
78 strings of 4 encoded characters. Proceeding from left to right, a
79 24-bit input group is formed by concatenating 3 8-bit input groups.
80 These 24 bits are then treated as 4 concatenated 6-bit groups, each
81 of which is translated into a single digit in the base64 alphabet.
82
83 Each 6-bit group is used as an index into an array of 64 printable
84 characters. The character referenced by the index is placed in the
85 output string.
86
87 Table 1: The Base64 Alphabet
88
89 Value Encoding Value Encoding Value Encoding Value Encoding
90 0 A 17 R 34 i 51 z
91 1 B 18 S 35 j 52 0
92 2 C 19 T 36 k 53 1
93 3 D 20 U 37 l 54 2
94 4 E 21 V 38 m 55 3
95 5 F 22 W 39 n 56 4
96 6 G 23 X 40 o 57 5
97 7 H 24 Y 41 p 58 6
98 8 I 25 Z 42 q 59 7
99 9 J 26 a 43 r 60 8
100 10 K 27 b 44 s 61 9
101 11 L 28 c 45 t 62 +
102 12 M 29 d 46 u 63 /
103 13 N 30 e 47 v
104 14 O 31 f 48 w (pad) =
105 15 P 32 g 49 x
106 16 Q 33 h 50 y
107
108 Special processing is performed if fewer than 24 bits are available
109 at the end of the data being encoded. A full encoding quantum is
110 always completed at the end of a quantity. When fewer than 24 input
111 bits are available in an input group, zero bits are added (on the
112 right) to form an integral number of 6-bit groups. Padding at the
113 end of the data is performed using the '=' character.
114
115 Since all base64 input is an integral number of octets, only the
116 -------------------------------------------------
117 following cases can arise:
118
119 (1) the final quantum of encoding input is an integral
120 multiple of 24 bits; here, the final unit of encoded
121 output will be an integral multiple of 4 characters
122 with no "=" padding,
123 (2) the final quantum of encoding input is exactly 8 bits;
124 here, the final unit of encoded output will be two
125 characters followed by two "=" padding characters, or
126 (3) the final quantum of encoding input is exactly 16 bits;
127 here, the final unit of encoded output will be three
128 characters followed by one "=" padding character.
129 */
130
131int
132b64_ntop(u_char const *src, size_t srclength, char *target, size_t targsize)
133{
134 size_t datalength = 0;
135 u_char input[3];
136 u_char output[4];
137 int i;
138
139 while (2 < srclength) {
140 input[0] = *src++;
141 input[1] = *src++;
142 input[2] = *src++;
143 srclength -= 3;
144
145 output[0] = input[0] >> 2;
146 output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4);
147 output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6);
148 output[3] = input[2] & 0x3f;
149 Assert(output[0] < 64);
150 Assert(output[1] < 64);
151 Assert(output[2] < 64);
152 Assert(output[3] < 64);
153
154 if (datalength + 4 > targsize)
155 return (-1);
156 target[datalength++] = Base64[output[0]];
157 target[datalength++] = Base64[output[1]];
158 target[datalength++] = Base64[output[2]];
159 target[datalength++] = Base64[output[3]];
160 }
161
162 /* Now we worry about padding. */
163 if (0 != srclength) {
164 /* Get what's left. */
165 input[0] = input[1] = input[2] = '\0';
166 for (i = 0; i < srclength; i++)
167 input[i] = *src++;
168
169 output[0] = input[0] >> 2;
170 output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4);
171 output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6);
172 Assert(output[0] < 64);
173 Assert(output[1] < 64);
174 Assert(output[2] < 64);
175
176 if (datalength + 4 > targsize)
177 return (-1);
178 target[datalength++] = Base64[output[0]];
179 target[datalength++] = Base64[output[1]];
180 if (srclength == 1)
181 target[datalength++] = Pad64;
182 else
183 target[datalength++] = Base64[output[2]];
184 target[datalength++] = Pad64;
185 }
186 if (datalength >= targsize)
187 return (-1);
188 target[datalength] = '\0'; /* Returned value doesn't count \0. */
189 return (datalength);
190}
191
192/* skips all whitespace anywhere.
193 converts characters, four at a time, starting at (or after)
194 src from base - 64 numbers into three 8 bit bytes in the target area.
195 it returns the number of data bytes stored at the target, or -1 on error.
196 */
197
198int
199b64_pton(char const *src, u_char *target, size_t targsize)
200{
201 int tarindex, state, ch;
202 char *pos;
203
204 state = 0;
205 tarindex = 0;
206
207 while ((ch = *src++) != '\0') {
208 if (isspace(ch)) /* Skip whitespace anywhere. */
209 continue;
210
211 if (ch == Pad64)
212 break;
213
214 pos = strchr(Base64, ch);
215 if (pos == 0) /* A non-base64 character. */
216 return (-1);
217
218 switch (state) {
219 case 0:
220 if (target) {
221 if (tarindex >= targsize)
222 return (-1);
223 target[tarindex] = (pos - Base64) << 2;
224 }
225 state = 1;
226 break;
227 case 1:
228 if (target) {
229 if (tarindex + 1 >= targsize)
230 return (-1);
231 target[tarindex] |= (pos - Base64) >> 4;
232 target[tarindex+1] = ((pos - Base64) & 0x0f)
233 << 4 ;
234 }
235 tarindex++;
236 state = 2;
237 break;
238 case 2:
239 if (target) {
240 if (tarindex + 1 >= targsize)
241 return (-1);
242 target[tarindex] |= (pos - Base64) >> 2;
243 target[tarindex+1] = ((pos - Base64) & 0x03)
244 << 6;
245 }
246 tarindex++;
247 state = 3;
248 break;
249 case 3:
250 if (target) {
251 if (tarindex >= targsize)
252 return (-1);
253 target[tarindex] |= (pos - Base64);
254 }
255 tarindex++;
256 state = 0;
257 break;
258 }
259 }
260
261 /*
262 * We are done decoding Base-64 chars. Let's see if we ended
263 * on a byte boundary, and/or with erroneous trailing characters.
264 */
265
266 if (ch == Pad64) { /* We got a pad char. */
267 ch = *src++; /* Skip it, get next. */
268 switch (state) {
269 case 0: /* Invalid = in first position */
270 case 1: /* Invalid = in second position */
271 return (-1);
272
273 case 2: /* Valid, means one byte of info */
274 /* Skip any number of spaces. */
275 for (; ch != '\0'; ch = *src++)
276 if (!isspace(ch))
277 break;
278 /* Make sure there is another trailing = sign. */
279 if (ch != Pad64)
280 return (-1);
281 ch = *src++; /* Skip the = */
282 /* Fall through to "single trailing =" case. */
283 /* FALLTHROUGH */
284
285 case 3: /* Valid, means two bytes of info */
286 /*
287 * We know this char is an =. Is there anything but
288 * whitespace after it?
289 */
290 for (; ch != '\0'; ch = *src++)
291 if (!isspace(ch))
292 return (-1);
293
294 /*
295 * Now make sure for cases 2 and 3 that the "extra"
296 * bits that slopped past the last full byte were
297 * zeros. If we don't check them, they become a
298 * subliminal channel.
299 */
300 if (target && target[tarindex] != 0)
301 return (-1);
302 }
303 } else {
304 /*
305 * We ended by seeing the end of the string. Make sure we
306 * have no partial bytes lying around.
307 */
308 if (state != 0)
309 return (-1);
310 }
311
312 return (tarindex);
313}
314
315#endif /* HAVE_B64_NTOP */
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-05 05:10:38 +0000