1 /*
2 * Copyright (c) 1996, 1998 by Internet Software Consortium.
3 *
4 * Permission to use, copy, modify, and distribute this software for any
5 * purpose with or without fee is hereby granted, provided that the above
6 * copyright notice and this permission notice appear in all copies.
7 *
8 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
9 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
10 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
11 * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
12 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
13 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
14 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
15 * SOFTWARE.
16 */
17
18 /*
19 * Portions Copyright (c) 1995 by International Business Machines, Inc.
20 *
21 * International Business Machines, Inc. (hereinafter called IBM) grants
22 * permission under its copyrights to use, copy, modify, and distribute this
23 * Software with or without fee, provided that the above copyright notice and
24 * all paragraphs of this notice appear in all copies, and that the name of IBM
25 * not be used in connection with the marketing of any product incorporating
26 * the Software or modifications thereof, without specific, written prior
27 * permission.
28 *
29 * To the extent it has a right to do so, IBM grants an immunity from suit
30 * under its patents, if any, for the use, sale or manufacture of products to
31 * the extent that such products are used for performing Domain Name System
32 * dynamic updates in TCP/IP networks by means of the Software. No immunity is
33 * granted for any product per se or for any other function of any product.
34 *
35 * THE SOFTWARE IS PROVIDED "AS IS", AND IBM DISCLAIMS ALL WARRANTIES,
36 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
37 * PARTICULAR PURPOSE. IN NO EVENT SHALL IBM BE LIABLE FOR ANY SPECIAL,
38 * DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER ARISING
39 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE, EVEN
40 * IF IBM IS APPRISED OF THE POSSIBILITY OF SUCH DAMAGES.
41 */
42 #include <config.h>
43
44 #include <sys/types.h>
45 #include <sys/param.h>
46 #include <sys/socket.h>
47
48 #include <netinet/in.h>
49 #include <arpa/inet.h>
50
51 #include <ctype.h>
52 #include <stdio.h>
53 #include <stdlib.h>
54 #include <string.h>
55
56 #define Assert(Cond) if (!(Cond)) abort()
57
58 static const char Base64[] =
59 "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
60 static const char Pad64 = '=';
61
62 /* (From RFC1521 and draft-ietf-dnssec-secext-03.txt)
63 The following encoding technique is taken from RFC 1521 by Borenstein
64 and Freed. It is reproduced here in a slightly edited form for
65 convenience.
66
67 A 65-character subset of US-ASCII is used, enabling 6 bits to be
68 represented per printable character. (The extra 65th character, "=",
69 is used to signify a special processing function.)
70
71 The encoding process represents 24-bit groups of input bits as output
72 strings of 4 encoded characters. Proceeding from left to right, a
73 24-bit input group is formed by concatenating 3 8-bit input groups.
74 These 24 bits are then treated as 4 concatenated 6-bit groups, each
75 of which is translated into a single digit in the base64 alphabet.
76
77 Each 6-bit group is used as an index into an array of 64 printable
78 characters. The character referenced by the index is placed in the
79 output string.
80
81 Table 1: The Base64 Alphabet
82
83 Value Encoding Value Encoding Value Encoding Value Encoding
84 0 A 17 R 34 i 51 z
85 1 B 18 S 35 j 52 0
86 2 C 19 T 36 k 53 1
87 3 D 20 U 37 l 54 2
88 4 E 21 V 38 m 55 3
89 5 F 22 W 39 n 56 4
90 6 G 23 X 40 o 57 5
91 7 H 24 Y 41 p 58 6
92 8 I 25 Z 42 q 59 7
93 9 J 26 a 43 r 60 8
94 10 K 27 b 44 s 61 9
95 11 L 28 c 45 t 62 +
96 12 M 29 d 46 u 63 /
97 13 N 30 e 47 v
98 14 O 31 f 48 w (pad) =
99 15 P 32 g 49 x
100 16 Q 33 h 50 y
101
102 Special processing is performed if fewer than 24 bits are available
103 at the end of the data being encoded. A full encoding quantum is
104 always completed at the end of a quantity. When fewer than 24 input
105 bits are available in an input group, zero bits are added (on the
106 right) to form an integral number of 6-bit groups. Padding at the
107 end of the data is performed using the '=' character.
108
109 Since all base64 input is an integral number of octets, only the
110 -------------------------------------------------
111 following cases can arise:
112
113 (1) the final quantum of encoding input is an integral
114 multiple of 24 bits; here, the final unit of encoded
115 output will be an integral multiple of 4 characters
116 with no "=" padding,
117 (2) the final quantum of encoding input is exactly 8 bits;
118 here, the final unit of encoded output will be two
119 characters followed by two "=" padding characters, or
120 (3) the final quantum of encoding input is exactly 16 bits;
121 here, the final unit of encoded output will be three
122 characters followed by one "=" padding character.
123 */
124
125 /* skips all whitespace anywhere.
126 converts characters, four at a time, starting at (or after)
127 src from base - 64 numbers into three 8 bit bytes in the target area.
128 it returns the number of data bytes stored at the target, or -1 on error.
129 */
130
131 static int b64rmap_initialized = 0;
132 static uint8_t b64rmap[256];
133
134 static const uint8_t b64rmap_special = 0xf0;
135 static const uint8_t b64rmap_end = 0xfd;
136 static const uint8_t b64rmap_space = 0xfe;
137 static const uint8_t b64rmap_invalid = 0xff;
138
139 /**
140 * Initializing the reverse map is not thread safe.
141 * Which is fine for NSD. For now...
142 **/
143 static void
b64_initialize_rmap()144 b64_initialize_rmap ()
145 {
146 int i;
147
148 /* Null: end of string, stop parsing */
149 b64rmap[0] = b64rmap_end;
150
151 for (i = 1; i < 256; ++i) {
152 /* Whitespaces */
153 if (isspace(i))
154 b64rmap[i] = b64rmap_space;
155 /* Padding: stop parsing */
156 else if (i == (unsigned char)Pad64)
157 b64rmap[i] = b64rmap_end;
158 /* Non-base64 char */
159 else
160 b64rmap[i] = b64rmap_invalid;
161 }
162
163 /* Fill reverse mapping for base64 chars */
164 for (i = 0; Base64[i] != '\0'; ++i)
165 b64rmap[(uint8_t)Base64[i]] = i;
166
167 b64rmap_initialized = 1;
168 }
169
170 static int
b64_pton_do(unsigned char const * src,uint8_t * target,size_t targsize)171 b64_pton_do(unsigned char const *src, uint8_t *target, size_t targsize)
172 {
173 int tarindex, state, ch;
174 uint8_t ofs;
175
176 state = 0;
177 tarindex = 0;
178
179 while (1)
180 {
181 ch = *src++;
182 ofs = b64rmap[ch];
183
184 if (ofs >= b64rmap_special) {
185 /* Ignore whitespaces */
186 if (ofs == b64rmap_space)
187 continue;
188 /* End of base64 characters */
189 if (ofs == b64rmap_end)
190 break;
191 /* A non-base64 character. */
192 return (-1);
193 }
194
195 switch (state) {
196 case 0:
197 if ((size_t)tarindex >= targsize)
198 return (-1);
199 target[tarindex] = ofs << 2;
200 state = 1;
201 break;
202 case 1:
203 if ((size_t)tarindex + 1 >= targsize)
204 return (-1);
205 target[tarindex] |= ofs >> 4;
206 target[tarindex+1] = (ofs & 0x0f)
207 << 4 ;
208 tarindex++;
209 state = 2;
210 break;
211 case 2:
212 if ((size_t)tarindex + 1 >= targsize)
213 return (-1);
214 target[tarindex] |= ofs >> 2;
215 target[tarindex+1] = (ofs & 0x03)
216 << 6;
217 tarindex++;
218 state = 3;
219 break;
220 case 3:
221 if ((size_t)tarindex >= targsize)
222 return (-1);
223 target[tarindex] |= ofs;
224 tarindex++;
225 state = 0;
226 break;
227 default:
228 abort();
229 }
230 }
231
232 /*
233 * We are done decoding Base-64 chars. Let's see if we ended
234 * on a byte boundary, and/or with erroneous trailing characters.
235 */
236
237 if (ch == Pad64) { /* We got a pad char. */
238 ch = *src++; /* Skip it, get next. */
239 switch (state) {
240 case 0: /* Invalid = in first position */
241 case 1: /* Invalid = in second position */
242 return (-1);
243
244 case 2: /* Valid, means one byte of info */
245 /* Skip any number of spaces. */
246 for ((void)NULL; ch != '\0'; ch = *src++)
247 if (b64rmap[ch] != b64rmap_space)
248 break;
249 /* Make sure there is another trailing = sign. */
250 if (ch != Pad64)
251 return (-1);
252 ch = *src++; /* Skip the = */
253 /* Fall through to "single trailing =" case. */
254 /* FALLTHROUGH */
255
256 case 3: /* Valid, means two bytes of info */
257 /*
258 * We know this char is an =. Is there anything but
259 * whitespace after it?
260 */
261 for ((void)NULL; ch != '\0'; ch = *src++)
262 if (b64rmap[ch] != b64rmap_space)
263 return (-1);
264
265 /*
266 * Now make sure for cases 2 and 3 that the "extra"
267 * bits that slopped past the last full byte were
268 * zeros. If we don't check them, they become a
269 * subliminal channel.
270 */
271 if (target[tarindex] != 0)
272 return (-1);
273 }
274 } else {
275 /*
276 * We ended by seeing the end of the string. Make sure we
277 * have no partial bytes lying around.
278 */
279 if (state != 0)
280 return (-1);
281 }
282
283 return (tarindex);
284 }
285
286
287 static int
b64_pton_len(unsigned char const * src)288 b64_pton_len(unsigned char const *src)
289 {
290 int tarindex, state, ch;
291 uint8_t ofs;
292
293 state = 0;
294 tarindex = 0;
295
296 while (1)
297 {
298 ch = *src++;
299 ofs = b64rmap[ch];
300
301 if (ofs >= b64rmap_special) {
302 /* Ignore whitespaces */
303 if (ofs == b64rmap_space)
304 continue;
305 /* End of base64 characters */
306 if (ofs == b64rmap_end)
307 break;
308 /* A non-base64 character. */
309 return (-1);
310 }
311
312 switch (state) {
313 case 0:
314 state = 1;
315 break;
316 case 1:
317 tarindex++;
318 state = 2;
319 break;
320 case 2:
321 tarindex++;
322 state = 3;
323 break;
324 case 3:
325 tarindex++;
326 state = 0;
327 break;
328 default:
329 abort();
330 }
331 }
332
333 /*
334 * We are done decoding Base-64 chars. Let's see if we ended
335 * on a byte boundary, and/or with erroneous trailing characters.
336 */
337
338 if (ch == Pad64) { /* We got a pad char. */
339 ch = *src++; /* Skip it, get next. */
340 switch (state) {
341 case 0: /* Invalid = in first position */
342 case 1: /* Invalid = in second position */
343 return (-1);
344
345 case 2: /* Valid, means one byte of info */
346 /* Skip any number of spaces. */
347 for ((void)NULL; ch != '\0'; ch = *src++)
348 if (b64rmap[ch] != b64rmap_space)
349 break;
350 /* Make sure there is another trailing = sign. */
351 if (ch != Pad64)
352 return (-1);
353 ch = *src++; /* Skip the = */
354 /* Fall through to "single trailing =" case. */
355 /* FALLTHROUGH */
356
357 case 3: /* Valid, means two bytes of info */
358 /*
359 * We know this char is an =. Is there anything but
360 * whitespace after it?
361 */
362 for ((void)NULL; ch != '\0'; ch = *src++)
363 if (b64rmap[ch] != b64rmap_space)
364 return (-1);
365
366 }
367 } else {
368 /*
369 * We ended by seeing the end of the string. Make sure we
370 * have no partial bytes lying around.
371 */
372 if (state != 0)
373 return (-1);
374 }
375
376 return (tarindex);
377 }
378
379
380 int
b64_pton(char const * src,uint8_t * target,size_t targsize)381 b64_pton(char const *src, uint8_t *target, size_t targsize)
382 {
383 if (!b64rmap_initialized)
384 b64_initialize_rmap ();
385
386 if (target)
387 return b64_pton_do ((unsigned char const*)src, target, targsize);
388 else
389 return b64_pton_len ((unsigned char const*)src);
390 }
391