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 following cases can arise:
111
112 (1) the final quantum of encoding input is an integral
113 multiple of 24 bits; here, the final unit of encoded
114 output will be an integral multiple of 4 characters
115 with no "=" padding,
116 (2) the final quantum of encoding input is exactly 8 bits;
117 here, the final unit of encoded output will be two
118 characters followed by two "=" padding characters, or
119 (3) the final quantum of encoding input is exactly 16 bits;
120 here, the final unit of encoded output will be three
121 characters followed by one "=" padding character.
122 */
123
124 /* skips all whitespace anywhere.
125 converts characters, four at a time, starting at (or after)
126 src from base - 64 numbers into three 8 bit bytes in the target area.
127 it returns the number of data bytes stored at the target, or -1 on error.
128 */
129
130 static int b64rmap_initialized = 0;
131 static uint8_t b64rmap[256];
132
133 static const uint8_t b64rmap_special = 0xf0;
134 static const uint8_t b64rmap_end = 0xfd;
135 static const uint8_t b64rmap_space = 0xfe;
136 static const uint8_t b64rmap_invalid = 0xff;
137
138 /**
139 * Initializing the reverse map is not thread safe.
140 * Which is fine for NSD. For now...
141 **/
142 static void
b64_initialize_rmap()143 b64_initialize_rmap ()
144 {
145 int i;
146 char ch;
147
148 /* Null: end of string, stop parsing */
149 b64rmap[0] = b64rmap_end;
150
151 for (i = 1; i < 256; ++i) {
152 ch = (char)i;
153 /* Whitespaces */
154 if (isspace(ch))
155 b64rmap[i] = b64rmap_space;
156 /* Padding: stop parsing */
157 else if (ch == Pad64)
158 b64rmap[i] = b64rmap_end;
159 /* Non-base64 char */
160 else
161 b64rmap[i] = b64rmap_invalid;
162 }
163
164 /* Fill reverse mapping for base64 chars */
165 for (i = 0; Base64[i] != '\0'; ++i)
166 b64rmap[(uint8_t)Base64[i]] = i;
167
168 b64rmap_initialized = 1;
169 }
170
171 static int
b64_pton_do(char const * src,uint8_t * target,size_t targsize)172 b64_pton_do(char const *src, uint8_t *target, size_t targsize)
173 {
174 int tarindex, state, ch;
175 uint8_t ofs;
176
177 state = 0;
178 tarindex = 0;
179
180 while (1)
181 {
182 ch = *src++;
183 ofs = b64rmap[ch];
184
185 if (ofs >= b64rmap_special) {
186 /* Ignore whitespaces */
187 if (ofs == b64rmap_space)
188 continue;
189 /* End of base64 characters */
190 if (ofs == b64rmap_end)
191 break;
192 /* A non-base64 character. */
193 return (-1);
194 }
195
196 switch (state) {
197 case 0:
198 if ((size_t)tarindex >= targsize)
199 return (-1);
200 target[tarindex] = ofs << 2;
201 state = 1;
202 break;
203 case 1:
204 if ((size_t)tarindex + 1 >= targsize)
205 return (-1);
206 target[tarindex] |= ofs >> 4;
207 target[tarindex+1] = (ofs & 0x0f)
208 << 4 ;
209 tarindex++;
210 state = 2;
211 break;
212 case 2:
213 if ((size_t)tarindex + 1 >= targsize)
214 return (-1);
215 target[tarindex] |= ofs >> 2;
216 target[tarindex+1] = (ofs & 0x03)
217 << 6;
218 tarindex++;
219 state = 3;
220 break;
221 case 3:
222 if ((size_t)tarindex >= targsize)
223 return (-1);
224 target[tarindex] |= ofs;
225 tarindex++;
226 state = 0;
227 break;
228 default:
229 abort();
230 }
231 }
232
233 /*
234 * We are done decoding Base-64 chars. Let's see if we ended
235 * on a byte boundary, and/or with erroneous trailing characters.
236 */
237
238 if (ch == Pad64) { /* We got a pad char. */
239 ch = *src++; /* Skip it, get next. */
240 switch (state) {
241 case 0: /* Invalid = in first position */
242 case 1: /* Invalid = in second position */
243 return (-1);
244
245 case 2: /* Valid, means one byte of info */
246 /* Skip any number of spaces. */
247 for ((void)NULL; ch != '\0'; ch = *src++)
248 if (b64rmap[ch] != b64rmap_space)
249 break;
250 /* Make sure there is another trailing = sign. */
251 if (ch != Pad64)
252 return (-1);
253 ch = *src++; /* Skip the = */
254 /* Fall through to "single trailing =" case. */
255 /* FALLTHROUGH */
256
257 case 3: /* Valid, means two bytes of info */
258 /*
259 * We know this char is an =. Is there anything but
260 * whitespace after it?
261 */
262 for ((void)NULL; ch != '\0'; ch = *src++)
263 if (b64rmap[ch] != b64rmap_space)
264 return (-1);
265
266 /*
267 * Now make sure for cases 2 and 3 that the "extra"
268 * bits that slopped past the last full byte were
269 * zeros. If we don't check them, they become a
270 * subliminal channel.
271 */
272 if (target[tarindex] != 0)
273 return (-1);
274 }
275 } else {
276 /*
277 * We ended by seeing the end of the string. Make sure we
278 * have no partial bytes lying around.
279 */
280 if (state != 0)
281 return (-1);
282 }
283
284 return (tarindex);
285 }
286
287
288 static int
b64_pton_len(char const * src)289 b64_pton_len(char const *src)
290 {
291 int tarindex, state, ch;
292 uint8_t ofs;
293
294 state = 0;
295 tarindex = 0;
296
297 while (1)
298 {
299 ch = *src++;
300 ofs = b64rmap[ch];
301
302 if (ofs >= b64rmap_special) {
303 /* Ignore whitespaces */
304 if (ofs == b64rmap_space)
305 continue;
306 /* End of base64 characters */
307 if (ofs == b64rmap_end)
308 break;
309 /* A non-base64 character. */
310 return (-1);
311 }
312
313 switch (state) {
314 case 0:
315 state = 1;
316 break;
317 case 1:
318 tarindex++;
319 state = 2;
320 break;
321 case 2:
322 tarindex++;
323 state = 3;
324 break;
325 case 3:
326 tarindex++;
327 state = 0;
328 break;
329 default:
330 abort();
331 }
332 }
333
334 /*
335 * We are done decoding Base-64 chars. Let's see if we ended
336 * on a byte boundary, and/or with erroneous trailing characters.
337 */
338
339 if (ch == Pad64) { /* We got a pad char. */
340 ch = *src++; /* Skip it, get next. */
341 switch (state) {
342 case 0: /* Invalid = in first position */
343 case 1: /* Invalid = in second position */
344 return (-1);
345
346 case 2: /* Valid, means one byte of info */
347 /* Skip any number of spaces. */
348 for ((void)NULL; ch != '\0'; ch = *src++)
349 if (b64rmap[ch] != b64rmap_space)
350 break;
351 /* Make sure there is another trailing = sign. */
352 if (ch != Pad64)
353 return (-1);
354 ch = *src++; /* Skip the = */
355 /* Fall through to "single trailing =" case. */
356 /* FALLTHROUGH */
357
358 case 3: /* Valid, means two bytes of info */
359 /*
360 * We know this char is an =. Is there anything but
361 * whitespace after it?
362 */
363 for ((void)NULL; ch != '\0'; ch = *src++)
364 if (b64rmap[ch] != b64rmap_space)
365 return (-1);
366
367 }
368 } else {
369 /*
370 * We ended by seeing the end of the string. Make sure we
371 * have no partial bytes lying around.
372 */
373 if (state != 0)
374 return (-1);
375 }
376
377 return (tarindex);
378 }
379
380
381 int
b64_pton(char const * src,uint8_t * target,size_t targsize)382 b64_pton(char const *src, uint8_t *target, size_t targsize)
383 {
384 if (!b64rmap_initialized)
385 b64_initialize_rmap ();
386
387 if (target)
388 return b64_pton_do (src, target, targsize);
389 else
390 return b64_pton_len (src);
391 }
392