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
43 #include <sys/cdefs.h>
44 __FBSDID("$FreeBSD$");
45
46 #include <sys/param.h>
47 #include <sys/socket.h>
48
49 #include <netinet/in.h>
50 #include <arpa/inet.h>
51 #include <arpa/nameser.h>
52
53 #include <ctype.h>
54 #include <resolv.h>
55 #include <stdio.h>
56 #include <stdlib.h>
57 #include <string.h>
58
59 #define Assert(Cond) if (!(Cond)) abort()
60
61 static const char Base64[] =
62 "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
63 static const char Pad64 = '=';
64
65 /* (From RFC1521 and draft-ietf-dnssec-secext-03.txt)
66 The following encoding technique is taken from RFC 1521 by Borenstein
67 and Freed. It is reproduced here in a slightly edited form for
68 convenience.
69
70 A 65-character subset of US-ASCII is used, enabling 6 bits to be
71 represented per printable character. (The extra 65th character, "=",
72 is used to signify a special processing function.)
73
74 The encoding process represents 24-bit groups of input bits as output
75 strings of 4 encoded characters. Proceeding from left to right, a
76 24-bit input group is formed by concatenating 3 8-bit input groups.
77 These 24 bits are then treated as 4 concatenated 6-bit groups, each
78 of which is translated into a single digit in the base64 alphabet.
79
80 Each 6-bit group is used as an index into an array of 64 printable
81 characters. The character referenced by the index is placed in the
82 output string.
83
84 Table 1: The Base64 Alphabet
85
86 Value Encoding Value Encoding Value Encoding Value Encoding
87 0 A 17 R 34 i 51 z
88 1 B 18 S 35 j 52 0
89 2 C 19 T 36 k 53 1
90 3 D 20 U 37 l 54 2
91 4 E 21 V 38 m 55 3
92 5 F 22 W 39 n 56 4
93 6 G 23 X 40 o 57 5
94 7 H 24 Y 41 p 58 6
95 8 I 25 Z 42 q 59 7
96 9 J 26 a 43 r 60 8
97 10 K 27 b 44 s 61 9
98 11 L 28 c 45 t 62 +
99 12 M 29 d 46 u 63 /
100 13 N 30 e 47 v
101 14 O 31 f 48 w (pad) =
102 15 P 32 g 49 x
103 16 Q 33 h 50 y
104
105 Special processing is performed if fewer than 24 bits are available
106 at the end of the data being encoded. A full encoding quantum is
107 always completed at the end of a quantity. When fewer than 24 input
108 bits are available in an input group, zero bits are added (on the
109 right) to form an integral number of 6-bit groups. Padding at the
110 end of the data is performed using the '=' character.
111
112 Since all base64 input is an integral number of octets, only the
113 -------------------------------------------------
114 following cases can arise:
115
116 (1) the final quantum of encoding input is an integral
117 multiple of 24 bits; here, the final unit of encoded
118 output will be an integral multiple of 4 characters
119 with no "=" padding,
120 (2) the final quantum of encoding input is exactly 8 bits;
121 here, the final unit of encoded output will be two
122 characters followed by two "=" padding characters, or
123 (3) the final quantum of encoding input is exactly 16 bits;
124 here, the final unit of encoded output will be three
125 characters followed by one "=" padding character.
126 */
127
128 int
b64_ntop(u_char const * src,size_t srclength,char * target,size_t targsize)129 b64_ntop(u_char const *src, size_t srclength, char *target, size_t targsize) {
130 size_t datalength = 0;
131 u_char input[3];
132 u_char output[4];
133 size_t i;
134
135 while (2 < srclength) {
136 input[0] = *src++;
137 input[1] = *src++;
138 input[2] = *src++;
139 srclength -= 3;
140
141 output[0] = input[0] >> 2;
142 output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4);
143 output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6);
144 output[3] = input[2] & 0x3f;
145 Assert(output[0] < 64);
146 Assert(output[1] < 64);
147 Assert(output[2] < 64);
148 Assert(output[3] < 64);
149
150 if (datalength + 4 > targsize)
151 return (-1);
152 target[datalength++] = Base64[output[0]];
153 target[datalength++] = Base64[output[1]];
154 target[datalength++] = Base64[output[2]];
155 target[datalength++] = Base64[output[3]];
156 }
157
158 /* Now we worry about padding. */
159 if (0 != srclength) {
160 /* Get what's left. */
161 input[0] = input[1] = input[2] = '\0';
162 for (i = 0; i < srclength; i++)
163 input[i] = *src++;
164
165 output[0] = input[0] >> 2;
166 output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4);
167 output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6);
168 Assert(output[0] < 64);
169 Assert(output[1] < 64);
170 Assert(output[2] < 64);
171
172 if (datalength + 4 > targsize)
173 return (-1);
174 target[datalength++] = Base64[output[0]];
175 target[datalength++] = Base64[output[1]];
176 if (srclength == 1)
177 target[datalength++] = Pad64;
178 else
179 target[datalength++] = Base64[output[2]];
180 target[datalength++] = Pad64;
181 }
182 if (datalength >= targsize)
183 return (-1);
184 target[datalength] = '\0'; /* Returned value doesn't count \0. */
185 return (datalength);
186 }
187
188 /* skips all whitespace anywhere.
189 converts characters, four at a time, starting at (or after)
190 src from base - 64 numbers into three 8 bit bytes in the target area.
191 it returns the number of data bytes stored at the target, or -1 on error.
192 */
193
194 int
b64_pton(const char * src,u_char * target,size_t targsize)195 b64_pton(const char *src, u_char *target, size_t targsize)
196 {
197 int tarindex, state, ch;
198 u_char nextbyte;
199 char *pos;
200
201 state = 0;
202 tarindex = 0;
203
204 while ((ch = *src++) != '\0') {
205 if (isspace((unsigned char)ch)) /* Skip whitespace anywhere. */
206 continue;
207
208 if (ch == Pad64)
209 break;
210
211 pos = strchr(Base64, ch);
212 if (pos == NULL) /* A non-base64 character. */
213 return (-1);
214
215 switch (state) {
216 case 0:
217 if (target) {
218 if ((size_t)tarindex >= targsize)
219 return (-1);
220 target[tarindex] = (pos - Base64) << 2;
221 }
222 state = 1;
223 break;
224 case 1:
225 if (target) {
226 if ((size_t)tarindex >= targsize)
227 return (-1);
228 target[tarindex] |= (pos - Base64) >> 4;
229 nextbyte = ((pos - Base64) & 0x0f) << 4;
230 if ((size_t)tarindex + 1 < targsize)
231 target[tarindex + 1] = nextbyte;
232 else if (nextbyte)
233 return (-1);
234 }
235 tarindex++;
236 state = 2;
237 break;
238 case 2:
239 if (target) {
240 if ((size_t)tarindex >= targsize)
241 return (-1);
242 target[tarindex] |= (pos - Base64) >> 2;
243 nextbyte = ((pos - Base64) & 0x03) << 6;
244 if ((size_t)tarindex + 1 < targsize)
245 target[tarindex + 1] = nextbyte;
246 else if (nextbyte)
247 return (-1);
248 }
249 tarindex++;
250 state = 3;
251 break;
252 case 3:
253 if (target) {
254 if ((size_t)tarindex >= targsize)
255 return (-1);
256 target[tarindex] |= (pos - Base64);
257 }
258 tarindex++;
259 state = 0;
260 break;
261 default:
262 abort();
263 }
264 }
265
266 /*
267 * We are done decoding Base-64 chars. Let's see if we ended
268 * on a byte boundary, and/or with erroneous trailing characters.
269 */
270
271 if (ch == Pad64) { /* We got a pad char. */
272 ch = *src++; /* Skip it, get next. */
273 switch (state) {
274 case 0: /* Invalid = in first position */
275 case 1: /* Invalid = in second position */
276 return (-1);
277
278 case 2: /* Valid, means one byte of info */
279 /* Skip any number of spaces. */
280 for ((void)NULL; ch != '\0'; ch = *src++)
281 if (!isspace((unsigned char)ch))
282 break;
283 /* Make sure there is another trailing = sign. */
284 if (ch != Pad64)
285 return (-1);
286 ch = *src++; /* Skip the = */
287 /* Fall through to "single trailing =" case. */
288 /* FALLTHROUGH */
289
290 case 3: /* Valid, means two bytes of info */
291 /*
292 * We know this char is an =. Is there anything but
293 * whitespace after it?
294 */
295 for ((void)NULL; ch != '\0'; ch = *src++)
296 if (!isspace((unsigned char)ch))
297 return (-1);
298
299 /*
300 * Now make sure for cases 2 and 3 that the "extra"
301 * bits that slopped past the last full byte were
302 * zeros. If we don't check them, they become a
303 * subliminal channel.
304 */
305 if (target && (size_t)tarindex < targsize &&
306 target[tarindex] != 0)
307 return (-1);
308 }
309 } else {
310 /*
311 * We ended by seeing the end of the string. Make sure we
312 * have no partial bytes lying around.
313 */
314 if (state != 0)
315 return (-1);
316 }
317
318 return (tarindex);
319 }
320