1 /*
2 * Copyright (c) 1996-1999 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/types.h>
44 #include <sys/param.h>
45 #include <sys/socket.h>
46
47 #include <netinet/in.h>
48 #include <arpa/inet.h>
49 #include <arpa/nameser.h>
50
51 #include <ctype.h>
52 #include <resolv.h>
53 #include <stdio.h>
54 #include <stdlib.h>
55 #include <string.h>
56
57 #define Assert(Cond) if (!(Cond)) abort()
58
59 static const char Base64[] =
60 "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
61 static const char Pad64 = '=';
62
63 /* (From RFC1521 and draft-ietf-dnssec-secext-03.txt)
64 The following encoding technique is taken from RFC 1521 by Borenstein
65 and Freed. It is reproduced here in a slightly edited form for
66 convenience.
67
68 A 65-character subset of US-ASCII is used, enabling 6 bits to be
69 represented per printable character. (The extra 65th character, "=",
70 is used to signify a special processing function.)
71
72 The encoding process represents 24-bit groups of input bits as output
73 strings of 4 encoded characters. Proceeding from left to right, a
74 24-bit input group is formed by concatenating 3 8-bit input groups.
75 These 24 bits are then treated as 4 concatenated 6-bit groups, each
76 of which is translated into a single digit in the base64 alphabet.
77
78 Each 6-bit group is used as an index into an array of 64 printable
79 characters. The character referenced by the index is placed in the
80 output string.
81
82 Table 1: The Base64 Alphabet
83
84 Value Encoding Value Encoding Value Encoding Value Encoding
85 0 A 17 R 34 i 51 z
86 1 B 18 S 35 j 52 0
87 2 C 19 T 36 k 53 1
88 3 D 20 U 37 l 54 2
89 4 E 21 V 38 m 55 3
90 5 F 22 W 39 n 56 4
91 6 G 23 X 40 o 57 5
92 7 H 24 Y 41 p 58 6
93 8 I 25 Z 42 q 59 7
94 9 J 26 a 43 r 60 8
95 10 K 27 b 44 s 61 9
96 11 L 28 c 45 t 62 +
97 12 M 29 d 46 u 63 /
98 13 N 30 e 47 v
99 14 O 31 f 48 w (pad) =
100 15 P 32 g 49 x
101 16 Q 33 h 50 y
102
103 Special processing is performed if fewer than 24 bits are available
104 at the end of the data being encoded. A full encoding quantum is
105 always completed at the end of a quantity. When fewer than 24 input
106 bits are available in an input group, zero bits are added (on the
107 right) to form an integral number of 6-bit groups. Padding at the
108 end of the data is performed using the '=' character.
109
110 Since all base64 input is an integral number of octets, only the
111 -------------------------------------------------
112 following cases can arise:
113
114 (1) the final quantum of encoding input is an integral
115 multiple of 24 bits; here, the final unit of encoded
116 output will be an integral multiple of 4 characters
117 with no "=" padding,
118 (2) the final quantum of encoding input is exactly 8 bits;
119 here, the final unit of encoded output will be two
120 characters followed by two "=" padding characters, or
121 (3) the final quantum of encoding input is exactly 16 bits;
122 here, the final unit of encoded output will be three
123 characters followed by one "=" padding character.
124 */
125
126 int
127 b64_ntop(u_char const *src, size_t srclength, char *target, size_t targsize) {
128 size_t datalength = 0;
129 u_char input[3];
130 u_char output[4];
131 size_t i;
132
133 while (2 < srclength) {
134 input[0] = *src++;
135 input[1] = *src++;
136 input[2] = *src++;
137 srclength -= 3;
138
139 output[0] = input[0] >> 2;
140 output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4);
141 output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6);
142 output[3] = input[2] & 0x3f;
143 Assert(output[0] < 64);
144 Assert(output[1] < 64);
145 Assert(output[2] < 64);
146 Assert(output[3] < 64);
147
148 if (datalength + 4 > targsize)
149 return (-1);
150 target[datalength++] = Base64[output[0]];
151 target[datalength++] = Base64[output[1]];
152 target[datalength++] = Base64[output[2]];
153 target[datalength++] = Base64[output[3]];
154 }
155
156 /* Now we worry about padding. */
157 if (0 != srclength) {
158 /* Get what's left. */
159 input[0] = input[1] = input[2] = '\0';
160 for (i = 0; i < srclength; i++)
161 input[i] = *src++;
162
163 output[0] = input[0] >> 2;
164 output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4);
165 output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6);
166 Assert(output[0] < 64);
167 Assert(output[1] < 64);
168 Assert(output[2] < 64);
169
170 if (datalength + 4 > targsize)
171 return (-1);
172 target[datalength++] = Base64[output[0]];
173 target[datalength++] = Base64[output[1]];
174 if (srclength == 1)
175 target[datalength++] = Pad64;
176 else
177 target[datalength++] = Base64[output[2]];
178 target[datalength++] = Pad64;
179 }
180 if (datalength >= targsize)
181 return (-1);
182 target[datalength] = '\0'; /* Returned value doesn't count \0. */
183 return (datalength);
184 }
185 libresolv_hidden_def (b64_ntop)
186
187 /* skips all whitespace anywhere.
188 converts characters, four at a time, starting at (or after)
189 src from base - 64 numbers into three 8 bit bytes in the target area.
190 it returns the number of data bytes stored at the target, or -1 on error.
191 */
192
193 int
194 b64_pton (char const *src, u_char *target, size_t targsize)
195 {
196 int tarindex, state, ch;
197 char *pos;
198
199 state = 0;
200 tarindex = 0;
201
202 while ((ch = *src++) != '\0') {
203 if (isspace(ch)) /* Skip whitespace anywhere. */
204 continue;
205
206 if (ch == Pad64)
207 break;
208
209 pos = strchr(Base64, ch);
210 if (pos == 0) /* A non-base64 character. */
211 return (-1);
212
213 switch (state) {
214 case 0:
215 if (target) {
216 if ((size_t)tarindex >= targsize)
217 return (-1);
218 target[tarindex] = (pos - Base64) << 2;
219 }
220 state = 1;
221 break;
222 case 1:
223 if (target) {
224 if ((size_t)tarindex + 1 >= targsize)
225 return (-1);
226 target[tarindex] |= (pos - Base64) >> 4;
227 target[tarindex+1] = ((pos - Base64) & 0x0f)
228 << 4 ;
229 }
230 tarindex++;
231 state = 2;
232 break;
233 case 2:
234 if (target) {
235 if ((size_t)tarindex + 1 >= targsize)
236 return (-1);
237 target[tarindex] |= (pos - Base64) >> 2;
238 target[tarindex+1] = ((pos - Base64) & 0x03)
239 << 6;
240 }
241 tarindex++;
242 state = 3;
243 break;
244 case 3:
245 if (target) {
246 if ((size_t)tarindex >= targsize)
247 return (-1);
248 target[tarindex] |= (pos - Base64);
249 }
250 tarindex++;
251 state = 0;
252 break;
253 default:
254 abort();
255 }
256 }
257
258 /*
259 * We are done decoding Base-64 chars. Let's see if we ended
260 * on a byte boundary, and/or with erroneous trailing characters.
261 */
262
263 if (ch == Pad64) { /* We got a pad char. */
264 ch = *src++; /* Skip it, get next. */
265 switch (state) {
266 case 0: /* Invalid = in first position */
267 case 1: /* Invalid = in second position */
268 return (-1);
269
270 case 2: /* Valid, means one byte of info */
271 /* Skip any number of spaces. */
272 for ((void)NULL; ch != '\0'; ch = *src++)
273 if (!isspace(ch))
274 break;
275 /* Make sure there is another trailing = sign. */
276 if (ch != Pad64)
277 return (-1);
278 ch = *src++; /* Skip the = */
279 /* Fall through to "single trailing =" case. */
280 /* FALLTHROUGH */
281
282 case 3: /* Valid, means two bytes of info */
283 /*
284 * We know this char is an =. Is there anything but
285 * whitespace after it?
286 */
287 for ((void)NULL; ch != '\0'; ch = *src++)
288 if (!isspace(ch))
289 return (-1);
290
291 /*
292 * Now make sure for cases 2 and 3 that the "extra"
293 * bits that slopped past the last full byte were
294 * zeros. If we don't check them, they become a
295 * subliminal channel.
296 */
297 if (target && target[tarindex] != 0)
298 return (-1);
299 }
300 } else {
301 /*
302 * We ended by seeing the end of the string. Make sure we
303 * have no partial bytes lying around.
304 */
305 if (state != 0)
306 return (-1);
307 }
308
309 return (tarindex);
310 }