1 /* $OpenBSD: base64.c,v 1.5 2006/10/21 09:55:03 otto 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 /* OPENBSD ORIGINAL: lib/libc/net/base64.c */
46
47 #include "includes.h"
48
49 #if (!defined(HAVE_B64_NTOP) && !defined(HAVE___B64_NTOP)) || (!defined(HAVE_B64_PTON) && !defined(HAVE___B64_PTON))
50
51 #include <sys/types.h>
52 #include <sys/param.h>
53 #include <sys/socket.h>
54 #include <netinet/in.h>
55 #include <arpa/inet.h>
56
57 #include <ctype.h>
58 #include <stdio.h>
59
60 #include <stdlib.h>
61 #include <string.h>
62
63 #include "base64.h"
64
65 static const char Base64[] =
66 "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
67 static const char Pad64 = '=';
68
69 /* (From RFC1521 and draft-ietf-dnssec-secext-03.txt)
70 The following encoding technique is taken from RFC 1521 by Borenstein
71 and Freed. It is reproduced here in a slightly edited form for
72 convenience.
73
74 A 65-character subset of US-ASCII is used, enabling 6 bits to be
75 represented per printable character. (The extra 65th character, "=",
76 is used to signify a special processing function.)
77
78 The encoding process represents 24-bit groups of input bits as output
79 strings of 4 encoded characters. Proceeding from left to right, a
80 24-bit input group is formed by concatenating 3 8-bit input groups.
81 These 24 bits are then treated as 4 concatenated 6-bit groups, each
82 of which is translated into a single digit in the base64 alphabet.
83
84 Each 6-bit group is used as an index into an array of 64 printable
85 characters. The character referenced by the index is placed in the
86 output string.
87
88 Table 1: The Base64 Alphabet
89
90 Value Encoding Value Encoding Value Encoding Value Encoding
91 0 A 17 R 34 i 51 z
92 1 B 18 S 35 j 52 0
93 2 C 19 T 36 k 53 1
94 3 D 20 U 37 l 54 2
95 4 E 21 V 38 m 55 3
96 5 F 22 W 39 n 56 4
97 6 G 23 X 40 o 57 5
98 7 H 24 Y 41 p 58 6
99 8 I 25 Z 42 q 59 7
100 9 J 26 a 43 r 60 8
101 10 K 27 b 44 s 61 9
102 11 L 28 c 45 t 62 +
103 12 M 29 d 46 u 63 /
104 13 N 30 e 47 v
105 14 O 31 f 48 w (pad) =
106 15 P 32 g 49 x
107 16 Q 33 h 50 y
108
109 Special processing is performed if fewer than 24 bits are available
110 at the end of the data being encoded. A full encoding quantum is
111 always completed at the end of a quantity. When fewer than 24 input
112 bits are available in an input group, zero bits are added (on the
113 right) to form an integral number of 6-bit groups. Padding at the
114 end of the data is performed using the '=' character.
115
116 Since all base64 input is an integral number of octets, only the
117 -------------------------------------------------
118 following cases can arise:
119
120 (1) the final quantum of encoding input is an integral
121 multiple of 24 bits; here, the final unit of encoded
122 output will be an integral multiple of 4 characters
123 with no "=" padding,
124 (2) the final quantum of encoding input is exactly 8 bits;
125 here, the final unit of encoded output will be two
126 characters followed by two "=" padding characters, or
127 (3) the final quantum of encoding input is exactly 16 bits;
128 here, the final unit of encoded output will be three
129 characters followed by one "=" padding character.
130 */
131
132 #if !defined(HAVE_B64_NTOP) && !defined(HAVE___B64_NTOP)
133 int
b64_ntop(u_char const * src,size_t srclength,char * target,size_t targsize)134 b64_ntop(u_char const *src, size_t srclength, char *target, size_t targsize)
135 {
136 size_t datalength = 0;
137 u_char input[3];
138 u_char output[4];
139 u_int i;
140
141 while (2 < srclength) {
142 input[0] = *src++;
143 input[1] = *src++;
144 input[2] = *src++;
145 srclength -= 3;
146
147 output[0] = input[0] >> 2;
148 output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4);
149 output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6);
150 output[3] = input[2] & 0x3f;
151
152 if (datalength + 4 > targsize)
153 return (-1);
154 target[datalength++] = Base64[output[0]];
155 target[datalength++] = Base64[output[1]];
156 target[datalength++] = Base64[output[2]];
157 target[datalength++] = Base64[output[3]];
158 }
159
160 /* Now we worry about padding. */
161 if (0 != srclength) {
162 /* Get what's left. */
163 input[0] = input[1] = input[2] = '\0';
164 for (i = 0; i < srclength; i++)
165 input[i] = *src++;
166
167 output[0] = input[0] >> 2;
168 output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4);
169 output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6);
170
171 if (datalength + 4 > targsize)
172 return (-1);
173 target[datalength++] = Base64[output[0]];
174 target[datalength++] = Base64[output[1]];
175 if (srclength == 1)
176 target[datalength++] = Pad64;
177 else
178 target[datalength++] = Base64[output[2]];
179 target[datalength++] = Pad64;
180 }
181 if (datalength >= targsize)
182 return (-1);
183 target[datalength] = '\0'; /* Returned value doesn't count \0. */
184 return (datalength);
185 }
186 #endif /* !defined(HAVE_B64_NTOP) && !defined(HAVE___B64_NTOP) */
187
188 #if !defined(HAVE_B64_PTON) && !defined(HAVE___B64_PTON)
189
190 /* skips all whitespace anywhere.
191 converts characters, four at a time, starting at (or after)
192 src from base - 64 numbers into three 8 bit bytes in the target area.
193 it returns the number of data bytes stored at the target, or -1 on error.
194 */
195
196 int
b64_pton(char const * src,u_char * target,size_t targsize)197 b64_pton(char const *src, u_char *target, size_t targsize)
198 {
199 u_int tarindex, state;
200 int ch;
201 char *pos;
202
203 state = 0;
204 tarindex = 0;
205
206 while ((ch = *src++) != '\0') {
207 if (isspace(ch)) /* Skip whitespace anywhere. */
208 continue;
209
210 if (ch == Pad64)
211 break;
212
213 pos = strchr(Base64, ch);
214 if (pos == 0) /* A non-base64 character. */
215 return (-1);
216
217 switch (state) {
218 case 0:
219 if (target) {
220 if (tarindex >= targsize)
221 return (-1);
222 target[tarindex] = (pos - Base64) << 2;
223 }
224 state = 1;
225 break;
226 case 1:
227 if (target) {
228 if (tarindex + 1 >= targsize)
229 return (-1);
230 target[tarindex] |= (pos - Base64) >> 4;
231 target[tarindex+1] = ((pos - Base64) & 0x0f)
232 << 4 ;
233 }
234 tarindex++;
235 state = 2;
236 break;
237 case 2:
238 if (target) {
239 if (tarindex + 1 >= targsize)
240 return (-1);
241 target[tarindex] |= (pos - Base64) >> 2;
242 target[tarindex+1] = ((pos - Base64) & 0x03)
243 << 6;
244 }
245 tarindex++;
246 state = 3;
247 break;
248 case 3:
249 if (target) {
250 if (tarindex >= targsize)
251 return (-1);
252 target[tarindex] |= (pos - Base64);
253 }
254 tarindex++;
255 state = 0;
256 break;
257 }
258 }
259
260 /*
261 * We are done decoding Base-64 chars. Let's see if we ended
262 * on a byte boundary, and/or with erroneous trailing characters.
263 */
264
265 if (ch == Pad64) { /* We got a pad char. */
266 ch = *src++; /* Skip it, get next. */
267 switch (state) {
268 case 0: /* Invalid = in first position */
269 case 1: /* Invalid = in second position */
270 return (-1);
271
272 case 2: /* Valid, means one byte of info */
273 /* Skip any number of spaces. */
274 for (; ch != '\0'; ch = *src++)
275 if (!isspace(ch))
276 break;
277 /* Make sure there is another trailing = sign. */
278 if (ch != Pad64)
279 return (-1);
280 ch = *src++; /* Skip the = */
281 /* Fall through to "single trailing =" case. */
282 /* FALLTHROUGH */
283
284 case 3: /* Valid, means two bytes of info */
285 /*
286 * We know this char is an =. Is there anything but
287 * whitespace after it?
288 */
289 for (; ch != '\0'; ch = *src++)
290 if (!isspace(ch))
291 return (-1);
292
293 /*
294 * Now make sure for cases 2 and 3 that the "extra"
295 * bits that slopped past the last full byte were
296 * zeros. If we don't check them, they become a
297 * subliminal channel.
298 */
299 if (target && target[tarindex] != 0)
300 return (-1);
301 }
302 } else {
303 /*
304 * We ended by seeing the end of the string. Make sure we
305 * have no partial bytes lying around.
306 */
307 if (state != 0)
308 return (-1);
309 }
310
311 return (tarindex);
312 }
313
314 #endif /* !defined(HAVE_B64_PTON) && !defined(HAVE___B64_PTON) */
315 #endif
316