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