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1.1 misho 1: /* $OpenBSD: base64.c,v 1.8 2015/01/16 16:48:51 deraadt 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: #include <sys/types.h>
46: #include <sys/socket.h>
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:
55: #include <stdlib.h>
56: #include <string.h>
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: -------------------------------------------------
111: following cases can arise:
112:
113: (1) the final quantum of encoding input is an integral
114: multiple of 24 bits; here, the final unit of encoded
115: output will be an integral multiple of 4 characters
116: with no "=" padding,
117: (2) the final quantum of encoding input is exactly 8 bits;
118: here, the final unit of encoded output will be two
119: characters followed by two "=" padding characters, or
120: (3) the final quantum of encoding input is exactly 16 bits;
121: here, the final unit of encoded output will be three
122: characters followed by one "=" padding character.
123: */
124:
125: int
126: b64_ntop(src, srclength, target, targsize)
127: u_char const *src;
128: size_t srclength;
129: char *target;
130: size_t targsize;
131: {
132: size_t datalength = 0;
133: u_char input[3];
134: u_char output[4];
135: int i;
136:
137: while (2 < srclength) {
138: input[0] = *src++;
139: input[1] = *src++;
140: input[2] = *src++;
141: srclength -= 3;
142:
143: output[0] = input[0] >> 2;
144: output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4);
145: output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6);
146: output[3] = input[2] & 0x3f;
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:
167: if (datalength + 4 > targsize)
168: return (-1);
169: target[datalength++] = Base64[output[0]];
170: target[datalength++] = Base64[output[1]];
171: if (srclength == 1)
172: target[datalength++] = Pad64;
173: else
174: target[datalength++] = Base64[output[2]];
175: target[datalength++] = Pad64;
176: }
177: if (datalength >= targsize)
178: return (-1);
179: target[datalength] = '\0'; /* Returned value doesn't count \0. */
180: return (datalength);
181: }
182:
183: /* skips all whitespace anywhere.
184: converts characters, four at a time, starting at (or after)
185: src from base - 64 numbers into three 8 bit bytes in the target area.
186: it returns the number of data bytes stored at the target, or -1 on error.
187: */
188:
189: int
190: b64_pton(src, target, targsize)
191: char const *src;
192: u_char *target;
193: size_t targsize;
194: {
195: int tarindex, state, ch;
196: u_char nextbyte;
197: char *pos;
198:
199: state = 0;
200: tarindex = 0;
201:
202: while ((ch = (unsigned char)*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 (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 (tarindex >= targsize)
225: return (-1);
226: target[tarindex] |= (pos - Base64) >> 4;
227: nextbyte = ((pos - Base64) & 0x0f) << 4;
228: if (tarindex + 1 < targsize)
229: target[tarindex+1] = nextbyte;
230: else if (nextbyte)
231: return (-1);
232: }
233: tarindex++;
234: state = 2;
235: break;
236: case 2:
237: if (target) {
238: if (tarindex >= targsize)
239: return (-1);
240: target[tarindex] |= (pos - Base64) >> 2;
241: nextbyte = ((pos - Base64) & 0x03) << 6;
242: if (tarindex + 1 < targsize)
243: target[tarindex+1] = nextbyte;
244: else if (nextbyte)
245: return (-1);
246: }
247: tarindex++;
248: state = 3;
249: break;
250: case 3:
251: if (target) {
252: if (tarindex >= targsize)
253: return (-1);
254: target[tarindex] |= (pos - Base64);
255: }
256: tarindex++;
257: state = 0;
258: break;
259: }
260: }
261:
262: /*
263: * We are done decoding Base-64 chars. Let's see if we ended
264: * on a byte boundary, and/or with erroneous trailing characters.
265: */
266:
267: if (ch == Pad64) { /* We got a pad char. */
268: ch = (unsigned char)*src++; /* Skip it, get next. */
269: switch (state) {
270: case 0: /* Invalid = in first position */
271: case 1: /* Invalid = in second position */
272: return (-1);
273:
274: case 2: /* Valid, means one byte of info */
275: /* Skip any number of spaces. */
276: for (; ch != '\0'; ch = (unsigned char)*src++)
277: if (!isspace(ch))
278: break;
279: /* Make sure there is another trailing = sign. */
280: if (ch != Pad64)
281: return (-1);
282: ch = (unsigned char)*src++; /* Skip the = */
283: /* Fall through to "single trailing =" case. */
284: /* FALLTHROUGH */
285:
286: case 3: /* Valid, means two bytes of info */
287: /*
288: * We know this char is an =. Is there anything but
289: * whitespace after it?
290: */
291: for (; ch != '\0'; ch = (unsigned char)*src++)
292: if (!isspace(ch))
293: return (-1);
294:
295: /*
296: * Now make sure for cases 2 and 3 that the "extra"
297: * bits that slopped past the last full byte were
298: * zeros. If we don't check them, they become a
299: * subliminal channel.
300: */
301: if (target && tarindex < targsize &&
302: target[tarindex] != 0)
303: return (-1);
304: }
305: } else {
306: /*
307: * We ended by seeing the end of the string. Make sure we
308: * have no partial bytes lying around.
309: */
310: if (state != 0)
311: return (-1);
312: }
313:
314: return (tarindex);
315: }