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 #include <config.h>
43
44 #include <sys/types.h>
45 #include <sys/param.h>
46 #include <sys/socket.h>
47
48 #include <netinet/in.h>
49 #include <arpa/inet.h>
50
51 #include <ctype.h>
52 #include <stdio.h>
53 #include <stdlib.h>
54 #include <string.h>
55
56 #define Assert(Cond) if (!(Cond)) abort()
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
b64_ntop(uint8_t const * src,size_t srclength,char * target,size_t targsize)126 b64_ntop(uint8_t const *src, size_t srclength, char *target, size_t targsize) {
127 size_t datalength = 0;
128 uint8_t input[3];
129 uint8_t output[4];
130 size_t i;
131
132 while (2 < srclength) {
133 input[0] = *src++;
134 input[1] = *src++;
135 input[2] = *src++;
136 srclength -= 3;
137
138 output[0] = input[0] >> 2;
139 output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4);
140 output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6);
141 output[3] = input[2] & 0x3f;
142 Assert(output[0] < 64);
143 Assert(output[1] < 64);
144 Assert(output[2] < 64);
145 Assert(output[3] < 64);
146
147 if (datalength + 4 > targsize)
148 return (-1);
149 target[datalength++] = Base64[output[0]];
150 target[datalength++] = Base64[output[1]];
151 target[datalength++] = Base64[output[2]];
152 target[datalength++] = Base64[output[3]];
153 }
154
155 /* Now we worry about padding. */
156 if (0 != srclength) {
157 /* Get what's left. */
158 input[0] = input[1] = input[2] = '\0';
159 for (i = 0; i < srclength; i++)
160 input[i] = *src++;
161
162 output[0] = input[0] >> 2;
163 output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4);
164 output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6);
165 Assert(output[0] < 64);
166 Assert(output[1] < 64);
167 Assert(output[2] < 64);
168
169 if (datalength + 4 > targsize)
170 return (-1);
171 target[datalength++] = Base64[output[0]];
172 target[datalength++] = Base64[output[1]];
173 if (srclength == 1)
174 target[datalength++] = Pad64;
175 else
176 target[datalength++] = Base64[output[2]];
177 target[datalength++] = Pad64;
178 }
179 if (datalength >= targsize)
180 return (-1);
181 target[datalength] = '\0'; /* Returned value doesn't count \0. */
182 return (datalength);
183 }
184