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 | * Copyright (c) 1995 IBM Corporation |
20 | * |
21 | * Permission is hereby granted, free of charge, to any person obtaining |
22 | * a copy of this software and associated documentation files (the |
23 | * 'Software'), to deal in the Software without restriction, including |
24 | * without limitation the rights to use, copy, modify, merge, publish, |
25 | * distribute, sublicense, and/or sell copies of the Software, and to |
26 | * permit persons to whom the Software is furnished to do so, subject to |
27 | * the following conditions: |
28 | * |
29 | * The above copyright notice and this permission notice shall be |
30 | * included in all copies or substantial portions of the Software. |
31 | * |
32 | * THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, |
33 | * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF |
34 | * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. |
35 | * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY |
36 | * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, |
37 | * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE |
38 | * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. |
39 | */ |
40 | |
41 | #include <sys/types.h> |
42 | #include <sys/param.h> |
43 | #include <sys/socket.h> |
44 | |
45 | #include <netinet/in.h> |
46 | #include <arpa/inet.h> |
47 | #include <arpa/nameser.h> |
48 | |
49 | #include <ctype.h> |
50 | #include <resolv.h> |
51 | #include <stdio.h> |
52 | #include <stdlib.h> |
53 | #include <string.h> |
54 | |
55 | #define Assert(Cond) if (!(Cond)) abort() |
56 | |
57 | static const char Base64[] = |
58 | "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/" ; |
59 | static const char Pad64 = '='; |
60 | |
61 | /* (From RFC1521 and draft-ietf-dnssec-secext-03.txt) |
62 | The following encoding technique is taken from RFC 1521 by Borenstein |
63 | and Freed. It is reproduced here in a slightly edited form for |
64 | convenience. |
65 | |
66 | A 65-character subset of US-ASCII is used, enabling 6 bits to be |
67 | represented per printable character. (The extra 65th character, "=", |
68 | is used to signify a special processing function.) |
69 | |
70 | The encoding process represents 24-bit groups of input bits as output |
71 | strings of 4 encoded characters. Proceeding from left to right, a |
72 | 24-bit input group is formed by concatenating 3 8-bit input groups. |
73 | These 24 bits are then treated as 4 concatenated 6-bit groups, each |
74 | of which is translated into a single digit in the base64 alphabet. |
75 | |
76 | Each 6-bit group is used as an index into an array of 64 printable |
77 | characters. The character referenced by the index is placed in the |
78 | output string. |
79 | |
80 | Table 1: The Base64 Alphabet |
81 | |
82 | Value Encoding Value Encoding Value Encoding Value Encoding |
83 | 0 A 17 R 34 i 51 z |
84 | 1 B 18 S 35 j 52 0 |
85 | 2 C 19 T 36 k 53 1 |
86 | 3 D 20 U 37 l 54 2 |
87 | 4 E 21 V 38 m 55 3 |
88 | 5 F 22 W 39 n 56 4 |
89 | 6 G 23 X 40 o 57 5 |
90 | 7 H 24 Y 41 p 58 6 |
91 | 8 I 25 Z 42 q 59 7 |
92 | 9 J 26 a 43 r 60 8 |
93 | 10 K 27 b 44 s 61 9 |
94 | 11 L 28 c 45 t 62 + |
95 | 12 M 29 d 46 u 63 / |
96 | 13 N 30 e 47 v |
97 | 14 O 31 f 48 w (pad) = |
98 | 15 P 32 g 49 x |
99 | 16 Q 33 h 50 y |
100 | |
101 | Special processing is performed if fewer than 24 bits are available |
102 | at the end of the data being encoded. A full encoding quantum is |
103 | always completed at the end of a quantity. When fewer than 24 input |
104 | bits are available in an input group, zero bits are added (on the |
105 | right) to form an integral number of 6-bit groups. Padding at the |
106 | end of the data is performed using the '=' character. |
107 | |
108 | Since all base64 input is an integral number of octets, only the |
109 | ------------------------------------------------- |
110 | following cases can arise: |
111 | |
112 | (1) the final quantum of encoding input is an integral |
113 | multiple of 24 bits; here, the final unit of encoded |
114 | output will be an integral multiple of 4 characters |
115 | with no "=" padding, |
116 | (2) the final quantum of encoding input is exactly 8 bits; |
117 | here, the final unit of encoded output will be two |
118 | characters followed by two "=" padding characters, or |
119 | (3) the final quantum of encoding input is exactly 16 bits; |
120 | here, the final unit of encoded output will be three |
121 | characters followed by one "=" padding character. |
122 | */ |
123 | |
124 | int |
125 | b64_ntop(u_char const *src, size_t srclength, char *target, size_t targsize) { |
126 | size_t datalength = 0; |
127 | u_char input[3]; |
128 | u_char output[4]; |
129 | size_t i; |
130 | |
131 | while (2 < srclength) { |
132 | input[0] = *src++; |
133 | input[1] = *src++; |
134 | input[2] = *src++; |
135 | srclength -= 3; |
136 | |
137 | output[0] = input[0] >> 2; |
138 | output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4); |
139 | output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6); |
140 | output[3] = input[2] & 0x3f; |
141 | Assert(output[0] < 64); |
142 | Assert(output[1] < 64); |
143 | Assert(output[2] < 64); |
144 | Assert(output[3] < 64); |
145 | |
146 | if (datalength + 4 > targsize) |
147 | return (-1); |
148 | target[datalength++] = Base64[output[0]]; |
149 | target[datalength++] = Base64[output[1]]; |
150 | target[datalength++] = Base64[output[2]]; |
151 | target[datalength++] = Base64[output[3]]; |
152 | } |
153 | |
154 | /* Now we worry about padding. */ |
155 | if (0 != srclength) { |
156 | /* Get what's left. */ |
157 | input[0] = input[1] = input[2] = '\0'; |
158 | for (i = 0; i < srclength; i++) |
159 | input[i] = *src++; |
160 | |
161 | output[0] = input[0] >> 2; |
162 | output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4); |
163 | output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6); |
164 | Assert(output[0] < 64); |
165 | Assert(output[1] < 64); |
166 | Assert(output[2] < 64); |
167 | |
168 | if (datalength + 4 > targsize) |
169 | return (-1); |
170 | target[datalength++] = Base64[output[0]]; |
171 | target[datalength++] = Base64[output[1]]; |
172 | if (srclength == 1) |
173 | target[datalength++] = Pad64; |
174 | else |
175 | target[datalength++] = Base64[output[2]]; |
176 | target[datalength++] = Pad64; |
177 | } |
178 | if (datalength >= targsize) |
179 | return (-1); |
180 | target[datalength] = '\0'; /* Returned value doesn't count \0. */ |
181 | return (datalength); |
182 | } |
183 | libresolv_hidden_def (b64_ntop) |
184 | |
185 | /* skips all whitespace anywhere. |
186 | converts characters, four at a time, starting at (or after) |
187 | src from base - 64 numbers into three 8 bit bytes in the target area. |
188 | it returns the number of data bytes stored at the target, or -1 on error. |
189 | */ |
190 | |
191 | int |
192 | b64_pton (char const *src, u_char *target, size_t targsize) |
193 | { |
194 | int tarindex, state, ch; |
195 | char *pos; |
196 | |
197 | state = 0; |
198 | tarindex = 0; |
199 | |
200 | while ((ch = *src++) != '\0') { |
201 | if (isspace(ch)) /* Skip whitespace anywhere. */ |
202 | continue; |
203 | |
204 | if (ch == Pad64) |
205 | break; |
206 | |
207 | pos = strchr(s: Base64, c: ch); |
208 | if (pos == 0) /* A non-base64 character. */ |
209 | return (-1); |
210 | |
211 | switch (state) { |
212 | case 0: |
213 | if (target) { |
214 | if ((size_t)tarindex >= targsize) |
215 | return (-1); |
216 | target[tarindex] = (pos - Base64) << 2; |
217 | } |
218 | state = 1; |
219 | break; |
220 | case 1: |
221 | if (target) { |
222 | if ((size_t)tarindex + 1 >= targsize) |
223 | return (-1); |
224 | target[tarindex] |= (pos - Base64) >> 4; |
225 | target[tarindex+1] = ((pos - Base64) & 0x0f) |
226 | << 4 ; |
227 | } |
228 | tarindex++; |
229 | state = 2; |
230 | break; |
231 | case 2: |
232 | if (target) { |
233 | if ((size_t)tarindex + 1 >= targsize) |
234 | return (-1); |
235 | target[tarindex] |= (pos - Base64) >> 2; |
236 | target[tarindex+1] = ((pos - Base64) & 0x03) |
237 | << 6; |
238 | } |
239 | tarindex++; |
240 | state = 3; |
241 | break; |
242 | case 3: |
243 | if (target) { |
244 | if ((size_t)tarindex >= targsize) |
245 | return (-1); |
246 | target[tarindex] |= (pos - Base64); |
247 | } |
248 | tarindex++; |
249 | state = 0; |
250 | break; |
251 | default: |
252 | abort(); |
253 | } |
254 | } |
255 | |
256 | /* |
257 | * We are done decoding Base-64 chars. Let's see if we ended |
258 | * on a byte boundary, and/or with erroneous trailing characters. |
259 | */ |
260 | |
261 | if (ch == Pad64) { /* We got a pad char. */ |
262 | ch = *src++; /* Skip it, get next. */ |
263 | switch (state) { |
264 | case 0: /* Invalid = in first position */ |
265 | case 1: /* Invalid = in second position */ |
266 | return (-1); |
267 | |
268 | case 2: /* Valid, means one byte of info */ |
269 | /* Skip any number of spaces. */ |
270 | for ((void)NULL; ch != '\0'; ch = *src++) |
271 | if (!isspace(ch)) |
272 | break; |
273 | /* Make sure there is another trailing = sign. */ |
274 | if (ch != Pad64) |
275 | return (-1); |
276 | ch = *src++; /* Skip the = */ |
277 | /* Fall through to "single trailing =" case. */ |
278 | /* FALLTHROUGH */ |
279 | |
280 | case 3: /* Valid, means two bytes of info */ |
281 | /* |
282 | * We know this char is an =. Is there anything but |
283 | * whitespace after it? |
284 | */ |
285 | for ((void)NULL; ch != '\0'; ch = *src++) |
286 | if (!isspace(ch)) |
287 | return (-1); |
288 | |
289 | /* |
290 | * Now make sure for cases 2 and 3 that the "extra" |
291 | * bits that slopped past the last full byte were |
292 | * zeros. If we don't check them, they become a |
293 | * subliminal channel. |
294 | */ |
295 | if (target && target[tarindex] != 0) |
296 | return (-1); |
297 | } |
298 | } else { |
299 | /* |
300 | * We ended by seeing the end of the string. Make sure we |
301 | * have no partial bytes lying around. |
302 | */ |
303 | if (state != 0) |
304 | return (-1); |
305 | } |
306 | |
307 | return (tarindex); |
308 | } |
309 | |