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| 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 | +} |
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