1/* 2 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC") 3 * Copyright (c) 1996-1999 by Internet Software Consortium. 4 * 5 * Permission to use, copy, modify, and distribute this software for any 6 * purpose with or without fee is hereby granted, provided that the above 7 * copyright notice and this permission notice appear in all copies. 8 * 9 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES 10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR 12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT 15 * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS 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 43#if !defined(LINT) && !defined(CODECENTER) 44static const char rcsid[] = "$Id: base64.c,v 1.4 2005/04/27 04:56:34 sra Exp $"; 45#endif /* not lint */ 46 47#include "port_before.h" 48 49#include <sys/types.h> 50#include <sys/param.h> 51#include <sys/socket.h> 52 53#include <netinet/in.h> 54#include <arpa/inet.h> 55#include <arpa/nameser.h> 56 57#include <ctype.h> 58#include <resolv.h> 59#include <stdio.h> 60#include <stdlib.h> 61#include <string.h> 62 63#include "port_after.h" 64 65#define Assert(Cond) if (!(Cond)) abort() 66 67static const char Base64[] = 68 "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; 69static const char Pad64 = '='; 70 71/* (From RFC1521 and draft-ietf-dnssec-secext-03.txt) 72 The following encoding technique is taken from RFC1521 by Borenstein 73 and Freed. It is reproduced here in a slightly edited form for 74 convenience. 75 76 A 65-character subset of US-ASCII is used, enabling 6 bits to be 77 represented per printable character. (The extra 65th character, "=", 78 is used to signify a special processing function.) 79 80 The encoding process represents 24-bit groups of input bits as output 81 strings of 4 encoded characters. Proceeding from left to right, a 82 24-bit input group is formed by concatenating 3 8-bit input groups. 83 These 24 bits are then treated as 4 concatenated 6-bit groups, each 84 of which is translated into a single digit in the base64 alphabet. 85 86 Each 6-bit group is used as an index into an array of 64 printable 87 characters. The character referenced by the index is placed in the 88 output string. 89 90 Table 1: The Base64 Alphabet 91 92 Value Encoding Value Encoding Value Encoding Value Encoding 93 0 A 17 R 34 i 51 z 94 1 B 18 S 35 j 52 0 95 2 C 19 T 36 k 53 1 96 3 D 20 U 37 l 54 2 97 4 E 21 V 38 m 55 3 98 5 F 22 W 39 n 56 4 99 6 G 23 X 40 o 57 5 100 7 H 24 Y 41 p 58 6 101 8 I 25 Z 42 q 59 7 102 9 J 26 a 43 r 60 8 103 10 K 27 b 44 s 61 9 104 11 L 28 c 45 t 62 + 105 12 M 29 d 46 u 63 / 106 13 N 30 e 47 v 107 14 O 31 f 48 w (pad) = 108 15 P 32 g 49 x 109 16 Q 33 h 50 y 110 111 Special processing is performed if fewer than 24 bits are available 112 at the end of the data being encoded. A full encoding quantum is 113 always completed at the end of a quantity. When fewer than 24 input 114 bits are available in an input group, zero bits are added (on the 115 right) to form an integral number of 6-bit groups. Padding at the 116 end of the data is performed using the '=' character. 117 118 Since all base64 input is an integral number of octets, only the 119 ------------------------------------------------- 120 following cases can arise: 121 122 (1) the final quantum of encoding input is an integral 123 multiple of 24 bits; here, the final unit of encoded 124 output will be an integral multiple of 4 characters 125 with no "=" padding, 126 (2) the final quantum of encoding input is exactly 8 bits; 127 here, the final unit of encoded output will be two 128 characters followed by two "=" padding characters, or 129 (3) the final quantum of encoding input is exactly 16 bits; 130 here, the final unit of encoded output will be three 131 characters followed by one "=" padding character. 132 */ 133 134int 135b64_ntop(u_char const *src, size_t srclength, char *target, size_t targsize) { 136 size_t datalength = 0; 137 u_char input[3]; 138 u_char output[4]; 139 size_t i; 140 141 while (2U < srclength) { 142 input[0] = *src++; 143 input[1] = *src++; 144 input[2] = *src++; 145 srclength -= 3; 146 147 output[0] = input[0] >> 2; 148 output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4); 149 output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6); 150 output[3] = input[2] & 0x3f; 151 Assert(output[0] < 64); 152 Assert(output[1] < 64); 153 Assert(output[2] < 64); 154 Assert(output[3] < 64); 155 156 if (datalength + 4 > targsize) 157 return (-1); 158 target[datalength++] = Base64[output[0]]; 159 target[datalength++] = Base64[output[1]]; 160 target[datalength++] = Base64[output[2]]; 161 target[datalength++] = Base64[output[3]]; 162 } 163 164 /* Now we worry about padding. */ 165 if (0U != srclength) { 166 /* Get what's left. */ 167 input[0] = input[1] = input[2] = '\0'; 168 for (i = 0; i < srclength; i++) 169 input[i] = *src++; 170 171 output[0] = input[0] >> 2; 172 output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4); 173 output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6); 174 Assert(output[0] < 64); 175 Assert(output[1] < 64); 176 Assert(output[2] < 64); 177 178 if (datalength + 4 > targsize) 179 return (-1); 180 target[datalength++] = Base64[output[0]]; 181 target[datalength++] = Base64[output[1]]; 182 if (srclength == 1U) 183 target[datalength++] = Pad64; 184 else 185 target[datalength++] = Base64[output[2]]; 186 target[datalength++] = Pad64; 187 } 188 if (datalength >= targsize) 189 return (-1); 190 target[datalength] = '\0'; /*%< Returned value doesn't count \\0. */ 191 return (datalength); 192} 193 194/* skips all whitespace anywhere. 195 converts characters, four at a time, starting at (or after) 196 src from base - 64 numbers into three 8 bit bytes in the target area. 197 it returns the number of data bytes stored at the target, or -1 on error. 198 */ 199 200int 201b64_pton(src, target, targsize) 202 char const *src; 203 u_char *target; 204 size_t targsize; 205{ 206 int tarindex, state, ch; 207 char *pos; 208 209 state = 0; 210 tarindex = 0; 211 212 while ((ch = *src++) != '\0') { 213 if (isspace(ch)) /*%< Skip whitespace anywhere. */ 214 continue; 215 216 if (ch == Pad64) 217 break; 218 219 pos = strchr(Base64, ch); 220 if (pos == 0) /*%< A non-base64 character. */ 221 return (-1); 222 223 switch (state) { 224 case 0: 225 if (target) { 226 if ((size_t)tarindex >= targsize) 227 return (-1); 228 target[tarindex] = (pos - Base64) << 2; 229 } 230 state = 1; 231 break; 232 case 1: 233 if (target) { 234 if ((size_t)tarindex + 1 >= targsize) 235 return (-1); 236 target[tarindex] |= (pos - Base64) >> 4; 237 target[tarindex+1] = ((pos - Base64) & 0x0f) 238 << 4 ; 239 } 240 tarindex++; 241 state = 2; 242 break; 243 case 2: 244 if (target) { 245 if ((size_t)tarindex + 1 >= targsize) 246 return (-1); 247 target[tarindex] |= (pos - Base64) >> 2; 248 target[tarindex+1] = ((pos - Base64) & 0x03) 249 << 6; 250 } 251 tarindex++; 252 state = 3; 253 break; 254 case 3: 255 if (target) { 256 if ((size_t)tarindex >= targsize) 257 return (-1); 258 target[tarindex] |= (pos - Base64); 259 } 260 tarindex++; 261 state = 0; 262 break; 263 default: 264 abort(); 265 } 266 } 267 268 /* 269 * We are done decoding Base-64 chars. Let's see if we ended 270 * on a byte boundary, and/or with erroneous trailing characters. 271 */ 272 273 if (ch == Pad64) { /*%< We got a pad char. */ 274 ch = *src++; /*%< Skip it, get next. */ 275 switch (state) { 276 case 0: /*%< Invalid = in first position */ 277 case 1: /*%< Invalid = in second position */ 278 return (-1); 279 280 case 2: /*%< Valid, means one byte of info */ 281 /* Skip any number of spaces. */ 282 for ((void)NULL; ch != '\0'; ch = *src++) 283 if (!isspace(ch)) 284 break; 285 /* Make sure there is another trailing = sign. */ 286 if (ch != Pad64) 287 return (-1); 288 ch = *src++; /*%< Skip the = */ 289 /* Fall through to "single trailing =" case. */ 290 /* FALLTHROUGH */ 291 292 case 3: /*%< Valid, means two bytes of info */ 293 /* 294 * We know this char is an =. Is there anything but 295 * whitespace after it? 296 */ 297 for ((void)NULL; ch != '\0'; ch = *src++) 298 if (!isspace(ch)) 299 return (-1); 300 301 /* 302 * Now make sure for cases 2 and 3 that the "extra" 303 * bits that slopped past the last full byte were 304 * zeros. If we don't check them, they become a 305 * subliminal channel. 306 */ 307 if (target && target[tarindex] != 0) 308 return (-1); 309 } 310 } else { 311 /* 312 * We ended by seeing the end of the string. Make sure we 313 * have no partial bytes lying around. 314 */ 315 if (state != 0) 316 return (-1); 317 } 318 319 return (tarindex); 320} 321 322/*! \file */ 323