1/* $OpenBSD: base64.c,v 1.4 2002/01/02 23:00:10 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#pragma ident "%Z%%M% %I% %E% SMI" 46 47#include "includes.h" 48 49#if !defined(HAVE_B64_NTOP) && !defined(HAVE___B64_NTOP) 50 51#include <sys/types.h> 52#include <sys/param.h> 53#include <sys/socket.h> 54#include <netinet/in.h> 55#include <arpa/inet.h> 56 57#include <ctype.h> 58#include <stdio.h> 59 60#include <stdlib.h> 61#include <string.h> 62 63#include "base64.h" 64 65/* XXX abort illegal in library */ 66#define Assert(Cond) if (!(Cond)) abort() 67 68static const char Base64[] = 69 "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; 70static const char Pad64 = '='; 71 72/* (From RFC1521 and draft-ietf-dnssec-secext-03.txt) 73 The following encoding technique is taken from RFC 1521 by Borenstein 74 and Freed. It is reproduced here in a slightly edited form for 75 convenience. 76 77 A 65-character subset of US-ASCII is used, enabling 6 bits to be 78 represented per printable character. (The extra 65th character, "=", 79 is used to signify a special processing function.) 80 81 The encoding process represents 24-bit groups of input bits as output 82 strings of 4 encoded characters. Proceeding from left to right, a 83 24-bit input group is formed by concatenating 3 8-bit input groups. 84 These 24 bits are then treated as 4 concatenated 6-bit groups, each 85 of which is translated into a single digit in the base64 alphabet. 86 87 Each 6-bit group is used as an index into an array of 64 printable 88 characters. The character referenced by the index is placed in the 89 output string. 90 91 Table 1: The Base64 Alphabet 92 93 Value Encoding Value Encoding Value Encoding Value Encoding 94 0 A 17 R 34 i 51 z 95 1 B 18 S 35 j 52 0 96 2 C 19 T 36 k 53 1 97 3 D 20 U 37 l 54 2 98 4 E 21 V 38 m 55 3 99 5 F 22 W 39 n 56 4 100 6 G 23 X 40 o 57 5 101 7 H 24 Y 41 p 58 6 102 8 I 25 Z 42 q 59 7 103 9 J 26 a 43 r 60 8 104 10 K 27 b 44 s 61 9 105 11 L 28 c 45 t 62 + 106 12 M 29 d 46 u 63 / 107 13 N 30 e 47 v 108 14 O 31 f 48 w (pad) = 109 15 P 32 g 49 x 110 16 Q 33 h 50 y 111 112 Special processing is performed if fewer than 24 bits are available 113 at the end of the data being encoded. A full encoding quantum is 114 always completed at the end of a quantity. When fewer than 24 input 115 bits are available in an input group, zero bits are added (on the 116 right) to form an integral number of 6-bit groups. Padding at the 117 end of the data is performed using the '=' character. 118 119 Since all base64 input is an integral number of octets, only the 120 ------------------------------------------------- 121 following cases can arise: 122 123 (1) the final quantum of encoding input is an integral 124 multiple of 24 bits; here, the final unit of encoded 125 output will be an integral multiple of 4 characters 126 with no "=" padding, 127 (2) the final quantum of encoding input is exactly 8 bits; 128 here, the final unit of encoded output will be two 129 characters followed by two "=" padding characters, or 130 (3) the final quantum of encoding input is exactly 16 bits; 131 here, the final unit of encoded output will be three 132 characters followed by one "=" padding character. 133 */ 134 135int 136b64_ntop(u_char const *src, size_t srclength, char *target, size_t targsize) 137{ 138 size_t datalength = 0; 139 u_char input[3]; 140 u_char output[4]; 141 int i; 142 143 while (2 < srclength) { 144 input[0] = *src++; 145 input[1] = *src++; 146 input[2] = *src++; 147 srclength -= 3; 148 149 output[0] = input[0] >> 2; 150 output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4); 151 output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6); 152 output[3] = input[2] & 0x3f; 153 Assert(output[0] < 64); 154 Assert(output[1] < 64); 155 Assert(output[2] < 64); 156 Assert(output[3] < 64); 157 158 if (datalength + 4 > targsize) 159 return (-1); 160 target[datalength++] = Base64[output[0]]; 161 target[datalength++] = Base64[output[1]]; 162 target[datalength++] = Base64[output[2]]; 163 target[datalength++] = Base64[output[3]]; 164 } 165 166 /* Now we worry about padding. */ 167 if (0 != srclength) { 168 /* Get what's left. */ 169 input[0] = input[1] = input[2] = '\0'; 170 for (i = 0; i < srclength; i++) 171 input[i] = *src++; 172 173 output[0] = input[0] >> 2; 174 output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4); 175 output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6); 176 Assert(output[0] < 64); 177 Assert(output[1] < 64); 178 Assert(output[2] < 64); 179 180 if (datalength + 4 > targsize) 181 return (-1); 182 target[datalength++] = Base64[output[0]]; 183 target[datalength++] = Base64[output[1]]; 184 if (srclength == 1) 185 target[datalength++] = Pad64; 186 else 187 target[datalength++] = Base64[output[2]]; 188 target[datalength++] = Pad64; 189 } 190 if (datalength >= targsize) 191 return (-1); 192 target[datalength] = '\0'; /* Returned value doesn't count \0. */ 193 return (datalength); 194} 195 196/* skips all whitespace anywhere. 197 converts characters, four at a time, starting at (or after) 198 src from base - 64 numbers into three 8 bit bytes in the target area. 199 it returns the number of data bytes stored at the target, or -1 on error. 200 */ 201 202int 203b64_pton(u_char const *src, u_char *target, size_t targsize) 204{ 205 int tarindex, state, ch; 206 char *pos; 207 208 state = 0; 209 tarindex = 0; 210 211 while ((ch = *src++) != '\0') { 212 if (isspace(ch)) /* Skip whitespace anywhere. */ 213 continue; 214 215 if (ch == Pad64) 216 break; 217 218 pos = strchr(Base64, ch); 219 if (pos == 0) /* A non-base64 character. */ 220 return (-1); 221 222 switch (state) { 223 case 0: 224 if (target) { 225 if (tarindex >= targsize) 226 return (-1); 227 target[tarindex] = (pos - Base64) << 2; 228 } 229 state = 1; 230 break; 231 case 1: 232 if (target) { 233 if (tarindex + 1 >= targsize) 234 return (-1); 235 target[tarindex] |= (pos - Base64) >> 4; 236 target[tarindex+1] = ((pos - Base64) & 0x0f) 237 << 4 ; 238 } 239 tarindex++; 240 state = 2; 241 break; 242 case 2: 243 if (target) { 244 if (tarindex + 1 >= targsize) 245 return (-1); 246 target[tarindex] |= (pos - Base64) >> 2; 247 target[tarindex+1] = ((pos - Base64) & 0x03) 248 << 6; 249 } 250 tarindex++; 251 state = 3; 252 break; 253 case 3: 254 if (target) { 255 if (tarindex >= targsize) 256 return (-1); 257 target[tarindex] |= (pos - Base64); 258 } 259 tarindex++; 260 state = 0; 261 break; 262 } 263 } 264 265 /* 266 * We are done decoding Base-64 chars. Let's see if we ended 267 * on a byte boundary, and/or with erroneous trailing characters. 268 */ 269 270 if (ch == Pad64) { /* We got a pad char. */ 271 ch = *src++; /* Skip it, get next. */ 272 switch (state) { 273 case 0: /* Invalid = in first position */ 274 case 1: /* Invalid = in second position */ 275 return (-1); 276 277 case 2: /* Valid, means one byte of info */ 278 /* Skip any number of spaces. */ 279 for (; ch != '\0'; ch = *src++) 280 if (!isspace(ch)) 281 break; 282 /* Make sure there is another trailing = sign. */ 283 if (ch != Pad64) 284 return (-1); 285 ch = *src++; /* Skip the = */ 286 /* Fall through to "single trailing =" case. */ 287 /* FALLTHROUGH */ 288 289 case 3: /* Valid, means two bytes of info */ 290 /* 291 * We know this char is an =. Is there anything but 292 * whitespace after it? 293 */ 294 for (; ch != '\0'; ch = *src++) 295 if (!isspace(ch)) 296 return (-1); 297 298 /* 299 * Now make sure for cases 2 and 3 that the "extra" 300 * bits that slopped past the last full byte were 301 * zeros. If we don't check them, they become a 302 * subliminal channel. 303 */ 304 if (target && target[tarindex] != 0) 305 return (-1); 306 } 307 } else { 308 /* 309 * We ended by seeing the end of the string. Make sure we 310 * have no partial bytes lying around. 311 */ 312 if (state != 0) 313 return (-1); 314 } 315 316 return (tarindex); 317} 318 319#endif /* !defined(HAVE_B64_NTOP) && !defined(HAVE___B64_NTOP) */ 320