1 /* $OpenBSD: base64.c,v 1.5 2006/10/21 09:55:03 otto 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 /* OPENBSD ORIGINAL: lib/libc/net/base64.c */ 46 47 #include "includes.h" 48 49 #if (!defined(HAVE_B64_NTOP) && !defined(HAVE___B64_NTOP)) || (!defined(HAVE_B64_PTON) && !defined(HAVE___B64_PTON)) 50 51 #include <sys/types.h> 52 #include <sys/socket.h> 53 #include <netinet/in.h> 54 #include <arpa/inet.h> 55 56 #include <ctype.h> 57 #include <stdio.h> 58 59 #include <stdlib.h> 60 #include <string.h> 61 62 #include "base64.h" 63 64 static const char Base64[] = 65 "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; 66 static const char Pad64 = '='; 67 68 /* (From RFC1521 and draft-ietf-dnssec-secext-03.txt) 69 The following encoding technique is taken from RFC 1521 by Borenstein 70 and Freed. It is reproduced here in a slightly edited form for 71 convenience. 72 73 A 65-character subset of US-ASCII is used, enabling 6 bits to be 74 represented per printable character. (The extra 65th character, "=", 75 is used to signify a special processing function.) 76 77 The encoding process represents 24-bit groups of input bits as output 78 strings of 4 encoded characters. Proceeding from left to right, a 79 24-bit input group is formed by concatenating 3 8-bit input groups. 80 These 24 bits are then treated as 4 concatenated 6-bit groups, each 81 of which is translated into a single digit in the base64 alphabet. 82 83 Each 6-bit group is used as an index into an array of 64 printable 84 characters. The character referenced by the index is placed in the 85 output string. 86 87 Table 1: The Base64 Alphabet 88 89 Value Encoding Value Encoding Value Encoding Value Encoding 90 0 A 17 R 34 i 51 z 91 1 B 18 S 35 j 52 0 92 2 C 19 T 36 k 53 1 93 3 D 20 U 37 l 54 2 94 4 E 21 V 38 m 55 3 95 5 F 22 W 39 n 56 4 96 6 G 23 X 40 o 57 5 97 7 H 24 Y 41 p 58 6 98 8 I 25 Z 42 q 59 7 99 9 J 26 a 43 r 60 8 100 10 K 27 b 44 s 61 9 101 11 L 28 c 45 t 62 + 102 12 M 29 d 46 u 63 / 103 13 N 30 e 47 v 104 14 O 31 f 48 w (pad) = 105 15 P 32 g 49 x 106 16 Q 33 h 50 y 107 108 Special processing is performed if fewer than 24 bits are available 109 at the end of the data being encoded. A full encoding quantum is 110 always completed at the end of a quantity. When fewer than 24 input 111 bits are available in an input group, zero bits are added (on the 112 right) to form an integral number of 6-bit groups. Padding at the 113 end of the data is performed using the '=' character. 114 115 Since all base64 input is an integral number of octets, only the 116 ------------------------------------------------- 117 following cases can arise: 118 119 (1) the final quantum of encoding input is an integral 120 multiple of 24 bits; here, the final unit of encoded 121 output will be an integral multiple of 4 characters 122 with no "=" padding, 123 (2) the final quantum of encoding input is exactly 8 bits; 124 here, the final unit of encoded output will be two 125 characters followed by two "=" padding characters, or 126 (3) the final quantum of encoding input is exactly 16 bits; 127 here, the final unit of encoded output will be three 128 characters followed by one "=" padding character. 129 */ 130 131 #if !defined(HAVE_B64_NTOP) && !defined(HAVE___B64_NTOP) 132 int 133 b64_ntop(u_char const *src, size_t srclength, char *target, size_t targsize) 134 { 135 size_t datalength = 0; 136 u_char input[3]; 137 u_char output[4]; 138 u_int i; 139 140 while (2 < srclength) { 141 input[0] = *src++; 142 input[1] = *src++; 143 input[2] = *src++; 144 srclength -= 3; 145 146 output[0] = input[0] >> 2; 147 output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4); 148 output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6); 149 output[3] = input[2] & 0x3f; 150 151 if (datalength + 4 > targsize) 152 return (-1); 153 target[datalength++] = Base64[output[0]]; 154 target[datalength++] = Base64[output[1]]; 155 target[datalength++] = Base64[output[2]]; 156 target[datalength++] = Base64[output[3]]; 157 } 158 159 /* Now we worry about padding. */ 160 if (0 != srclength) { 161 /* Get what's left. */ 162 input[0] = input[1] = input[2] = '\0'; 163 for (i = 0; i < srclength; i++) 164 input[i] = *src++; 165 166 output[0] = input[0] >> 2; 167 output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4); 168 output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6); 169 170 if (datalength + 4 > targsize) 171 return (-1); 172 target[datalength++] = Base64[output[0]]; 173 target[datalength++] = Base64[output[1]]; 174 if (srclength == 1) 175 target[datalength++] = Pad64; 176 else 177 target[datalength++] = Base64[output[2]]; 178 target[datalength++] = Pad64; 179 } 180 if (datalength >= targsize) 181 return (-1); 182 target[datalength] = '\0'; /* Returned value doesn't count \0. */ 183 return (datalength); 184 } 185 #endif /* !defined(HAVE_B64_NTOP) && !defined(HAVE___B64_NTOP) */ 186 187 #if !defined(HAVE_B64_PTON) && !defined(HAVE___B64_PTON) 188 189 /* skips all whitespace anywhere. 190 converts characters, four at a time, starting at (or after) 191 src from base - 64 numbers into three 8 bit bytes in the target area. 192 it returns the number of data bytes stored at the target, or -1 on error. 193 */ 194 195 int 196 b64_pton(char const *src, u_char *target, size_t targsize) 197 { 198 u_int tarindex, state; 199 int ch; 200 char *pos; 201 202 state = 0; 203 tarindex = 0; 204 205 while ((ch = *src++) != '\0') { 206 if (isspace(ch)) /* Skip whitespace anywhere. */ 207 continue; 208 209 if (ch == Pad64) 210 break; 211 212 pos = strchr(Base64, ch); 213 if (pos == 0) /* A non-base64 character. */ 214 return (-1); 215 216 switch (state) { 217 case 0: 218 if (target) { 219 if (tarindex >= targsize) 220 return (-1); 221 target[tarindex] = (pos - Base64) << 2; 222 } 223 state = 1; 224 break; 225 case 1: 226 if (target) { 227 if (tarindex + 1 >= targsize) 228 return (-1); 229 target[tarindex] |= (pos - Base64) >> 4; 230 target[tarindex+1] = ((pos - Base64) & 0x0f) 231 << 4 ; 232 } 233 tarindex++; 234 state = 2; 235 break; 236 case 2: 237 if (target) { 238 if (tarindex + 1 >= targsize) 239 return (-1); 240 target[tarindex] |= (pos - Base64) >> 2; 241 target[tarindex+1] = ((pos - Base64) & 0x03) 242 << 6; 243 } 244 tarindex++; 245 state = 3; 246 break; 247 case 3: 248 if (target) { 249 if (tarindex >= targsize) 250 return (-1); 251 target[tarindex] |= (pos - Base64); 252 } 253 tarindex++; 254 state = 0; 255 break; 256 } 257 } 258 259 /* 260 * We are done decoding Base-64 chars. Let's see if we ended 261 * on a byte boundary, and/or with erroneous trailing characters. 262 */ 263 264 if (ch == Pad64) { /* We got a pad char. */ 265 ch = *src++; /* Skip it, get next. */ 266 switch (state) { 267 case 0: /* Invalid = in first position */ 268 case 1: /* Invalid = in second position */ 269 return (-1); 270 271 case 2: /* Valid, means one byte of info */ 272 /* Skip any number of spaces. */ 273 for (; ch != '\0'; ch = *src++) 274 if (!isspace(ch)) 275 break; 276 /* Make sure there is another trailing = sign. */ 277 if (ch != Pad64) 278 return (-1); 279 ch = *src++; /* Skip the = */ 280 /* Fall through to "single trailing =" case. */ 281 /* FALLTHROUGH */ 282 283 case 3: /* Valid, means two bytes of info */ 284 /* 285 * We know this char is an =. Is there anything but 286 * whitespace after it? 287 */ 288 for (; ch != '\0'; ch = *src++) 289 if (!isspace(ch)) 290 return (-1); 291 292 /* 293 * Now make sure for cases 2 and 3 that the "extra" 294 * bits that slopped past the last full byte were 295 * zeros. If we don't check them, they become a 296 * subliminal channel. 297 */ 298 if (target && target[tarindex] != 0) 299 return (-1); 300 } 301 } else { 302 /* 303 * We ended by seeing the end of the string. Make sure we 304 * have no partial bytes lying around. 305 */ 306 if (state != 0) 307 return (-1); 308 } 309 310 return (tarindex); 311 } 312 313 #endif /* !defined(HAVE_B64_PTON) && !defined(HAVE___B64_PTON) */ 314 #endif 315