1 /* 2 * Copyright (c) 1996, 1998 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 * 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 /* 44 * $FreeBSD: src/lib/libc/net/base64.c,v 1.4 1999/11/04 04:30:43 ache Exp $ 45 */ 46 47 #include <sys/types.h> 48 #include <sys/socket.h> 49 50 #include <netinet/in.h> 51 #include <arpa/inet.h> 52 53 #include <ctype.h> 54 #include <resolv.h> 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(const unsigned char *src, size_t srclength, char *target, 127 size_t targsize) 128 { 129 size_t datalength = 0; 130 unsigned char input[3]; 131 unsigned char output[4]; 132 size_t i; 133 134 while (2 < srclength) { 135 input[0] = *src++; 136 input[1] = *src++; 137 input[2] = *src++; 138 srclength -= 3; 139 140 output[0] = input[0] >> 2; 141 output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4); 142 output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6); 143 output[3] = input[2] & 0x3f; 144 145 if (datalength + 4 > targsize) 146 return (-1); 147 target[datalength++] = Base64[output[0]]; 148 target[datalength++] = Base64[output[1]]; 149 target[datalength++] = Base64[output[2]]; 150 target[datalength++] = Base64[output[3]]; 151 } 152 153 /* Now we worry about padding. */ 154 if (0 != srclength) { 155 /* Get what's left. */ 156 input[0] = input[1] = input[2] = '\0'; 157 for (i = 0; i < srclength; i++) 158 input[i] = *src++; 159 160 output[0] = input[0] >> 2; 161 output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4); 162 output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6); 163 164 if (datalength + 4 > targsize) 165 return (-1); 166 target[datalength++] = Base64[output[0]]; 167 target[datalength++] = Base64[output[1]]; 168 if (srclength == 1) 169 target[datalength++] = Pad64; 170 else 171 target[datalength++] = Base64[output[2]]; 172 target[datalength++] = Pad64; 173 } 174 175 if (datalength >= targsize) 176 return (-1); 177 target[datalength] = '\0'; /* Returned value doesn't count \0. */ 178 return (datalength); 179 } 180 181 /* skips all whitespace anywhere. 182 converts characters, four at a time, starting at (or after) 183 src from base - 64 numbers into three 8 bit bytes in the target area. 184 it returns the number of data bytes stored at the target, or -1 on error. 185 */ 186 187 int 188 b64_pton(const char *src, unsigned char *target, size_t targsize) 189 { 190 int state; 191 size_t tarindex; 192 unsigned char ch, nextbyte; 193 char *pos; 194 195 state = 0; 196 tarindex = 0; 197 198 while ((ch = (unsigned char)*src++) != '\0') { 199 if (isspace(ch)) /* Skip whitespace anywhere. */ 200 continue; 201 202 if (ch == Pad64) 203 break; 204 205 pos = strchr(Base64, ch); 206 if (pos == NULL) /* A non-base64 character. */ 207 return (-1); 208 209 switch (state) { 210 case 0: 211 if (target) { 212 if (tarindex >= targsize) 213 return (-1); 214 target[tarindex] = (pos - Base64) << 2; 215 } 216 state = 1; 217 break; 218 case 1: 219 if (target) { 220 if (tarindex >= targsize) 221 return (-1); 222 target[tarindex] |= (pos - Base64) >> 4; 223 nextbyte = ((pos - Base64) & 0x0f) << 4; 224 if (tarindex + 1 < targsize) 225 target[tarindex+1] = nextbyte; 226 else if (nextbyte) 227 return (-1); 228 } 229 tarindex++; 230 state = 2; 231 break; 232 case 2: 233 if (target) { 234 if (tarindex >= targsize) 235 return (-1); 236 target[tarindex] |= (pos - Base64) >> 2; 237 nextbyte = ((pos - Base64) & 0x03) << 6; 238 if (tarindex + 1 < targsize) 239 target[tarindex+1] = nextbyte; 240 else if (nextbyte) 241 return (-1); 242 } 243 tarindex++; 244 state = 3; 245 break; 246 case 3: 247 if (target) { 248 if (tarindex >= targsize) 249 return (-1); 250 target[tarindex] |= (pos - Base64); 251 } 252 tarindex++; 253 state = 0; 254 break; 255 default: /* Impossible */ 256 abort(); 257 } 258 } 259 260 /* 261 * We are done decoding Base-64 chars. Let's see if we ended 262 * on a byte boundary, and/or with erroneous trailing characters. 263 */ 264 265 if (ch == Pad64) { /* We got a pad char. */ 266 ch = (unsigned char)*src++; /* Skip it, get next. */ 267 switch (state) { 268 case 0: /* Invalid = in first position */ 269 case 1: /* Invalid = in second position */ 270 return (-1); 271 272 case 2: /* Valid, means one byte of info */ 273 /* Skip any number of spaces. */ 274 for (; ch != '\0'; ch = (unsigned char)*src++) 275 if (!isspace(ch)) 276 break; 277 /* Make sure there is another trailing = sign. */ 278 if (ch != Pad64) 279 return (-1); 280 ch = (unsigned char)*src++; /* Skip the = */ 281 /* Fall through to "single trailing =" case. */ 282 /* FALLTHROUGH */ 283 284 case 3: /* Valid, means two bytes of info */ 285 /* 286 * We know this char is an =. Is there anything but 287 * whitespace after it? 288 */ 289 for (; ch != '\0'; ch = (unsigned char)*src++) 290 if (!isspace(ch)) 291 return (-1); 292 293 /* 294 * Now make sure for cases 2 and 3 that the "extra" 295 * bits that slopped past the last full byte were 296 * zeros. If we don't check them, they become a 297 * subliminal channel. 298 */ 299 if (target && tarindex < targsize && 300 target[tarindex] != 0) 301 return (-1); 302 } 303 } else { 304 /* 305 * We ended by seeing the end of the string. Make sure we 306 * have no partial bytes lying around. 307 */ 308 if (state != 0) 309 return (-1); 310 } 311 312 return ((int)tarindex); 313 } 314