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 * $DragonFly: src/lib/libc/net/base64.c,v 1.3 2005/09/19 09:25:15 asmodai Exp $ 46 */ 47 48 #include <sys/types.h> 49 #include <sys/param.h> 50 #include <sys/socket.h> 51 52 #include <netinet/in.h> 53 #include <arpa/inet.h> 54 #include <arpa/nameser.h> 55 56 #include <ctype.h> 57 #include <resolv.h> 58 #include <stdio.h> 59 #include <stdlib.h> 60 #include <string.h> 61 62 #define Assert(Cond) if (!(Cond)) abort() 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 int 132 b64_ntop(u_char const *src, size_t srclength, char *target, size_t targsize) { 133 size_t datalength = 0; 134 u_char input[3]; 135 u_char output[4]; 136 size_t i; 137 138 while (2 < srclength) { 139 input[0] = *src++; 140 input[1] = *src++; 141 input[2] = *src++; 142 srclength -= 3; 143 144 output[0] = input[0] >> 2; 145 output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4); 146 output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6); 147 output[3] = input[2] & 0x3f; 148 Assert(output[0] < 64); 149 Assert(output[1] < 64); 150 Assert(output[2] < 64); 151 Assert(output[3] < 64); 152 153 if (datalength + 4 > targsize) 154 return (-1); 155 target[datalength++] = Base64[output[0]]; 156 target[datalength++] = Base64[output[1]]; 157 target[datalength++] = Base64[output[2]]; 158 target[datalength++] = Base64[output[3]]; 159 } 160 161 /* Now we worry about padding. */ 162 if (0 != srclength) { 163 /* Get what's left. */ 164 input[0] = input[1] = input[2] = '\0'; 165 for (i = 0; i < srclength; i++) 166 input[i] = *src++; 167 168 output[0] = input[0] >> 2; 169 output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4); 170 output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6); 171 Assert(output[0] < 64); 172 Assert(output[1] < 64); 173 Assert(output[2] < 64); 174 175 if (datalength + 4 > targsize) 176 return (-1); 177 target[datalength++] = Base64[output[0]]; 178 target[datalength++] = Base64[output[1]]; 179 if (srclength == 1) 180 target[datalength++] = Pad64; 181 else 182 target[datalength++] = Base64[output[2]]; 183 target[datalength++] = Pad64; 184 } 185 if (datalength >= targsize) 186 return (-1); 187 target[datalength] = '\0'; /* Returned value doesn't count \0. */ 188 return (datalength); 189 } 190 191 /* skips all whitespace anywhere. 192 converts characters, four at a time, starting at (or after) 193 src from base - 64 numbers into three 8 bit bytes in the target area. 194 it returns the number of data bytes stored at the target, or -1 on error. 195 */ 196 197 int 198 b64_pton(src, target, targsize) 199 char const *src; 200 u_char *target; 201 size_t targsize; 202 { 203 int tarindex, state, ch; 204 char *pos; 205 206 state = 0; 207 tarindex = 0; 208 209 while ((ch = *src++) != '\0') { 210 if (isspace((unsigned char)ch)) /* Skip whitespace anywhere. */ 211 continue; 212 213 if (ch == Pad64) 214 break; 215 216 pos = strchr(Base64, ch); 217 if (pos == 0) /* A non-base64 character. */ 218 return (-1); 219 220 switch (state) { 221 case 0: 222 if (target) { 223 if ((size_t)tarindex >= targsize) 224 return (-1); 225 target[tarindex] = (pos - Base64) << 2; 226 } 227 state = 1; 228 break; 229 case 1: 230 if (target) { 231 if ((size_t)tarindex + 1 >= targsize) 232 return (-1); 233 target[tarindex] |= (pos - Base64) >> 4; 234 target[tarindex+1] = ((pos - Base64) & 0x0f) 235 << 4 ; 236 } 237 tarindex++; 238 state = 2; 239 break; 240 case 2: 241 if (target) { 242 if ((size_t)tarindex + 1 >= targsize) 243 return (-1); 244 target[tarindex] |= (pos - Base64) >> 2; 245 target[tarindex+1] = ((pos - Base64) & 0x03) 246 << 6; 247 } 248 tarindex++; 249 state = 3; 250 break; 251 case 3: 252 if (target) { 253 if ((size_t)tarindex >= targsize) 254 return (-1); 255 target[tarindex] |= (pos - Base64); 256 } 257 tarindex++; 258 state = 0; 259 break; 260 default: 261 abort(); 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 ((void)NULL; ch != '\0'; ch = *src++) 280 if (!isspace((unsigned char)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 ((void)NULL; ch != '\0'; ch = *src++) 295 if (!isspace((unsigned char)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