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