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