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 * $FreeBSD: src/lib/libc/net/base64.c,v 1.4 1999/11/04 04:30:43 ache Exp $ 44 * $DragonFly: src/lib/libc/net/base64.c,v 1.2 2003/06/17 04:26:44 dillon Exp $ 45 */ 46 47 #include <sys/types.h> 48 #include <sys/param.h> 49 #include <sys/socket.h> 50 51 #include <netinet/in.h> 52 #include <arpa/inet.h> 53 #include <arpa/nameser.h> 54 55 #include <ctype.h> 56 #include <resolv.h> 57 #include <stdio.h> 58 #include <stdlib.h> 59 #include <string.h> 60 61 #define Assert(Cond) if (!(Cond)) abort() 62 63 static const char Base64[] = 64 "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; 65 static const char Pad64 = '='; 66 67 /* (From RFC1521 and draft-ietf-dnssec-secext-03.txt) 68 The following encoding technique is taken from RFC 1521 by Borenstein 69 and Freed. It is reproduced here in a slightly edited form for 70 convenience. 71 72 A 65-character subset of US-ASCII is used, enabling 6 bits to be 73 represented per printable character. (The extra 65th character, "=", 74 is used to signify a special processing function.) 75 76 The encoding process represents 24-bit groups of input bits as output 77 strings of 4 encoded characters. Proceeding from left to right, a 78 24-bit input group is formed by concatenating 3 8-bit input groups. 79 These 24 bits are then treated as 4 concatenated 6-bit groups, each 80 of which is translated into a single digit in the base64 alphabet. 81 82 Each 6-bit group is used as an index into an array of 64 printable 83 characters. The character referenced by the index is placed in the 84 output string. 85 86 Table 1: The Base64 Alphabet 87 88 Value Encoding Value Encoding Value Encoding Value Encoding 89 0 A 17 R 34 i 51 z 90 1 B 18 S 35 j 52 0 91 2 C 19 T 36 k 53 1 92 3 D 20 U 37 l 54 2 93 4 E 21 V 38 m 55 3 94 5 F 22 W 39 n 56 4 95 6 G 23 X 40 o 57 5 96 7 H 24 Y 41 p 58 6 97 8 I 25 Z 42 q 59 7 98 9 J 26 a 43 r 60 8 99 10 K 27 b 44 s 61 9 100 11 L 28 c 45 t 62 + 101 12 M 29 d 46 u 63 / 102 13 N 30 e 47 v 103 14 O 31 f 48 w (pad) = 104 15 P 32 g 49 x 105 16 Q 33 h 50 y 106 107 Special processing is performed if fewer than 24 bits are available 108 at the end of the data being encoded. A full encoding quantum is 109 always completed at the end of a quantity. When fewer than 24 input 110 bits are available in an input group, zero bits are added (on the 111 right) to form an integral number of 6-bit groups. Padding at the 112 end of the data is performed using the '=' character. 113 114 Since all base64 input is an integral number of octets, only the 115 ------------------------------------------------- 116 following cases can arise: 117 118 (1) the final quantum of encoding input is an integral 119 multiple of 24 bits; here, the final unit of encoded 120 output will be an integral multiple of 4 characters 121 with no "=" padding, 122 (2) the final quantum of encoding input is exactly 8 bits; 123 here, the final unit of encoded output will be two 124 characters followed by two "=" padding characters, or 125 (3) the final quantum of encoding input is exactly 16 bits; 126 here, the final unit of encoded output will be three 127 characters followed by one "=" padding character. 128 */ 129 130 int 131 b64_ntop(u_char const *src, size_t srclength, char *target, size_t targsize) { 132 size_t datalength = 0; 133 u_char input[3]; 134 u_char output[4]; 135 size_t i; 136 137 while (2 < srclength) { 138 input[0] = *src++; 139 input[1] = *src++; 140 input[2] = *src++; 141 srclength -= 3; 142 143 output[0] = input[0] >> 2; 144 output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4); 145 output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6); 146 output[3] = input[2] & 0x3f; 147 Assert(output[0] < 64); 148 Assert(output[1] < 64); 149 Assert(output[2] < 64); 150 Assert(output[3] < 64); 151 152 if (datalength + 4 > targsize) 153 return (-1); 154 target[datalength++] = Base64[output[0]]; 155 target[datalength++] = Base64[output[1]]; 156 target[datalength++] = Base64[output[2]]; 157 target[datalength++] = Base64[output[3]]; 158 } 159 160 /* Now we worry about padding. */ 161 if (0 != srclength) { 162 /* Get what's left. */ 163 input[0] = input[1] = input[2] = '\0'; 164 for (i = 0; i < srclength; i++) 165 input[i] = *src++; 166 167 output[0] = input[0] >> 2; 168 output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4); 169 output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6); 170 Assert(output[0] < 64); 171 Assert(output[1] < 64); 172 Assert(output[2] < 64); 173 174 if (datalength + 4 > targsize) 175 return (-1); 176 target[datalength++] = Base64[output[0]]; 177 target[datalength++] = Base64[output[1]]; 178 if (srclength == 1) 179 target[datalength++] = Pad64; 180 else 181 target[datalength++] = Base64[output[2]]; 182 target[datalength++] = Pad64; 183 } 184 if (datalength >= targsize) 185 return (-1); 186 target[datalength] = '\0'; /* Returned value doesn't count \0. */ 187 return (datalength); 188 } 189 190 /* skips all whitespace anywhere. 191 converts characters, four at a time, starting at (or after) 192 src from base - 64 numbers into three 8 bit bytes in the target area. 193 it returns the number of data bytes stored at the target, or -1 on error. 194 */ 195 196 int 197 b64_pton(src, target, targsize) 198 char const *src; 199 u_char *target; 200 size_t targsize; 201 { 202 int tarindex, state, ch; 203 char *pos; 204 205 state = 0; 206 tarindex = 0; 207 208 while ((ch = *src++) != '\0') { 209 if (isspace((unsigned char)ch)) /* Skip whitespace anywhere. */ 210 continue; 211 212 if (ch == Pad64) 213 break; 214 215 pos = strchr(Base64, ch); 216 if (pos == 0) /* A non-base64 character. */ 217 return (-1); 218 219 switch (state) { 220 case 0: 221 if (target) { 222 if ((size_t)tarindex >= targsize) 223 return (-1); 224 target[tarindex] = (pos - Base64) << 2; 225 } 226 state = 1; 227 break; 228 case 1: 229 if (target) { 230 if ((size_t)tarindex + 1 >= targsize) 231 return (-1); 232 target[tarindex] |= (pos - Base64) >> 4; 233 target[tarindex+1] = ((pos - Base64) & 0x0f) 234 << 4 ; 235 } 236 tarindex++; 237 state = 2; 238 break; 239 case 2: 240 if (target) { 241 if ((size_t)tarindex + 1 >= targsize) 242 return (-1); 243 target[tarindex] |= (pos - Base64) >> 2; 244 target[tarindex+1] = ((pos - Base64) & 0x03) 245 << 6; 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 && target[tarindex] != 0) 304 return (-1); 305 } 306 } else { 307 /* 308 * We ended by seeing the end of the string. Make sure we 309 * have no partial bytes lying around. 310 */ 311 if (state != 0) 312 return (-1); 313 } 314 315 return (tarindex); 316 } 317