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 1.4 2005/11/13 02:04:47 swildner 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 { 134 size_t datalength = 0; 135 u_char input[3]; 136 u_char output[4]; 137 size_t i; 138 139 while (2 < srclength) { 140 input[0] = *src++; 141 input[1] = *src++; 142 input[2] = *src++; 143 srclength -= 3; 144 145 output[0] = input[0] >> 2; 146 output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4); 147 output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6); 148 output[3] = input[2] & 0x3f; 149 Assert(output[0] < 64); 150 Assert(output[1] < 64); 151 Assert(output[2] < 64); 152 Assert(output[3] < 64); 153 154 if (datalength + 4 > targsize) 155 return (-1); 156 target[datalength++] = Base64[output[0]]; 157 target[datalength++] = Base64[output[1]]; 158 target[datalength++] = Base64[output[2]]; 159 target[datalength++] = Base64[output[3]]; 160 } 161 162 /* Now we worry about padding. */ 163 if (0 != srclength) { 164 /* Get what's left. */ 165 input[0] = input[1] = input[2] = '\0'; 166 for (i = 0; i < srclength; i++) 167 input[i] = *src++; 168 169 output[0] = input[0] >> 2; 170 output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4); 171 output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6); 172 Assert(output[0] < 64); 173 Assert(output[1] < 64); 174 Assert(output[2] < 64); 175 176 if (datalength + 4 > targsize) 177 return (-1); 178 target[datalength++] = Base64[output[0]]; 179 target[datalength++] = Base64[output[1]]; 180 if (srclength == 1) 181 target[datalength++] = Pad64; 182 else 183 target[datalength++] = Base64[output[2]]; 184 target[datalength++] = Pad64; 185 } 186 if (datalength >= targsize) 187 return (-1); 188 target[datalength] = '\0'; /* Returned value doesn't count \0. */ 189 return (datalength); 190 } 191 192 /* skips all whitespace anywhere. 193 converts characters, four at a time, starting at (or after) 194 src from base - 64 numbers into three 8 bit bytes in the target area. 195 it returns the number of data bytes stored at the target, or -1 on error. 196 */ 197 198 int 199 b64_pton(char const *src, u_char *target, size_t targsize) 200 { 201 int tarindex, state, ch; 202 char *pos; 203 204 state = 0; 205 tarindex = 0; 206 207 while ((ch = *src++) != '\0') { 208 if (isspace((unsigned char)ch)) /* Skip whitespace anywhere. */ 209 continue; 210 211 if (ch == Pad64) 212 break; 213 214 pos = strchr(Base64, ch); 215 if (pos == 0) /* A non-base64 character. */ 216 return (-1); 217 218 switch (state) { 219 case 0: 220 if (target) { 221 if ((size_t)tarindex >= targsize) 222 return (-1); 223 target[tarindex] = (pos - Base64) << 2; 224 } 225 state = 1; 226 break; 227 case 1: 228 if (target) { 229 if ((size_t)tarindex + 1 >= targsize) 230 return (-1); 231 target[tarindex] |= (pos - Base64) >> 4; 232 target[tarindex+1] = ((pos - Base64) & 0x0f) 233 << 4 ; 234 } 235 tarindex++; 236 state = 2; 237 break; 238 case 2: 239 if (target) { 240 if ((size_t)tarindex + 1 >= targsize) 241 return (-1); 242 target[tarindex] |= (pos - Base64) >> 2; 243 target[tarindex+1] = ((pos - Base64) & 0x03) 244 << 6; 245 } 246 tarindex++; 247 state = 3; 248 break; 249 case 3: 250 if (target) { 251 if ((size_t)tarindex >= targsize) 252 return (-1); 253 target[tarindex] |= (pos - Base64); 254 } 255 tarindex++; 256 state = 0; 257 break; 258 default: 259 abort(); 260 } 261 } 262 263 /* 264 * We are done decoding Base-64 chars. Let's see if we ended 265 * on a byte boundary, and/or with erroneous trailing characters. 266 */ 267 268 if (ch == Pad64) { /* We got a pad char. */ 269 ch = *src++; /* Skip it, get next. */ 270 switch (state) { 271 case 0: /* Invalid = in first position */ 272 case 1: /* Invalid = in second position */ 273 return (-1); 274 275 case 2: /* Valid, means one byte of info */ 276 /* Skip any number of spaces. */ 277 for ((void)NULL; ch != '\0'; ch = *src++) 278 if (!isspace((unsigned char)ch)) 279 break; 280 /* Make sure there is another trailing = sign. */ 281 if (ch != Pad64) 282 return (-1); 283 ch = *src++; /* Skip the = */ 284 /* Fall through to "single trailing =" case. */ 285 /* FALLTHROUGH */ 286 287 case 3: /* Valid, means two bytes of info */ 288 /* 289 * We know this char is an =. Is there anything but 290 * whitespace after it? 291 */ 292 for ((void)NULL; ch != '\0'; ch = *src++) 293 if (!isspace((unsigned char)ch)) 294 return (-1); 295 296 /* 297 * Now make sure for cases 2 and 3 that the "extra" 298 * bits that slopped past the last full byte were 299 * zeros. If we don't check them, they become a 300 * subliminal channel. 301 */ 302 if (target && target[tarindex] != 0) 303 return (-1); 304 } 305 } else { 306 /* 307 * We ended by seeing the end of the string. Make sure we 308 * have no partial bytes lying around. 309 */ 310 if (state != 0) 311 return (-1); 312 } 313 314 return (tarindex); 315 } 316