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 */ 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 { 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(char const *src, u_char *target, size_t targsize) 199 { 200 int tarindex, state, ch; 201 char *pos; 202 203 state = 0; 204 tarindex = 0; 205 206 while ((ch = *src++) != '\0') { 207 if (isspace((unsigned char)ch)) /* Skip whitespace anywhere. */ 208 continue; 209 210 if (ch == Pad64) 211 break; 212 213 pos = strchr(Base64, ch); 214 if (pos == NULL) /* A non-base64 character. */ 215 return (-1); 216 217 switch (state) { 218 case 0: 219 if (target) { 220 if ((size_t)tarindex >= targsize) 221 return (-1); 222 target[tarindex] = (pos - Base64) << 2; 223 } 224 state = 1; 225 break; 226 case 1: 227 if (target) { 228 if ((size_t)tarindex + 1 >= targsize) 229 return (-1); 230 target[tarindex] |= (pos - Base64) >> 4; 231 target[tarindex+1] = ((pos - Base64) & 0x0f) 232 << 4 ; 233 } 234 tarindex++; 235 state = 2; 236 break; 237 case 2: 238 if (target) { 239 if ((size_t)tarindex + 1 >= targsize) 240 return (-1); 241 target[tarindex] |= (pos - Base64) >> 2; 242 target[tarindex+1] = ((pos - Base64) & 0x03) 243 << 6; 244 } 245 tarindex++; 246 state = 3; 247 break; 248 case 3: 249 if (target) { 250 if ((size_t)tarindex >= targsize) 251 return (-1); 252 target[tarindex] |= (pos - Base64); 253 } 254 tarindex++; 255 state = 0; 256 break; 257 default: 258 abort(); 259 } 260 } 261 262 /* 263 * We are done decoding Base-64 chars. Let's see if we ended 264 * on a byte boundary, and/or with erroneous trailing characters. 265 */ 266 267 if (ch == Pad64) { /* We got a pad char. */ 268 ch = *src++; /* Skip it, get next. */ 269 switch (state) { 270 case 0: /* Invalid = in first position */ 271 case 1: /* Invalid = in second position */ 272 return (-1); 273 274 case 2: /* Valid, means one byte of info */ 275 /* Skip any number of spaces. */ 276 for ((void)NULL; ch != '\0'; ch = *src++) 277 if (!isspace((unsigned char)ch)) 278 break; 279 /* Make sure there is another trailing = sign. */ 280 if (ch != Pad64) 281 return (-1); 282 ch = *src++; /* Skip the = */ 283 /* Fall through to "single trailing =" case. */ 284 /* FALLTHROUGH */ 285 286 case 3: /* Valid, means two bytes of info */ 287 /* 288 * We know this char is an =. Is there anything but 289 * whitespace after it? 290 */ 291 for ((void)NULL; ch != '\0'; ch = *src++) 292 if (!isspace((unsigned char)ch)) 293 return (-1); 294 295 /* 296 * Now make sure for cases 2 and 3 that the "extra" 297 * bits that slopped past the last full byte were 298 * zeros. If we don't check them, they become a 299 * subliminal channel. 300 */ 301 if (target && target[tarindex] != 0) 302 return (-1); 303 } 304 } else { 305 /* 306 * We ended by seeing the end of the string. Make sure we 307 * have no partial bytes lying around. 308 */ 309 if (state != 0) 310 return (-1); 311 } 312 313 return (tarindex); 314 } 315