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 #include <ldns/config.h> 43 44 #include <ldns/ldns.h> 45 46 #include <sys/types.h> 47 #include <sys/param.h> 48 #ifdef HAVE_SYS_SOCKET_H 49 #include <sys/socket.h> 50 #endif 51 52 #ifdef HAVE_NETINET_IN_H 53 #include <netinet/in.h> 54 #endif 55 #ifdef HAVE_ARPA_INET_H 56 #include <arpa/inet.h> 57 #endif 58 59 #include <ctype.h> 60 #include <stdio.h> 61 #include <stdlib.h> 62 #include <string.h> 63 64 #define Assert(Cond) if (!(Cond)) abort() 65 66 static const char Base64[] = 67 "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; 68 static const char Pad64 = '='; 69 70 /* (From RFC1521 and draft-ietf-dnssec-secext-03.txt) 71 The following encoding technique is taken from RFC 1521 by Borenstein 72 and Freed. It is reproduced here in a slightly edited form for 73 convenience. 74 75 A 65-character subset of US-ASCII is used, enabling 6 bits to be 76 represented per printable character. (The extra 65th character, "=", 77 is used to signify a special processing function.) 78 79 The encoding process represents 24-bit groups of input bits as output 80 strings of 4 encoded characters. Proceeding from left to right, a 81 24-bit input group is formed by concatenating 3 8-bit input groups. 82 These 24 bits are then treated as 4 concatenated 6-bit groups, each 83 of which is translated into a single digit in the base64 alphabet. 84 85 Each 6-bit group is used as an index into an array of 64 printable 86 characters. The character referenced by the index is placed in the 87 output string. 88 89 Table 1: The Base64 Alphabet 90 91 Value Encoding Value Encoding Value Encoding Value Encoding 92 0 A 17 R 34 i 51 z 93 1 B 18 S 35 j 52 0 94 2 C 19 T 36 k 53 1 95 3 D 20 U 37 l 54 2 96 4 E 21 V 38 m 55 3 97 5 F 22 W 39 n 56 4 98 6 G 23 X 40 o 57 5 99 7 H 24 Y 41 p 58 6 100 8 I 25 Z 42 q 59 7 101 9 J 26 a 43 r 60 8 102 10 K 27 b 44 s 61 9 103 11 L 28 c 45 t 62 + 104 12 M 29 d 46 u 63 / 105 13 N 30 e 47 v 106 14 O 31 f 48 w (pad) = 107 15 P 32 g 49 x 108 16 Q 33 h 50 y 109 110 Special processing is performed if fewer than 24 bits are available 111 at the end of the data being encoded. A full encoding quantum is 112 always completed at the end of a quantity. When fewer than 24 input 113 bits are available in an input group, zero bits are added (on the 114 right) to form an integral number of 6-bit groups. Padding at the 115 end of the data is performed using the '=' character. 116 117 Since all base64 input is an integral number of octets, only the 118 ------------------------------------------------- 119 following cases can arise: 120 121 (1) the final quantum of encoding input is an integral 122 multiple of 24 bits; here, the final unit of encoded 123 output will be an integral multiple of 4 characters 124 with no "=" padding, 125 (2) the final quantum of encoding input is exactly 8 bits; 126 here, the final unit of encoded output will be two 127 characters followed by two "=" padding characters, or 128 (3) the final quantum of encoding input is exactly 16 bits; 129 here, the final unit of encoded output will be three 130 characters followed by one "=" padding character. 131 */ 132 133 /* skips all whitespace anywhere. 134 converts characters, four at a time, starting at (or after) 135 src from base - 64 numbers into three 8 bit bytes in the target area. 136 it returns the number of data bytes stored at the target, or -1 on error. 137 */ 138 139 int 140 ldns_b64_pton(char const *src, uint8_t *target, size_t targsize) 141 { 142 int tarindex, state, ch; 143 char *pos; 144 145 state = 0; 146 tarindex = 0; 147 148 if (strlen(src) == 0) { 149 return 0; 150 } 151 152 while ((ch = *src++) != '\0') { 153 if (isspace((unsigned char)ch)) /* Skip whitespace anywhere. */ 154 continue; 155 156 if (ch == Pad64) 157 break; 158 159 pos = strchr(Base64, ch); 160 if (pos == 0) { 161 /* A non-base64 character. */ 162 return (-1); 163 } 164 165 switch (state) { 166 case 0: 167 if (target) { 168 if ((size_t)tarindex >= targsize) 169 return (-1); 170 target[tarindex] = (pos - Base64) << 2; 171 } 172 state = 1; 173 break; 174 case 1: 175 if (target) { 176 if ((size_t)tarindex + 1 >= targsize) 177 return (-1); 178 target[tarindex] |= (pos - Base64) >> 4; 179 target[tarindex+1] = ((pos - Base64) & 0x0f) 180 << 4 ; 181 } 182 tarindex++; 183 state = 2; 184 break; 185 case 2: 186 if (target) { 187 if ((size_t)tarindex + 1 >= targsize) 188 return (-1); 189 target[tarindex] |= (pos - Base64) >> 2; 190 target[tarindex+1] = ((pos - Base64) & 0x03) 191 << 6; 192 } 193 tarindex++; 194 state = 3; 195 break; 196 case 3: 197 if (target) { 198 if ((size_t)tarindex >= targsize) 199 return (-1); 200 target[tarindex] |= (pos - Base64); 201 } 202 tarindex++; 203 state = 0; 204 break; 205 default: 206 abort(); 207 } 208 } 209 210 /* 211 * We are done decoding Base-64 chars. Let's see if we ended 212 * on a byte boundary, and/or with erroneous trailing characters. 213 */ 214 215 if (ch == Pad64) { /* We got a pad char. */ 216 ch = *src++; /* Skip it, get next. */ 217 switch (state) { 218 case 0: /* Invalid = in first position */ 219 case 1: /* Invalid = in second position */ 220 return (-1); 221 222 case 2: /* Valid, means one byte of info */ 223 /* Skip any number of spaces. */ 224 for ((void)NULL; ch != '\0'; ch = *src++) 225 if (!isspace((unsigned char)ch)) 226 break; 227 /* Make sure there is another trailing = sign. */ 228 if (ch != Pad64) 229 return (-1); 230 ch = *src++; /* Skip the = */ 231 /* Fall through to "single trailing =" case. */ 232 /* FALLTHROUGH */ 233 234 case 3: /* Valid, means two bytes of info */ 235 /* 236 * We know this char is an =. Is there anything but 237 * whitespace after it? 238 */ 239 for ((void)NULL; ch != '\0'; ch = *src++) 240 if (!isspace((unsigned char)ch)) 241 return (-1); 242 243 /* 244 * Now make sure for cases 2 and 3 that the "extra" 245 * bits that slopped past the last full byte were 246 * zeros. If we don't check them, they become a 247 * subliminal channel. 248 */ 249 if (target && target[tarindex] != 0) 250 return (-1); 251 } 252 } else { 253 /* 254 * We ended by seeing the end of the string. Make sure we 255 * have no partial bytes lying around. 256 */ 257 if (state != 0) 258 return (-1); 259 } 260 261 return (tarindex); 262 } 263