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