1 | /* |
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2 | * Copyright (c) 1996-1999 by Internet Software Consortium. |
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3 | * |
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4 | * Permission to use, copy, modify, and distribute this software for any |
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5 | * purpose with or without fee is hereby granted, provided that the above |
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6 | * copyright notice and this permission notice appear in all copies. |
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7 | * |
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8 | * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS |
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9 | * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES |
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10 | * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE |
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11 | * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL |
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12 | * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR |
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13 | * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS |
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14 | * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS |
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15 | * SOFTWARE. |
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16 | */ |
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17 | |
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18 | /* |
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19 | * Portions Copyright (c) 1995 by International Business Machines, Inc. |
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20 | * |
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21 | * International Business Machines, Inc. (hereinafter called IBM) grants |
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22 | * permission under its copyrights to use, copy, modify, and distribute this |
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23 | * Software with or without fee, provided that the above copyright notice and |
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24 | * all paragraphs of this notice appear in all copies, and that the name of IBM |
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25 | * not be used in connection with the marketing of any product incorporating |
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26 | * the Software or modifications thereof, without specific, written prior |
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27 | * permission. |
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28 | * |
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29 | * To the extent it has a right to do so, IBM grants an immunity from suit |
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30 | * under its patents, if any, for the use, sale or manufacture of products to |
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31 | * the extent that such products are used for performing Domain Name System |
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32 | * dynamic updates in TCP/IP networks by means of the Software. No immunity is |
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33 | * granted for any product per se or for any other function of any product. |
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34 | * |
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35 | * THE SOFTWARE IS PROVIDED "AS IS", AND IBM DISCLAIMS ALL WARRANTIES, |
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36 | * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A |
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37 | * PARTICULAR PURPOSE. IN NO EVENT SHALL IBM BE LIABLE FOR ANY SPECIAL, |
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38 | * DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER ARISING |
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39 | * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE, EVEN |
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40 | * IF IBM IS APPRISED OF THE POSSIBILITY OF SUCH DAMAGES. |
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41 | */ |
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42 | |
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43 | #if !defined(LINT) && !defined(CODECENTER) |
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44 | static const char rcsid[] = "$BINDId: base64.c,v 8.7 1999/10/13 16:39:33 vixie Exp $"; |
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45 | #endif /* not lint */ |
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46 | |
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47 | #include <sys/types.h> |
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48 | #include <sys/param.h> |
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49 | #include <sys/socket.h> |
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50 | |
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51 | #include <netinet/in.h> |
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52 | #include <arpa/inet.h> |
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53 | #include <arpa/nameser.h> |
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54 | |
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55 | #include <ctype.h> |
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56 | #include <resolv.h> |
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57 | #include <stdio.h> |
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58 | #include <stdlib.h> |
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59 | #include <string.h> |
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60 | |
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61 | #include "libc-symbols.h" |
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62 | |
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63 | #define Assert(Cond) if (!(Cond)) abort() |
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64 | |
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65 | static const char Base64[] = |
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66 | "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; |
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67 | static const char Pad64 = '='; |
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68 | |
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69 | /* (From RFC1521 and draft-ietf-dnssec-secext-03.txt) |
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70 | The following encoding technique is taken from RFC 1521 by Borenstein |
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71 | and Freed. It is reproduced here in a slightly edited form for |
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72 | convenience. |
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73 | |
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74 | A 65-character subset of US-ASCII is used, enabling 6 bits to be |
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75 | represented per printable character. (The extra 65th character, "=", |
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76 | is used to signify a special processing function.) |
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77 | |
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78 | The encoding process represents 24-bit groups of input bits as output |
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79 | strings of 4 encoded characters. Proceeding from left to right, a |
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80 | 24-bit input group is formed by concatenating 3 8-bit input groups. |
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81 | These 24 bits are then treated as 4 concatenated 6-bit groups, each |
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82 | of which is translated into a single digit in the base64 alphabet. |
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83 | |
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84 | Each 6-bit group is used as an index into an array of 64 printable |
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85 | characters. The character referenced by the index is placed in the |
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86 | output string. |
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87 | |
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88 | Table 1: The Base64 Alphabet |
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89 | |
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90 | Value Encoding Value Encoding Value Encoding Value Encoding |
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91 | 0 A 17 R 34 i 51 z |
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92 | 1 B 18 S 35 j 52 0 |
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93 | 2 C 19 T 36 k 53 1 |
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94 | 3 D 20 U 37 l 54 2 |
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95 | 4 E 21 V 38 m 55 3 |
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96 | 5 F 22 W 39 n 56 4 |
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97 | 6 G 23 X 40 o 57 5 |
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98 | 7 H 24 Y 41 p 58 6 |
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99 | 8 I 25 Z 42 q 59 7 |
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100 | 9 J 26 a 43 r 60 8 |
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101 | 10 K 27 b 44 s 61 9 |
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102 | 11 L 28 c 45 t 62 + |
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103 | 12 M 29 d 46 u 63 / |
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104 | 13 N 30 e 47 v |
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105 | 14 O 31 f 48 w (pad) = |
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106 | 15 P 32 g 49 x |
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107 | 16 Q 33 h 50 y |
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108 | |
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109 | Special processing is performed if fewer than 24 bits are available |
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110 | at the end of the data being encoded. A full encoding quantum is |
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111 | always completed at the end of a quantity. When fewer than 24 input |
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112 | bits are available in an input group, zero bits are added (on the |
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113 | right) to form an integral number of 6-bit groups. Padding at the |
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114 | end of the data is performed using the '=' character. |
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115 | |
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116 | Since all base64 input is an integral number of octets, only the |
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117 | ------------------------------------------------- |
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118 | following cases can arise: |
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119 | |
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120 | (1) the final quantum of encoding input is an integral |
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121 | multiple of 24 bits; here, the final unit of encoded |
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122 | output will be an integral multiple of 4 characters |
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123 | with no "=" padding, |
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124 | (2) the final quantum of encoding input is exactly 8 bits; |
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125 | here, the final unit of encoded output will be two |
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126 | characters followed by two "=" padding characters, or |
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127 | (3) the final quantum of encoding input is exactly 16 bits; |
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128 | here, the final unit of encoded output will be three |
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129 | characters followed by one "=" padding character. |
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130 | */ |
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131 | |
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132 | int |
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133 | b64_ntop(u_char const *src, size_t srclength, char *target, size_t targsize) { |
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134 | size_t datalength = 0; |
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135 | u_char input[3]; |
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136 | u_char output[4]; |
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137 | size_t i; |
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138 | |
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139 | while (2 < srclength) { |
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140 | input[0] = *src++; |
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141 | input[1] = *src++; |
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142 | input[2] = *src++; |
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143 | srclength -= 3; |
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144 | |
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145 | output[0] = input[0] >> 2; |
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146 | output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4); |
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147 | output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6); |
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148 | output[3] = input[2] & 0x3f; |
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149 | Assert(output[0] < 64); |
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150 | Assert(output[1] < 64); |
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151 | Assert(output[2] < 64); |
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152 | Assert(output[3] < 64); |
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153 | |
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154 | if (datalength + 4 > targsize) |
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155 | return (-1); |
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156 | target[datalength++] = Base64[output[0]]; |
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157 | target[datalength++] = Base64[output[1]]; |
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158 | target[datalength++] = Base64[output[2]]; |
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159 | target[datalength++] = Base64[output[3]]; |
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160 | } |
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161 | |
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162 | /* Now we worry about padding. */ |
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163 | if (0 != srclength) { |
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164 | /* Get what's left. */ |
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165 | input[0] = input[1] = input[2] = '\0'; |
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166 | for (i = 0; i < srclength; i++) |
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167 | input[i] = *src++; |
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168 | |
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169 | output[0] = input[0] >> 2; |
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170 | output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4); |
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171 | output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6); |
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172 | Assert(output[0] < 64); |
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173 | Assert(output[1] < 64); |
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174 | Assert(output[2] < 64); |
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175 | |
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176 | if (datalength + 4 > targsize) |
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177 | return (-1); |
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178 | target[datalength++] = Base64[output[0]]; |
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179 | target[datalength++] = Base64[output[1]]; |
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180 | if (srclength == 1) |
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181 | target[datalength++] = Pad64; |
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182 | else |
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183 | target[datalength++] = Base64[output[2]]; |
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184 | target[datalength++] = Pad64; |
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185 | } |
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186 | if (datalength >= targsize) |
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187 | return (-1); |
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188 | target[datalength] = '\0'; /* Returned value doesn't count \0. */ |
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189 | return (datalength); |
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190 | } |
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191 | libresolv_hidden_def (b64_ntop) |
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192 | |
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193 | /* skips all whitespace anywhere. |
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194 | converts characters, four at a time, starting at (or after) |
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195 | src from base - 64 numbers into three 8 bit bytes in the target area. |
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196 | it returns the number of data bytes stored at the target, or -1 on error. |
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197 | */ |
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198 | |
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199 | int |
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200 | b64_pton(src, target, targsize) |
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201 | char const *src; |
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202 | u_char *target; |
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203 | size_t targsize; |
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204 | { |
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205 | int tarindex, state, ch; |
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206 | char *pos; |
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207 | |
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208 | state = 0; |
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209 | tarindex = 0; |
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210 | |
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211 | while ((ch = *src++) != '\0') { |
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212 | if (isspace(ch)) /* Skip whitespace anywhere. */ |
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213 | continue; |
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214 | |
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215 | if (ch == Pad64) |
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216 | break; |
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217 | |
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218 | pos = strchr(Base64, ch); |
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219 | if (pos == 0) /* A non-base64 character. */ |
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220 | return (-1); |
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221 | |
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222 | switch (state) { |
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223 | case 0: |
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224 | if (target) { |
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225 | if ((size_t)tarindex >= targsize) |
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226 | return (-1); |
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227 | target[tarindex] = (pos - Base64) << 2; |
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228 | } |
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229 | state = 1; |
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230 | break; |
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231 | case 1: |
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232 | if (target) { |
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233 | if ((size_t)tarindex + 1 >= targsize) |
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234 | return (-1); |
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235 | target[tarindex] |= (pos - Base64) >> 4; |
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236 | target[tarindex+1] = ((pos - Base64) & 0x0f) |
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237 | << 4 ; |
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238 | } |
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239 | tarindex++; |
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240 | state = 2; |
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241 | break; |
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242 | case 2: |
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243 | if (target) { |
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244 | if ((size_t)tarindex + 1 >= targsize) |
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245 | return (-1); |
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246 | target[tarindex] |= (pos - Base64) >> 2; |
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247 | target[tarindex+1] = ((pos - Base64) & 0x03) |
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248 | << 6; |
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249 | } |
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250 | tarindex++; |
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251 | state = 3; |
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252 | break; |
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253 | case 3: |
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254 | if (target) { |
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255 | if ((size_t)tarindex >= targsize) |
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256 | return (-1); |
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257 | target[tarindex] |= (pos - Base64); |
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258 | } |
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259 | tarindex++; |
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260 | state = 0; |
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261 | break; |
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262 | default: |
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263 | abort(); |
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264 | } |
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265 | } |
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266 | |
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267 | /* |
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268 | * We are done decoding Base-64 chars. Let's see if we ended |
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269 | * on a byte boundary, and/or with erroneous trailing characters. |
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270 | */ |
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271 | |
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272 | if (ch == Pad64) { /* We got a pad char. */ |
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273 | ch = *src++; /* Skip it, get next. */ |
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274 | switch (state) { |
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275 | case 0: /* Invalid = in first position */ |
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276 | case 1: /* Invalid = in second position */ |
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277 | return (-1); |
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278 | |
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279 | case 2: /* Valid, means one byte of info */ |
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280 | /* Skip any number of spaces. */ |
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281 | for ((void)NULL; ch != '\0'; ch = *src++) |
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282 | if (!isspace(ch)) |
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283 | break; |
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284 | /* Make sure there is another trailing = sign. */ |
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285 | if (ch != Pad64) |
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286 | return (-1); |
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287 | ch = *src++; /* Skip the = */ |
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288 | /* Fall through to "single trailing =" case. */ |
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289 | /* FALLTHROUGH */ |
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290 | |
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291 | case 3: /* Valid, means two bytes of info */ |
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292 | /* |
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293 | * We know this char is an =. Is there anything but |
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294 | * whitespace after it? |
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295 | */ |
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296 | for ((void)NULL; ch != '\0'; ch = *src++) |
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297 | if (!isspace(ch)) |
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298 | return (-1); |
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299 | |
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300 | /* |
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301 | * Now make sure for cases 2 and 3 that the "extra" |
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302 | * bits that slopped past the last full byte were |
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303 | * zeros. If we don't check them, they become a |
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304 | * subliminal channel. |
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305 | */ |
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306 | if (target && target[tarindex] != 0) |
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307 | return (-1); |
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308 | } |
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309 | } else { |
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310 | /* |
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311 | * We ended by seeing the end of the string. Make sure we |
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312 | * have no partial bytes lying around. |
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313 | */ |
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314 | if (state != 0) |
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315 | return (-1); |
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316 | } |
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317 | |
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318 | return (tarindex); |
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319 | } |
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