1 | /*- |
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2 | * Copyright (c) 2013-2014 Universitetet i Oslo |
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3 | * All rights reserved. |
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4 | * |
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5 | * Redistribution and use in source and binary forms, with or without |
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6 | * modification, are permitted provided that the following conditions |
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7 | * are met: |
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8 | * 1. Redistributions of source code must retain the above copyright |
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9 | * notice, this list of conditions and the following disclaimer. |
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10 | * 2. Redistributions in binary form must reproduce the above copyright |
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11 | * notice, this list of conditions and the following disclaimer in the |
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12 | * documentation and/or other materials provided with the distribution. |
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13 | * 3. The name of the author may not be used to endorse or promote |
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14 | * products derived from this software without specific prior written |
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15 | * permission. |
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16 | * |
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17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND |
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18 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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19 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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20 | * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE |
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21 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
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22 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
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23 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
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24 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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25 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
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26 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
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27 | * SUCH DAMAGE. |
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28 | * |
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29 | * $Id: oath_key_from_uri.c 772 2014-03-09 11:45:05Z des $ |
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30 | */ |
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31 | |
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32 | #ifdef HAVE_CONFIG_H |
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33 | # include "config.h" |
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34 | #endif |
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35 | |
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36 | #include <sys/types.h> |
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37 | |
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38 | #include <inttypes.h> |
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39 | #include <string.h> |
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40 | |
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41 | #include <security/pam_appl.h> |
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42 | #include <security/openpam.h> |
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43 | |
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44 | #include "openpam_strlcmp.h" |
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45 | |
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46 | #include <security/oath.h> |
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47 | |
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48 | /* |
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49 | * OATH |
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50 | * |
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51 | * Creates an OATH key from a Google otpauth URI |
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52 | */ |
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53 | |
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54 | struct oath_key * |
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55 | oath_key_from_uri(const char *uri) |
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56 | { |
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57 | struct oath_key *key; |
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58 | const char *p, *q, *r; |
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59 | uintmax_t n; |
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60 | char *e; |
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61 | |
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62 | if ((key = oath_key_alloc()) == NULL) |
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63 | return (NULL); |
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64 | |
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65 | /* check method */ |
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66 | p = uri; |
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67 | if (strlcmp("otpauth://", p, 10) != 0) |
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68 | goto invalid; |
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69 | p += 10; |
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70 | |
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71 | /* check mode (hotp = event, totp = time-sync) */ |
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72 | if ((q = strchr(p, '/')) == NULL) |
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73 | goto invalid; |
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74 | if (strlcmp("hotp", p, q - p) == 0) { |
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75 | key->mode = om_hotp; |
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76 | } else if (strlcmp("totp", p, q - p) == 0) { |
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77 | key->mode = om_totp; |
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78 | } else { |
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79 | goto invalid; |
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80 | } |
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81 | p = q + 1; |
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82 | |
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83 | /* extract label */ |
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84 | if ((q = strchr(p, '?')) == NULL) |
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85 | goto invalid; |
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86 | key->labellen = oath_uri_decode(p, q - p, key->label, |
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87 | sizeof key->label); |
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88 | if (key->labellen > sizeof key->label) |
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89 | goto invalid; |
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90 | p = q + 1; |
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91 | |
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92 | /* extract parameters */ |
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93 | key->counter = UINT64_MAX; |
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94 | key->lastused = UINT64_MAX; |
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95 | while (*p != '\0') { |
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96 | if ((q = strchr(p, '=')) == NULL) |
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97 | goto invalid; |
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98 | q = q + 1; |
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99 | if ((r = strchr(p, '&')) == NULL) |
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100 | r = strchr(p, '\0'); |
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101 | if (r < q) |
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102 | /* & before = */ |
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103 | goto invalid; |
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104 | /* p points to key, q points to value, r points to & or NUL */ |
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105 | if (strlcmp("secret=", p, q - p) == 0) { |
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106 | if (key->keylen != 0) |
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107 | /* dupe */ |
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108 | goto invalid; |
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109 | key->keylen = sizeof key->key; |
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110 | if (base32_dec(q, r - q, (char *)key->key, &key->keylen) != 0) |
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111 | goto invalid; |
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112 | if (base32_enclen(key->keylen) != (size_t)(r - q)) |
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113 | goto invalid; |
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114 | } else if (strlcmp("algorithm=", p, q - p) == 0) { |
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115 | if (key->hash != oh_undef) |
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116 | /* dupe */ |
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117 | goto invalid; |
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118 | if (strlcmp("SHA1", q, r - q) == 0) |
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119 | key->hash = oh_sha1; |
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120 | else if (strlcmp("SHA256", q, r - q) == 0) |
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121 | key->hash = oh_sha256; |
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122 | else if (strlcmp("SHA512", q, r - q) == 0) |
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123 | key->hash = oh_sha512; |
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124 | else if (strlcmp("MD5", q, r - q) == 0) |
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125 | key->hash = oh_md5; |
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126 | else |
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127 | goto invalid; |
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128 | } else if (strlcmp("digits=", p, q - p) == 0) { |
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129 | if (key->digits != 0) |
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130 | /* dupe */ |
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131 | goto invalid; |
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132 | /* only 6 or 8 */ |
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133 | if (r - q != 1 || (*q != '6' && *q != '8')) |
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134 | goto invalid; |
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135 | key->digits = *q - '0'; |
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136 | } else if (strlcmp("counter=", p, q - p) == 0) { |
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137 | if (key->counter != UINT64_MAX) |
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138 | /* dupe */ |
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139 | goto invalid; |
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140 | n = strtoumax(q, &e, 10); |
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141 | if (e != r || n >= UINT64_MAX) |
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142 | goto invalid; |
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143 | key->counter = (uint64_t)n; |
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144 | } else if (strlcmp("lastused=", p, q - p) == 0) { |
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145 | if (key->lastused != UINT64_MAX) |
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146 | /* dupe */ |
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147 | goto invalid; |
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148 | n = strtoumax(q, &e, 10); |
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149 | if (e != r || n >= UINT64_MAX) |
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150 | goto invalid; |
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151 | key->lastused = (uint64_t)n; |
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152 | } else if (strlcmp("period=", p, q - p) == 0) { |
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153 | if (key->timestep != 0) |
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154 | /* dupe */ |
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155 | goto invalid; |
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156 | n = strtoumax(q, &e, 10); |
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157 | if (e != r || n > OATH_MAX_TIMESTEP) |
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158 | goto invalid; |
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159 | key->timestep = n; |
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160 | } else { |
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161 | goto invalid; |
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162 | } |
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163 | /* final parameter? */ |
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164 | if (*r == '\0') |
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165 | break; |
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166 | /* skip & and continue */ |
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167 | p = r + 1; |
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168 | } |
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169 | |
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170 | /* sanity checks and default values */ |
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171 | if (key->mode == om_hotp) { |
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172 | if (key->counter == UINT64_MAX) |
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173 | key->counter = 0; |
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174 | if (key->timestep != 0) |
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175 | goto invalid; |
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176 | if (key->lastused != UINT64_MAX) |
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177 | goto invalid; |
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178 | } else if (key->mode == om_totp) { |
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179 | if (key->counter != UINT64_MAX) |
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180 | goto invalid; |
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181 | if (key->timestep == 0) |
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182 | key->timestep = OATH_DEF_TIMESTEP; |
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183 | if (key->lastused == UINT64_MAX) |
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184 | key->lastused = 0; |
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185 | } else { |
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186 | /* unreachable */ |
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187 | oath_key_free(key); |
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188 | return (NULL); |
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189 | } |
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190 | if (key->hash == oh_undef) |
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191 | key->hash = oh_sha1; |
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192 | if (key->digits == 0) |
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193 | key->digits = 6; |
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194 | if (key->keylen == 0) |
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195 | goto invalid; |
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196 | return (key); |
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197 | |
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198 | invalid: |
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199 | openpam_log(PAM_LOG_NOTICE, "invalid OATH URI: %s", uri); |
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200 | oath_key_free(key); |
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201 | return (NULL); |
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202 | } |
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203 | |
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204 | /** |
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205 | * The =oath_key_from_uri parses a Google otpauth URI into a key |
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206 | * structure. |
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207 | * |
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208 | * The =uri parameter points to a NUL-terminated string containing the |
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209 | * URI. |
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210 | * |
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211 | * Keys created with =oath_key_from_uri must be freed using |
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212 | * =oath_key_free. |
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213 | * |
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214 | * >oath_key_alloc |
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215 | * >oath_key_free |
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216 | * >oath_key_to_uri |
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217 | * |
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218 | * REFERENCES |
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219 | * |
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220 | * https://code.google.com/p/google-authenticator/wiki/KeyUriFormat |
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221 | * |
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222 | * AUTHOR UIO |
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223 | */ |
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