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380
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1 /* LibTomCrypt, modular cryptographic library -- Tom St Denis |
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2 * |
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3 * LibTomCrypt is a library that provides various cryptographic |
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4 * algorithms in a highly modular and flexible manner. |
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5 * |
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6 * The library is free for all purposes without any express |
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7 * guarantee it works. |
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8 * |
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9 * Tom St Denis, [email protected], http://libtomcrypt.com |
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10 */ |
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11 #include "tomcrypt.h" |
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12 |
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13 /** |
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14 @file der_decode_sequence_flexi.c |
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15 ASN.1 DER, decode an array of ASN.1 types with a flexi parser, Tom St Denis |
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16 */ |
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17 |
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18 #ifdef LTC_DER |
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19 |
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20 static unsigned long fetch_length(const unsigned char *in, unsigned long inlen) |
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21 { |
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22 unsigned long x, y, z; |
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23 |
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24 y = 0; |
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25 |
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26 /* skip type and read len */ |
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27 if (inlen < 2) { |
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28 return 0xFFFFFFFF; |
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29 } |
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30 ++in; ++y; |
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31 |
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32 /* read len */ |
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33 x = *in++; ++y; |
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34 |
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35 /* <128 means literal */ |
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36 if (x < 128) { |
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37 return x+y; |
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38 } |
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39 x &= 0x7F; /* the lower 7 bits are the length of the length */ |
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40 inlen -= 2; |
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41 |
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42 /* len means len of len! */ |
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43 if (x == 0 || x > 4 || x > inlen) { |
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44 return 0xFFFFFFFF; |
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45 } |
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46 |
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47 y += x; |
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48 z = 0; |
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49 while (x--) { |
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50 z = (z<<8) | ((unsigned long)*in); |
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51 ++in; |
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52 } |
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53 return z+y; |
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54 } |
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55 |
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56 /** |
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57 ASN.1 DER Flexi(ble) decoder will decode arbitrary DER packets and create a linked list of the decoded elements. |
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58 @param in The input buffer |
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59 @param inlen [in/out] The length of the input buffer and on output the amount of decoded data |
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60 @param out [out] A pointer to the linked list |
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61 @return CRYPT_OK on success. |
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62 */ |
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63 int der_decode_sequence_flexi(const unsigned char *in, unsigned long *inlen, ltc_asn1_list **out) |
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64 { |
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65 ltc_asn1_list *l; |
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66 unsigned long err, type, len, totlen, x, y; |
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67 void *realloc_tmp; |
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68 |
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69 LTC_ARGCHK(in != NULL); |
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70 LTC_ARGCHK(inlen != NULL); |
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71 LTC_ARGCHK(out != NULL); |
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72 |
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73 l = NULL; |
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74 totlen = 0; |
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75 |
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76 /* scan the input and and get lengths and what not */ |
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77 while (*inlen) { |
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78 /* read the type byte */ |
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79 type = *in; |
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80 |
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81 /* fetch length */ |
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82 len = fetch_length(in, *inlen); |
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83 if (len > *inlen) { |
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84 err = CRYPT_INVALID_PACKET; |
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85 goto error; |
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86 } |
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87 |
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88 /* alloc new link */ |
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89 if (l == NULL) { |
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90 l = XCALLOC(1, sizeof(*l)); |
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91 if (l == NULL) { |
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92 err = CRYPT_MEM; |
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93 goto error; |
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94 } |
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95 } else { |
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96 l->next = XCALLOC(1, sizeof(*l)); |
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97 if (l->next == NULL) { |
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98 err = CRYPT_MEM; |
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99 goto error; |
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100 } |
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101 l->next->prev = l; |
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102 l = l->next; |
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103 } |
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104 |
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105 /* now switch on type */ |
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106 switch (type) { |
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107 case 0x01: /* BOOLEAN */ |
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108 l->type = LTC_ASN1_BOOLEAN; |
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109 l->size = 1; |
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110 l->data = XCALLOC(1, sizeof(int)); |
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111 |
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112 if ((err = der_decode_boolean(in, *inlen, l->data)) != CRYPT_OK) { |
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113 goto error; |
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114 } |
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115 |
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116 if ((err = der_length_boolean(&len)) != CRYPT_OK) { |
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117 goto error; |
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118 } |
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119 break; |
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120 |
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121 case 0x02: /* INTEGER */ |
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122 /* init field */ |
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123 l->type = LTC_ASN1_INTEGER; |
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124 l->size = 1; |
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125 if ((err = mp_init(&l->data)) != CRYPT_OK) { |
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126 goto error; |
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127 } |
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128 |
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129 /* decode field */ |
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130 if ((err = der_decode_integer(in, *inlen, l->data)) != CRYPT_OK) { |
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131 goto error; |
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132 } |
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133 |
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134 /* calc length of object */ |
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135 if ((err = der_length_integer(l->data, &len)) != CRYPT_OK) { |
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136 goto error; |
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137 } |
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138 break; |
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139 |
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140 case 0x03: /* BIT */ |
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141 /* init field */ |
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142 l->type = LTC_ASN1_BIT_STRING; |
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143 l->size = len * 8; /* *8 because we store decoded bits one per char and they are encoded 8 per char. */ |
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144 |
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145 if ((l->data = XCALLOC(1, l->size)) == NULL) { |
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146 err = CRYPT_MEM; |
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147 goto error; |
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148 } |
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149 |
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150 if ((err = der_decode_bit_string(in, *inlen, l->data, &l->size)) != CRYPT_OK) { |
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151 goto error; |
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152 } |
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153 |
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154 if ((err = der_length_bit_string(l->size, &len)) != CRYPT_OK) { |
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155 goto error; |
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156 } |
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157 break; |
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158 |
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159 case 0x04: /* OCTET */ |
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160 |
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161 /* init field */ |
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162 l->type = LTC_ASN1_OCTET_STRING; |
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163 l->size = len; |
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164 |
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165 if ((l->data = XCALLOC(1, l->size)) == NULL) { |
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166 err = CRYPT_MEM; |
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167 goto error; |
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168 } |
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169 |
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170 if ((err = der_decode_octet_string(in, *inlen, l->data, &l->size)) != CRYPT_OK) { |
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171 goto error; |
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172 } |
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173 |
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174 if ((err = der_length_octet_string(l->size, &len)) != CRYPT_OK) { |
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175 goto error; |
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176 } |
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177 break; |
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178 |
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179 case 0x05: /* NULL */ |
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180 |
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181 /* valid NULL is 0x05 0x00 */ |
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182 if (in[0] != 0x05 || in[1] != 0x00) { |
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183 err = CRYPT_INVALID_PACKET; |
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184 goto error; |
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185 } |
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186 |
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187 /* simple to store ;-) */ |
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188 l->type = LTC_ASN1_NULL; |
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189 l->data = NULL; |
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190 l->size = 0; |
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191 len = 2; |
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192 |
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193 break; |
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194 |
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195 case 0x06: /* OID */ |
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196 |
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197 /* init field */ |
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198 l->type = LTC_ASN1_OBJECT_IDENTIFIER; |
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199 l->size = len; |
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200 |
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201 if ((l->data = XCALLOC(len, sizeof(unsigned long))) == NULL) { |
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202 err = CRYPT_MEM; |
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203 goto error; |
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204 } |
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205 |
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206 if ((err = der_decode_object_identifier(in, *inlen, l->data, &l->size)) != CRYPT_OK) { |
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207 goto error; |
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208 } |
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209 |
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210 if ((err = der_length_object_identifier(l->data, l->size, &len)) != CRYPT_OK) { |
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211 goto error; |
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212 } |
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213 |
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214 /* resize it to save a bunch of mem */ |
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215 if ((realloc_tmp = XREALLOC(l->data, l->size * sizeof(unsigned long))) == NULL) { |
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216 /* out of heap but this is not an error */ |
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217 break; |
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218 } |
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219 l->data = realloc_tmp; |
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220 break; |
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221 |
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222 case 0x0C: /* UTF8 */ |
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223 |
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224 /* init field */ |
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225 l->type = LTC_ASN1_UTF8_STRING; |
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226 l->size = len; |
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227 |
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228 if ((l->data = XCALLOC(sizeof(wchar_t), l->size)) == NULL) { |
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229 err = CRYPT_MEM; |
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230 goto error; |
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231 } |
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232 |
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233 if ((err = der_decode_utf8_string(in, *inlen, l->data, &l->size)) != CRYPT_OK) { |
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234 goto error; |
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235 } |
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236 |
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237 if ((err = der_length_utf8_string(l->data, l->size, &len)) != CRYPT_OK) { |
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238 goto error; |
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239 } |
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240 break; |
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241 |
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242 case 0x13: /* PRINTABLE */ |
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243 |
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244 /* init field */ |
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245 l->type = LTC_ASN1_PRINTABLE_STRING; |
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246 l->size = len; |
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247 |
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248 if ((l->data = XCALLOC(1, l->size)) == NULL) { |
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249 err = CRYPT_MEM; |
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250 goto error; |
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251 } |
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252 |
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253 if ((err = der_decode_printable_string(in, *inlen, l->data, &l->size)) != CRYPT_OK) { |
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254 goto error; |
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255 } |
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256 |
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257 if ((err = der_length_printable_string(l->data, l->size, &len)) != CRYPT_OK) { |
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258 goto error; |
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259 } |
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260 break; |
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261 |
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262 case 0x16: /* IA5 */ |
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263 |
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264 /* init field */ |
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265 l->type = LTC_ASN1_IA5_STRING; |
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266 l->size = len; |
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267 |
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268 if ((l->data = XCALLOC(1, l->size)) == NULL) { |
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269 err = CRYPT_MEM; |
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270 goto error; |
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271 } |
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272 |
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273 if ((err = der_decode_ia5_string(in, *inlen, l->data, &l->size)) != CRYPT_OK) { |
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274 goto error; |
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275 } |
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276 |
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277 if ((err = der_length_ia5_string(l->data, l->size, &len)) != CRYPT_OK) { |
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278 goto error; |
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279 } |
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280 break; |
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281 |
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282 case 0x17: /* UTC TIME */ |
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283 |
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284 /* init field */ |
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285 l->type = LTC_ASN1_UTCTIME; |
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286 l->size = 1; |
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287 |
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288 if ((l->data = XCALLOC(1, sizeof(ltc_utctime))) == NULL) { |
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289 err = CRYPT_MEM; |
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290 goto error; |
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291 } |
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292 |
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293 len = *inlen; |
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294 if ((err = der_decode_utctime(in, &len, l->data)) != CRYPT_OK) { |
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295 goto error; |
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296 } |
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297 |
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298 if ((err = der_length_utctime(l->data, &len)) != CRYPT_OK) { |
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299 goto error; |
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300 } |
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301 break; |
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302 |
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303 case 0x30: /* SEQUENCE */ |
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304 case 0x31: /* SET */ |
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305 |
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306 /* init field */ |
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307 l->type = (type == 0x30) ? LTC_ASN1_SEQUENCE : LTC_ASN1_SET; |
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308 |
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309 /* we have to decode the SEQUENCE header and get it's length */ |
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310 |
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311 /* move past type */ |
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312 ++in; --(*inlen); |
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313 |
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314 /* read length byte */ |
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315 x = *in++; --(*inlen); |
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316 |
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317 /* smallest SEQUENCE/SET header */ |
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318 y = 2; |
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319 |
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320 /* now if it's > 127 the next bytes are the length of the length */ |
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321 if (x > 128) { |
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322 x &= 0x7F; |
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323 in += x; |
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324 *inlen -= x; |
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325 |
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326 /* update sequence header len */ |
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327 y += x; |
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328 } |
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329 |
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330 /* Sequence elements go as child */ |
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331 len = len - y; |
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332 if ((err = der_decode_sequence_flexi(in, &len, &(l->child))) != CRYPT_OK) { |
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333 goto error; |
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334 } |
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335 |
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336 /* len update */ |
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337 totlen += y; |
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338 |
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339 /* link them up y0 */ |
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340 l->child->parent = l; |
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341 |
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342 break; |
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343 default: |
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344 /* invalid byte ... this is a soft error */ |
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345 /* remove link */ |
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346 l = l->prev; |
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347 XFREE(l->next); |
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348 l->next = NULL; |
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349 goto outside; |
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350 } |
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351 |
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352 /* advance pointers */ |
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353 totlen += len; |
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354 in += len; |
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355 *inlen -= len; |
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356 } |
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357 |
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358 outside: |
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359 |
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360 /* rewind l please */ |
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361 while (l->prev != NULL || l->parent != NULL) { |
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362 if (l->parent != NULL) { |
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363 l = l->parent; |
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364 } else { |
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365 l = l->prev; |
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366 } |
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367 } |
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368 |
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369 /* return */ |
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370 *out = l; |
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371 *inlen = totlen; |
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372 return CRYPT_OK; |
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373 |
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374 error: |
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375 /* free list */ |
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376 der_sequence_free(l); |
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377 |
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378 return err; |
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379 } |
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380 |
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381 #endif |
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382 |
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383 |
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384 /* $Source: /cvs/libtom/libtomcrypt/src/pk/asn1/der/sequence/der_decode_sequence_flexi.c,v $ */ |
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385 /* $Revision: 1.25 $ */ |
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386 /* $Date: 2006/11/26 02:25:18 $ */ |
