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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_utf8_string.c |
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15 ASN.1 DER, encode a UTF8 STRING, Tom St Denis |
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16 */ |
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17 |
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18 |
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19 #ifdef LTC_DER |
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20 |
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21 /** |
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22 Store a UTF8 STRING |
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23 @param in The DER encoded UTF8 STRING |
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24 @param inlen The size of the DER UTF8 STRING |
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25 @param out [out] The array of utf8s stored (one per char) |
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26 @param outlen [in/out] The number of utf8s stored |
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27 @return CRYPT_OK if successful |
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28 */ |
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29 int der_decode_utf8_string(const unsigned char *in, unsigned long inlen, |
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30 wchar_t *out, unsigned long *outlen) |
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31 { |
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32 wchar_t tmp; |
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33 unsigned long x, y, z, len; |
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34 |
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35 LTC_ARGCHK(in != NULL); |
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36 LTC_ARGCHK(out != NULL); |
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37 LTC_ARGCHK(outlen != NULL); |
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38 |
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39 /* must have header at least */ |
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40 if (inlen < 2) { |
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41 return CRYPT_INVALID_PACKET; |
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42 } |
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43 |
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44 /* check for 0x0C */ |
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45 if ((in[0] & 0x1F) != 0x0C) { |
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46 return CRYPT_INVALID_PACKET; |
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47 } |
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48 x = 1; |
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49 |
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50 /* decode the length */ |
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51 if (in[x] & 0x80) { |
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52 /* valid # of bytes in length are 1,2,3 */ |
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53 y = in[x] & 0x7F; |
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54 if ((y == 0) || (y > 3) || ((x + y) > inlen)) { |
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55 return CRYPT_INVALID_PACKET; |
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56 } |
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57 |
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58 /* read the length in */ |
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59 len = 0; |
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60 ++x; |
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61 while (y--) { |
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62 len = (len << 8) | in[x++]; |
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63 } |
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64 } else { |
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65 len = in[x++] & 0x7F; |
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66 } |
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67 |
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68 if (len + x > inlen) { |
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69 return CRYPT_INVALID_PACKET; |
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70 } |
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71 |
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72 /* proceed to decode */ |
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73 for (y = 0; x < inlen; ) { |
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74 /* get first byte */ |
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75 tmp = in[x++]; |
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76 |
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77 /* count number of bytes */ |
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78 for (z = 0; (tmp & 0x80) && (z <= 4); z++, tmp = (tmp << 1) & 0xFF); |
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79 |
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80 if (z > 4 || (x + (z - 1) > inlen)) { |
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81 return CRYPT_INVALID_PACKET; |
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82 } |
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83 |
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84 /* decode, grab upper bits */ |
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85 tmp >>= z; |
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86 |
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87 /* grab remaining bytes */ |
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88 if (z > 1) { --z; } |
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89 while (z-- != 0) { |
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90 if ((in[x] & 0xC0) != 0x80) { |
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91 return CRYPT_INVALID_PACKET; |
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92 } |
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93 tmp = (tmp << 6) | ((wchar_t)in[x++] & 0x3F); |
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94 } |
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95 |
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96 if (y > *outlen) { |
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97 *outlen = y; |
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98 return CRYPT_BUFFER_OVERFLOW; |
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99 } |
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100 out[y++] = tmp; |
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101 } |
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102 *outlen = y; |
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103 |
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104 return CRYPT_OK; |
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105 } |
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106 |
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107 #endif |
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108 |
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109 /* $Source: /cvs/libtom/libtomcrypt/src/pk/asn1/der/utf8/der_decode_utf8_string.c,v $ */ |
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110 /* $Revision: 1.7 $ */ |
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111 /* $Date: 2006/11/26 02:27:37 $ */ |
