1 | /* -*- c-basic-offset: 8 -*-
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2 | rdesktop: A Remote Desktop Protocol client.
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3 | ASN.1 utility functions
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4 | Copyright 2012 Henrik Andersson <hean01@cendio.se> for Cendio AB
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5 |
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6 | This program is free software: you can redistribute it and/or modify
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7 | it under the terms of the GNU General Public License as published by
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8 | the Free Software Foundation, either version 3 of the License, or
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9 | (at your option) any later version.
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10 |
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11 | This program is distributed in the hope that it will be useful,
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12 | but WITHOUT ANY WARRANTY; without even the implied warranty of
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13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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14 | GNU General Public License for more details.
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15 |
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16 | You should have received a copy of the GNU General Public License
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17 | along with this program. If not, see <http://www.gnu.org/licenses/>.
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18 | */
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19 |
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20 | /*
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21 | * Oracle GPL Disclaimer: For the avoidance of doubt, except that if any license choice
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22 | * other than GPL or LGPL is available it will apply instead, Oracle elects to use only
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23 | * the General Public License version 2 (GPLv2) at this time for any software where
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24 | * a choice of GPL license versions is made available with the language indicating
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25 | * that GPLv2 or any later version may be used, or where a choice of which version
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26 | * of the GPL is applied is otherwise unspecified.
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27 | */
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28 |
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29 | #include "rdesktop.h"
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30 |
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31 |
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32 | /* Parse an ASN.1 BER header */
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33 | RD_BOOL
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34 | ber_parse_header(STREAM s, int tagval, int *length)
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35 | {
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36 | int tag, len;
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37 |
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38 | if (tagval > 0xff)
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39 | {
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40 | in_uint16_be(s, tag);
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41 | }
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42 | else
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43 | {
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44 | in_uint8(s, tag);
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45 | }
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46 |
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47 | if (tag != tagval)
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48 | {
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49 | error("expected tag %d, got %d\n", tagval, tag);
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50 | return False;
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51 | }
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52 |
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53 | in_uint8(s, len);
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54 |
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55 | if (len & 0x80)
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56 | {
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57 | len &= ~0x80;
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58 | *length = 0;
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59 | while (len--)
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60 | next_be(s, *length);
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61 | }
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62 | else
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63 | *length = len;
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64 |
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65 | return s_check(s);
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66 | }
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67 |
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68 | /* Output an ASN.1 BER header */
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69 | void
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70 | ber_out_header(STREAM s, int tagval, int length)
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71 | {
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72 | if (tagval > 0xff)
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73 | {
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74 | out_uint16_be(s, tagval);
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75 | }
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76 | else
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77 | {
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78 | out_uint8(s, tagval);
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79 | }
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80 |
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81 | if (length >= 0x80)
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82 | {
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83 | out_uint8(s, 0x82);
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84 | out_uint16_be(s, length);
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85 | }
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86 | else
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87 | out_uint8(s, length);
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88 | }
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89 |
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90 | /* Output an ASN.1 BER integer */
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91 | void
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92 | ber_out_integer(STREAM s, int value)
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93 | {
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94 | ber_out_header(s, BER_TAG_INTEGER, 2);
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95 | out_uint16_be(s, value);
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96 | }
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97 |
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98 | RD_BOOL
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99 | ber_in_header(STREAM s, int *tagval, int *decoded_len)
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100 | {
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101 | in_uint8(s, *tagval);
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102 | in_uint8(s, *decoded_len);
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103 |
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104 | if (*decoded_len < 0x80)
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105 | return True;
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106 | else if (*decoded_len == 0x81)
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107 | {
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108 | in_uint8(s, *decoded_len);
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109 | return True;
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110 | }
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111 | else if (*decoded_len == 0x82)
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112 | {
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113 | in_uint16_be(s, *decoded_len);
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114 | return True;
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115 | }
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116 |
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117 | return False;
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118 | }
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