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292 | daniel-mar | 1 | /* |
2 | This file is part of "Filter Foundry", a filter plugin for Adobe Photoshop |
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3 | Copyright (C) 2003-2009 Toby Thain, toby@telegraphics.com.au |
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4 | Copyright (C) 2018-2021 Daniel Marschall, ViaThinkSoft |
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5 | |||
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 2 of the License, or |
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9 | (at your option) any later version. |
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10 | |||
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 | |||
16 | You should have received a copy of the GNU General Public License |
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17 | along with this program; if not, write to the Free Software |
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18 | Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
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19 | */ |
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20 | |||
21 | #include <stddef.h> |
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22 | #include <stdint.h> |
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23 | #include <assert.h> |
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24 | #include <time.h> |
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25 | |||
26 | #include "ff.h" |
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27 | |||
28 | const volatile uint32_t cObfuscV4Seed = 0x52830517; // this value will be manipulated during the building of each individual filter (see make_win.c) |
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29 | |||
30 | int rand_msvcc(unsigned int* seed) { |
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31 | *seed = *seed * 214013L + 2531011L; |
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32 | return (*seed >> 16) & 0x7fff; /* Scale between 0 and RAND_MAX */ |
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33 | } |
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34 | |||
35 | int rand_openwatcom(unsigned int* seed) { |
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36 | // https://github.com/open-watcom/open-watcom-v2/blob/master/bld/clib/math/c/rand.c |
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37 | *seed = *seed * 1103515245L + 12345L; |
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38 | return (*seed >> 16) & 0x7fff; /* Scale between 0 and RAND_MAX */ |
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39 | } |
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40 | |||
293 | daniel-mar | 41 | void xorshift(unsigned char** p, uint32_t* x32, size_t num) { |
292 | daniel-mar | 42 | size_t i; |
43 | unsigned char* x = *p; |
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44 | for (i = 0; i < num; i++) { |
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45 | // https://de.wikipedia.org/wiki/Xorshift |
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46 | *x32 ^= *x32 << 13; |
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47 | *x32 ^= *x32 >> 17; |
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48 | *x32 ^= *x32 << 5; |
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49 | *x++ ^= *x32; |
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50 | } |
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51 | *p = x; |
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52 | } |
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53 | |||
293 | daniel-mar | 54 | int obfuscation_version(PARM_T* pparm) { |
309 | daniel-mar | 55 | uint32_t obfusc_info = pparm->unknown2; |
292 | daniel-mar | 56 | |
57 | if (obfusc_info == 0x00000000) { // 00 00 00 00 |
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58 | // Photoshop FilterFactory default initialization |
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59 | // (no obfuscation) |
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60 | return 0; |
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61 | } |
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62 | else if (obfusc_info == 0x00000001) { // 01 00 00 00 |
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63 | // Premiere FilterFactory default initialization |
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64 | // (no obfuscation) |
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65 | return 0; |
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66 | } |
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67 | else if (obfusc_info == 0x90E364A3) { // A3 64 E3 90 |
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68 | // Version 1 obfuscation (Filter Foundry 1.4b8,9,10) |
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69 | return 1; |
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70 | } |
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71 | else if (obfusc_info == 0xE2CFCA34) { // 34 CA CF E2 |
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72 | // Version 2 obfuscation (Filter Foundry 1.7b1) |
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73 | return 2; |
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74 | } |
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293 | daniel-mar | 75 | else if ((obfusc_info >= 4) && (obfusc_info <= 0xFF)) { // xx 00 00 00 |
292 | daniel-mar | 76 | // Version 4 obfuscation (Filter Foundry 1.7.0.7) |
77 | // Version 5 obfuscation (Filter Foundry 1.7.0.8) |
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293 | daniel-mar | 78 | // Future: Version 6, 7, 8, ... 255 |
292 | daniel-mar | 79 | return obfusc_info; |
80 | } |
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81 | else { |
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82 | // Version 3 obfuscation (Filter Foundry 1.7.0.5) |
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83 | // obfusc_info is the srand() seed and is equal to the time(0) build timestamp |
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84 | return 3; |
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85 | } |
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86 | } |
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87 | |||
311 | daniel-mar | 88 | uint32_t crc32b(char *data, int nLength) { |
89 | int i, j, k; |
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90 | unsigned int byte, crc, mask; |
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91 | |||
92 | i = 0; |
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93 | crc = 0xFFFFFFFF; |
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94 | |||
95 | for(k=0;k<nLength;k++) { |
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96 | byte = data[k]; |
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97 | crc = crc ^ byte; |
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98 | for (j = 7; j >= 0; j--) { |
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99 | mask = -(crc & 1); |
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100 | crc = (crc >> 1) ^ (0xEDB88320 & mask); |
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101 | } |
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102 | i++; |
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103 | } |
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104 | return ~crc; |
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105 | } |
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106 | |||
309 | daniel-mar | 107 | uint32_t obfusc(PARM_T* pparm) { |
293 | daniel-mar | 108 | // Windows: Version 5 obfuscation (Introduced in Filter Foundry 1.7.0.8) |
109 | // Macintosh: Version 4 obfuscation (Introduced in Filter Foundry 1.7.0.7) |
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292 | daniel-mar | 110 | |
111 | unsigned char* p; |
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112 | size_t size, seed_position; |
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309 | daniel-mar | 113 | uint32_t seed, initial_seed; |
114 | uint32_t obfusc_version; |
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292 | daniel-mar | 115 | |
116 | #ifdef MAC_ENV |
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293 | daniel-mar | 117 | // For Mac, we use obfuscation version 4, because the placing the seed into the produced executable code is not implemented in Mac! |
118 | // (It needs to be implemented in make_mac.c) |
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119 | initial_seed = OBFUSC_V4_DEFAULT_SEED; |
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120 | obfusc_version = 4; |
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292 | daniel-mar | 121 | #else |
293 | daniel-mar | 122 | // In obfuscation version 5, the seed is also the checksum. It will be verified at deobfusc()! |
311 | daniel-mar | 123 | initial_seed = crc32b(pparm,sizeof(PARM_T)); |
293 | daniel-mar | 124 | obfusc_version = 5; |
292 | daniel-mar | 125 | #endif |
126 | |||
127 | seed_position = offsetof(PARM_T, unknown2); |
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128 | size = sizeof(PARM_T); |
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293 | daniel-mar | 129 | seed = initial_seed; |
292 | daniel-mar | 130 | |
309 | daniel-mar | 131 | if (obfusc_version == 5) { |
132 | // make v4 and v5 intentionally incompatible to avoid a downgrade-attack |
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133 | seed ^= 0xFFFFFFFF; |
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134 | } |
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135 | |||
292 | daniel-mar | 136 | p = (unsigned char*)pparm; |
293 | daniel-mar | 137 | xorshift(&p, &seed, seed_position); |
309 | daniel-mar | 138 | *((uint32_t*)p) = obfusc_version; |
292 | daniel-mar | 139 | p += 4; |
293 | daniel-mar | 140 | xorshift(&p, &seed, size - seed_position - 4); |
292 | daniel-mar | 141 | |
142 | return initial_seed; |
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143 | } |
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144 | |||
145 | void deobfusc(PARM_T* pparm) { |
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309 | daniel-mar | 146 | uint32_t obfusc_version; |
292 | daniel-mar | 147 | size_t size = sizeof(PARM_T); |
148 | |||
293 | daniel-mar | 149 | obfusc_version = obfuscation_version(pparm); |
292 | daniel-mar | 150 | |
151 | switch (obfusc_version) { |
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152 | case 0: |
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153 | // no obfuscation |
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154 | return; |
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155 | case 1: { |
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156 | // Version 1 obfuscation (Filter Foundry 1.4b8,9,10) |
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157 | // Filter built with VC++ (official release by Toby Thain) |
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158 | |||
159 | unsigned char* p; |
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160 | size_t i; |
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309 | daniel-mar | 161 | uint32_t seed; |
292 | daniel-mar | 162 | |
163 | seed = 0xdc43df3c; |
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164 | |||
165 | for (i = size, p = (unsigned char*)pparm; i--;) { |
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166 | *p++ ^= rand_msvcc(&seed); |
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167 | } |
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168 | break; |
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169 | } |
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170 | case 2: { |
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171 | // Version 2 obfuscation (Filter Foundry 1.7b1) |
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172 | // Compiler independent |
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173 | |||
174 | unsigned char* p; |
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175 | size_t i; |
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309 | daniel-mar | 176 | uint32_t seed; |
292 | daniel-mar | 177 | |
178 | seed = 0x95d4a68f; |
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179 | |||
180 | for (i = size, p = (unsigned char*)pparm; i--;) { |
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181 | seed ^= seed << 13; |
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182 | seed ^= seed >> 17; |
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183 | seed ^= seed << 5; |
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184 | *p++ ^= seed; |
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185 | } |
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186 | break; |
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187 | } |
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188 | case 3: { |
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189 | // Version 3 obfuscation (Filter Foundry 1.7.0.5) |
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190 | // NO loading of other implementation supported, but that doesn't matter since |
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191 | // obfuscation and protection is combined in Filter Factory >= 1.7.0.5. |
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192 | // Using rand() is more secure, because it differs from compiler to compiler, so |
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193 | // it is harder to read a protected 8BF plugin. |
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194 | // Note that rand() in combination with srand() is deterministic, so it is safe |
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195 | // to use it: https://stackoverflow.com/questions/55438293/does-rand-function-in-c-follows-non-determinstc-algorithm |
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196 | // Note: 32-Bit FF is built using OpenWatcom (to support Win95), while 64-Bit FF is built using Microsoft Visual C++ |
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197 | |||
198 | unsigned char* p; |
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199 | size_t i; |
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309 | daniel-mar | 200 | uint32_t seed; |
292 | daniel-mar | 201 | size_t seed_position; |
202 | |||
203 | seed = pparm->unknown2; |
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204 | seed_position = offsetof(PARM_T, unknown2); // = offsetof(PARM_T_PREMIERE, unknown1) |
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205 | |||
206 | srand(seed); |
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207 | p = (unsigned char*)pparm; |
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208 | for (i = 0; i < seed_position; i++) *p++ ^= rand(); |
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309 | daniel-mar | 209 | *((uint32_t*)p) = 0; // here was the seed. Fill it with 0x00000000 |
292 | daniel-mar | 210 | p += 4; |
211 | for (i = 0; i < size - seed_position - 4; i++) *p++ ^= rand(); |
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212 | break; |
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213 | } |
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214 | case 4: |
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215 | case 5: { |
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216 | // Version 4 obfuscation (Filter Foundry 1.7.0.7) |
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217 | // Version 5 obfuscation (Filter Foundry 1.7.0.8) |
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218 | // Not compiler dependent, but individual for each build |
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219 | // It is important that this code works for both x86 and x64 indepdently from the used compiler, |
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220 | // otherwise, the cross-make x86/x64 won't work! |
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221 | // Version 5 contains a seed requirement (checksum). |
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222 | |||
223 | unsigned char* p; |
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224 | size_t seed_position; |
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309 | daniel-mar | 225 | uint32_t seed, initial_seed; |
292 | daniel-mar | 226 | |
309 | daniel-mar | 227 | initial_seed = cObfuscV4Seed; // this value will be manipulated during the building of each individual filter (see make_win.c) |
228 | |||
229 | seed = initial_seed; |
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292 | daniel-mar | 230 | seed_position = offsetof(PARM_T, unknown2); // = offsetof(PARM_T_PREMIERE, unknown1) |
231 | |||
309 | daniel-mar | 232 | if (obfusc_version == 5) { |
233 | // make v4 and v5 intentionally incompatible to avoid a downgrade-attack |
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234 | seed ^= 0xFFFFFFFF; |
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235 | } |
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236 | |||
292 | daniel-mar | 237 | p = (unsigned char*)pparm; |
293 | daniel-mar | 238 | xorshift(&p, &seed, seed_position); |
292 | daniel-mar | 239 | p += 4; // obfusc info == 4 |
293 | daniel-mar | 240 | xorshift(&p, &seed, size - seed_position - 4); |
292 | daniel-mar | 241 | |
242 | if (obfusc_version == 5) { |
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311 | daniel-mar | 243 | if (crc32b(pparm,sizeof(PARM_T)) != initial_seed) { |
292 | daniel-mar | 244 | // Integrity check failed! |
309 | daniel-mar | 245 | memset(pparm, 0, sizeof(PARM_T)); // invalidate everything |
292 | daniel-mar | 246 | } |
247 | } |
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248 | |||
249 | break; |
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250 | } |
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251 | default: { |
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252 | // Obfuscation version unexpected! |
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309 | daniel-mar | 253 | memset(pparm, 0, sizeof(PARM_T)); // invalidate everything |
311 | daniel-mar | 254 | |
255 | // If "return" is present: Calling function will receive an invalid cbSize value, hence showing "incompatible obfuscation" |
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256 | // If "return" is not present: Then the code below will set a correct cbSize and iProtect flag if obfusc_version>=3, which will raise the error "filter is protected" |
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257 | return; |
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292 | daniel-mar | 258 | } |
259 | } |
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260 | |||
309 | daniel-mar | 261 | if ((pparm->cbSize != PARM_SIZE) && |
262 | //(pparm->cbSize != PARM_SIZE_PREMIERE) && |
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263 | (pparm->cbSize != PARM_SIG_MAC)) { |
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264 | memset(pparm, 0, sizeof(PARM_T)); // invalidate everything |
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265 | } |
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266 | |||
292 | daniel-mar | 267 | if (obfusc_version >= 3) { |
268 | // Filter Foundry >= 1.7.0.5 builds combines obfuscation and protection |
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269 | // when a standalone filter is built. Theoretically, you can un-protect a |
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270 | // plugin, even if it is obfuscated, just by bit-flipping the LSB of byte 0x164. |
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271 | // Therefore, we enforce that the plugin is protected! |
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272 | pparm->iProtected = 1; |
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273 | |||
274 | // Furthermore, if obfuscation 3+ failed (since the seed is individual for each 8BF file), |
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293 | daniel-mar | 275 | // we still want that load_*.c is able to detect pparm->iProtected instead |
276 | // of throwing the error "Incompatible obfuscation". |
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292 | daniel-mar | 277 | pparm->cbSize = PARM_SIZE; |
278 | } |
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279 | } |