Rev 6614 | Go to most recent revision | Details | Compare with Previous | Last modification | View Log | RSS feed
Rev | Author | Line No. | Line |
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6767 | clevermous | 1 | ; Processings of PE format. |
2 | ; Works in conjunction with modules.inc for non-PE-specific code. |
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3 | |||
4 | ; PE-specific part of init_module_struct. |
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5 | ; Fills fields of MODULE struct from PE image. |
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6 | macro init_module_struct_pe_specific |
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7 | { |
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8 | ; We need a module timestamp for bound imports. |
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9 | ; In a full PE, there are two timestamps, one in the header |
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10 | ; and one in the export table; existing tools use the first one. |
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11 | ; A stripped PE header has no timestamp, so read the export table; |
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12 | ; the stripper should write the correct value there. |
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13 | cmp byte [esi], 'M' |
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14 | jz .parse_mz |
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15 | cmp [esi+STRIPPED_PE_HEADER.NumberOfRvaAndSizes], SPE_DIRECTORY_EXPORT |
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16 | jbe @f |
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17 | mov edx, [esi+sizeof.STRIPPED_PE_HEADER+SPE_DIRECTORY_EXPORT*sizeof.IMAGE_DATA_DIRECTORY+IMAGE_DATA_DIRECTORY.VirtualAddress] |
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18 | @@: |
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19 | mov [eax+MODULE.timestamp], edx |
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20 | mov edx, esi |
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21 | sub edx, [esi+STRIPPED_PE_HEADER.ImageBase] |
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22 | mov [eax+MODULE.basedelta], edx |
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23 | mov edx, [esi+STRIPPED_PE_HEADER.SizeOfImage] |
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24 | mov [eax+MODULE.size], edx |
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25 | ret |
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26 | .parse_mz: |
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27 | mov ecx, [esi+3Ch] |
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28 | add ecx, esi |
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29 | mov edx, [ecx+IMAGE_NT_HEADERS.FileHeader.TimeDateStamp] |
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30 | mov [eax+MODULE.timestamp], edx |
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31 | mov edx, esi |
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32 | sub edx, [ecx+IMAGE_NT_HEADERS.OptionalHeader.ImageBase] |
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33 | mov [eax+MODULE.basedelta], edx |
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34 | mov edx, [ecx+IMAGE_NT_HEADERS.OptionalHeader.SizeOfImage] |
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35 | mov [eax+MODULE.size], edx |
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36 | ret |
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37 | } |
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38 | |||
6614 | clevermous | 39 | ; Check whether PE module has been loaded at preferred address. |
40 | ; If not, relocate the module. |
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41 | ; |
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42 | ; in: esi = PE base address |
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43 | ; in: [esp+4] = module name for debug print |
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44 | ; out: CF=1 - fail |
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6767 | clevermous | 45 | proc fixup_pe_relocations c uses ebp, modulename |
6614 | clevermous | 46 | ; 1. Fetch some data from PE header or stripped PE header. |
47 | ; We need: |
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48 | ; * ImageBase - preferred address, compare with esi = actual load address; |
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49 | ; ebp will keep the delta |
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50 | ; * RVA and size of fixups directory |
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51 | ; * flag IMAGE_FILE_RELOCS_STRIPPED from Characteristics |
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52 | ; If the actual address equals the preferred address, do nothing. |
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53 | ; If fixups directory is present, proceed to 2. |
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54 | ; If there is no fixups directory, there are two options: |
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55 | ; * either the directory has not been created |
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56 | ; * or the module has no fixups (data-only module, for example). |
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57 | ; In the first case, IMAGE_FILE_RELOCS_STRIPPED is set, and this is an error. |
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58 | ; In the second case, IMAGE_FILE_RELOCS_STRIPPED is not set; do nothing. |
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59 | mov ebp, esi |
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6767 | clevermous | 60 | cmp byte [esi], 'M' |
6614 | clevermous | 61 | jz .parse_mz |
62 | sub ebp, [esi+STRIPPED_PE_HEADER.ImageBase] |
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63 | jnz @f |
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64 | .nothing: |
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65 | ret |
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66 | @@: |
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67 | mov dl, byte [esi+STRIPPED_PE_HEADER.Characteristics] |
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68 | lea eax, [esi+sizeof.STRIPPED_PE_HEADER+SPE_DIRECTORY_BASERELOC*sizeof.IMAGE_DATA_DIRECTORY] |
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69 | cmp [esi+STRIPPED_PE_HEADER.NumberOfRvaAndSizes], SPE_DIRECTORY_BASERELOC |
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70 | ja .common |
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71 | .norelocs: |
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72 | test dl, IMAGE_FILE_RELOCS_STRIPPED |
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73 | jz .nothing |
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6767 | clevermous | 74 | ccall loader_say_error, msg_noreloc1, [modulename], msg_noreloc2, 0 |
6614 | clevermous | 75 | stc |
76 | ret |
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77 | .parse_mz: |
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78 | mov eax, [esi+3Ch] |
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79 | add eax, esi |
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80 | sub ebp, [eax+IMAGE_NT_HEADERS.OptionalHeader.ImageBase] |
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81 | jz .nothing |
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6767 | clevermous | 82 | mov dl, byte [eax+IMAGE_NT_HEADERS.FileHeader.Characteristics] |
6614 | clevermous | 83 | cmp [eax+IMAGE_NT_HEADERS.OptionalHeader.NumberOfDirectories], IMAGE_DIRECTORY_ENTRY_BASERELOC |
84 | jbe .norelocs |
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85 | add eax, IMAGE_NT_HEADERS.OptionalHeader.DataDirectory+IMAGE_DIRECTORY_ENTRY_BASERELOC*sizeof.IMAGE_DATA_DIRECTORY |
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86 | .common: |
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6767 | clevermous | 87 | cmp [eax+IMAGE_DATA_DIRECTORY.isize], 0 |
88 | jz .norelocs |
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6614 | clevermous | 89 | mov edi, [eax+IMAGE_DATA_DIRECTORY.VirtualAddress] |
6767 | clevermous | 90 | push -1 |
91 | push -1 |
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6614 | clevermous | 92 | push [eax+IMAGE_DATA_DIRECTORY.isize] |
93 | virtual at esp |
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94 | .sizeleft dd ? |
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6767 | clevermous | 95 | .next_page_original_access dd ? |
96 | .next_page_addr dd ? |
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6614 | clevermous | 97 | end virtual |
98 | add edi, esi |
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99 | ; 2. We need to relocate and we have the relocation table. |
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100 | ; esi = PE base address |
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101 | ; edi = pointer to current data of relocation table |
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102 | ; 2a. Relocation table is organized into blocks describing every page. |
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103 | ; End of table is defined from table size fetched from the header. |
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6767 | clevermous | 104 | ; Loop 2b-2i over all blocks until no more data is left. |
6614 | clevermous | 105 | .pageloop: |
106 | ; 2b. Load the header of the current block: address and size. |
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107 | ; Advance total size. |
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108 | ; Size in the block includes size of the header, subtract it. |
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109 | ; If there is no data in this block, go to 2g. |
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110 | mov edx, [edi+IMAGE_BASE_RELOCATION.VirtualAddress] |
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111 | mov ecx, [edi+IMAGE_BASE_RELOCATION.SizeOfBlock] |
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112 | sub [.sizeleft], ecx |
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113 | add edi, sizeof.IMAGE_BASE_RELOCATION |
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114 | sub ecx, sizeof.IMAGE_BASE_RELOCATION |
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115 | jbe .pagedone |
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6767 | clevermous | 116 | push esi |
117 | fpo_delta = fpo_delta + 4 |
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118 | ; 2c. Check whether we have mprotect-ed the current page at the previous step. |
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119 | ; If so, go to 2e. |
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120 | cmp [.next_page_addr+fpo_delta], edx |
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121 | jz .mprotected_earlier |
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122 | ; 2d. We are going to modify data, so mprotect the current page to be writable. |
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6614 | clevermous | 123 | ; Save the old protection, we will restore it after the block is processed. |
124 | ; Ignore any error. |
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6767 | clevermous | 125 | ; Go to 2f after. |
6614 | clevermous | 126 | PROT_READ = 1 |
127 | PROT_WRITE = 2 |
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128 | PROT_EXEC = 4 |
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6767 | clevermous | 129 | push ecx |
6614 | clevermous | 130 | mov eax, 68 |
131 | mov ebx, 30 |
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132 | mov ecx, PROT_READ+PROT_WRITE |
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133 | add edx, esi |
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134 | mov esi, 0x1000 |
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135 | call FS_SYSCALL_PTR |
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136 | pop ecx |
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6767 | clevermous | 137 | jmp .mprotected |
138 | ; 2e. We have already mprotect-ed the current page, |
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139 | ; move corresponding variables. |
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140 | .mprotected_earlier: |
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141 | mov [.next_page_addr+fpo_delta], -1 |
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142 | mov eax, [.next_page_original_access+fpo_delta] |
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143 | .mprotected: |
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6614 | clevermous | 144 | push eax |
6767 | clevermous | 145 | fpo_delta = fpo_delta + 4 |
146 | ; 2g. Block data is an array of word values. Repeat 2h for every of those. |
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6614 | clevermous | 147 | .relocloop: |
148 | sub ecx, 2 |
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149 | jb .relocdone |
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6767 | clevermous | 150 | ; 2h. Every value consists of a 4-bit type and 12-bit offset in the page. |
6614 | clevermous | 151 | ; x86 uses two types: 0 = no data (used for padding), 3 = 32-bit relative. |
152 | movzx eax, word [edi] |
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153 | add edi, 2 |
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154 | mov ebx, eax |
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155 | and ebx, 0xFFF |
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156 | shr eax, 12 |
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157 | jz .relocloop |
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158 | cmp al, IMAGE_REL_BASED_HIGHLOW |
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159 | jnz .badreloc |
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6767 | clevermous | 160 | ; If the target dword intersects page boundary, |
161 | ; we need to mprotect the next page too. |
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162 | cmp ebx, 0xFFC |
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163 | jbe .no_mprotect_next |
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164 | push ebx ecx edx |
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165 | fpo_delta = fpo_delta + 12 |
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166 | lea eax, [.next_page_original_access+fpo_delta] |
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167 | call .restore_old_access |
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168 | mov eax, 68 |
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169 | mov ebx, 30 |
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170 | mov ecx, PROT_READ+PROT_WRITE |
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171 | mov esi, 0x1000 |
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172 | add edx, esi |
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173 | call FS_SYSCALL_PTR |
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174 | mov [.next_page_original_access+fpo_delta], eax |
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175 | mov [.next_page_addr+fpo_delta], edx |
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176 | pop edx ecx ebx |
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177 | fpo_delta = fpo_delta - 12 |
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178 | .no_mprotect_next: |
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6614 | clevermous | 179 | add [edx+ebx], ebp |
180 | jmp .relocloop |
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181 | .relocdone: |
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6767 | clevermous | 182 | ; 2i. Restore memory protection changed in 2d. |
6614 | clevermous | 183 | pop ecx |
6767 | clevermous | 184 | fpo_delta = fpo_delta - 4 |
6614 | clevermous | 185 | cmp ecx, -1 |
186 | jz @f |
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187 | mov eax, 68 |
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188 | mov ebx, 30 |
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189 | mov esi, 0x1000 |
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190 | call FS_SYSCALL_PTR |
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191 | @@: |
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192 | pop esi |
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6767 | clevermous | 193 | fpo_delta = fpo_delta - 4 |
6614 | clevermous | 194 | .pagedone: |
6767 | clevermous | 195 | cmp [.sizeleft+fpo_delta], 0 |
6614 | clevermous | 196 | jnz .pageloop |
6767 | clevermous | 197 | lea eax, [.next_page_original_access+fpo_delta] |
198 | call .restore_old_access |
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199 | add esp, 12 |
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6614 | clevermous | 200 | ; 3. For performance reasons, relocation should be avoided |
201 | ; by choosing an appropriate preferred address. |
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202 | ; If we have actually relocated something, yell to the debug board, |
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203 | ; so the programmer can notice that. |
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6767 | clevermous | 204 | ; It's a warning, not an error, so don't call loader_say_error. |
6614 | clevermous | 205 | mov ecx, msg_relocated1 |
206 | call sys_msg_board_str |
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6767 | clevermous | 207 | mov ecx, [modulename] |
6614 | clevermous | 208 | call sys_msg_board_str |
209 | mov ecx, msg_relocated2 |
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210 | call sys_msg_board_str |
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211 | clc |
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212 | ret |
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213 | .badreloc: |
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6767 | clevermous | 214 | pop ecx |
215 | pop esi |
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216 | add esp, 12 |
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217 | ccall loader_say_error, msg_bad_relocation, [modulename], 0 |
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6614 | clevermous | 218 | stc |
219 | ret |
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6767 | clevermous | 220 | |
221 | .restore_old_access: |
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222 | cmp dword [eax+4], -1 |
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223 | jz @f |
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224 | mov ecx, [eax] |
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225 | mov edx, [eax+4] |
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226 | mov eax, 68 |
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227 | mov ebx, 30 |
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228 | mov esi, 0x1000 |
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229 | call FS_SYSCALL_PTR |
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230 | @@: |
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231 | retn |
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6614 | clevermous | 232 | endp |
6767 | clevermous | 233 | |
234 | ; Resolves static dependencies in the given PE module. |
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235 | ; Recursively loads and initializes all dependencies. |
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236 | ; in: esi -> MODULE struct |
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237 | ; out: eax=0 - success, eax=-1 - error |
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238 | ; modules_mutex should be locked |
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239 | proc resolve_pe_imports |
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240 | locals |
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241 | export_base dd ? |
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242 | export_ptr dd ? |
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243 | export_size dd ? |
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244 | import_module dd ? |
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245 | import_dir dd ? |
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246 | import_descriptor dd ? |
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247 | bound_import_dir dd ? |
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248 | bound_import_cur_module dd ? |
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249 | relocated_bound_modules_count dd ? |
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250 | relocated_bound_modules_ptr dd ? |
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251 | cur_page dd -0x1000 ; the page at 0xFFFFF000 is never allocated |
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252 | cur_page_old_access dd ? |
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253 | next_page dd -1 |
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254 | next_page_old_access dd ? |
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255 | endl |
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256 | |||
257 | ; General case of resolving imports against one module that is already loaded: |
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258 | ; binding either does not exist or has mismatched timestamp, |
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259 | ; so we need to walk through all imported symbols and resolve each one. |
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260 | ; in: ebp -> IMAGE_IMPORT_DESCRIPTOR |
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261 | macro resolve_import_from_module fail_action |
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262 | { |
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263 | local .label1, .loop, .done |
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264 | ; common preparation that doesn't need to be repeated per each symbol |
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265 | mov eax, [import_module] |
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266 | mov eax, [eax+MODULE.base] |
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267 | call prepare_import_from_module |
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268 | ; There are two arrays of dwords pointed to by FirstThunk and OriginalFirstThunk. |
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269 | ; Target array is FirstThunk: addresses of imported symbols should be written |
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270 | ; there, that is where the program expects to find them. |
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271 | ; Source array can be either FirstThunk or OriginalFirstThunk. |
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272 | ; Normally, FirstThunk and OriginalFirstThunk in a just-compiled binary |
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273 | ; point to two identical copies of the same array. |
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274 | ; Binding of the binary rewrites FirstThunk array with actual addresses, |
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275 | ; but keeps OriginalFirstThunk as is. |
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276 | ; If OriginalFirstThunk and FirstThunk are both present, use OriginalFirstThunk |
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277 | ; as source array. |
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278 | ; However, a compiler is allowed to generate a binary without OriginalFirstThunk; |
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279 | ; it is impossible to bind such a binary, but it is still valid. |
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280 | ; If OriginalFirstThunk is absent, use FirstThunk as source array. |
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281 | mov ebx, [ebp+IMAGE_IMPORT_DESCRIPTOR.OriginalFirstThunk] |
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282 | mov ebp, [ebp+IMAGE_IMPORT_DESCRIPTOR.FirstThunk] |
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283 | test ebx, ebx |
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284 | jnz .label1 |
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285 | mov ebx, ebp |
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286 | .label1: |
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287 | ; FirstThunk and OriginalFirstThunk are RVAs. |
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288 | add ebx, [esi+MODULE.base] |
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289 | add ebp, [esi+MODULE.base] |
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290 | ; Source array is terminated with zero dword. |
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291 | .loop: |
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292 | cmp dword [ebx], 0 |
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293 | jz .done |
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294 | mov ecx, [ebx] |
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295 | get_address_for_thunk ; should preserve esi,edi,ebp |
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296 | test eax, eax |
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297 | jz fail_action |
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298 | mov edi, eax |
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299 | mov edx, ebp |
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300 | call .ensure_writable ; should preserve edx,ebx,esi,ebp |
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301 | mov [edx], edi |
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302 | add ebx, 4 |
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303 | add ebp, 4 |
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304 | jmp .loop |
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305 | .done: |
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306 | } |
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307 | |||
308 | ; Resolve one imported symbol. |
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309 | ; in: ecx = ordinal or RVA of thunk |
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310 | ; out: eax = address of exported function |
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311 | macro get_address_for_thunk |
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312 | { |
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313 | local .ordinal, .common |
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314 | ; Ordinal imports have bit 31 set, name imports have bit 31 clear. |
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315 | btr ecx, 31 |
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316 | jc .ordinal |
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317 | ; Thunk for name import is RVA of IMAGE_IMPORT_BY_NAME structure. |
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318 | add ecx, [esi+MODULE.base] |
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319 | movzx edx, [ecx+IMAGE_IMPORT_BY_NAME.Hint] |
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320 | add ecx, IMAGE_IMPORT_BY_NAME.Name |
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321 | call get_exported_function_by_name |
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322 | jmp .common |
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323 | .ordinal: |
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324 | ; Thunk for ordinal import is just an ordinal, |
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325 | ; bit 31 has been cleared by btr instruction. |
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326 | call get_exported_function_by_ordinal |
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327 | .common: |
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328 | } |
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329 | |||
330 | ; We have four main variants: |
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331 | ; normal unbound import, old-style bound import, new-style bound import, |
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332 | ; no import. |
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333 | ; * Normal unbound import: |
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334 | ; we have an array of import descriptors, one per imported module, |
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335 | ; pointed to by import directory. |
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336 | ; We should loop over all descriptors and apply resolve_import_from_module |
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337 | ; for each one. |
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338 | ; * Old-style bound import: |
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339 | ; we have the same array of import descriptors, but timestamp field is set up. |
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340 | ; We should do the same loop, but we can do a lightweight processing |
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341 | ; of modules with correct timestamp. In the best case, "lightweight processing" |
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342 | ; means just skipping them, but corrections arise for relocated modules |
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343 | ; and forwarded exports. |
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344 | ; * New-style bound import: |
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345 | ; we have two parallel arrays of import descriptors and bound descriptors, |
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346 | ; pointed to by two directories. Timestamp field has a special value -1 |
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347 | ; in import descriptors, real timestamps are in bound descriptors. |
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348 | ; There can be different strategies; we loop over bound descriptors |
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349 | ; and scan for corresponding import descriptors only if needed, |
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350 | ; this accelerates the fast path where all timestamps are correct and |
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351 | ; dependencies are not relocated. |
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352 | ; * No import: not really different from normal import with no descriptors. |
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353 | ; There are two large parts in this function: |
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354 | ; step 2 handles unbound and old-style bound import, where we loop over import descriptors; |
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355 | ; step 3 handles new-style bound import, where we loop over bound descriptors. |
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356 | ; 1. Fetch addresses of two directories. We are not interested in their sizes. |
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357 | ; ebp = import RVA |
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358 | ; ebx = bound import RVA |
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359 | xor ebx, ebx |
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360 | xor ebp, ebp |
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361 | ; PE and stripped PE have different places for directories. |
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362 | mov eax, [esi+MODULE.base] |
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363 | cmp byte [eax], 'M' |
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364 | jz .parse_mz |
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365 | cmp [eax+STRIPPED_PE_HEADER.NumberOfRvaAndSizes], SPE_DIRECTORY_IMPORT |
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366 | jbe .common |
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367 | mov ebp, [eax+sizeof.STRIPPED_PE_HEADER+SPE_DIRECTORY_IMPORT*sizeof.IMAGE_DATA_DIRECTORY] |
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368 | cmp [eax+STRIPPED_PE_HEADER.NumberOfRvaAndSizes], SPE_DIRECTORY_BOUND_IMPORT |
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369 | jbe .common |
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370 | mov ebx, [eax+sizeof.STRIPPED_PE_HEADER+SPE_DIRECTORY_BOUND_IMPORT*sizeof.IMAGE_DATA_DIRECTORY] |
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371 | jmp .common |
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372 | .parse_mz: |
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373 | add eax, [eax+3Ch] |
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374 | cmp [eax+IMAGE_NT_HEADERS.OptionalHeader.NumberOfDirectories], IMAGE_DIRECTORY_ENTRY_IMPORT |
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375 | jbe .common |
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376 | mov ebp, [eax+IMAGE_NT_HEADERS.OptionalHeader.DataDirectory+IMAGE_DIRECTORY_ENTRY_IMPORT*sizeof.IMAGE_DATA_DIRECTORY] |
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377 | cmp [eax+IMAGE_NT_HEADERS.OptionalHeader.NumberOfDirectories], IMAGE_DIRECTORY_ENTRY_BOUND_IMPORT |
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378 | jbe .common |
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379 | mov ebx, [eax+IMAGE_NT_HEADERS.OptionalHeader.DataDirectory+IMAGE_DIRECTORY_ENTRY_BOUND_IMPORT*sizeof.IMAGE_DATA_DIRECTORY] |
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380 | .common: |
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381 | mov [import_dir], ebp |
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382 | ; If bound import is present, go to 3. |
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383 | ; If both directories are absent, no import - nothing to do. |
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384 | ; Otherwise, advance to 2. |
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385 | test ebx, ebx |
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386 | jnz .bound_import |
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387 | test ebp, ebp |
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388 | jz .done |
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389 | ; 2. Unbound import or old-style bound import. |
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390 | ; Repeat 2a-2h for all descriptors in the directory. |
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391 | add ebp, [esi+MODULE.base] ; directories contain RVA |
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392 | .normal_import_loop: |
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393 | ; 2a. Check whether this descriptor is an end mark with zero fields. |
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394 | ; Look at Name field. |
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395 | mov edi, [ebp+IMAGE_IMPORT_DESCRIPTOR.Name] |
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396 | test edi, edi |
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397 | jz .done |
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398 | ; 2b. Load the target module. |
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399 | add edi, [esi+MODULE.base] ; Name field is RVA |
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400 | call load_imported_module ; should preserve esi,ebp |
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401 | test eax, eax |
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402 | jz .failed |
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403 | mov [import_module], eax |
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404 | ; 2c. Check whether the descriptor has a non-stale old-style binding. |
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405 | ; Zero timestamp means "not bound". |
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406 | ; Mismatched timestamp means "stale binding". |
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407 | ; In both cases, go to 2g. |
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408 | mov edx, [ebp+IMAGE_IMPORT_DESCRIPTOR.TimeDateStamp] |
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409 | test edx, edx |
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410 | jz .resolve_normal_import |
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411 | cmp edx, [eax+MODULE.timestamp] |
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412 | jnz .resolve_normal_import |
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413 | ; 2d. The descriptor has a non-stale old-style binding. |
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414 | ; There are two cases when we still need to do something: |
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415 | ; * if the target module has been relocated, we need to add |
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416 | ; relocation delta to all addresses; |
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417 | ; * if some exports are forwarded, old-style binding cannot bind them: |
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418 | ; there is only one timestamp field, we can't verify timestamps |
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419 | ; of forward targets. |
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420 | ; Thunks for forwarded exports contain index of next forwarded export |
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421 | ; instead of target address, making a single-linked list terminated by -1. |
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422 | ; ForwarderChain is the head of the list. |
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423 | ; If both problems are present, we resort to 2g as if binding is stale, |
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424 | ; it shouldn't be encountered normally anyway: relocations should be avoided, |
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425 | ; and forwarded exports should be new-style bound. |
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426 | ; If the target module is not relocated, go to 2f. |
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427 | ; If the target module is relocated and there are no forwarded exports, |
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428 | ; advance to 2e. |
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429 | cmp [eax+MODULE.basedelta], 0 |
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430 | jz .normal_import_check_forwarders |
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431 | cmp [ebp+IMAGE_IMPORT_DESCRIPTOR.ForwarderChain], -1 |
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432 | jnz .resolve_normal_import |
||
433 | ; 2e. Binding is correct, but we need to add MODULE.basedelta |
||
434 | ; to all imported addresses in FirstThunk array. |
||
435 | ; For consistency with generic-case resolve_import_from_module, |
||
436 | ; check for end of thunks by looking at OriginalFirstThunk array. |
||
437 | ; After that, go to 2h. |
||
438 | mov edx, [ebp+IMAGE_IMPORT_DESCRIPTOR.FirstThunk] |
||
439 | add edx, [esi+MODULE.base] |
||
440 | mov ebx, [ebp+IMAGE_IMPORT_DESCRIPTOR.OriginalFirstThunk] |
||
441 | add ebx, [esi+MODULE.base] |
||
442 | mov edi, [eax+MODULE.basedelta] |
||
443 | .normal_import_add_delta: |
||
444 | cmp dword [ebx], 0 |
||
445 | jz .normal_import_next |
||
446 | call .ensure_writable ; should preserve esi,edi,ebp,ebx,edx |
||
447 | add dword [edx], edi |
||
448 | add edx, 4 |
||
449 | add ebx, 4 |
||
450 | jmp .normal_import_add_delta |
||
451 | .normal_import_check_forwarders: |
||
452 | ; 2f. The target module is not relocated. |
||
453 | ; Exports that are not forwarded are correct. |
||
454 | ; Go through ForwarderChain list and resolve all exports from it. |
||
455 | ; After that, go to 2h. |
||
456 | mov edi, [ebp+IMAGE_IMPORT_DESCRIPTOR.ForwarderChain] |
||
457 | cmp edi, -1 |
||
458 | jz .normal_import_next ; don't prepare_import_from_module for empty list |
||
459 | mov eax, [import_module] |
||
460 | mov eax, [eax+MODULE.base] |
||
461 | call prepare_import_from_module |
||
462 | .normal_import_forward_chain: |
||
463 | mov ebx, [ebp+IMAGE_IMPORT_DESCRIPTOR.OriginalFirstThunk] |
||
464 | add ebx, [esi+MODULE.base] |
||
465 | mov ecx, [ebx+edi*4] |
||
466 | get_address_for_thunk ; should preserve esi,edi,ebp |
||
467 | test eax, eax |
||
468 | jz .failed |
||
469 | mov ebx, eax |
||
470 | mov edx, [ebp+IMAGE_IMPORT_DESCRIPTOR.FirstThunk] |
||
471 | add edx, [esi+MODULE.base] |
||
472 | lea edx, [edx+edi*4] |
||
473 | call .ensure_writable ; should preserve edx,ebx,esi,ebp |
||
474 | mov edi, [edx] ; next forwarded export |
||
475 | mov [edx], ebx ; store the address |
||
476 | cmp edi, -1 |
||
477 | jnz .normal_import_forward_chain |
||
478 | jmp .normal_import_next |
||
479 | .resolve_normal_import: |
||
480 | ; 2g. Run generic-case resolver. |
||
481 | mov [import_descriptor], ebp |
||
482 | resolve_import_from_module .failed ; should preserve esi |
||
483 | mov ebp, [import_descriptor] |
||
484 | .normal_import_next: |
||
485 | ; 2h. Advance to next descriptor and continue the loop. |
||
486 | add ebp, sizeof.IMAGE_IMPORT_DESCRIPTOR |
||
487 | jmp .normal_import_loop |
||
488 | .bound_import: |
||
489 | ; 3. New-style bound import. |
||
490 | ; Repeat 3a-3o for all descriptors in bound import directory. |
||
491 | mov [bound_import_dir], ebx |
||
492 | add ebx, [esi+MODULE.base] |
||
493 | .bound_import_loop: |
||
494 | ; 3a. Check whether this descriptor is an end mark with zero fields. |
||
495 | movzx edi, [ebx+IMAGE_BOUND_IMPORT_DESCRIPTOR.OffsetModuleName] |
||
496 | mov [bound_import_cur_module], edi |
||
497 | test edi, edi |
||
498 | jz .done |
||
499 | ; Bound import descriptors come in groups. |
||
500 | ; The first descriptor in each group corresponds to the main imported module. |
||
501 | ; If some exports from the module are forwarded, additional descriptors |
||
502 | ; are created for modules where those exports are forwarded to. |
||
503 | ; Number of additional descriptors is given by one field in the first descriptor. |
||
504 | ; 3b. Prepare for loop at 3c-3f with loading targets of all exports. |
||
505 | ; This includes the target module and all modules in chains of forwarded exports. |
||
506 | movzx ebp, [ebx+IMAGE_BOUND_IMPORT_DESCRIPTOR.NumberOfModuleForwarderRefs] |
||
507 | mov [relocated_bound_modules_count], 0 |
||
508 | mov [relocated_bound_modules_ptr], 0 |
||
509 | mov [import_module], 0 |
||
510 | .bound_import_forwarder_loop: |
||
511 | ; 3c. Load a referenced module. |
||
512 | ; Names in bound import descriptors are relative to bound import directory, |
||
513 | ; not RVAs. |
||
514 | add edi, [bound_import_dir] |
||
515 | call load_imported_module ; should preserve ebx,esi,ebp |
||
516 | test eax, eax |
||
517 | jz .bound_import_failed |
||
518 | ; The target module is first in the list. |
||
519 | cmp [import_module], 0 |
||
520 | jnz @f |
||
521 | mov [import_module], eax |
||
522 | @@: |
||
523 | ; 3d. Check whether timestamp in the descriptor matches module timestamp. |
||
524 | ; If not, go to 3h which after some preparations will resort to generic-case |
||
525 | ; resolve_import_from_module; in this case, we stop processing the group, |
||
526 | ; resolve_import_from_module will take care about additional modules anyway. |
||
527 | mov edx, [ebx+IMAGE_BOUND_IMPORT_DESCRIPTOR.TimeDateStamp] |
||
528 | test edx, edx |
||
529 | jz .bound_import_wrong_timestamp |
||
530 | cmp edx, [eax+MODULE.timestamp] |
||
531 | jnz .bound_import_wrong_timestamp |
||
532 | ; 3e. Collect all referenced modules that have been relocated. |
||
533 | cmp [eax+MODULE.basedelta], 0 |
||
534 | jz .bound_import_forwarder_next |
||
535 | mov edi, eax |
||
536 | ; We don't want to reallocate too often, since reallocation |
||
537 | ; may involve copying our data to a new place. |
||
538 | ; We always reserve space that is a power of two; in this way, |
||
539 | ; the wasted space is never greater than the used space, |
||
540 | ; and total time of copying the data is O(number of modules). |
||
541 | mov eax, [relocated_bound_modules_ptr] |
||
542 | mov edx, [relocated_bound_modules_count] |
||
543 | ; X is a power of two or zero if and only if (X and (X - 1)) is zero |
||
544 | lea ecx, [edx-1] |
||
545 | test ecx, edx |
||
546 | jnz .bound_import_norealloc |
||
547 | ; if the current size is zero, allocate 1 item, |
||
548 | ; otherwise double number of items. |
||
549 | ; Item size is 4 bytes. |
||
550 | lea edx, [edx*8] |
||
551 | test edx, edx |
||
552 | jnz @f |
||
553 | mov edx, 4 |
||
554 | @@: |
||
555 | stdcall realloc, [relocated_bound_modules_ptr], edx |
||
556 | test eax, eax |
||
557 | jz .bound_import_failed |
||
558 | mov [relocated_bound_modules_ptr], eax |
||
559 | .bound_import_norealloc: |
||
560 | mov edx, [relocated_bound_modules_count] |
||
561 | inc [relocated_bound_modules_count] |
||
562 | mov [eax+edx*4], edi |
||
563 | .bound_import_forwarder_next: |
||
564 | ; 3f. Advance to the next descriptor in the group. |
||
565 | add ebx, sizeof.IMAGE_BOUND_IMPORT_DESCRIPTOR |
||
566 | movzx edi, [ebx+IMAGE_BOUND_IMPORT_DESCRIPTOR.OffsetModuleName] |
||
567 | dec ebp |
||
568 | jns .bound_import_forwarder_loop |
||
569 | ; 3g. All timestamps are correct. |
||
570 | ; If all targets are not relocated, then we have nothing to do |
||
571 | ; with exports from the current module, so continue loop at 3a; |
||
572 | ; ebx already points to the next descriptor. |
||
573 | ; Otherwise, go to 3i. |
||
574 | cmp [relocated_bound_modules_count], 0 |
||
575 | jz .bound_import_loop |
||
576 | jmp .bound_import_fix |
||
577 | .bound_import_wrong_timestamp: |
||
578 | ; 3h. We have aborted the loop over the group; |
||
579 | ; advance ebx so that it points to the first descriptor of the next group, |
||
580 | ; make a mark so that 3l will know that we need to reimport everything. |
||
581 | ; We don't need [relocated_bound_modules_count] in this case anymore, |
||
582 | ; use zero value as a mark. |
||
583 | lea ebx, [ebx+(ebp+1)*sizeof.IMAGE_BOUND_IMPORT_DESCRIPTOR] |
||
584 | mov [relocated_bound_modules_count], 0 |
||
585 | .bound_import_fix: |
||
586 | ; 3i. We need to do something with exported addresses. |
||
587 | ; Find corresponding import descriptors; there can be more than one. |
||
588 | ; Repeat 3j-3n for all import descriptors. |
||
589 | mov ebp, [import_dir] |
||
590 | add ebp, [esi+MODULE.base] |
||
591 | .look_related_descriptors: |
||
592 | ; 3j. Check whether we have reached end of import table. |
||
593 | ; If so, go to 3o. |
||
594 | mov edx, [ebp+IMAGE_IMPORT_DESCRIPTOR.Name] |
||
595 | test edx, edx |
||
596 | jz .bound_import_next |
||
597 | ; 3k. Check whether the current import descriptor matches the current |
||
598 | ; bound import descriptor. Check Name fields. |
||
599 | ; If so, advance to 3l. |
||
600 | ; Otherwise, advance to the next import descriptor and return to 3j. |
||
601 | add edx, [esi+MODULE.base] |
||
602 | mov edi, [bound_import_cur_module] |
||
603 | @@: |
||
604 | mov al, [edx] |
||
605 | cmp [edi], al |
||
606 | jnz .next_related_descriptor |
||
607 | test al, al |
||
608 | jz .found_related_descriptor |
||
609 | inc edx |
||
610 | inc edi |
||
611 | jmp @b |
||
612 | .next_related_descriptor_restore: |
||
613 | mov ebp, [import_descriptor] |
||
614 | .next_related_descriptor: |
||
615 | add ebp, sizeof.IMAGE_IMPORT_DESCRIPTOR |
||
616 | jmp .look_related_descriptors |
||
617 | .found_related_descriptor: |
||
618 | ; 3l. Check what we should do: |
||
619 | ; advance to 3m, if we need to reimport everything, |
||
620 | ; go to 3n, if we just need to relocate something. |
||
621 | mov [import_descriptor], ebp |
||
622 | cmp [relocated_bound_modules_count], 0 |
||
623 | jnz .bound_import_add_delta |
||
624 | ; 3m. Apply resolve_import_from_module and return to 3j. |
||
625 | resolve_import_from_module .bound_import_failed ; should preserve ebx,esi |
||
626 | jmp .next_related_descriptor_restore |
||
627 | .bound_import_add_delta: |
||
628 | ; 3n. Loop over all imported symbols. |
||
629 | ; For every imported symbol, check whether it fits within one of relocated |
||
630 | ; modules, and if so, apply relocation to it. |
||
631 | ; For consistency with generic-case resolve_import_from_module, |
||
632 | ; determine end of thunks from OriginalFirstThunk array. |
||
633 | mov edx, [ebp+IMAGE_IMPORT_DESCRIPTOR.FirstThunk] |
||
634 | add edx, [esi+MODULE.base] |
||
635 | mov ebx, [ebp+IMAGE_IMPORT_DESCRIPTOR.OriginalFirstThunk] |
||
636 | add ebx, [esi+MODULE.base] |
||
637 | .bound_import_add_delta_loop: |
||
638 | cmp dword [ebx], 0 |
||
639 | jz .next_related_descriptor_restore |
||
640 | mov ecx, [relocated_bound_modules_ptr] |
||
641 | mov ebp, [relocated_bound_modules_count] |
||
642 | push esi |
||
643 | .find_delta_module: |
||
644 | mov esi, [ecx] |
||
645 | mov eax, [edx] |
||
646 | sub eax, [esi+MODULE.base] |
||
647 | add eax, [esi+MODULE.basedelta] |
||
648 | cmp eax, [esi+MODULE.size] |
||
649 | jb .found_delta_module |
||
650 | add ecx, 4 |
||
651 | dec ebp |
||
652 | jnz .find_delta_module |
||
653 | pop esi |
||
654 | .bound_import_add_delta_next: |
||
655 | add ebx, 4 |
||
656 | add edx, 4 |
||
657 | jmp .bound_import_add_delta_loop |
||
658 | .found_delta_module: |
||
659 | mov ebp, [esi+MODULE.basedelta] |
||
660 | pop esi |
||
661 | call .ensure_writable ; should preserve esi,ebp,ebx,edx |
||
662 | add [edx], ebp |
||
663 | jmp .bound_import_add_delta_next |
||
664 | .bound_import_next: |
||
665 | ; 3o. Free the data we might have allocated and return to 3a. |
||
666 | cmp [relocated_bound_modules_ptr], 0 |
||
667 | jz .bound_import_loop |
||
668 | stdcall free, [relocated_bound_modules_ptr] |
||
669 | jmp .bound_import_loop |
||
670 | .done: |
||
671 | call .restore_protection |
||
672 | xor eax, eax |
||
673 | ret |
||
674 | .bound_import_failed: |
||
675 | cmp [relocated_bound_modules_ptr], 0 |
||
676 | jz .failed |
||
677 | stdcall free, [relocated_bound_modules_ptr] |
||
678 | .failed: |
||
679 | call .restore_protection |
||
680 | xor eax, eax |
||
681 | dec eax |
||
682 | ret |
||
683 | |||
684 | ; Local helper functions. |
||
685 | fpo_delta = fpo_delta + 4 |
||
686 | ; Import table may reside in read-only pages. |
||
687 | ; We should mprotect any page where we are going to write to. |
||
688 | ; Things get interesting when one thunk spans two pages. |
||
689 | ; in: edx = address of dword to make writable |
||
690 | .ensure_writable: |
||
691 | ; 1. Fast path: if we have already mprotect-ed one page and |
||
692 | ; the requested dword is in the same page, do nothing. |
||
693 | mov eax, edx |
||
694 | sub eax, [cur_page] |
||
695 | cmp eax, 0x1000 - 4 |
||
696 | ja .cur_page_not_sufficient |
||
697 | .ensure_writable.nothing: |
||
698 | retn |
||
699 | .cur_page_not_sufficient: |
||
700 | ; 2. If the requested dword begins in the current page |
||
701 | ; and ends in the next page, mprotect the next page and return. |
||
702 | push ebx esi edx |
||
703 | fpo_delta = fpo_delta + 12 |
||
704 | cmp eax, 0x1000 |
||
705 | jae .wrong_cur_page |
||
706 | cmp [next_page], -1 |
||
707 | jnz @f |
||
708 | mov eax, 68 |
||
709 | mov ebx, 30 |
||
710 | mov ecx, PROT_READ+PROT_WRITE |
||
711 | mov edx, [cur_page] |
||
712 | mov esi, 0x1000 |
||
713 | add edx, esi |
||
714 | mov [next_page], edx |
||
715 | call FS_SYSCALL_PTR |
||
716 | mov [next_page_old_access], eax |
||
717 | @@: |
||
718 | pop edx esi ebx |
||
719 | retn |
||
720 | .wrong_cur_page: |
||
721 | ; The requested dword does not intersect with the current page. |
||
722 | ; 3. Restore the protection of the current page, |
||
723 | ; it is unlikely to be used again. |
||
724 | cmp [cur_page], -0x1000 |
||
725 | jz @f |
||
726 | mov eax, 68 |
||
727 | mov ebx, 30 |
||
728 | mov ecx, [cur_page_old_access] |
||
729 | mov edx, [cur_page] |
||
730 | mov esi, 0x1000 |
||
731 | call FS_SYSCALL_PTR |
||
732 | @@: |
||
733 | ; 4. If the next page has been mprotect-ed too, |
||
734 | ; switch to it as the current page and restart the function. |
||
735 | cmp [next_page], -1 |
||
736 | jz @f |
||
737 | mov eax, [next_page] |
||
738 | mov [cur_page], eax |
||
739 | mov eax, [next_page_old_access] |
||
740 | mov [cur_page_old_access], eax |
||
741 | mov [next_page], -1 |
||
742 | pop edx esi ebx |
||
743 | jmp .ensure_writable |
||
744 | @@: |
||
745 | ; 5. This is the entirely new page to mprotect. |
||
746 | mov edx, [esp] |
||
747 | and edx, not 0xFFF |
||
748 | mov eax, 68 |
||
749 | mov ebx, 30 |
||
750 | mov ecx, PROT_READ+PROT_WRITE |
||
751 | mov [cur_page], edx |
||
752 | mov esi, 0x1000 |
||
753 | call FS_SYSCALL_PTR |
||
754 | mov [cur_page_old_access], eax |
||
755 | pop edx esi ebx |
||
756 | fpo_delta = fpo_delta - 12 |
||
757 | retn |
||
758 | |||
759 | ; Called at end of processing, |
||
760 | ; restores protection of pages that we have mprotect-ed for write. |
||
761 | .restore_protection: |
||
762 | push esi |
||
763 | fpo_delta = fpo_delta + 4 |
||
764 | cmp [next_page], -1 |
||
765 | jz @f |
||
766 | mov eax, 68 |
||
767 | mov ebx, 30 |
||
768 | mov ecx, [next_page_old_access] |
||
769 | mov edx, [next_page] |
||
770 | mov esi, 0x1000 |
||
771 | call FS_SYSCALL_PTR |
||
772 | @@: |
||
773 | cmp [cur_page], -0x1000 |
||
774 | jz @f |
||
775 | mov eax, 68 |
||
776 | mov ebx, 30 |
||
777 | mov ecx, [cur_page_old_access] |
||
778 | mov edx, [cur_page] |
||
779 | mov esi, 0x1000 |
||
780 | call FS_SYSCALL_PTR |
||
781 | @@: |
||
782 | pop esi |
||
783 | fpo_delta = fpo_delta - 4 |
||
784 | retn |
||
785 | endp |
||
786 | |||
787 | ; Part of resolving symbol from a module that is the same for all symbols. |
||
788 | ; resolve_pe_imports calls it only once per module. |
||
789 | ; Fetches export directory from the module. |
||
790 | ; Non-standard calling convention: saves results to first 2 dwords on the stack. |
||
791 | ; in: eax = module base |
||
792 | proc prepare_import_from_module c, export_base, export_ptr, export_size |
||
793 | ; The implementation is straightforward. |
||
794 | mov [export_base], eax |
||
795 | cmp byte [eax], 'M' |
||
796 | jz .parse_mz |
||
797 | cmp [eax+STRIPPED_PE_HEADER.NumberOfRvaAndSizes], SPE_DIRECTORY_EXPORT |
||
798 | jbe .noexport |
||
799 | mov edx, [eax+sizeof.STRIPPED_PE_HEADER+SPE_DIRECTORY_EXPORT*sizeof.IMAGE_DATA_DIRECTORY+IMAGE_DATA_DIRECTORY.VirtualAddress] |
||
800 | add edx, eax |
||
801 | mov [export_ptr], edx |
||
802 | mov edx, [eax+sizeof.STRIPPED_PE_HEADER+SPE_DIRECTORY_EXPORT*sizeof.IMAGE_DATA_DIRECTORY+IMAGE_DATA_DIRECTORY.isize] |
||
803 | mov [export_size], edx |
||
804 | ret |
||
805 | .parse_mz: |
||
806 | mov ecx, [eax+3Ch] |
||
807 | add ecx, eax |
||
808 | cmp [ecx+IMAGE_NT_HEADERS.OptionalHeader.NumberOfDirectories], IMAGE_DIRECTORY_ENTRY_EXPORT |
||
809 | jbe .noexport |
||
810 | mov edx, [ecx+IMAGE_NT_HEADERS.OptionalHeader.DataDirectory.VirtualAddress+IMAGE_DIRECTORY_ENTRY_EXPORT*sizeof.IMAGE_DATA_DIRECTORY] |
||
811 | add edx, eax |
||
812 | mov [export_ptr], edx |
||
813 | mov edx, [ecx+IMAGE_NT_HEADERS.OptionalHeader.DataDirectory.isize+IMAGE_DIRECTORY_ENTRY_EXPORT*sizeof.IMAGE_DATA_DIRECTORY] |
||
814 | mov [export_size], edx |
||
815 | ret |
||
816 | .noexport: |
||
817 | mov [export_ptr], 0 |
||
818 | mov [export_size], 0 |
||
819 | ret |
||
820 | endp |
||
821 | |||
822 | ; PE format supports export by name and by ordinal. |
||
823 | ; Any exported symbol always have an ordinal. |
||
824 | ; It may have a name, it may have no name. |
||
825 | ; A symbol can even have multiple names, usually this happens |
||
826 | ; when several functions with the same body like 'ret' are merged. |
||
827 | ; |
||
828 | ; Addresses of all exported symbols are contained in one array AddressOfFunctions. |
||
829 | ; Ordinal of a symbol is an index in this array + Base. |
||
830 | ; Base is defined in export directory, usually it equals 1. |
||
831 | ; |
||
832 | ; Export by name is more complicated. There are two parallel arrays |
||
833 | ; AddressOfNames and AddressOfNameOrdinals with the same length. |
||
834 | ; This length can be less or greater than length of AddressOfFunctions. |
||
835 | ; AddressOfNames is a sorted array with all exported names. |
||
836 | ; AddressOfNameOrdinals, contrary to the title, gives index in AddressOfFunctions. |
||
837 | ; Looking up a name means |
||
838 | ; * scanning AddressOfNames array to find the index of the corresponding name |
||
839 | ; * looking in AddressOfNameOrdinals at the index found above to get another index; |
||
840 | ; index in AddressOfNames/AddressOfNameOrdinals has no other meaning |
||
841 | ; * finally, looking in AddressOfFunctions with that second index. |
||
842 | |||
843 | ; Resolve symbol from a module by name. |
||
844 | ; prepare_import_from_module should be called beforehand. |
||
845 | ; in: ecx -> name, edx = hint for lookup in name table |
||
846 | ; out: eax = exported address or NULL |
||
847 | ; if [module] is zero, modules_mutex should be unlocked |
||
848 | ; if [module] is nonzero, modules_mutex should be locked |
||
849 | proc get_exported_function_by_name c uses ebx esi edi, export_base, export_ptr, export_size, module |
||
850 | locals |
||
851 | forward_export_base dd ? |
||
852 | forward_export_ptr dd ? |
||
853 | forward_export_size dd ? |
||
854 | forward_export_module dd ? |
||
855 | endl |
||
856 | ; 1. Find length of the name, including terminating zero. |
||
857 | mov esi, ecx |
||
858 | @@: |
||
859 | inc ecx |
||
860 | cmp byte [ecx-1], 0 |
||
861 | jnz @b |
||
862 | sub ecx, esi |
||
863 | ; 2. Validate that export directory is present at all. |
||
864 | mov eax, [export_ptr] |
||
865 | test eax, eax |
||
866 | jz .export_name_not_found |
||
867 | ; 3. Check whether the hint is correct. |
||
868 | ; The hint is a zero-based index in name table. |
||
869 | ; Theoretically, zero is a valid hint. |
||
870 | ; Unfortunately, in practice everyone uses zero if the hint is unknown, |
||
871 | ; which is a quite typical situation, so treating zero as a valid hint |
||
872 | ; would waste processor cycles much more often than save. |
||
873 | ; So only check the hint if it is between 1 and NumberOfNames-1 inclusive. |
||
874 | ; 3a. Validate the hint. |
||
875 | mov ebx, [eax+IMAGE_EXPORT_DIRECTORY.AddressOfNames] |
||
876 | add ebx, [export_base] |
||
877 | cmp edx, [eax+IMAGE_EXPORT_DIRECTORY.NumberOfNames] |
||
878 | jae .ignore_hint |
||
879 | test edx, edx |
||
880 | jz .ignore_hint |
||
881 | ; 3b. Check the hinted name. |
||
882 | ; If it matches, go to 5. If not, we're out of luck, use normal lookup. |
||
883 | mov edi, [ebx+edx*4] |
||
884 | add edi, [export_base] |
||
885 | push ecx esi |
||
886 | repz cmpsb |
||
887 | pop esi ecx |
||
888 | jz .found |
||
889 | .ignore_hint: |
||
890 | ; 4. Binary search over name table. |
||
891 | ; Export names are sorted with respect to repz cmpsb. |
||
892 | ; edi <= (the target index) < edx |
||
893 | xor edi, edi |
||
894 | mov edx, [eax+IMAGE_EXPORT_DIRECTORY.NumberOfNames] |
||
895 | .export_name_search.loop: |
||
896 | ; if there are no indexes between edi and edx, name is invalid |
||
897 | cmp edi, edx |
||
898 | jae .export_name_not_found |
||
899 | ; try the index in the middle of current range |
||
900 | lea eax, [edi+edx] |
||
901 | shr eax, 1 |
||
902 | ; compare |
||
903 | push ecx esi edi |
||
904 | fpo_delta = fpo_delta + 12 |
||
905 | mov edi, [ebx+eax*4] |
||
906 | add edi, [export_base] |
||
907 | repz cmpsb |
||
908 | pop edi esi ecx |
||
909 | fpo_delta = fpo_delta - 12 |
||
910 | ; exact match -> found, go to 5 |
||
911 | ; string at esi = target, string at edi = current attempt |
||
912 | ; (string at esi) < (string at edi) -> current index is too high, update upper range |
||
913 | ; (string at esi) > (string at edi) -> current index is too low, update lower range |
||
914 | jz .found |
||
915 | jb @f |
||
916 | lea edi, [eax+1] |
||
917 | jmp .export_name_search.loop |
||
918 | @@: |
||
919 | mov edx, eax |
||
920 | jmp .export_name_search.loop |
||
921 | ; Generic error handler. |
||
922 | .export_name_not_found: |
||
923 | mov ebx, esi |
||
924 | mov esi, [module] |
||
925 | test esi, esi |
||
926 | jnz @f |
||
927 | mutex_lock modules_mutex |
||
928 | mov ecx, [export_base] |
||
929 | call find_module_by_addr |
||
930 | mutex_unlock modules_mutex |
||
931 | @@: |
||
932 | mov eax, msg_unknown |
||
933 | test esi, esi |
||
934 | jz @f |
||
935 | mov eax, [esi+MODULE.filename] |
||
936 | @@: |
||
937 | ccall loader_say_error, msg_export_name_not_found, ebx, msg_export_not_found, eax, 0 |
||
938 | .return0: |
||
939 | xor eax, eax |
||
940 | ret |
||
941 | .found: |
||
942 | ; 5. We have found an index in AddressOfNames/AddressOfNameOrdinals arrays, |
||
943 | ; convert it to index in AddressOfFunctions array. |
||
944 | mov edx, [export_ptr] |
||
945 | mov ebx, [edx+IMAGE_EXPORT_DIRECTORY.AddressOfNameOrdinals] |
||
946 | add ebx, [export_base] |
||
947 | movzx eax, word [ebx+eax*2] |
||
948 | ; 6. Fetch the exported address from AddressOfFunctions array. |
||
949 | cmp eax, [edx+IMAGE_EXPORT_DIRECTORY.NumberOfFunctions] |
||
950 | jae .export_name_not_found |
||
951 | mov ebx, [edx+IMAGE_EXPORT_DIRECTORY.AddressOfFunctions] |
||
952 | add ebx, [export_base] |
||
953 | mov eax, [ebx+eax*4] |
||
954 | test eax, eax |
||
955 | jz .export_name_not_found |
||
956 | .check_forwarded: |
||
957 | ; This part of code is also used by get_exported_function_by_ordinal. |
||
958 | ; 7. Check whether the address is inside the export directory. |
||
959 | ; If not, we are done. |
||
960 | add eax, [export_base] |
||
961 | mov esi, eax |
||
962 | sub esi, edx |
||
963 | cmp esi, [export_size] |
||
964 | jb .export_is_forwarded |
||
965 | ret |
||
966 | .export_is_forwarded: |
||
967 | ; The export is forwarded to another module. |
||
968 | ; The address we have got points to the string " |
||
969 | ; 8. Get the target module name. It is everything before the first dot, |
||
970 | ; minus DLL extension. |
||
971 | ; 8a. Find the dot. |
||
972 | mov ebx, eax |
||
973 | @@: |
||
974 | inc eax |
||
975 | cmp byte [eax-1], '.' |
||
976 | jz .dot_found |
||
977 | cmp byte [eax-1], 0 |
||
978 | jnz @b |
||
979 | jmp .export_name_not_found |
||
980 | .dot_found: |
||
981 | ; 8b. Allocate the memory. |
||
982 | sub eax, ebx |
||
983 | mov edi, eax |
||
984 | add eax, 4 ; dll + terminating zero |
||
985 | stdcall malloc, eax |
||
986 | test eax, eax |
||
987 | jz .return0 |
||
988 | ; 8c. Copy module name. |
||
989 | mov esi, ebx |
||
990 | mov ecx, edi |
||
991 | mov edi, eax |
||
992 | rep movsb |
||
993 | mov dword [edi], 'dll' |
||
994 | mov ebx, esi ; save pointer to |
||
995 | mov edi, eax ; module name |
||
996 | ; 9. Load the target module. |
||
997 | ; 9a. Get the pointer to MODULE struct for ourselves. |
||
998 | mov esi, [module] |
||
999 | test esi, esi |
||
1000 | jnz @f |
||
1001 | mutex_lock modules_mutex |
||
1002 | mov ecx, [export_base] |
||
1003 | call find_module_by_addr |
||
1004 | test esi, esi |
||
1005 | jz .load_forwarded_failed |
||
1006 | @@: |
||
1007 | ; 9b. Call the worker. |
||
1008 | call load_imported_module |
||
1009 | test eax, eax |
||
1010 | jz .load_forwarded_failed |
||
1011 | mov esi, eax |
||
1012 | ; 9c. We don't need module name anymore, free the memory allocated at 8b. |
||
1013 | stdcall free, edi |
||
1014 | ; 10. Resolve the forwarded export recursively. |
||
1015 | ; 10a. Prepare for importing. |
||
1016 | mov [forward_export_module], esi |
||
1017 | mov eax, [esi+MODULE.base] |
||
1018 | call prepare_import_from_module |
||
1019 | ; 10b. Check whether we are importing by ordinal or by name. |
||
1020 | ; Forwarded export by ordinal has ebx -> "# |
||
1021 | cmp byte [ebx], '#' |
||
1022 | jnz .no_ordinal |
||
1023 | lea edx, [ebx+1] |
||
1024 | xor ecx, ecx ; ordinal |
||
1025 | @@: |
||
1026 | movzx eax, byte [edx] |
||
1027 | sub eax, '0' |
||
1028 | cmp eax, 10 |
||
1029 | jae .no_ordinal |
||
1030 | lea ecx, [ecx*5] |
||
1031 | lea ecx, [ecx*2+eax] |
||
1032 | inc edx |
||
1033 | cmp byte [edx], 0 |
||
1034 | jnz @b |
||
1035 | ; 10c. We are importing by ordinal. Call the worker. |
||
1036 | call get_exported_function_by_ordinal |
||
1037 | jmp @f |
||
1038 | ret |
||
1039 | .no_ordinal: |
||
1040 | ; 10d. We are importing by name. Call the worker. |
||
1041 | mov ecx, ebx |
||
1042 | or edx, -1 |
||
1043 | call get_exported_function_by_name |
||
1044 | @@: |
||
1045 | cmp [module], 0 |
||
1046 | jnz @f |
||
1047 | push eax |
||
1048 | mutex_unlock modules_mutex |
||
1049 | pop eax |
||
1050 | @@: |
||
1051 | ret |
||
1052 | .load_forwarded_failed: |
||
1053 | cmp [module], 0 |
||
1054 | jnz @f |
||
1055 | mutex_unlock modules_mutex |
||
1056 | @@: |
||
1057 | stdcall free, edi |
||
1058 | xor eax, eax |
||
1059 | ret |
||
1060 | endp |
||
1061 | |||
1062 | ; Resolve symbol from a module by name. |
||
1063 | ; prepare_import_from_module should be called beforehand. |
||
1064 | ; in: ecx = ordinal |
||
1065 | ; out: eax = exported address or NULL |
||
1066 | ; if [module] is zero, modules_mutex should be unlocked |
||
1067 | ; if [module] is nonzero, modules_mutex should be locked |
||
1068 | proc get_exported_function_by_ordinal c uses ebx esi edi, export_base, export_ptr, export_size, module |
||
1069 | locals |
||
1070 | forward_export_base dd ? |
||
1071 | forward_export_ptr dd ? |
||
1072 | forward_export_size dd ? |
||
1073 | forward_export_module dd ? |
||
1074 | endl |
||
1075 | ; 1. Validate that export directory is present at all. |
||
1076 | mov edx, [export_ptr] |
||
1077 | test edx, edx |
||
1078 | jz .export_ordinal_not_found |
||
1079 | ; 2. Convert ordinal to index in AddressOfFunctions array. |
||
1080 | mov eax, ecx ; keep ecx for error message |
||
1081 | sub eax, [edx+IMAGE_EXPORT_DIRECTORY.Base] |
||
1082 | ; 3. Validate the index. |
||
1083 | cmp eax, [edx+IMAGE_EXPORT_DIRECTORY.NumberOfFunctions] |
||
1084 | jae .export_ordinal_not_found |
||
1085 | ; 4. Fetch the exported address from AddressOfFunctions array. |
||
1086 | ; On success, continue to check for forwarded exports in get_exported_function_by_name. |
||
1087 | mov ebx, [edx+IMAGE_EXPORT_DIRECTORY.AddressOfFunctions] |
||
1088 | add ebx, [export_base] |
||
1089 | mov eax, [ebx+eax*4] |
||
1090 | test eax, eax |
||
1091 | jnz get_exported_function_by_name.check_forwarded |
||
1092 | ; Generic error handler. |
||
1093 | .export_ordinal_not_found: |
||
1094 | sub esp, 16 |
||
1095 | fpo_delta = fpo_delta + 16 |
||
1096 | ; Convert ordinal to string. |
||
1097 | lea edi, [esp+15] |
||
1098 | mov byte [edi], 0 |
||
1099 | @@: |
||
1100 | mov eax, 0xCCCCCCCD |
||
1101 | mul ecx |
||
1102 | shr edx, 3 ; edx = quotient of ecx / 10 |
||
1103 | lea eax, [edx*5] |
||
1104 | add eax, eax |
||
1105 | sub ecx, eax ; ecx = remainder of ecx % 10 |
||
1106 | add cl, '0' |
||
1107 | dec edi |
||
1108 | mov byte [edi], cl |
||
1109 | mov ecx, edx |
||
1110 | test edx, edx |
||
1111 | jnz @b |
||
1112 | ; Get module name. |
||
1113 | mov esi, [module] |
||
1114 | test esi, esi |
||
1115 | jnz @f |
||
1116 | mutex_lock modules_mutex |
||
1117 | mov ecx, [export_base] |
||
1118 | call find_module_by_addr |
||
1119 | mutex_unlock modules_mutex |
||
1120 | @@: |
||
1121 | mov eax, msg_unknown |
||
1122 | test esi, esi |
||
1123 | jz @f |
||
1124 | mov eax, [esi+MODULE.filename] |
||
1125 | @@: |
||
1126 | ccall loader_say_error, msg_export_ordinal_not_found, edi, msg_export_not_found, eax, 0 |
||
1127 | add esp, 16 |
||
1128 | fpo_delta = fpo_delta - 16 |
||
1129 | xor eax, eax |
||
1130 | ret |
||
1131 | endp>>=> |