153 lines
3.0 KiB
C
153 lines
3.0 KiB
C
/*
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* patch.c
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*
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* Copyright 2020 crt0mega <crt0mega@c-r-t.tk>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
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* MA 02110-1301, USA.
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*
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*
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*/
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#include <stdio.h>
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#include <stdbool.h>
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#include <stdint.h>
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#define IS_LAA 0x0020
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bool ispe(char *filename)
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{
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FILE *pFile;
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int16_t header;
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int32_t peloc;
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int32_t peheader;
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pFile = fopen(filename, "rb");
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fread(&header, sizeof(header), 1, pFile);
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if (header != 0x5a4d) //Check presence of MZ magic bytes
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{
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fclose(pFile);
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return false;
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}
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fseek(pFile, 0x3c, SEEK_SET);
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fread(&peloc, sizeof(peloc), 1, pFile); //Get PE header location
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fseek(pFile, peloc, SEEK_SET);
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fread(&peheader, sizeof(peheader), 1, pFile);
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if (peheader != 0x4550) // Check presence of PE magic bytes
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{
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fclose(pFile);
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return false;
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}
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fclose(pFile);
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return true;
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}
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bool ispatched(char *filename)
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{
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FILE *pFile;
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int32_t peloc;
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int32_t peheader;
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int16_t laa;
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if (!ispe(filename))
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{
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printf("How did we even get here?!");
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return false;
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}
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pFile = fopen(filename, "rb");
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fseek(pFile, 0x3c, SEEK_SET);
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fread(&peloc, sizeof(peloc), 1, pFile);
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fseek(pFile, peloc, SEEK_SET); // Seek to PE Location and
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fread(&peheader, sizeof(peheader), 1, pFile); // Fetch header
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if (peheader != 0x4550)
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{
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printf("How the hell did we even geht here?!");
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return false;
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}
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fseek(pFile, 0x12, SEEK_CUR); // Seek to characteristics
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fread(&laa, sizeof(laa), 1, pFile); // Read characteristics
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fclose(pFile);
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if ((laa & IS_LAA) == IS_LAA)
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{
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return true;
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}
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return false;
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}
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bool patch(char *filename)
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{
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FILE *pFile;
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int32_t peloc;
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int32_t peheader;
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int16_t laa;
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if (!ispe(filename))
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{
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printf("How did we even get here?!\n");
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return false;
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}
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pFile = fopen(filename, "r+b");
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fseek(pFile, 0x3c, SEEK_SET);
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fread(&peloc, sizeof(peloc), 1, pFile);
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fseek(pFile, peloc, SEEK_SET); // Seek to PE Location and
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fread(&peheader, sizeof(peheader), 1, pFile); // Fetch header
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if (peheader != 0x4550)
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{
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printf("How the hell did we even geht here?!\n");
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return false;
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}
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fseek(pFile, 0x12, SEEK_CUR); // Seek to characteristics
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fread(&laa, sizeof(laa), 1, pFile); // Read characteristics
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int16_t setlaa;
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if ((laa & IS_LAA) == IS_LAA)
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{
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setlaa=laa&~IS_LAA;
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}
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else
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{
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setlaa=laa|IS_LAA;
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}
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fseek(pFile, -sizeof(laa), SEEK_CUR); // Seek back
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fwrite(&setlaa, 1, sizeof(setlaa), pFile); // Write new value
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fclose(pFile);
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return true;
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}
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