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#ifndef FUNCCRYPT_H
#define FUNCCRYPT_H 1
#include <stdlib.h>
#include <stdint.h>
#if !defined(__GNUC__) || !defined(__GNUC_MINOR__)
#error "This is only verified to work with a GCC compiler!"
#endif
/* Force GCC struct for MingW compilers and pack them,
* which means the struct is 1-byte aligned.
*/
#define GCC_PACKED __attribute__((packed, gcc_struct))
typedef struct crypt_header {
uint64_t key;
uint8_t crpyted;
uint32_t marker;
uint64_t func_body[0];
} GCC_PACKED crypt_header;
typedef enum crypt_return {
CRET_ERROR, /* Neither prologue marker nor epilogue marker found. */
CRET_ERROR_MEM, /* set memory page protection failed */
CRET_PROLOGUE, /* prologue marker found */
CRET_EPILOGUE, /* epilogue marker found */
CRET_CHECK, /* all pre (en|de)cryption checks successful */
CRET_OK_ENC, /* encryption succeeded */
CRET_OK_DEC, /* decryption succeeded */
} crypt_return;
#define CRYPT_FUNC_MAXSIZ 0x100
#define CRYPT_FUNC(fn) \
crypt_func((void *)fn)
#define CRYPT_RETVAL() __cr
#define CRYPT_PROLOGUE(fn) \
crypt_return __cr; \
{ \
__cr = CRYPT_FUNC(fn); \
if (__cr != CRET_OK_DEC) \
asm volatile goto("jmp %l0 \n" \
: : : : cr_epilogue); \
asm volatile goto("jmp %l0 \n" \
: : : : cr_prologue); \
asm volatile( \
".byte " \
/* key: */ "0x00, 0x00, 0x00, 0x00," \
"0x00, 0x00, 0x00, 0x00," \
/* crypted: */ "0x00," \
/* marker: */ "0xDE, 0xC0, 0xDE, 0xC0; \n" \
); \
} \
cr_prologue: {
#define CRYPT_EPILOGUE(fn) \
} { \
asm volatile goto("jmp %l0 \n" \
: : : : cr_epilogue); \
asm volatile( \
".byte " \
/* Insert encryption pad, so we can find the end marker,
* while the function body is encrypted.
* (XOR 64 bit encryption == 8 byte)
*/ \
"0x00, 0x00, 0x00, 0x00," \
"0x00, 0x00, 0x00, 0x00," \
/* marker: */ "0xFE, 0xCA, 0xFE, 0xCA; \n" \
); \
} \
cr_epilogue: \
if (CRYPT_RETVAL() == CRET_OK_DEC) \
CRYPT_FUNC(fn);
#define CRYPT_FNDEF(name, ...) \
void name( __VA_ARGS__ ) { \
CRYPT_PROLOGUE( name );
#define CRYPT_FNEND(name) \
CRYPT_EPILOGUE(name); \
}
#ifdef _DEBUG
extern const char *crypt_strs[];
extern void printHexBuf(uint8_t *buf, size_t siz, size_t chars_per_line);
#endif
extern crypt_return crypt_func(void *fn_start);
#endif
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