union VALUETYPE {

	uint8_t b;

	uint16_t h;

	uint32_t l;

	uint64_t q;

	uint8_t hs[2];	/* 2 bytes of a fixed-endian "short" */

	uint8_t hl[4];	/* 4 bytes of a fixed-endian "long" */

	uint8_t hq[8];	/* 8 bytes of a fixed-endian "quad" */

	char s[MAXstring];	/* the search string or regex pattern */

	unsigned char us[MAXstring];

	uint64_t guid[2];

	float f;

	double d;

};

struct magic {

	/* Word 1 */

	uint16_t cont_level;	/* level of ">" */

	uint8_t flag;

#define INDIR		0x01	/* if '(...)' appears */

#define OFFADD		0x02	/* if '>&' or '>...(&' appears */

#define INDIROFFADD	0x04	/* if '>&(' appears */

#define UNSIGNED	0x08	/* comparison is unsigned */

#define NOSPACE		0x10	/* suppress space character before output */

#define BINTEST		0x20	/* test is for a binary type (set only

				   for top-level tests) */

#define TEXTTEST	0x40	/* for passing to file_softmagic */

#define OFFNEGATIVE	0x80	/* relative to the end of file */

	uint8_t factor;

	/* Word 2 */

	uint8_t reln;		/* relation (0=eq, '>'=gt, etc) */

	uint8_t vallen;		/* length of string value, if any */

	uint8_t type;		/* comparison type (FILE_*) */

	uint8_t in_type;	/* type of indirection */

#define 			FILE_INVALID	0

#define 			FILE_BYTE	1

#define				FILE_SHORT	2

#define				FILE_DEFAULT	3

#define				FILE_LONG	4

#define				FILE_STRING	5

#define				FILE_DATE	6

#define				FILE_BESHORT	7

#define				FILE_BELONG	8

#define				FILE_BEDATE	9

#define				FILE_LESHORT	10

#define				FILE_LELONG	11

#define				FILE_LEDATE	12

#define				FILE_PSTRING	13

#define				FILE_LDATE	14

#define				FILE_BELDATE	15

#define				FILE_LELDATE	16

#define				FILE_REGEX	17

#define				FILE_BESTRING16	18

#define				FILE_LESTRING16	19

#define				FILE_SEARCH	20

#define				FILE_MEDATE	21

#define				FILE_MELDATE	22

#define				FILE_MELONG	23

#define				FILE_QUAD	24

#define				FILE_LEQUAD	25

#define				FILE_BEQUAD	26

#define				FILE_QDATE	27

#define				FILE_LEQDATE	28

#define				FILE_BEQDATE	29

#define				FILE_QLDATE	30

#define				FILE_LEQLDATE	31

#define				FILE_BEQLDATE	32

#define				FILE_FLOAT	33

#define				FILE_BEFLOAT	34

#define				FILE_LEFLOAT	35

#define				FILE_DOUBLE	36

#define				FILE_BEDOUBLE	37

#define				FILE_LEDOUBLE	38

#define				FILE_BEID3	39

#define				FILE_LEID3	40

#define				FILE_INDIRECT	41

#define				FILE_QWDATE	42

#define				FILE_LEQWDATE	43

#define				FILE_BEQWDATE	44

#define				FILE_NAME	45

#define				FILE_USE	46

#define				FILE_CLEAR	47

#define				FILE_DER	48

#define				FILE_GUID	49

#define				FILE_OFFSET	50

#define				FILE_BEVARINT	51

#define				FILE_LEVARINT	52

#define				FILE_NAMES_SIZE	53 /* size of array to contain all names */

#define IS_STRING(t) \

	((t) == FILE_STRING || \

	 (t) == FILE_PSTRING || \

	 (t) == FILE_BESTRING16 || \

	 (t) == FILE_LESTRING16 || \

	 (t) == FILE_REGEX || \

	 (t) == FILE_SEARCH || \

	 (t) == FILE_INDIRECT || \

	 (t) == FILE_NAME || \

	 (t) == FILE_USE)

#define FILE_FMT_NONE 0

#define FILE_FMT_NUM  1 /* "cduxXi" */

#define FILE_FMT_STR  2 /* "s" */

#define FILE_FMT_QUAD 3 /* "ll" */

#define FILE_FMT_FLOAT 4 /* "eEfFgG" */

#define FILE_FMT_DOUBLE 5 /* "eEfFgG" */

	/* Word 3 */

	uint8_t in_op;		/* operator for indirection */

	uint8_t mask_op;	/* operator for mask */

#ifdef ENABLE_CONDITIONALS

	uint8_t cond;		/* conditional type */

#else

	uint8_t dummy;

#endif

	uint8_t factor_op;

#define		FILE_FACTOR_OP_PLUS	'+'

#define		FILE_FACTOR_OP_MINUS	'-'

#define		FILE_FACTOR_OP_TIMES	'*'

#define		FILE_FACTOR_OP_DIV	'/'

#define		FILE_FACTOR_OP_NONE	'\0'

#define				FILE_OPS	"&|^+-*/%"

#define				FILE_OPAND	0

#define				FILE_OPOR	1

#define				FILE_OPXOR	2

#define				FILE_OPADD	3

#define				FILE_OPMINUS	4

#define				FILE_OPMULTIPLY	5

#define				FILE_OPDIVIDE	6

#define				FILE_OPMODULO	7

#define				FILE_OPS_MASK	0x07 /* mask for above ops */

#define				FILE_UNUSED_1	0x08

#define				FILE_UNUSED_2	0x10

#define				FILE_OPSIGNED	0x20

#define				FILE_OPINVERSE	0x40

#define				FILE_OPINDIRECT	0x80

#ifdef ENABLE_CONDITIONALS

#define				COND_NONE	0

#define				COND_IF		1

#define				COND_ELIF	2

#define				COND_ELSE	3

#endif /* ENABLE_CONDITIONALS */

	/* Word 4 */

	int32_t offset;		/* offset to magic number */

	/* Word 5 */

	int32_t in_offset;	/* offset from indirection */

	/* Word 6 */

	uint32_t lineno;	/* line number in magic file */

	/* Word 7,8 */

	union {

		uint64_t _mask;	/* for use with numeric and date types */

		struct {

			uint32_t _count;	/* repeat/line count */

			uint32_t _flags;	/* modifier flags */

		} _s;		/* for use with string types */

	} _u;

#define num_mask _u._mask

#define str_range _u._s._count

#define str_flags _u._s._flags

	/* Words 9-24 */

	union VALUETYPE value;	/* either number or string */

	/* Words 25-40 */

	char desc[MAXDESC];	/* description */

	/* Words 41-60 */

	char mimetype[MAXMIME]; /* MIME type */

	/* Words 61-62 */

	char apple[8];		/* APPLE CREATOR/TYPE */

	/* Words 63-78 */

	char ext[64];		/* Popular extensions */

};

int main(){

    FILE *fp = fopen("./flag.mgc","rb");

    struct magic buffer[100];

    fseek(fp,0x178,SEEK_SET);

    fread(buffer,sizeof(struct magic),0x42,fp);

}

void print_buffer(struct magic buffer,int index){

	printf("buffer[%d]->cont_level = 0x%x\n",index,buffer.cont_level);

	printf("buffer[%d]->flag = 0x%x\n",index,buffer.flag);

	printf("buffer[%d]->factor = 0x%x\n",index,buffer.factor);

	printf("buffer[%d]->reln = 0x%x\n",index,buffer.reln);

	printf("buffer[%d]->vallen = 0x%x\n",index,buffer.vallen);

	printf("buffer[%d]->type = 0x%x\n",index,buffer.type);

	printf("buffer[%d]->in_type = 0x%x\n",index,buffer.in_type);

	printf("buffer[%d]->in_op = 0x%x\n",index,buffer.in_op);

	printf("buffer[%d]->mask_op = 0x%x\n",index,buffer.mask_op);

	printf("buffer[%d]->dummy = 0x%x\n",index,buffer.dummy);

	printf("buffer[%d]->factor_op = 0x%x\n",index,buffer.factor_op);

	printf("buffer[%d]->offset = 0x%x\n",index,buffer.offset);

	printf("buffer[%d]->in_offset = 0x%x\n",index,buffer.in_offset);

	printf("buffer[%d]->lineno = 0x%x\n",index,buffer.lineno);

	printf("buffer[%d]->num_mask = 0x%x\n",index,buffer.num_mask);

	printf("buffer[%d]->str_range = 0x%x\n",index,buffer.str_range);

	printf("buffer[%d]->str_flags = 0x%x\n",index,buffer.str_flags);

	if(buffer.type==5){

		printf("buffer[%d]->value = \"%s\"\n",index,buffer.value);

	}

	else{

		printf("buffer[%d]->value = 0x%x\n",index,buffer.value);

	}

	printf("buffer[%d]->desc = \"%s\"\n",index,buffer.desc);

	printf("buffer[%d]->mimetype = \"%s\"\n",index,buffer.mimetype);

	printf("buffer[%d]->apple = \"%s\"\n",index,buffer.apple);

	printf("buffer[%d]->ext = \"%s\"\n\n",index,buffer.ext);

}

#include<stdio.h>

#ifndef __int8_t_defined  

# define __int8_t_defined  

typedef signed char             int8_t;   

typedef short int               int16_t;  

typedef int                     int32_t;  

# if __WORDSIZE == 64  

typedef long int                int64_t;  

# else  

__extension__  

typedef long long int           int64_t;  

# endif  

#endif  

typedef unsigned char           uint8_t;  

typedef unsigned short int      uint16_t;  

#ifndef __uint32_t_defined  

typedef unsigned int            uint32_t;  

# define __uint32_t_defined  

#endif  

#if __WORDSIZE == 64  

typedef unsigned long int       uint64_t;  

#else  

__extension__  

typedef unsigned long long int  uint64_t;  

#endif

#define MAXDESC	64		/* max len of text description/MIME type */

#define MAXMIME	80		/* max len of text MIME type */

#define MAXstring 128		/* max len of "string" types */

#define MAGIC_SETS	2

union VALUETYPE {

	uint8_t b;

	uint16_t h;

	uint32_t l;

	uint64_t q;

	uint8_t hs[2];	/* 2 bytes of a fixed-endian "short" */

	uint8_t hl[4];	/* 4 bytes of a fixed-endian "long" */

	uint8_t hq[8];	/* 8 bytes of a fixed-endian "quad" */

	char s[MAXstring];	/* the search string or regex pattern */

	unsigned char us[MAXstring];

	uint64_t guid[2];

	float f;

	double d;

};

struct magic {

	/* Word 1 */

	uint16_t cont_level;	/* level of ">" */

	uint8_t flag;

#define INDIR		0x01	/* if '(...)' appears */

#define OFFADD		0x02	/* if '>&' or '>...(&' appears */

#define INDIROFFADD	0x04	/* if '>&(' appears */

#define UNSIGNED	0x08	/* comparison is unsigned */

#define NOSPACE		0x10	/* suppress space character before output */

#define BINTEST		0x20	/* test is for a binary type (set only

				   for top-level tests) */

#define TEXTTEST	0x40	/* for passing to file_softmagic */

#define OFFNEGATIVE	0x80	/* relative to the end of file */

	uint8_t factor;

	/* Word 2 */

	uint8_t reln;		/* relation (0=eq, '>'=gt, etc) */

	uint8_t vallen;		/* length of string value, if any */

	uint8_t type;		/* comparison type (FILE_*) */

	uint8_t in_type;	/* type of indirection */

#define 			FILE_INVALID	0

#define 			FILE_BYTE	1

#define				FILE_SHORT	2

#define				FILE_DEFAULT	3

#define				FILE_LONG	4

#define				FILE_STRING	5

#define				FILE_DATE	6

#define				FILE_BESHORT	7

#define				FILE_BELONG	8

#define				FILE_BEDATE	9

#define				FILE_LESHORT	10

#define				FILE_LELONG	11

#define				FILE_LEDATE	12

#define				FILE_PSTRING	13

#define				FILE_LDATE	14

#define				FILE_BELDATE	15

#define				FILE_LELDATE	16

#define				FILE_REGEX	17

#define				FILE_BESTRING16	18

#define				FILE_LESTRING16	19

#define				FILE_SEARCH	20

#define				FILE_MEDATE	21

#define				FILE_MELDATE	22

#define				FILE_MELONG	23

#define				FILE_QUAD	24

#define				FILE_LEQUAD	25

#define				FILE_BEQUAD	26

#define				FILE_QDATE	27

#define				FILE_LEQDATE	28

#define				FILE_BEQDATE	29

#define				FILE_QLDATE	30

#define				FILE_LEQLDATE	31

#define				FILE_BEQLDATE	32

#define				FILE_FLOAT	33

#define				FILE_BEFLOAT	34

#define				FILE_LEFLOAT	35

#define				FILE_DOUBLE	36

#define				FILE_BEDOUBLE	37

#define				FILE_LEDOUBLE	38

#define				FILE_BEID3	39

#define				FILE_LEID3	40

#define				FILE_INDIRECT	41

#define				FILE_QWDATE	42

#define				FILE_LEQWDATE	43

#define				FILE_BEQWDATE	44

#define				FILE_NAME	45

#define				FILE_USE	46

#define				FILE_CLEAR	47

#define				FILE_DER	48

#define				FILE_GUID	49

#define				FILE_OFFSET	50

#define				FILE_BEVARINT	51

#define				FILE_LEVARINT	52

#define				FILE_NAMES_SIZE	53 /* size of array to contain all names */

#define IS_STRING(t) \

	((t) == FILE_STRING || \

	 (t) == FILE_PSTRING || \

	 (t) == FILE_BESTRING16 || \

	 (t) == FILE_LESTRING16 || \

	 (t) == FILE_REGEX || \

	 (t) == FILE_SEARCH || \

	 (t) == FILE_INDIRECT || \

	 (t) == FILE_NAME || \

	 (t) == FILE_USE)

#define FILE_FMT_NONE 0

#define FILE_FMT_NUM  1 /* "cduxXi" */

#define FILE_FMT_STR  2 /* "s" */

#define FILE_FMT_QUAD 3 /* "ll" */

#define FILE_FMT_FLOAT 4 /* "eEfFgG" */

#define FILE_FMT_DOUBLE 5 /* "eEfFgG" */

	/* Word 3 */

	uint8_t in_op;		/* operator for indirection */

	uint8_t mask_op;	/* operator for mask */

#ifdef ENABLE_CONDITIONALS

	uint8_t cond;		/* conditional type */

#else

	uint8_t dummy;

#endif

	uint8_t factor_op;

#define		FILE_FACTOR_OP_PLUS	'+'

#define		FILE_FACTOR_OP_MINUS	'-'

#define		FILE_FACTOR_OP_TIMES	'*'

#define		FILE_FACTOR_OP_DIV	'/'

#define		FILE_FACTOR_OP_NONE	'\0'

#define				FILE_OPS	"&|^+-*/%"

#define				FILE_OPAND	0

#define				FILE_OPOR	1

#define				FILE_OPXOR	2

#define				FILE_OPADD	3

#define				FILE_OPMINUS	4

#define				FILE_OPMULTIPLY	5

#define				FILE_OPDIVIDE	6

#define				FILE_OPMODULO	7

#define				FILE_OPS_MASK	0x07 /* mask for above ops */

#define				FILE_UNUSED_1	0x08

#define				FILE_UNUSED_2	0x10

#define				FILE_OPSIGNED	0x20

#define				FILE_OPINVERSE	0x40

#define				FILE_OPINDIRECT	0x80

#ifdef ENABLE_CONDITIONALS

#define				COND_NONE	0

#define				COND_IF		1

#define				COND_ELIF	2

#define				COND_ELSE	3

#endif /* ENABLE_CONDITIONALS */

	/* Word 4 */

	int32_t offset;		/* offset to magic number */

	/* Word 5 */

	int32_t in_offset;	/* offset from indirection */

	/* Word 6 */

	uint32_t lineno;	/* line number in magic file */

	/* Word 7,8 */

	union {

		uint64_t _mask;	/* for use with numeric and date types */

		struct {

			uint32_t _count;	/* repeat/line count */

			uint32_t _flags;	/* modifier flags */

		} _s;		/* for use with string types */

	} _u;

#define num_mask _u._mask

#define str_range _u._s._count

#define str_flags _u._s._flags

	/* Words 9-24 */

	union VALUETYPE value;	/* either number or string */

	/* Words 25-40 */

	char desc[MAXDESC];	/* description */

	/* Words 41-60 */

	char mimetype[MAXMIME]; /* MIME type */

	/* Words 61-62 */

	char apple[8];		/* APPLE CREATOR/TYPE */

	/* Words 63-78 */

	char ext[64];		/* Popular extensions */

};

int main(){

    char flag[1000],flag_index[1000];

    FILE *fp = fopen("./flag.mgc","rb");

    struct magic buffer[100];

    fseek(fp,0x178,SEEK_SET);

    fread(buffer,sizeof(struct magic),0x42,fp);

    int xor_val = 0;

    for(int i=0;i<0x42;i++){

        //printf ("% d\n",buffer [i].mask_op);// 输出全是 2, 对照 mask_op, 可知是异或操作

        if(buffer[i].mask_op){

            xor_val = buffer[i]._u._mask&0xff;

        }

        else{

            xor_val = 0;

        }

        switch(buffer[i].type){

		case FILE_BYTE:

			//printf("8%c\n",buffer[i].value.b);

            flag[flag_index[buffer[i].offset]] = buffer[i].value.b^xor_val;

			break;

		case FILE_SHORT:

		case FILE_BESHORT:

		case FILE_LESHORT:

			//printf("16%c\n",buffer[i].value.h);

            flag_index[buffer[i].offset] = buffer[i].value.h^xor_val;

			break;

		case FILE_DATE:

		case FILE_BEDATE:

		case FILE_LEDATE:

		case FILE_MEDATE:

		case FILE_LDATE:

		case FILE_BELDATE:

		case FILE_LELDATE:

		case FILE_MELDATE:

		case FILE_LONG:

		case FILE_BELONG:

		case FILE_LELONG:

		case FILE_MELONG:

		case FILE_FLOAT:

		case FILE_BEFLOAT:

		case FILE_LEFLOAT:

			printf("32%c",buffer[i].value.l);

			break;

		case FILE_QUAD:

		case FILE_BEQUAD:

		case FILE_LEQUAD:

		case FILE_QDATE:

		case FILE_QLDATE:

		case FILE_QWDATE:

		case FILE_BEQDATE:

		case FILE_BEQLDATE:

		case FILE_BEQWDATE:

		case FILE_LEQDATE:

		case FILE_LEQLDATE:

		case FILE_LEQWDATE:

		case FILE_DOUBLE:

		case FILE_BEDOUBLE:

		case FILE_LEDOUBLE:

		case FILE_OFFSET:

		case FILE_BEVARINT:

		case FILE_LEVARINT:

			printf("%c",buffer[i].value.q);

			break;

		case FILE_STRING:

		case FILE_PSTRING:

		case FILE_BESTRING16:

		case FILE_LESTRING16:

		case FILE_REGEX:

		case FILE_SEARCH:

		case FILE_DEFAULT:

		case FILE_INDIRECT:

		case FILE_NAME:

		case FILE_USE:

		case FILE_CLEAR:

		case FILE_DER:

		case FILE_GUID:

            //printf("%s\n",buffer[i].value.s);

            for(int k=0;k<buffer[i].vallen;k++){

                flag[k+buffer[i].offset] = buffer[i].value.s[k];

            }

            break;

        default:

            break;

        }

    }

    int len=0;

    for(int i=0;i<100;i++){

        printf("%c",flag[i]);

        //flag{_oh_yes_you_got_the_flag___^_^__}

    }

}