Hafl MD4 hash from linux/fs/ext/hash.c

hash.c

// SPDX-License-Identifier: GPL-2.0
/*
 *  linux/fs/ext4/hash.c
 *
 * Copyright (C) 2002 by Theodore Ts'o
 */

#include <stdio.h>
#include <string.h>

#define DELTA 0x9E3779B9
#define EXT4_HTREE_EOF_32BIT   ((1UL  << (32 - 1)) - 1)

static void TEA_transform(unsigned int buf[4], unsigned int const in[])
{
	unsigned int	sum = 0;
	unsigned int	b0 = buf[0], b1 = buf[1];
	unsigned int	a = in[0], b = in[1], c = in[2], d = in[3];
	int	n = 16;

	do {
		sum += DELTA;
		b0 += ((b1 << 4)+a) ^ (b1+sum) ^ ((b1 >> 5)+b);
		b1 += ((b0 << 4)+c) ^ (b0+sum) ^ ((b0 >> 5)+d);
	} while (--n);

	buf[0] += b0;
	buf[1] += b1;
}

/* F, G and H are basic MD4 functions: selection, majority, parity */
#define F(x, y, z) ((z) ^ ((x) & ((y) ^ (z))))
#define G(x, y, z) (((x) & (y)) + (((x) ^ (y)) & (z)))
#define H(x, y, z) ((x) ^ (y) ^ (z))

/*
 * The generic round function.  The application is so specific that
 * we don't bother protecting all the arguments with parens, as is generally
 * good macro practice, in favor of extra legibility.
 * Rotation is separate from addition to prevent recomputation
 */
#define ROUND(f, a, b, c, d, x, s)	\
	(a += f(b, c, d) + x, a = rol32(a, s))
#define K1 0
#define K2 013240474631UL
#define K3 015666365641UL

static inline unsigned int rol32(unsigned int word, unsigned int shift)
{
    return (word << (shift & 31)) | (word >> ((-shift) & 31));
}

/*
 * Basic cut-down MD4 transform.  Returns only 32 bits of result.
 */
static unsigned int half_md4_transform(unsigned int buf[4], unsigned int const in[8])
{
	unsigned int a = buf[0], b = buf[1], c = buf[2], d = buf[3];

	/* Round 1 */
	ROUND(F, a, b, c, d, in[0] + K1,  3);
	ROUND(F, d, a, b, c, in[1] + K1,  7);
	ROUND(F, c, d, a, b, in[2] + K1, 11);
	ROUND(F, b, c, d, a, in[3] + K1, 19);
	ROUND(F, a, b, c, d, in[4] + K1,  3);
	ROUND(F, d, a, b, c, in[5] + K1,  7);
	ROUND(F, c, d, a, b, in[6] + K1, 11);
	ROUND(F, b, c, d, a, in[7] + K1, 19);

	/* Round 2 */
	ROUND(G, a, b, c, d, in[1] + K2,  3);
	ROUND(G, d, a, b, c, in[3] + K2,  5);
	ROUND(G, c, d, a, b, in[5] + K2,  9);
	ROUND(G, b, c, d, a, in[7] + K2, 13);
	ROUND(G, a, b, c, d, in[0] + K2,  3);
	ROUND(G, d, a, b, c, in[2] + K2,  5);
	ROUND(G, c, d, a, b, in[4] + K2,  9);
	ROUND(G, b, c, d, a, in[6] + K2, 13);

	/* Round 3 */
	ROUND(H, a, b, c, d, in[3] + K3,  3);
	ROUND(H, d, a, b, c, in[7] + K3,  9);
	ROUND(H, c, d, a, b, in[2] + K3, 11);
	ROUND(H, b, c, d, a, in[6] + K3, 15);
	ROUND(H, a, b, c, d, in[1] + K3,  3);
	ROUND(H, d, a, b, c, in[5] + K3,  9);
	ROUND(H, c, d, a, b, in[0] + K3, 11);
	ROUND(H, b, c, d, a, in[4] + K3, 15);

	buf[0] += a;
	buf[1] += b;
	buf[2] += c;
	buf[3] += d;

	return buf[1]; /* "most hashed" word */
}
#undef ROUND
#undef K1
#undef K2
#undef K3
#undef F
#undef G
#undef H

/* The old legacy hash */
static unsigned int dx_hack_hash_unsigned(const char *name, int len)
{
	unsigned int hash, hash0 = 0x12a3fe2d, hash1 = 0x37abe8f9;
	const unsigned char *ucp = (const unsigned char *) name;

	while (len--) {
		hash = hash1 + (hash0 ^ (((int) *ucp++) * 7152373));

		if (hash & 0x80000000)
			hash -= 0x7fffffff;
		hash1 = hash0;
		hash0 = hash;
	}
	return hash0 << 1;
}

static unsigned int dx_hack_hash_signed(const char *name, int len)
{
	unsigned int hash, hash0 = 0x12a3fe2d, hash1 = 0x37abe8f9;
	const signed char *scp = (const signed char *) name;

	while (len--) {
		hash = hash1 + (hash0 ^ (((int) *scp++) * 7152373));

		if (hash & 0x80000000)
			hash -= 0x7fffffff;
		hash1 = hash0;
		hash0 = hash;
	}
	return hash0 << 1;
}

static void str2hashbuf_signed(const char *msg, int len, unsigned int *buf, int num)
{
	unsigned int	pad, val;
	int	i;
	const signed char *scp = (const signed char *) msg;

	pad = (unsigned int)len | ((unsigned int)len << 8);
	pad |= pad << 16;

	val = pad;
	if (len > num*4)
		len = num * 4;
	for (i = 0; i < len; i++) {
		val = ((int) scp[i]) + (val << 8);
		if ((i % 4) == 3) {
			*buf++ = val;
			val = pad;
			num--;
		}
	}
	if (--num >= 0)
		*buf++ = val;
	while (--num >= 0)
		*buf++ = pad;
}

static void str2hashbuf_unsigned(const char *msg, int len, unsigned int *buf, int num)
{
	unsigned int	pad, val;
	int	i;
	const unsigned char *ucp = (const unsigned char *) msg;

	pad = (unsigned int)len | ((unsigned int)len << 8);
	pad |= pad << 16;

	val = pad;
	if (len > num*4)
		len = num * 4;
	for (i = 0; i < len; i++) {
		val = ((int) ucp[i]) + (val << 8);
		if ((i % 4) == 3) {
			*buf++ = val;
			val = pad;
			num--;
		}
	}
	if (--num >= 0)
		*buf++ = val;
	while (--num >= 0)
		*buf++ = pad;
}

int __ext4fs_dirhash(const char *name, int len) {
	unsigned int	hash;
	unsigned int	minor_hash = 0;
	const char	*p;
	int		i;
	unsigned int		in[8], buf[4];
	void		(*str2hashbuf)(const char *, int, unsigned int *, int) =
				str2hashbuf_signed;

	/* Initialize the default seed for the hash checksum functions */
  /* It needs to read from super block */
	buf[0] = 0xf69696b6;
	buf[1] = 0xa14ee5ab;
	buf[2] = 0xef542e8a;
	buf[3] = 0x6d4dea7a;

	p = name;
	while (len > 0) {
		(*str2hashbuf)(p, len, in, 8);
		half_md4_transform(buf, in);
		len -= 32;
		p += 32;
	}
	minor_hash = buf[2];
	hash = buf[1];

    printf("hash: %x\n", hash);
    printf("minor_hash: %x\n", minor_hash);

	hash = hash & ~1;
	if (hash == (EXT4_HTREE_EOF_32BIT << 1))
		hash = (EXT4_HTREE_EOF_32BIT - 1) << 1;

    printf("hash: %x\n", hash);
    printf("minor_hash: %x\n", minor_hash);
	return 0;
}

int main(int argc, char *argv[]) {
    int len = strlen(argv[1]);
    __ext4fs_dirhash(argv[1], len);
    return 0;
}