[linux-2.6-block.git] / fs / f2fs / hash.c

// SPDX-License-Identifier: GPL-2.0
/*
 * fs/f2fs/hash.c
 *
 * Copyright (c) 2012 Samsung Electronics Co., Ltd.
 *             http://www.samsung.com/
 *
 * Portions of this code from linux/fs/ext3/hash.c
 *
 * Copyright (C) 2002 by Theodore Ts'o
 */
#include <linux/types.h>
#include <linux/fs.h>
#include <linux/f2fs_fs.h>
#include <linux/cryptohash.h>
#include <linux/pagemap.h>

#include "f2fs.h"

/*
 * Hashing code copied from ext3
 */
#define DELTA 0x9E3779B9

static void TEA_transform(unsigned int buf[4], unsigned int const in[])
{
	__u32 sum = 0;
	__u32 b0 = buf[0], b1 = buf[1];
	__u32 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;
}

static void str2hashbuf(const unsigned char *msg, size_t len,
				unsigned int *buf, int num)
{
	unsigned pad, val;
	int i;

	pad = (__u32)len | ((__u32)len << 8);
	pad |= pad << 16;

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

f2fs_hash_t f2fs_dentry_hash(const struct qstr *name_info,
				struct fscrypt_name *fname)
{
	__u32 hash;
	f2fs_hash_t f2fs_hash;
	const unsigned char *p;
	__u32 in[8], buf[4];
	const unsigned char *name = name_info->name;
	size_t len = name_info->len;

	/* encrypted bigname case */
	if (fname && !fname->disk_name.name)
		return cpu_to_le32(fname->hash);

	if (is_dot_dotdot(name_info))
		return 0;

	/* Initialize the default seed for the hash checksum functions */
	buf[0] = 0x67452301;
	buf[1] = 0xefcdab89;
	buf[2] = 0x98badcfe;
	buf[3] = 0x10325476;

	p = name;
	while (1) {
		str2hashbuf(p, len, in, 4);
		TEA_transform(buf, in);
		p += 16;
		if (len <= 16)
			break;
		len -= 16;
	}
	hash = buf[0];
	f2fs_hash = cpu_to_le32(hash & ~F2FS_HASH_COL_BIT);
	return f2fs_hash;
}
Commit	Line	Data
7c1a000d	1	// SPDX-License-Identifier: GPL-2.0
0a8165d7	2	/*
6b4ea016 JK	3	* fs/f2fs/hash.c
	4	*
	5	* Copyright (c) 2012 Samsung Electronics Co., Ltd.
	6	* http://www.samsung.com/
	7	*
	8	* Portions of this code from linux/fs/ext3/hash.c
	9	*
	10	* Copyright (C) 2002 by Theodore Ts'o
6b4ea016 JK	11	*/
	12	#include <linux/types.h>
	13	#include <linux/fs.h>
	14	#include <linux/f2fs_fs.h>
	15	#include <linux/cryptohash.h>
	16	#include <linux/pagemap.h>
	17
	18	#include "f2fs.h"
	19
	20	/*
	21	* Hashing code copied from ext3
	22	*/
	23	#define DELTA 0x9E3779B9
	24
	25	static void TEA_transform(unsigned int buf[4], unsigned int const in[])
	26	{
	27	__u32 sum = 0;
	28	__u32 b0 = buf[0], b1 = buf[1];
	29	__u32 a = in[0], b = in[1], c = in[2], d = in[3];
	30	int n = 16;
	31
	32	do {
	33	sum += DELTA;
	34	b0 += ((b1 << 4)+a) ^ (b1+sum) ^ ((b1 >> 5)+b);
	35	b1 += ((b0 << 4)+c) ^ (b0+sum) ^ ((b0 >> 5)+d);
	36	} while (--n);
	37
	38	buf[0] += b0;
	39	buf[1] += b1;
	40	}
	41
3304b564 JK	42	static void str2hashbuf(const unsigned char *msg, size_t len,
3304b564 JK	43	unsigned int *buf, int num)
6b4ea016 JK	44	{
	45	unsigned pad, val;
	46	int i;
	47
	48	pad = (__u32)len \| ((__u32)len << 8);
	49	pad \|= pad << 16;
	50
	51	val = pad;
	52	if (len > num * 4)
	53	len = num * 4;
	54	for (i = 0; i < len; i++) {
	55	if ((i % 4) == 0)
	56	val = pad;
	57	val = msg[i] + (val << 8);
	58	if ((i % 4) == 3) {
	59	*buf++ = val;
	60	val = pad;
	61	num--;
	62	}
	63	}
	64	if (--num >= 0)
	65	*buf++ = val;
	66	while (--num >= 0)
	67	*buf++ = pad;
	68	}
	69
6332cd32 JK	70	f2fs_hash_t f2fs_dentry_hash(const struct qstr *name_info,
6332cd32 JK	71	struct fscrypt_name *fname)
6b4ea016	72	{
2b50638d	73	__u32 hash;
6b4ea016	74	f2fs_hash_t f2fs_hash;
3304b564	75	const unsigned char *p;
6b4ea016	76	__u32 in[8], buf[4];
3304b564	77	const unsigned char *name = name_info->name;
eee6160f	78	size_t len = name_info->len;
6b4ea016	79
6332cd32 JK	80	/* encrypted bigname case */
	81	if (fname && !fname->disk_name.name)
	82	return cpu_to_le32(fname->hash);
	83
eaa693f4	84	if (is_dot_dotdot(name_info))
38e0abdc NJ	85	return 0;
38e0abdc NJ	86
6b4ea016 JK	87	/* Initialize the default seed for the hash checksum functions */
	88	buf[0] = 0x67452301;
	89	buf[1] = 0xefcdab89;
	90	buf[2] = 0x98badcfe;
	91	buf[3] = 0x10325476;
	92
	93	p = name;
9836b8b9	94	while (1) {
6b4ea016 JK	95	str2hashbuf(p, len, in, 4);
6b4ea016 JK	96	TEA_transform(buf, in);
6b4ea016	97	p += 16;
9836b8b9 LR	98	if (len <= 16)
	99	break;
	100	len -= 16;
6b4ea016 JK	101	}
6b4ea016 JK	102	hash = buf[0];
25ca923b	103	f2fs_hash = cpu_to_le32(hash & ~F2FS_HASH_COL_BIT);
6b4ea016 JK	104	return f2fs_hash;
6b4ea016 JK	105	}