// SPDX-License-Identifier: GPL-2.0/* * linux/fs/ext4/hash.c * * Copyright (C) 2002 by Theodore Ts'o */ #include <linux/fs.h>#include <linux/unicode.h>#include <linux/compiler.h>#include <linux/bitops.h>#include <linux/unaligned.h>#include "ext4.h" #define DELTA 0x9E3779B9 static void TEA_transform(__u32 buf[4], __u32 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;} /* 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 /* * Basic cut-down MD4 transform. Returns only 32 bits of result. */static __u32 half_md4_transform(__u32 buf[4], __u32 const in[8]){ __u32 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 __u32 dx_hack_hash_unsigned(const char *name, int len){ __u32 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 __u32 dx_hack_hash_signed(const char *name, int len){ __u32 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, __u32 *buf, int num){ __u32 pad, val; int i; const signed char *scp = (const signed char *) msg; pad = (__u32)len | ((__u32)len << 8); pad |= pad << 16; if (len > num*4) len = num * 4; while (len >= 4) { val = ((__u32)scp[0] << 24) + ((__u32)scp[1] << 16) + ((__u32)scp[2] << 8) + scp[3]; *buf++ = val; scp += 4; len -= 4; num--; } val = pad; for (i = 0; i < len; i++) val = scp[i] + (val << 8); if (--num >= 0) *buf++ = val; while (--num >= 0) *buf++ = pad; } static void str2hashbuf_unsigned(const char *msg, int len, __u32 *buf, int num){ __u32 pad, val; int i; const unsigned char *ucp = (const unsigned char *) msg; pad = (__u32)len | ((__u32)len << 8); pad |= pad << 16; if (len > num*4) len = num * 4; while (len >= 4) { val = get_unaligned_be32(ucp); *buf++ = val; ucp += 4; len -= 4; num--; } val = pad; for (i = 0; i < len; i++) val = ucp[i] + (val << 8); if (--num >= 0) *buf++ = val; while (--num >= 0) *buf++ = pad; } /* * Returns the hash of a filename. If len is 0 and name is NULL, then * this function can be used to test whether or not a hash version is * supported. * * The seed is an 4 longword (32 bits) "secret" which can be used to * uniquify a hash. If the seed is all zero's, then some default seed * may be used. * * A particular hash version specifies whether or not the seed is * represented, and whether or not the returned hash is 32 bits or 64 * bits. 32 bit hashes will return 0 for the minor hash. */static int __ext4fs_dirhash(const struct inode *dir, const char *name, int len, struct dx_hash_info *hinfo){ __u32 hash; __u32 minor_hash = 0; const char *p; int i; __u32 in[8], buf[4]; bool use_unsigned = false; /* Initialize the default seed for the hash checksum functions */ buf[0] = 0x67452301; buf[1] = 0xefcdab89; buf[2] = 0x98badcfe; buf[3] = 0x10325476; /* Check to see if the seed is all zero's */ if (hinfo->seed) { for (i = 0; i < 4; i++) { if (hinfo->seed[i]) { memcpy(buf, hinfo->seed, sizeof(buf)); break; } } } switch (hinfo->hash_version) { case DX_HASH_LEGACY_UNSIGNED: hash = dx_hack_hash_unsigned(name, len); break; case DX_HASH_LEGACY: hash = dx_hack_hash_signed(name, len); break; case DX_HASH_HALF_MD4_UNSIGNED: use_unsigned = true; fallthrough; case DX_HASH_HALF_MD4: p = name; while (len > 0) { if (use_unsigned) str2hashbuf_unsigned(p, len, in, 8); else str2hashbuf_signed(p, len, in, 8); half_md4_transform(buf, in); len -= 32; p += 32; } minor_hash = buf[2]; hash = buf[1]; break; case DX_HASH_TEA_UNSIGNED: use_unsigned = true; fallthrough; case DX_HASH_TEA: p = name; while (len > 0) { if (use_unsigned) str2hashbuf_unsigned(p, len, in, 4); else str2hashbuf_signed(p, len, in, 4); TEA_transform(buf, in); len -= 16; p += 16; } hash = buf[0]; minor_hash = buf[1]; break; case DX_HASH_SIPHASH: { struct qstr qname = QSTR_INIT(name, len); __u64 combined_hash; if (fscrypt_has_encryption_key(dir)) { combined_hash = fscrypt_fname_siphash(dir, &qname); } else { ext4_warning_inode(dir, "Siphash requires key"); return -EINVAL; } hash = (__u32)(combined_hash >> 32); minor_hash = (__u32)combined_hash; break; } default: hinfo->hash = 0; hinfo->minor_hash = 0; ext4_warning(dir->i_sb, "invalid/unsupported hash tree version %u", hinfo->hash_version); return -EINVAL; } hash = hash & ~1; if (hash == (EXT4_HTREE_EOF_32BIT << 1)) hash = (EXT4_HTREE_EOF_32BIT - 1) << 1; hinfo->hash = hash; hinfo->minor_hash = minor_hash; return 0;} int ext4fs_dirhash(const struct inode *dir, const char *name, int len, struct dx_hash_info *hinfo){#if IS_ENABLED(CONFIG_UNICODE) const struct unicode_map *um = dir->i_sb->s_encoding; int r, dlen; unsigned char *buff; struct qstr qstr = {.name = name, .len = len }; if (len && IS_CASEFOLDED(dir) && (!IS_ENCRYPTED(dir) || fscrypt_has_encryption_key(dir))) { buff = kzalloc(PATH_MAX, GFP_KERNEL); if (!buff) return -ENOMEM; dlen = utf8_casefold(um, &qstr, buff, PATH_MAX); if (dlen < 0) { kfree(buff); goto opaque_seq; } r = __ext4fs_dirhash(dir, buff, dlen, hinfo); kfree(buff); return r; }opaque_seq:#endif return __ext4fs_dirhash(dir, name, len, hinfo);} #if IS_ENABLED(CONFIG_EXT4_KUNIT_TESTS)EXPORT_SYMBOL_FOR_EXT4_TEST(ext4fs_dirhash);#endif
// SPDX-License-Identifier: GPL-2.0
/*
* linux/fs/ext4/hash.c
*
* Copyright (C) 2002 by Theodore Ts'o
*/
#include <linux/fs.h>
#include <linux/unicode.h>
#include <linux/compiler.h>
#include <linux/bitops.h>
#include <linux/unaligned.h>
#include "ext4.h"
#define DELTA 0x9E3779B9
static void TEA_transform(__u32 buf[4], __u32 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;
}
/* 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
/*
* Basic cut-down MD4 transform. Returns only 32 bits of result.
*/
static __u32 half_md4_transform(__u32 buf[4], __u32 const in[8])
{
__u32 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 __u32 dx_hack_hash_unsigned(const char *name, int len)
{
__u32 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 __u32 dx_hack_hash_signed(const char *name, int len)
{
__u32 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, __u32 *buf, int num)
{
__u32 pad, val;
int i;
const signed char *scp = (const signed char *) msg;
pad = (__u32)len | ((__u32)len << 8);
pad |= pad << 16;
if (len > num*4)
len = num * 4;
while (len >= 4) {
val = ((__u32)scp[0] << 24) + ((__u32)scp[1] << 16) + ((__u32)scp[2] << 8) + scp[3];
*buf++ = val;
scp += 4;
len -= 4;
num--;
}
val = pad;
for (i = 0; i < len; i++)
val = scp[i] + (val << 8);
if (--num >= 0)
*buf++ = val;
while (--num >= 0)
*buf++ = pad;
}
static void str2hashbuf_unsigned(const char *msg, int len, __u32 *buf, int num)
{
__u32 pad, val;
int i;
const unsigned char *ucp = (const unsigned char *) msg;
pad = (__u32)len | ((__u32)len << 8);
pad |= pad << 16;
if (len > num*4)
len = num * 4;
while (len >= 4) {
val = get_unaligned_be32(ucp);
*buf++ = val;
ucp += 4;
len -= 4;
num--;
}
val = pad;
for (i = 0; i < len; i++)
val = ucp[i] + (val << 8);
if (--num >= 0)
*buf++ = val;
while (--num >= 0)
*buf++ = pad;
}
/*
* Returns the hash of a filename. If len is 0 and name is NULL, then
* this function can be used to test whether or not a hash version is
* supported.
*
* The seed is an 4 longword (32 bits) "secret" which can be used to
* uniquify a hash. If the seed is all zero's, then some default seed
* may be used.
*
* A particular hash version specifies whether or not the seed is
* represented, and whether or not the returned hash is 32 bits or 64
* bits. 32 bit hashes will return 0 for the minor hash.
*/
static int __ext4fs_dirhash(const struct inode *dir, const char *name, int len,
struct dx_hash_info *hinfo)
{
__u32 hash;
__u32 minor_hash = 0;
const char *p;
int i;
__u32 in[8], buf[4];
bool use_unsigned = false;
/* Initialize the default seed for the hash checksum functions */
buf[0] = 0x67452301;
buf[1] = 0xefcdab89;
buf[2] = 0x98badcfe;
buf[3] = 0x10325476;
/* Check to see if the seed is all zero's */
if (hinfo->seed) {
for (i = 0; i < 4; i++) {
if (hinfo->seed[i]) {
memcpy(buf, hinfo->seed, sizeof(buf));
break;
}
}
}
switch (hinfo->hash_version) {
case DX_HASH_LEGACY_UNSIGNED:
hash = dx_hack_hash_unsigned(name, len);
break;
case DX_HASH_LEGACY:
hash = dx_hack_hash_signed(name, len);
break;
case DX_HASH_HALF_MD4_UNSIGNED:
use_unsigned = true;
fallthrough;
case DX_HASH_HALF_MD4:
p = name;
while (len > 0) {
if (use_unsigned)
str2hashbuf_unsigned(p, len, in, 8);
else
str2hashbuf_signed(p, len, in, 8);
half_md4_transform(buf, in);
len -= 32;
p += 32;
}
minor_hash = buf[2];
hash = buf[1];
break;
case DX_HASH_TEA_UNSIGNED:
use_unsigned = true;
fallthrough;
case DX_HASH_TEA:
p = name;
while (len > 0) {
if (use_unsigned)
str2hashbuf_unsigned(p, len, in, 4);
else
str2hashbuf_signed(p, len, in, 4);
TEA_transform(buf, in);
len -= 16;
p += 16;
}
hash = buf[0];
minor_hash = buf[1];
break;
case DX_HASH_SIPHASH:
{
struct qstr qname = QSTR_INIT(name, len);
__u64 combined_hash;
if (fscrypt_has_encryption_key(dir)) {
combined_hash = fscrypt_fname_siphash(dir, &qname);
} else {
ext4_warning_inode(dir, "Siphash requires key");
return -EINVAL;
}
hash = (__u32)(combined_hash >> 32);
minor_hash = (__u32)combined_hash;
break;
}
default:
hinfo->hash = 0;
hinfo->minor_hash = 0;
ext4_warning(dir->i_sb,
"invalid/unsupported hash tree version %u",
hinfo->hash_version);
return -EINVAL;
}
hash = hash & ~1;
if (hash == (EXT4_HTREE_EOF_32BIT << 1))
hash = (EXT4_HTREE_EOF_32BIT - 1) << 1;
hinfo->hash = hash;
hinfo->minor_hash = minor_hash;
return 0;
}
int ext4fs_dirhash(const struct inode *dir, const char *name, int len,
struct dx_hash_info *hinfo)
{
#if IS_ENABLED(CONFIG_UNICODE)
const struct unicode_map *um = dir->i_sb->s_encoding;
int r, dlen;
unsigned char *buff;
struct qstr qstr = {.name = name, .len = len };
if (len && IS_CASEFOLDED(dir) &&
(!IS_ENCRYPTED(dir) || fscrypt_has_encryption_key(dir))) {
buff = kzalloc(PATH_MAX, GFP_KERNEL);
if (!buff)
return -ENOMEM;
dlen = utf8_casefold(um, &qstr, buff, PATH_MAX);
if (dlen < 0) {
kfree(buff);
goto opaque_seq;
}
r = __ext4fs_dirhash(dir, buff, dlen, hinfo);
kfree(buff);
return r;
}
opaque_seq:
#endif
return __ext4fs_dirhash(dir, name, len, hinfo);
}
#if IS_ENABLED(CONFIG_EXT4_KUNIT_TESTS)
EXPORT_SYMBOL_FOR_EXT4_TEST(ext4fs_dirhash);
#endif