1f5166768STheodore Ts'o // SPDX-License-Identifier: GPL-2.0
2ac27a0ecSDave Kleikamp /*
3617ba13bSMingming Cao * linux/fs/ext4/hash.c
4ac27a0ecSDave Kleikamp *
5ac27a0ecSDave Kleikamp * Copyright (C) 2002 by Theodore Ts'o
6ac27a0ecSDave Kleikamp */
7ac27a0ecSDave Kleikamp
8ac27a0ecSDave Kleikamp #include <linux/fs.h>
9b886ee3eSGabriel Krisman Bertazi #include <linux/unicode.h>
101c83a9aaSJason A. Donenfeld #include <linux/compiler.h>
111c83a9aaSJason A. Donenfeld #include <linux/bitops.h>
123dcf5451SChristoph Hellwig #include "ext4.h"
13ac27a0ecSDave Kleikamp
14ac27a0ecSDave Kleikamp #define DELTA 0x9E3779B9
15ac27a0ecSDave Kleikamp
TEA_transform(__u32 buf[4],__u32 const in[])16ac27a0ecSDave Kleikamp static void TEA_transform(__u32 buf[4], __u32 const in[])
17ac27a0ecSDave Kleikamp {
18ac27a0ecSDave Kleikamp __u32 sum = 0;
19ac27a0ecSDave Kleikamp __u32 b0 = buf[0], b1 = buf[1];
20ac27a0ecSDave Kleikamp __u32 a = in[0], b = in[1], c = in[2], d = in[3];
21ac27a0ecSDave Kleikamp int n = 16;
22ac27a0ecSDave Kleikamp
23ac27a0ecSDave Kleikamp do {
24ac27a0ecSDave Kleikamp sum += DELTA;
25ac27a0ecSDave Kleikamp b0 += ((b1 << 4)+a) ^ (b1+sum) ^ ((b1 >> 5)+b);
26ac27a0ecSDave Kleikamp b1 += ((b0 << 4)+c) ^ (b0+sum) ^ ((b0 >> 5)+d);
27ac27a0ecSDave Kleikamp } while (--n);
28ac27a0ecSDave Kleikamp
29ac27a0ecSDave Kleikamp buf[0] += b0;
30ac27a0ecSDave Kleikamp buf[1] += b1;
31ac27a0ecSDave Kleikamp }
32ac27a0ecSDave Kleikamp
331c83a9aaSJason A. Donenfeld /* F, G and H are basic MD4 functions: selection, majority, parity */
341c83a9aaSJason A. Donenfeld #define F(x, y, z) ((z) ^ ((x) & ((y) ^ (z))))
351c83a9aaSJason A. Donenfeld #define G(x, y, z) (((x) & (y)) + (((x) ^ (y)) & (z)))
361c83a9aaSJason A. Donenfeld #define H(x, y, z) ((x) ^ (y) ^ (z))
371c83a9aaSJason A. Donenfeld
381c83a9aaSJason A. Donenfeld /*
391c83a9aaSJason A. Donenfeld * The generic round function. The application is so specific that
401c83a9aaSJason A. Donenfeld * we don't bother protecting all the arguments with parens, as is generally
411c83a9aaSJason A. Donenfeld * good macro practice, in favor of extra legibility.
421c83a9aaSJason A. Donenfeld * Rotation is separate from addition to prevent recomputation
431c83a9aaSJason A. Donenfeld */
441c83a9aaSJason A. Donenfeld #define ROUND(f, a, b, c, d, x, s) \
451c83a9aaSJason A. Donenfeld (a += f(b, c, d) + x, a = rol32(a, s))
461c83a9aaSJason A. Donenfeld #define K1 0
471c83a9aaSJason A. Donenfeld #define K2 013240474631UL
481c83a9aaSJason A. Donenfeld #define K3 015666365641UL
491c83a9aaSJason A. Donenfeld
501c83a9aaSJason A. Donenfeld /*
511c83a9aaSJason A. Donenfeld * Basic cut-down MD4 transform. Returns only 32 bits of result.
521c83a9aaSJason A. Donenfeld */
half_md4_transform(__u32 buf[4],__u32 const in[8])531c83a9aaSJason A. Donenfeld static __u32 half_md4_transform(__u32 buf[4], __u32 const in[8])
541c83a9aaSJason A. Donenfeld {
551c83a9aaSJason A. Donenfeld __u32 a = buf[0], b = buf[1], c = buf[2], d = buf[3];
561c83a9aaSJason A. Donenfeld
571c83a9aaSJason A. Donenfeld /* Round 1 */
581c83a9aaSJason A. Donenfeld ROUND(F, a, b, c, d, in[0] + K1, 3);
591c83a9aaSJason A. Donenfeld ROUND(F, d, a, b, c, in[1] + K1, 7);
601c83a9aaSJason A. Donenfeld ROUND(F, c, d, a, b, in[2] + K1, 11);
611c83a9aaSJason A. Donenfeld ROUND(F, b, c, d, a, in[3] + K1, 19);
621c83a9aaSJason A. Donenfeld ROUND(F, a, b, c, d, in[4] + K1, 3);
631c83a9aaSJason A. Donenfeld ROUND(F, d, a, b, c, in[5] + K1, 7);
641c83a9aaSJason A. Donenfeld ROUND(F, c, d, a, b, in[6] + K1, 11);
651c83a9aaSJason A. Donenfeld ROUND(F, b, c, d, a, in[7] + K1, 19);
661c83a9aaSJason A. Donenfeld
671c83a9aaSJason A. Donenfeld /* Round 2 */
681c83a9aaSJason A. Donenfeld ROUND(G, a, b, c, d, in[1] + K2, 3);
691c83a9aaSJason A. Donenfeld ROUND(G, d, a, b, c, in[3] + K2, 5);
701c83a9aaSJason A. Donenfeld ROUND(G, c, d, a, b, in[5] + K2, 9);
711c83a9aaSJason A. Donenfeld ROUND(G, b, c, d, a, in[7] + K2, 13);
721c83a9aaSJason A. Donenfeld ROUND(G, a, b, c, d, in[0] + K2, 3);
731c83a9aaSJason A. Donenfeld ROUND(G, d, a, b, c, in[2] + K2, 5);
741c83a9aaSJason A. Donenfeld ROUND(G, c, d, a, b, in[4] + K2, 9);
751c83a9aaSJason A. Donenfeld ROUND(G, b, c, d, a, in[6] + K2, 13);
761c83a9aaSJason A. Donenfeld
771c83a9aaSJason A. Donenfeld /* Round 3 */
781c83a9aaSJason A. Donenfeld ROUND(H, a, b, c, d, in[3] + K3, 3);
791c83a9aaSJason A. Donenfeld ROUND(H, d, a, b, c, in[7] + K3, 9);
801c83a9aaSJason A. Donenfeld ROUND(H, c, d, a, b, in[2] + K3, 11);
811c83a9aaSJason A. Donenfeld ROUND(H, b, c, d, a, in[6] + K3, 15);
821c83a9aaSJason A. Donenfeld ROUND(H, a, b, c, d, in[1] + K3, 3);
831c83a9aaSJason A. Donenfeld ROUND(H, d, a, b, c, in[5] + K3, 9);
841c83a9aaSJason A. Donenfeld ROUND(H, c, d, a, b, in[0] + K3, 11);
851c83a9aaSJason A. Donenfeld ROUND(H, b, c, d, a, in[4] + K3, 15);
861c83a9aaSJason A. Donenfeld
871c83a9aaSJason A. Donenfeld buf[0] += a;
881c83a9aaSJason A. Donenfeld buf[1] += b;
891c83a9aaSJason A. Donenfeld buf[2] += c;
901c83a9aaSJason A. Donenfeld buf[3] += d;
911c83a9aaSJason A. Donenfeld
921c83a9aaSJason A. Donenfeld return buf[1]; /* "most hashed" word */
931c83a9aaSJason A. Donenfeld }
941c83a9aaSJason A. Donenfeld #undef ROUND
951c83a9aaSJason A. Donenfeld #undef K1
961c83a9aaSJason A. Donenfeld #undef K2
971c83a9aaSJason A. Donenfeld #undef K3
981c83a9aaSJason A. Donenfeld #undef F
991c83a9aaSJason A. Donenfeld #undef G
1001c83a9aaSJason A. Donenfeld #undef H
101ac27a0ecSDave Kleikamp
102ac27a0ecSDave Kleikamp /* The old legacy hash */
dx_hack_hash_unsigned(const char * name,int len)103f99b2589STheodore Ts'o static __u32 dx_hack_hash_unsigned(const char *name, int len)
104ac27a0ecSDave Kleikamp {
105f99b2589STheodore Ts'o __u32 hash, hash0 = 0x12a3fe2d, hash1 = 0x37abe8f9;
106f99b2589STheodore Ts'o const unsigned char *ucp = (const unsigned char *) name;
107ac27a0ecSDave Kleikamp
108f99b2589STheodore Ts'o while (len--) {
109f99b2589STheodore Ts'o hash = hash1 + (hash0 ^ (((int) *ucp++) * 7152373));
110f99b2589STheodore Ts'o
111f99b2589STheodore Ts'o if (hash & 0x80000000)
112f99b2589STheodore Ts'o hash -= 0x7fffffff;
113ac27a0ecSDave Kleikamp hash1 = hash0;
114ac27a0ecSDave Kleikamp hash0 = hash;
115ac27a0ecSDave Kleikamp }
116f99b2589STheodore Ts'o return hash0 << 1;
117ac27a0ecSDave Kleikamp }
118ac27a0ecSDave Kleikamp
dx_hack_hash_signed(const char * name,int len)119f99b2589STheodore Ts'o static __u32 dx_hack_hash_signed(const char *name, int len)
120f99b2589STheodore Ts'o {
121f99b2589STheodore Ts'o __u32 hash, hash0 = 0x12a3fe2d, hash1 = 0x37abe8f9;
122f99b2589STheodore Ts'o const signed char *scp = (const signed char *) name;
123f99b2589STheodore Ts'o
124f99b2589STheodore Ts'o while (len--) {
125f99b2589STheodore Ts'o hash = hash1 + (hash0 ^ (((int) *scp++) * 7152373));
126f99b2589STheodore Ts'o
127f99b2589STheodore Ts'o if (hash & 0x80000000)
128f99b2589STheodore Ts'o hash -= 0x7fffffff;
129f99b2589STheodore Ts'o hash1 = hash0;
130f99b2589STheodore Ts'o hash0 = hash;
131f99b2589STheodore Ts'o }
132f99b2589STheodore Ts'o return hash0 << 1;
133f99b2589STheodore Ts'o }
134f99b2589STheodore Ts'o
str2hashbuf_signed(const char * msg,int len,__u32 * buf,int num)135f99b2589STheodore Ts'o static void str2hashbuf_signed(const char *msg, int len, __u32 *buf, int num)
136ac27a0ecSDave Kleikamp {
137ac27a0ecSDave Kleikamp __u32 pad, val;
138ac27a0ecSDave Kleikamp int i;
139f99b2589STheodore Ts'o const signed char *scp = (const signed char *) msg;
140ac27a0ecSDave Kleikamp
141ac27a0ecSDave Kleikamp pad = (__u32)len | ((__u32)len << 8);
142ac27a0ecSDave Kleikamp pad |= pad << 16;
143ac27a0ecSDave Kleikamp
144ac27a0ecSDave Kleikamp val = pad;
145ac27a0ecSDave Kleikamp if (len > num*4)
146ac27a0ecSDave Kleikamp len = num * 4;
147ac27a0ecSDave Kleikamp for (i = 0; i < len; i++) {
148f99b2589STheodore Ts'o val = ((int) scp[i]) + (val << 8);
149f99b2589STheodore Ts'o if ((i % 4) == 3) {
150f99b2589STheodore Ts'o *buf++ = val;
151f99b2589STheodore Ts'o val = pad;
152f99b2589STheodore Ts'o num--;
153f99b2589STheodore Ts'o }
154f99b2589STheodore Ts'o }
155f99b2589STheodore Ts'o if (--num >= 0)
156f99b2589STheodore Ts'o *buf++ = val;
157f99b2589STheodore Ts'o while (--num >= 0)
158f99b2589STheodore Ts'o *buf++ = pad;
159f99b2589STheodore Ts'o }
160f99b2589STheodore Ts'o
str2hashbuf_unsigned(const char * msg,int len,__u32 * buf,int num)161f99b2589STheodore Ts'o static void str2hashbuf_unsigned(const char *msg, int len, __u32 *buf, int num)
162f99b2589STheodore Ts'o {
163f99b2589STheodore Ts'o __u32 pad, val;
164f99b2589STheodore Ts'o int i;
165f99b2589STheodore Ts'o const unsigned char *ucp = (const unsigned char *) msg;
166f99b2589STheodore Ts'o
167f99b2589STheodore Ts'o pad = (__u32)len | ((__u32)len << 8);
168f99b2589STheodore Ts'o pad |= pad << 16;
169f99b2589STheodore Ts'o
170f99b2589STheodore Ts'o val = pad;
171f99b2589STheodore Ts'o if (len > num*4)
172f99b2589STheodore Ts'o len = num * 4;
173f99b2589STheodore Ts'o for (i = 0; i < len; i++) {
174f99b2589STheodore Ts'o val = ((int) ucp[i]) + (val << 8);
175ac27a0ecSDave Kleikamp if ((i % 4) == 3) {
176ac27a0ecSDave Kleikamp *buf++ = val;
177ac27a0ecSDave Kleikamp val = pad;
178ac27a0ecSDave Kleikamp num--;
179ac27a0ecSDave Kleikamp }
180ac27a0ecSDave Kleikamp }
181ac27a0ecSDave Kleikamp if (--num >= 0)
182ac27a0ecSDave Kleikamp *buf++ = val;
183ac27a0ecSDave Kleikamp while (--num >= 0)
184ac27a0ecSDave Kleikamp *buf++ = pad;
185ac27a0ecSDave Kleikamp }
186ac27a0ecSDave Kleikamp
187ac27a0ecSDave Kleikamp /*
188ac27a0ecSDave Kleikamp * Returns the hash of a filename. If len is 0 and name is NULL, then
189ac27a0ecSDave Kleikamp * this function can be used to test whether or not a hash version is
190ac27a0ecSDave Kleikamp * supported.
191ac27a0ecSDave Kleikamp *
192ac27a0ecSDave Kleikamp * The seed is an 4 longword (32 bits) "secret" which can be used to
193ac27a0ecSDave Kleikamp * uniquify a hash. If the seed is all zero's, then some default seed
194ac27a0ecSDave Kleikamp * may be used.
195ac27a0ecSDave Kleikamp *
196ac27a0ecSDave Kleikamp * A particular hash version specifies whether or not the seed is
197ac27a0ecSDave Kleikamp * represented, and whether or not the returned hash is 32 bits or 64
198ac27a0ecSDave Kleikamp * bits. 32 bit hashes will return 0 for the minor hash.
199ac27a0ecSDave Kleikamp */
__ext4fs_dirhash(const struct inode * dir,const char * name,int len,struct dx_hash_info * hinfo)200471fbbeaSDaniel Rosenberg static int __ext4fs_dirhash(const struct inode *dir, const char *name, int len,
201b886ee3eSGabriel Krisman Bertazi struct dx_hash_info *hinfo)
202ac27a0ecSDave Kleikamp {
203ac27a0ecSDave Kleikamp __u32 hash;
204ac27a0ecSDave Kleikamp __u32 minor_hash = 0;
205ac27a0ecSDave Kleikamp const char *p;
206ac27a0ecSDave Kleikamp int i;
207ac27a0ecSDave Kleikamp __u32 in[8], buf[4];
208f99b2589STheodore Ts'o void (*str2hashbuf)(const char *, int, __u32 *, int) =
209f99b2589STheodore Ts'o str2hashbuf_signed;
210ac27a0ecSDave Kleikamp
211ac27a0ecSDave Kleikamp /* Initialize the default seed for the hash checksum functions */
212ac27a0ecSDave Kleikamp buf[0] = 0x67452301;
213ac27a0ecSDave Kleikamp buf[1] = 0xefcdab89;
214ac27a0ecSDave Kleikamp buf[2] = 0x98badcfe;
215ac27a0ecSDave Kleikamp buf[3] = 0x10325476;
216ac27a0ecSDave Kleikamp
217ac27a0ecSDave Kleikamp /* Check to see if the seed is all zero's */
218ac27a0ecSDave Kleikamp if (hinfo->seed) {
219ac27a0ecSDave Kleikamp for (i = 0; i < 4; i++) {
2200e79537dSCong Ding if (hinfo->seed[i]) {
2210e79537dSCong Ding memcpy(buf, hinfo->seed, sizeof(buf));
222ac27a0ecSDave Kleikamp break;
223ac27a0ecSDave Kleikamp }
2240e79537dSCong Ding }
225ac27a0ecSDave Kleikamp }
226ac27a0ecSDave Kleikamp
227ac27a0ecSDave Kleikamp switch (hinfo->hash_version) {
228f99b2589STheodore Ts'o case DX_HASH_LEGACY_UNSIGNED:
229f99b2589STheodore Ts'o hash = dx_hack_hash_unsigned(name, len);
230ac27a0ecSDave Kleikamp break;
231f99b2589STheodore Ts'o case DX_HASH_LEGACY:
232f99b2589STheodore Ts'o hash = dx_hack_hash_signed(name, len);
233f99b2589STheodore Ts'o break;
234f99b2589STheodore Ts'o case DX_HASH_HALF_MD4_UNSIGNED:
235f99b2589STheodore Ts'o str2hashbuf = str2hashbuf_unsigned;
23670d7ced2SShijie Luo fallthrough;
237ac27a0ecSDave Kleikamp case DX_HASH_HALF_MD4:
238ac27a0ecSDave Kleikamp p = name;
239ac27a0ecSDave Kleikamp while (len > 0) {
240f99b2589STheodore Ts'o (*str2hashbuf)(p, len, in, 8);
241ac27a0ecSDave Kleikamp half_md4_transform(buf, in);
242ac27a0ecSDave Kleikamp len -= 32;
243ac27a0ecSDave Kleikamp p += 32;
244ac27a0ecSDave Kleikamp }
245ac27a0ecSDave Kleikamp minor_hash = buf[2];
246ac27a0ecSDave Kleikamp hash = buf[1];
247ac27a0ecSDave Kleikamp break;
248f99b2589STheodore Ts'o case DX_HASH_TEA_UNSIGNED:
249f99b2589STheodore Ts'o str2hashbuf = str2hashbuf_unsigned;
25070d7ced2SShijie Luo fallthrough;
251ac27a0ecSDave Kleikamp case DX_HASH_TEA:
252ac27a0ecSDave Kleikamp p = name;
253ac27a0ecSDave Kleikamp while (len > 0) {
254f99b2589STheodore Ts'o (*str2hashbuf)(p, len, in, 4);
255ac27a0ecSDave Kleikamp TEA_transform(buf, in);
256ac27a0ecSDave Kleikamp len -= 16;
257ac27a0ecSDave Kleikamp p += 16;
258ac27a0ecSDave Kleikamp }
259ac27a0ecSDave Kleikamp hash = buf[0];
260ac27a0ecSDave Kleikamp minor_hash = buf[1];
261ac27a0ecSDave Kleikamp break;
262471fbbeaSDaniel Rosenberg case DX_HASH_SIPHASH:
263471fbbeaSDaniel Rosenberg {
264471fbbeaSDaniel Rosenberg struct qstr qname = QSTR_INIT(name, len);
265471fbbeaSDaniel Rosenberg __u64 combined_hash;
266471fbbeaSDaniel Rosenberg
267471fbbeaSDaniel Rosenberg if (fscrypt_has_encryption_key(dir)) {
268471fbbeaSDaniel Rosenberg combined_hash = fscrypt_fname_siphash(dir, &qname);
269471fbbeaSDaniel Rosenberg } else {
270471fbbeaSDaniel Rosenberg ext4_warning_inode(dir, "Siphash requires key");
271471fbbeaSDaniel Rosenberg return -1;
272471fbbeaSDaniel Rosenberg }
273471fbbeaSDaniel Rosenberg
274471fbbeaSDaniel Rosenberg hash = (__u32)(combined_hash >> 32);
275471fbbeaSDaniel Rosenberg minor_hash = (__u32)combined_hash;
276471fbbeaSDaniel Rosenberg break;
277471fbbeaSDaniel Rosenberg }
278ac27a0ecSDave Kleikamp default:
279ac27a0ecSDave Kleikamp hinfo->hash = 0;
2804b3cb1d1STheodore Ts'o hinfo->minor_hash = 0;
2814b3cb1d1STheodore Ts'o ext4_warning(dir->i_sb,
2824b3cb1d1STheodore Ts'o "invalid/unsupported hash tree version %u",
2834b3cb1d1STheodore Ts'o hinfo->hash_version);
2844b3cb1d1STheodore Ts'o return -EINVAL;
285ac27a0ecSDave Kleikamp }
286ac27a0ecSDave Kleikamp hash = hash & ~1;
287d1f5273eSFan Yong if (hash == (EXT4_HTREE_EOF_32BIT << 1))
288d1f5273eSFan Yong hash = (EXT4_HTREE_EOF_32BIT - 1) << 1;
289ac27a0ecSDave Kleikamp hinfo->hash = hash;
290ac27a0ecSDave Kleikamp hinfo->minor_hash = minor_hash;
291ac27a0ecSDave Kleikamp return 0;
292ac27a0ecSDave Kleikamp }
293b886ee3eSGabriel Krisman Bertazi
ext4fs_dirhash(const struct inode * dir,const char * name,int len,struct dx_hash_info * hinfo)294b886ee3eSGabriel Krisman Bertazi int ext4fs_dirhash(const struct inode *dir, const char *name, int len,
295b886ee3eSGabriel Krisman Bertazi struct dx_hash_info *hinfo)
296b886ee3eSGabriel Krisman Bertazi {
2975298d4bfSChristoph Hellwig #if IS_ENABLED(CONFIG_UNICODE)
298f8f4acb6SDaniel Rosenberg const struct unicode_map *um = dir->i_sb->s_encoding;
299b886ee3eSGabriel Krisman Bertazi int r, dlen;
300b886ee3eSGabriel Krisman Bertazi unsigned char *buff;
301b886ee3eSGabriel Krisman Bertazi struct qstr qstr = {.name = name, .len = len };
302b886ee3eSGabriel Krisman Bertazi
303*b8142793SEric Biggers if (len && IS_CASEFOLDED(dir) &&
304471fbbeaSDaniel Rosenberg (!IS_ENCRYPTED(dir) || fscrypt_has_encryption_key(dir))) {
305b886ee3eSGabriel Krisman Bertazi buff = kzalloc(sizeof(char) * PATH_MAX, GFP_KERNEL);
306b886ee3eSGabriel Krisman Bertazi if (!buff)
307b886ee3eSGabriel Krisman Bertazi return -ENOMEM;
308b886ee3eSGabriel Krisman Bertazi
309b886ee3eSGabriel Krisman Bertazi dlen = utf8_casefold(um, &qstr, buff, PATH_MAX);
310b886ee3eSGabriel Krisman Bertazi if (dlen < 0) {
311b886ee3eSGabriel Krisman Bertazi kfree(buff);
312b886ee3eSGabriel Krisman Bertazi goto opaque_seq;
313b886ee3eSGabriel Krisman Bertazi }
314b886ee3eSGabriel Krisman Bertazi
315471fbbeaSDaniel Rosenberg r = __ext4fs_dirhash(dir, buff, dlen, hinfo);
316b886ee3eSGabriel Krisman Bertazi
317b886ee3eSGabriel Krisman Bertazi kfree(buff);
318b886ee3eSGabriel Krisman Bertazi return r;
319b886ee3eSGabriel Krisman Bertazi }
320b886ee3eSGabriel Krisman Bertazi opaque_seq:
321b886ee3eSGabriel Krisman Bertazi #endif
322471fbbeaSDaniel Rosenberg return __ext4fs_dirhash(dir, name, len, hinfo);
323b886ee3eSGabriel Krisman Bertazi }
324