[CIFS] Fix plaintext authentication
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / crypto / lrw.c
blob8ef664e3bcd9a90c93a5436e551549e72df1ff82
1 /* LRW: as defined by Cyril Guyot in
2 * http://grouper.ieee.org/groups/1619/email/pdf00017.pdf
4 * Copyright (c) 2006 Rik Snel <rsnel@cube.dyndns.org>
6 * Based om ecb.c
7 * Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
9 * This program is free software; you can redistribute it and/or modify it
10 * under the terms of the GNU General Public License as published by the Free
11 * Software Foundation; either version 2 of the License, or (at your option)
12 * any later version.
14 /* This implementation is checked against the test vectors in the above
15 * document and by a test vector provided by Ken Buchanan at
16 * http://www.mail-archive.com/stds-p1619@listserv.ieee.org/msg00173.html
18 * The test vectors are included in the testing module tcrypt.[ch] */
19 #include <crypto/algapi.h>
20 #include <linux/err.h>
21 #include <linux/init.h>
22 #include <linux/kernel.h>
23 #include <linux/module.h>
24 #include <linux/scatterlist.h>
25 #include <linux/slab.h>
27 #include <crypto/b128ops.h>
28 #include <crypto/gf128mul.h>
30 struct priv {
31 struct crypto_cipher *child;
32 /* optimizes multiplying a random (non incrementing, as at the
33 * start of a new sector) value with key2, we could also have
34 * used 4k optimization tables or no optimization at all. In the
35 * latter case we would have to store key2 here */
36 struct gf128mul_64k *table;
37 /* stores:
38 * key2*{ 0,0,...0,0,0,0,1 }, key2*{ 0,0,...0,0,0,1,1 },
39 * key2*{ 0,0,...0,0,1,1,1 }, key2*{ 0,0,...0,1,1,1,1 }
40 * key2*{ 0,0,...1,1,1,1,1 }, etc
41 * needed for optimized multiplication of incrementing values
42 * with key2 */
43 be128 mulinc[128];
46 static inline void setbit128_bbe(void *b, int bit)
48 __set_bit(bit ^ 0x78, b);
51 static int setkey(struct crypto_tfm *parent, const u8 *key,
52 unsigned int keylen)
54 struct priv *ctx = crypto_tfm_ctx(parent);
55 struct crypto_cipher *child = ctx->child;
56 int err, i;
57 be128 tmp = { 0 };
58 int bsize = crypto_cipher_blocksize(child);
60 crypto_cipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
61 crypto_cipher_set_flags(child, crypto_tfm_get_flags(parent) &
62 CRYPTO_TFM_REQ_MASK);
63 if ((err = crypto_cipher_setkey(child, key, keylen - bsize)))
64 return err;
65 crypto_tfm_set_flags(parent, crypto_cipher_get_flags(child) &
66 CRYPTO_TFM_RES_MASK);
68 if (ctx->table)
69 gf128mul_free_64k(ctx->table);
71 /* initialize multiplication table for Key2 */
72 ctx->table = gf128mul_init_64k_bbe((be128 *)(key + keylen - bsize));
73 if (!ctx->table)
74 return -ENOMEM;
76 /* initialize optimization table */
77 for (i = 0; i < 128; i++) {
78 setbit128_bbe(&tmp, i);
79 ctx->mulinc[i] = tmp;
80 gf128mul_64k_bbe(&ctx->mulinc[i], ctx->table);
83 return 0;
86 struct sinfo {
87 be128 t;
88 struct crypto_tfm *tfm;
89 void (*fn)(struct crypto_tfm *, u8 *, const u8 *);
92 static inline void inc(be128 *iv)
94 be64_add_cpu(&iv->b, 1);
95 if (!iv->b)
96 be64_add_cpu(&iv->a, 1);
99 static inline void lrw_round(struct sinfo *s, void *dst, const void *src)
101 be128_xor(dst, &s->t, src); /* PP <- T xor P */
102 s->fn(s->tfm, dst, dst); /* CC <- E(Key2,PP) */
103 be128_xor(dst, dst, &s->t); /* C <- T xor CC */
106 /* this returns the number of consequative 1 bits starting
107 * from the right, get_index128(00 00 00 00 00 00 ... 00 00 10 FB) = 2 */
108 static inline int get_index128(be128 *block)
110 int x;
111 __be32 *p = (__be32 *) block;
113 for (p += 3, x = 0; x < 128; p--, x += 32) {
114 u32 val = be32_to_cpup(p);
116 if (!~val)
117 continue;
119 return x + ffz(val);
122 return x;
125 static int crypt(struct blkcipher_desc *d,
126 struct blkcipher_walk *w, struct priv *ctx,
127 void (*fn)(struct crypto_tfm *, u8 *, const u8 *))
129 int err;
130 unsigned int avail;
131 const int bs = crypto_cipher_blocksize(ctx->child);
132 struct sinfo s = {
133 .tfm = crypto_cipher_tfm(ctx->child),
134 .fn = fn
136 be128 *iv;
137 u8 *wsrc;
138 u8 *wdst;
140 err = blkcipher_walk_virt(d, w);
141 if (!(avail = w->nbytes))
142 return err;
144 wsrc = w->src.virt.addr;
145 wdst = w->dst.virt.addr;
147 /* calculate first value of T */
148 iv = (be128 *)w->iv;
149 s.t = *iv;
151 /* T <- I*Key2 */
152 gf128mul_64k_bbe(&s.t, ctx->table);
154 goto first;
156 for (;;) {
157 do {
158 /* T <- I*Key2, using the optimization
159 * discussed in the specification */
160 be128_xor(&s.t, &s.t, &ctx->mulinc[get_index128(iv)]);
161 inc(iv);
163 first:
164 lrw_round(&s, wdst, wsrc);
166 wsrc += bs;
167 wdst += bs;
168 } while ((avail -= bs) >= bs);
170 err = blkcipher_walk_done(d, w, avail);
171 if (!(avail = w->nbytes))
172 break;
174 wsrc = w->src.virt.addr;
175 wdst = w->dst.virt.addr;
178 return err;
181 static int encrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
182 struct scatterlist *src, unsigned int nbytes)
184 struct priv *ctx = crypto_blkcipher_ctx(desc->tfm);
185 struct blkcipher_walk w;
187 blkcipher_walk_init(&w, dst, src, nbytes);
188 return crypt(desc, &w, ctx,
189 crypto_cipher_alg(ctx->child)->cia_encrypt);
192 static int decrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
193 struct scatterlist *src, unsigned int nbytes)
195 struct priv *ctx = crypto_blkcipher_ctx(desc->tfm);
196 struct blkcipher_walk w;
198 blkcipher_walk_init(&w, dst, src, nbytes);
199 return crypt(desc, &w, ctx,
200 crypto_cipher_alg(ctx->child)->cia_decrypt);
203 static int init_tfm(struct crypto_tfm *tfm)
205 struct crypto_cipher *cipher;
206 struct crypto_instance *inst = (void *)tfm->__crt_alg;
207 struct crypto_spawn *spawn = crypto_instance_ctx(inst);
208 struct priv *ctx = crypto_tfm_ctx(tfm);
209 u32 *flags = &tfm->crt_flags;
211 cipher = crypto_spawn_cipher(spawn);
212 if (IS_ERR(cipher))
213 return PTR_ERR(cipher);
215 if (crypto_cipher_blocksize(cipher) != 16) {
216 *flags |= CRYPTO_TFM_RES_BAD_BLOCK_LEN;
217 return -EINVAL;
220 ctx->child = cipher;
221 return 0;
224 static void exit_tfm(struct crypto_tfm *tfm)
226 struct priv *ctx = crypto_tfm_ctx(tfm);
227 if (ctx->table)
228 gf128mul_free_64k(ctx->table);
229 crypto_free_cipher(ctx->child);
232 static struct crypto_instance *alloc(struct rtattr **tb)
234 struct crypto_instance *inst;
235 struct crypto_alg *alg;
236 int err;
238 err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_BLKCIPHER);
239 if (err)
240 return ERR_PTR(err);
242 alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER,
243 CRYPTO_ALG_TYPE_MASK);
244 if (IS_ERR(alg))
245 return ERR_CAST(alg);
247 inst = crypto_alloc_instance("lrw", alg);
248 if (IS_ERR(inst))
249 goto out_put_alg;
251 inst->alg.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER;
252 inst->alg.cra_priority = alg->cra_priority;
253 inst->alg.cra_blocksize = alg->cra_blocksize;
255 if (alg->cra_alignmask < 7) inst->alg.cra_alignmask = 7;
256 else inst->alg.cra_alignmask = alg->cra_alignmask;
257 inst->alg.cra_type = &crypto_blkcipher_type;
259 if (!(alg->cra_blocksize % 4))
260 inst->alg.cra_alignmask |= 3;
261 inst->alg.cra_blkcipher.ivsize = alg->cra_blocksize;
262 inst->alg.cra_blkcipher.min_keysize =
263 alg->cra_cipher.cia_min_keysize + alg->cra_blocksize;
264 inst->alg.cra_blkcipher.max_keysize =
265 alg->cra_cipher.cia_max_keysize + alg->cra_blocksize;
267 inst->alg.cra_ctxsize = sizeof(struct priv);
269 inst->alg.cra_init = init_tfm;
270 inst->alg.cra_exit = exit_tfm;
272 inst->alg.cra_blkcipher.setkey = setkey;
273 inst->alg.cra_blkcipher.encrypt = encrypt;
274 inst->alg.cra_blkcipher.decrypt = decrypt;
276 out_put_alg:
277 crypto_mod_put(alg);
278 return inst;
281 static void free(struct crypto_instance *inst)
283 crypto_drop_spawn(crypto_instance_ctx(inst));
284 kfree(inst);
287 static struct crypto_template crypto_tmpl = {
288 .name = "lrw",
289 .alloc = alloc,
290 .free = free,
291 .module = THIS_MODULE,
294 static int __init crypto_module_init(void)
296 return crypto_register_template(&crypto_tmpl);
299 static void __exit crypto_module_exit(void)
301 crypto_unregister_template(&crypto_tmpl);
304 module_init(crypto_module_init);
305 module_exit(crypto_module_exit);
307 MODULE_LICENSE("GPL");
308 MODULE_DESCRIPTION("LRW block cipher mode");