crypto: shash - Export/import hash state only
[linux-2.6.git] / crypto / shash.c
1 /*
2  * Synchronous Cryptographic Hash operations.
3  *
4  * Copyright (c) 2008 Herbert Xu <herbert@gondor.apana.org.au>
5  *
6  * This program is free software; you can redistribute it and/or modify it
7  * under the terms of the GNU General Public License as published by the Free
8  * Software Foundation; either version 2 of the License, or (at your option)
9  * any later version.
10  *
11  */
12
13 #include <crypto/scatterwalk.h>
14 #include <crypto/internal/hash.h>
15 #include <linux/err.h>
16 #include <linux/kernel.h>
17 #include <linux/module.h>
18 #include <linux/slab.h>
19 #include <linux/seq_file.h>
20
21 #include "internal.h"
22
23 static const struct crypto_type crypto_shash_type;
24
25 static int shash_setkey_unaligned(struct crypto_shash *tfm, const u8 *key,
26                                   unsigned int keylen)
27 {
28         struct shash_alg *shash = crypto_shash_alg(tfm);
29         unsigned long alignmask = crypto_shash_alignmask(tfm);
30         unsigned long absize;
31         u8 *buffer, *alignbuffer;
32         int err;
33
34         absize = keylen + (alignmask & ~(CRYPTO_MINALIGN - 1));
35         buffer = kmalloc(absize, GFP_KERNEL);
36         if (!buffer)
37                 return -ENOMEM;
38
39         alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
40         memcpy(alignbuffer, key, keylen);
41         err = shash->setkey(tfm, alignbuffer, keylen);
42         memset(alignbuffer, 0, keylen);
43         kfree(buffer);
44         return err;
45 }
46
47 int crypto_shash_setkey(struct crypto_shash *tfm, const u8 *key,
48                         unsigned int keylen)
49 {
50         struct shash_alg *shash = crypto_shash_alg(tfm);
51         unsigned long alignmask = crypto_shash_alignmask(tfm);
52
53         if (!shash->setkey)
54                 return -ENOSYS;
55
56         if ((unsigned long)key & alignmask)
57                 return shash_setkey_unaligned(tfm, key, keylen);
58
59         return shash->setkey(tfm, key, keylen);
60 }
61 EXPORT_SYMBOL_GPL(crypto_shash_setkey);
62
63 static inline unsigned int shash_align_buffer_size(unsigned len,
64                                                    unsigned long mask)
65 {
66         return len + (mask & ~(__alignof__(u8 __attribute__ ((aligned))) - 1));
67 }
68
69 static int shash_update_unaligned(struct shash_desc *desc, const u8 *data,
70                                   unsigned int len)
71 {
72         struct crypto_shash *tfm = desc->tfm;
73         struct shash_alg *shash = crypto_shash_alg(tfm);
74         unsigned long alignmask = crypto_shash_alignmask(tfm);
75         unsigned int unaligned_len = alignmask + 1 -
76                                      ((unsigned long)data & alignmask);
77         u8 buf[shash_align_buffer_size(unaligned_len, alignmask)]
78                 __attribute__ ((aligned));
79
80         if (unaligned_len > len)
81                 unaligned_len = len;
82
83         memcpy(buf, data, unaligned_len);
84
85         return shash->update(desc, buf, unaligned_len) ?:
86                shash->update(desc, data + unaligned_len, len - unaligned_len);
87 }
88
89 int crypto_shash_update(struct shash_desc *desc, const u8 *data,
90                         unsigned int len)
91 {
92         struct crypto_shash *tfm = desc->tfm;
93         struct shash_alg *shash = crypto_shash_alg(tfm);
94         unsigned long alignmask = crypto_shash_alignmask(tfm);
95
96         if ((unsigned long)data & alignmask)
97                 return shash_update_unaligned(desc, data, len);
98
99         return shash->update(desc, data, len);
100 }
101 EXPORT_SYMBOL_GPL(crypto_shash_update);
102
103 static int shash_final_unaligned(struct shash_desc *desc, u8 *out)
104 {
105         struct crypto_shash *tfm = desc->tfm;
106         unsigned long alignmask = crypto_shash_alignmask(tfm);
107         struct shash_alg *shash = crypto_shash_alg(tfm);
108         unsigned int ds = crypto_shash_digestsize(tfm);
109         u8 buf[shash_align_buffer_size(ds, alignmask)]
110                 __attribute__ ((aligned));
111         int err;
112
113         err = shash->final(desc, buf);
114         memcpy(out, buf, ds);
115         return err;
116 }
117
118 int crypto_shash_final(struct shash_desc *desc, u8 *out)
119 {
120         struct crypto_shash *tfm = desc->tfm;
121         struct shash_alg *shash = crypto_shash_alg(tfm);
122         unsigned long alignmask = crypto_shash_alignmask(tfm);
123
124         if ((unsigned long)out & alignmask)
125                 return shash_final_unaligned(desc, out);
126
127         return shash->final(desc, out);
128 }
129 EXPORT_SYMBOL_GPL(crypto_shash_final);
130
131 static int shash_finup_unaligned(struct shash_desc *desc, const u8 *data,
132                                  unsigned int len, u8 *out)
133 {
134         return crypto_shash_update(desc, data, len) ?:
135                crypto_shash_final(desc, out);
136 }
137
138 int crypto_shash_finup(struct shash_desc *desc, const u8 *data,
139                        unsigned int len, u8 *out)
140 {
141         struct crypto_shash *tfm = desc->tfm;
142         struct shash_alg *shash = crypto_shash_alg(tfm);
143         unsigned long alignmask = crypto_shash_alignmask(tfm);
144
145         if (((unsigned long)data | (unsigned long)out) & alignmask ||
146             !shash->finup)
147                 return shash_finup_unaligned(desc, data, len, out);
148
149         return shash->finup(desc, data, len, out);
150 }
151 EXPORT_SYMBOL_GPL(crypto_shash_finup);
152
153 static int shash_digest_unaligned(struct shash_desc *desc, const u8 *data,
154                                   unsigned int len, u8 *out)
155 {
156         return crypto_shash_init(desc) ?:
157                crypto_shash_finup(desc, data, len, out);
158 }
159
160 int crypto_shash_digest(struct shash_desc *desc, const u8 *data,
161                         unsigned int len, u8 *out)
162 {
163         struct crypto_shash *tfm = desc->tfm;
164         struct shash_alg *shash = crypto_shash_alg(tfm);
165         unsigned long alignmask = crypto_shash_alignmask(tfm);
166
167         if (((unsigned long)data | (unsigned long)out) & alignmask ||
168             !shash->digest)
169                 return shash_digest_unaligned(desc, data, len, out);
170
171         return shash->digest(desc, data, len, out);
172 }
173 EXPORT_SYMBOL_GPL(crypto_shash_digest);
174
175 static int shash_no_export(struct shash_desc *desc, void *out)
176 {
177         return -ENOSYS;
178 }
179
180 static int shash_no_import(struct shash_desc *desc, const void *in)
181 {
182         return -ENOSYS;
183 }
184
185 static int shash_async_setkey(struct crypto_ahash *tfm, const u8 *key,
186                               unsigned int keylen)
187 {
188         struct crypto_shash **ctx = crypto_ahash_ctx(tfm);
189
190         return crypto_shash_setkey(*ctx, key, keylen);
191 }
192
193 static int shash_async_init(struct ahash_request *req)
194 {
195         struct crypto_shash **ctx = crypto_ahash_ctx(crypto_ahash_reqtfm(req));
196         struct shash_desc *desc = ahash_request_ctx(req);
197
198         desc->tfm = *ctx;
199         desc->flags = req->base.flags;
200
201         return crypto_shash_init(desc);
202 }
203
204 static int shash_async_update(struct ahash_request *req)
205 {
206         struct shash_desc *desc = ahash_request_ctx(req);
207         struct crypto_hash_walk walk;
208         int nbytes;
209
210         for (nbytes = crypto_hash_walk_first(req, &walk); nbytes > 0;
211              nbytes = crypto_hash_walk_done(&walk, nbytes))
212                 nbytes = crypto_shash_update(desc, walk.data, nbytes);
213
214         return nbytes;
215 }
216
217 static int shash_async_final(struct ahash_request *req)
218 {
219         return crypto_shash_final(ahash_request_ctx(req), req->result);
220 }
221
222 static int shash_async_digest(struct ahash_request *req)
223 {
224         struct scatterlist *sg = req->src;
225         unsigned int offset = sg->offset;
226         unsigned int nbytes = req->nbytes;
227         int err;
228
229         if (nbytes < min(sg->length, ((unsigned int)(PAGE_SIZE)) - offset)) {
230                 struct crypto_shash **ctx =
231                         crypto_ahash_ctx(crypto_ahash_reqtfm(req));
232                 struct shash_desc *desc = ahash_request_ctx(req);
233                 void *data;
234
235                 desc->tfm = *ctx;
236                 desc->flags = req->base.flags;
237
238                 data = crypto_kmap(sg_page(sg), 0);
239                 err = crypto_shash_digest(desc, data + offset, nbytes,
240                                           req->result);
241                 crypto_kunmap(data, 0);
242                 crypto_yield(desc->flags);
243                 goto out;
244         }
245
246         err = shash_async_init(req);
247         if (err)
248                 goto out;
249
250         err = shash_async_update(req);
251         if (err)
252                 goto out;
253
254         err = shash_async_final(req);
255
256 out:
257         return err;
258 }
259
260 static void crypto_exit_shash_ops_async(struct crypto_tfm *tfm)
261 {
262         struct crypto_shash **ctx = crypto_tfm_ctx(tfm);
263
264         crypto_free_shash(*ctx);
265 }
266
267 static int crypto_init_shash_ops_async(struct crypto_tfm *tfm)
268 {
269         struct crypto_alg *calg = tfm->__crt_alg;
270         struct shash_alg *alg = __crypto_shash_alg(calg);
271         struct ahash_tfm *crt = &tfm->crt_ahash;
272         struct crypto_shash **ctx = crypto_tfm_ctx(tfm);
273         struct crypto_shash *shash;
274
275         if (!crypto_mod_get(calg))
276                 return -EAGAIN;
277
278         shash = crypto_create_tfm(calg, &crypto_shash_type);
279         if (IS_ERR(shash)) {
280                 crypto_mod_put(calg);
281                 return PTR_ERR(shash);
282         }
283
284         *ctx = shash;
285         tfm->exit = crypto_exit_shash_ops_async;
286
287         crt->init = shash_async_init;
288         crt->update = shash_async_update;
289         crt->final  = shash_async_final;
290         crt->digest = shash_async_digest;
291         crt->setkey = shash_async_setkey;
292
293         crt->digestsize = alg->digestsize;
294         crt->reqsize = sizeof(struct shash_desc) + crypto_shash_descsize(shash);
295
296         return 0;
297 }
298
299 static int shash_compat_setkey(struct crypto_hash *tfm, const u8 *key,
300                                unsigned int keylen)
301 {
302         struct shash_desc *desc = crypto_hash_ctx(tfm);
303
304         return crypto_shash_setkey(desc->tfm, key, keylen);
305 }
306
307 static int shash_compat_init(struct hash_desc *hdesc)
308 {
309         struct shash_desc *desc = crypto_hash_ctx(hdesc->tfm);
310
311         desc->flags = hdesc->flags;
312
313         return crypto_shash_init(desc);
314 }
315
316 static int shash_compat_update(struct hash_desc *hdesc, struct scatterlist *sg,
317                                unsigned int len)
318 {
319         struct shash_desc *desc = crypto_hash_ctx(hdesc->tfm);
320         struct crypto_hash_walk walk;
321         int nbytes;
322
323         for (nbytes = crypto_hash_walk_first_compat(hdesc, &walk, sg, len);
324              nbytes > 0; nbytes = crypto_hash_walk_done(&walk, nbytes))
325                 nbytes = crypto_shash_update(desc, walk.data, nbytes);
326
327         return nbytes;
328 }
329
330 static int shash_compat_final(struct hash_desc *hdesc, u8 *out)
331 {
332         return crypto_shash_final(crypto_hash_ctx(hdesc->tfm), out);
333 }
334
335 static int shash_compat_digest(struct hash_desc *hdesc, struct scatterlist *sg,
336                                unsigned int nbytes, u8 *out)
337 {
338         unsigned int offset = sg->offset;
339         int err;
340
341         if (nbytes < min(sg->length, ((unsigned int)(PAGE_SIZE)) - offset)) {
342                 struct shash_desc *desc = crypto_hash_ctx(hdesc->tfm);
343                 void *data;
344
345                 desc->flags = hdesc->flags;
346
347                 data = crypto_kmap(sg_page(sg), 0);
348                 err = crypto_shash_digest(desc, data + offset, nbytes, out);
349                 crypto_kunmap(data, 0);
350                 crypto_yield(desc->flags);
351                 goto out;
352         }
353
354         err = shash_compat_init(hdesc);
355         if (err)
356                 goto out;
357
358         err = shash_compat_update(hdesc, sg, nbytes);
359         if (err)
360                 goto out;
361
362         err = shash_compat_final(hdesc, out);
363
364 out:
365         return err;
366 }
367
368 static void crypto_exit_shash_ops_compat(struct crypto_tfm *tfm)
369 {
370         struct shash_desc *desc= crypto_tfm_ctx(tfm);
371
372         crypto_free_shash(desc->tfm);
373 }
374
375 static int crypto_init_shash_ops_compat(struct crypto_tfm *tfm)
376 {
377         struct hash_tfm *crt = &tfm->crt_hash;
378         struct crypto_alg *calg = tfm->__crt_alg;
379         struct shash_alg *alg = __crypto_shash_alg(calg);
380         struct shash_desc *desc = crypto_tfm_ctx(tfm);
381         struct crypto_shash *shash;
382
383         if (!crypto_mod_get(calg))
384                 return -EAGAIN;
385
386         shash = crypto_create_tfm(calg, &crypto_shash_type);
387         if (IS_ERR(shash)) {
388                 crypto_mod_put(calg);
389                 return PTR_ERR(shash);
390         }
391
392         desc->tfm = shash;
393         tfm->exit = crypto_exit_shash_ops_compat;
394
395         crt->init = shash_compat_init;
396         crt->update = shash_compat_update;
397         crt->final  = shash_compat_final;
398         crt->digest = shash_compat_digest;
399         crt->setkey = shash_compat_setkey;
400
401         crt->digestsize = alg->digestsize;
402
403         return 0;
404 }
405
406 static int crypto_init_shash_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
407 {
408         switch (mask & CRYPTO_ALG_TYPE_MASK) {
409         case CRYPTO_ALG_TYPE_HASH_MASK:
410                 return crypto_init_shash_ops_compat(tfm);
411         case CRYPTO_ALG_TYPE_AHASH_MASK:
412                 return crypto_init_shash_ops_async(tfm);
413         }
414
415         return -EINVAL;
416 }
417
418 static unsigned int crypto_shash_ctxsize(struct crypto_alg *alg, u32 type,
419                                          u32 mask)
420 {
421         struct shash_alg *salg = __crypto_shash_alg(alg);
422
423         switch (mask & CRYPTO_ALG_TYPE_MASK) {
424         case CRYPTO_ALG_TYPE_HASH_MASK:
425                 return sizeof(struct shash_desc) + salg->descsize;
426         case CRYPTO_ALG_TYPE_AHASH_MASK:
427                 return sizeof(struct crypto_shash *);
428         }
429
430         return 0;
431 }
432
433 static int crypto_shash_init_tfm(struct crypto_tfm *tfm,
434                                  const struct crypto_type *frontend)
435 {
436         return 0;
437 }
438
439 static unsigned int crypto_shash_extsize(struct crypto_alg *alg,
440                                          const struct crypto_type *frontend)
441 {
442         return alg->cra_ctxsize;
443 }
444
445 static void crypto_shash_show(struct seq_file *m, struct crypto_alg *alg)
446         __attribute__ ((unused));
447 static void crypto_shash_show(struct seq_file *m, struct crypto_alg *alg)
448 {
449         struct shash_alg *salg = __crypto_shash_alg(alg);
450
451         seq_printf(m, "type         : shash\n");
452         seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
453         seq_printf(m, "digestsize   : %u\n", salg->digestsize);
454         seq_printf(m, "descsize     : %u\n", salg->descsize);
455 }
456
457 static const struct crypto_type crypto_shash_type = {
458         .ctxsize = crypto_shash_ctxsize,
459         .extsize = crypto_shash_extsize,
460         .init = crypto_init_shash_ops,
461         .init_tfm = crypto_shash_init_tfm,
462 #ifdef CONFIG_PROC_FS
463         .show = crypto_shash_show,
464 #endif
465         .maskclear = ~CRYPTO_ALG_TYPE_MASK,
466         .maskset = CRYPTO_ALG_TYPE_MASK,
467         .type = CRYPTO_ALG_TYPE_SHASH,
468         .tfmsize = offsetof(struct crypto_shash, base),
469 };
470
471 struct crypto_shash *crypto_alloc_shash(const char *alg_name, u32 type,
472                                         u32 mask)
473 {
474         return crypto_alloc_tfm(alg_name, &crypto_shash_type, type, mask);
475 }
476 EXPORT_SYMBOL_GPL(crypto_alloc_shash);
477
478 static int shash_prepare_alg(struct shash_alg *alg)
479 {
480         struct crypto_alg *base = &alg->base;
481
482         if (alg->digestsize > PAGE_SIZE / 8 ||
483             alg->descsize > PAGE_SIZE / 8 ||
484             alg->statesize > PAGE_SIZE / 8)
485                 return -EINVAL;
486
487         base->cra_type = &crypto_shash_type;
488         base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
489         base->cra_flags |= CRYPTO_ALG_TYPE_SHASH;
490
491         if (!alg->import)
492                 alg->import = shash_no_import;
493         if (!alg->export)
494                 alg->export = shash_no_export;
495
496         return 0;
497 }
498
499 int crypto_register_shash(struct shash_alg *alg)
500 {
501         struct crypto_alg *base = &alg->base;
502         int err;
503
504         err = shash_prepare_alg(alg);
505         if (err)
506                 return err;
507
508         return crypto_register_alg(base);
509 }
510 EXPORT_SYMBOL_GPL(crypto_register_shash);
511
512 int crypto_unregister_shash(struct shash_alg *alg)
513 {
514         return crypto_unregister_alg(&alg->base);
515 }
516 EXPORT_SYMBOL_GPL(crypto_unregister_shash);
517
518 int shash_register_instance(struct crypto_template *tmpl,
519                             struct shash_instance *inst)
520 {
521         int err;
522
523         err = shash_prepare_alg(&inst->alg);
524         if (err)
525                 return err;
526
527         return crypto_register_instance(tmpl, shash_crypto_instance(inst));
528 }
529 EXPORT_SYMBOL_GPL(shash_register_instance);
530
531 void shash_free_instance(struct crypto_instance *inst)
532 {
533         crypto_drop_spawn(crypto_instance_ctx(inst));
534         kfree(shash_instance(inst));
535 }
536 EXPORT_SYMBOL_GPL(shash_free_instance);
537
538 int crypto_init_shash_spawn(struct crypto_shash_spawn *spawn,
539                             struct shash_alg *alg,
540                             struct crypto_instance *inst)
541 {
542         return crypto_init_spawn2(&spawn->base, &alg->base, inst,
543                                   &crypto_shash_type);
544 }
545 EXPORT_SYMBOL_GPL(crypto_init_shash_spawn);
546
547 struct shash_alg *shash_attr_alg(struct rtattr *rta, u32 type, u32 mask)
548 {
549         struct crypto_alg *alg;
550
551         alg = crypto_attr_alg2(rta, &crypto_shash_type, type, mask);
552         return IS_ERR(alg) ? ERR_CAST(alg) :
553                container_of(alg, struct shash_alg, base);
554 }
555 EXPORT_SYMBOL_GPL(shash_attr_alg);
556
557 MODULE_LICENSE("GPL");
558 MODULE_DESCRIPTION("Synchronous cryptographic hash type");