crypto: shash - Fix unaligned calculation with short length
[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_update(desc, data, len) ?:
158                crypto_shash_final(desc, out);
159 }
160
161 int crypto_shash_digest(struct shash_desc *desc, const u8 *data,
162                         unsigned int len, u8 *out)
163 {
164         struct crypto_shash *tfm = desc->tfm;
165         struct shash_alg *shash = crypto_shash_alg(tfm);
166         unsigned long alignmask = crypto_shash_alignmask(tfm);
167
168         if (((unsigned long)data | (unsigned long)out) & alignmask ||
169             !shash->digest)
170                 return shash_digest_unaligned(desc, data, len, out);
171
172         return shash->digest(desc, data, len, out);
173 }
174 EXPORT_SYMBOL_GPL(crypto_shash_digest);
175
176 int crypto_shash_import(struct shash_desc *desc, const u8 *in)
177 {
178         struct crypto_shash *tfm = desc->tfm;
179         struct shash_alg *alg = crypto_shash_alg(tfm);
180
181         memcpy(shash_desc_ctx(desc), in, crypto_shash_descsize(tfm));
182
183         if (alg->reinit)
184                 alg->reinit(desc);
185
186         return 0;
187 }
188 EXPORT_SYMBOL_GPL(crypto_shash_import);
189
190 static int shash_async_setkey(struct crypto_ahash *tfm, const u8 *key,
191                               unsigned int keylen)
192 {
193         struct crypto_shash **ctx = crypto_ahash_ctx(tfm);
194
195         return crypto_shash_setkey(*ctx, key, keylen);
196 }
197
198 static int shash_async_init(struct ahash_request *req)
199 {
200         struct crypto_shash **ctx = crypto_ahash_ctx(crypto_ahash_reqtfm(req));
201         struct shash_desc *desc = ahash_request_ctx(req);
202
203         desc->tfm = *ctx;
204         desc->flags = req->base.flags;
205
206         return crypto_shash_init(desc);
207 }
208
209 static int shash_async_update(struct ahash_request *req)
210 {
211         struct shash_desc *desc = ahash_request_ctx(req);
212         struct crypto_hash_walk walk;
213         int nbytes;
214
215         for (nbytes = crypto_hash_walk_first(req, &walk); nbytes > 0;
216              nbytes = crypto_hash_walk_done(&walk, nbytes))
217                 nbytes = crypto_shash_update(desc, walk.data, nbytes);
218
219         return nbytes;
220 }
221
222 static int shash_async_final(struct ahash_request *req)
223 {
224         return crypto_shash_final(ahash_request_ctx(req), req->result);
225 }
226
227 static int shash_async_digest(struct ahash_request *req)
228 {
229         struct scatterlist *sg = req->src;
230         unsigned int offset = sg->offset;
231         unsigned int nbytes = req->nbytes;
232         int err;
233
234         if (nbytes < min(sg->length, ((unsigned int)(PAGE_SIZE)) - offset)) {
235                 struct crypto_shash **ctx =
236                         crypto_ahash_ctx(crypto_ahash_reqtfm(req));
237                 struct shash_desc *desc = ahash_request_ctx(req);
238                 void *data;
239
240                 desc->tfm = *ctx;
241                 desc->flags = req->base.flags;
242
243                 data = crypto_kmap(sg_page(sg), 0);
244                 err = crypto_shash_digest(desc, data + offset, nbytes,
245                                           req->result);
246                 crypto_kunmap(data, 0);
247                 crypto_yield(desc->flags);
248                 goto out;
249         }
250
251         err = shash_async_init(req);
252         if (err)
253                 goto out;
254
255         err = shash_async_update(req);
256         if (err)
257                 goto out;
258
259         err = shash_async_final(req);
260
261 out:
262         return err;
263 }
264
265 static void crypto_exit_shash_ops_async(struct crypto_tfm *tfm)
266 {
267         struct crypto_shash **ctx = crypto_tfm_ctx(tfm);
268
269         crypto_free_shash(*ctx);
270 }
271
272 static int crypto_init_shash_ops_async(struct crypto_tfm *tfm)
273 {
274         struct crypto_alg *calg = tfm->__crt_alg;
275         struct shash_alg *alg = __crypto_shash_alg(calg);
276         struct ahash_tfm *crt = &tfm->crt_ahash;
277         struct crypto_shash **ctx = crypto_tfm_ctx(tfm);
278         struct crypto_shash *shash;
279
280         if (!crypto_mod_get(calg))
281                 return -EAGAIN;
282
283         shash = crypto_create_tfm(calg, &crypto_shash_type);
284         if (IS_ERR(shash)) {
285                 crypto_mod_put(calg);
286                 return PTR_ERR(shash);
287         }
288
289         *ctx = shash;
290         tfm->exit = crypto_exit_shash_ops_async;
291
292         crt->init = shash_async_init;
293         crt->update = shash_async_update;
294         crt->final  = shash_async_final;
295         crt->digest = shash_async_digest;
296         crt->setkey = shash_async_setkey;
297
298         crt->digestsize = alg->digestsize;
299         crt->reqsize = sizeof(struct shash_desc) + crypto_shash_descsize(shash);
300
301         return 0;
302 }
303
304 static int shash_compat_setkey(struct crypto_hash *tfm, const u8 *key,
305                                unsigned int keylen)
306 {
307         struct shash_desc *desc = crypto_hash_ctx(tfm);
308
309         return crypto_shash_setkey(desc->tfm, key, keylen);
310 }
311
312 static int shash_compat_init(struct hash_desc *hdesc)
313 {
314         struct shash_desc *desc = crypto_hash_ctx(hdesc->tfm);
315
316         desc->flags = hdesc->flags;
317
318         return crypto_shash_init(desc);
319 }
320
321 static int shash_compat_update(struct hash_desc *hdesc, struct scatterlist *sg,
322                                unsigned int len)
323 {
324         struct shash_desc *desc = crypto_hash_ctx(hdesc->tfm);
325         struct crypto_hash_walk walk;
326         int nbytes;
327
328         for (nbytes = crypto_hash_walk_first_compat(hdesc, &walk, sg, len);
329              nbytes > 0; nbytes = crypto_hash_walk_done(&walk, nbytes))
330                 nbytes = crypto_shash_update(desc, walk.data, nbytes);
331
332         return nbytes;
333 }
334
335 static int shash_compat_final(struct hash_desc *hdesc, u8 *out)
336 {
337         return crypto_shash_final(crypto_hash_ctx(hdesc->tfm), out);
338 }
339
340 static int shash_compat_digest(struct hash_desc *hdesc, struct scatterlist *sg,
341                                unsigned int nbytes, u8 *out)
342 {
343         unsigned int offset = sg->offset;
344         int err;
345
346         if (nbytes < min(sg->length, ((unsigned int)(PAGE_SIZE)) - offset)) {
347                 struct shash_desc *desc = crypto_hash_ctx(hdesc->tfm);
348                 void *data;
349
350                 desc->flags = hdesc->flags;
351
352                 data = crypto_kmap(sg_page(sg), 0);
353                 err = crypto_shash_digest(desc, data + offset, nbytes, out);
354                 crypto_kunmap(data, 0);
355                 crypto_yield(desc->flags);
356                 goto out;
357         }
358
359         err = shash_compat_init(hdesc);
360         if (err)
361                 goto out;
362
363         err = shash_compat_update(hdesc, sg, nbytes);
364         if (err)
365                 goto out;
366
367         err = shash_compat_final(hdesc, out);
368
369 out:
370         return err;
371 }
372
373 static void crypto_exit_shash_ops_compat(struct crypto_tfm *tfm)
374 {
375         struct shash_desc *desc= crypto_tfm_ctx(tfm);
376
377         crypto_free_shash(desc->tfm);
378 }
379
380 static int crypto_init_shash_ops_compat(struct crypto_tfm *tfm)
381 {
382         struct hash_tfm *crt = &tfm->crt_hash;
383         struct crypto_alg *calg = tfm->__crt_alg;
384         struct shash_alg *alg = __crypto_shash_alg(calg);
385         struct shash_desc *desc = crypto_tfm_ctx(tfm);
386         struct crypto_shash *shash;
387
388         if (!crypto_mod_get(calg))
389                 return -EAGAIN;
390
391         shash = crypto_create_tfm(calg, &crypto_shash_type);
392         if (IS_ERR(shash)) {
393                 crypto_mod_put(calg);
394                 return PTR_ERR(shash);
395         }
396
397         desc->tfm = shash;
398         tfm->exit = crypto_exit_shash_ops_compat;
399
400         crt->init = shash_compat_init;
401         crt->update = shash_compat_update;
402         crt->final  = shash_compat_final;
403         crt->digest = shash_compat_digest;
404         crt->setkey = shash_compat_setkey;
405
406         crt->digestsize = alg->digestsize;
407
408         return 0;
409 }
410
411 static int crypto_init_shash_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
412 {
413         switch (mask & CRYPTO_ALG_TYPE_MASK) {
414         case CRYPTO_ALG_TYPE_HASH_MASK:
415                 return crypto_init_shash_ops_compat(tfm);
416         case CRYPTO_ALG_TYPE_AHASH_MASK:
417                 return crypto_init_shash_ops_async(tfm);
418         }
419
420         return -EINVAL;
421 }
422
423 static unsigned int crypto_shash_ctxsize(struct crypto_alg *alg, u32 type,
424                                          u32 mask)
425 {
426         struct shash_alg *salg = __crypto_shash_alg(alg);
427
428         switch (mask & CRYPTO_ALG_TYPE_MASK) {
429         case CRYPTO_ALG_TYPE_HASH_MASK:
430                 return sizeof(struct shash_desc) + salg->descsize;
431         case CRYPTO_ALG_TYPE_AHASH_MASK:
432                 return sizeof(struct crypto_shash *);
433         }
434
435         return 0;
436 }
437
438 static int crypto_shash_init_tfm(struct crypto_tfm *tfm,
439                                  const struct crypto_type *frontend)
440 {
441         return 0;
442 }
443
444 static unsigned int crypto_shash_extsize(struct crypto_alg *alg,
445                                          const struct crypto_type *frontend)
446 {
447         return alg->cra_ctxsize;
448 }
449
450 static void crypto_shash_show(struct seq_file *m, struct crypto_alg *alg)
451         __attribute__ ((unused));
452 static void crypto_shash_show(struct seq_file *m, struct crypto_alg *alg)
453 {
454         struct shash_alg *salg = __crypto_shash_alg(alg);
455
456         seq_printf(m, "type         : shash\n");
457         seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
458         seq_printf(m, "digestsize   : %u\n", salg->digestsize);
459         seq_printf(m, "descsize     : %u\n", salg->descsize);
460 }
461
462 static const struct crypto_type crypto_shash_type = {
463         .ctxsize = crypto_shash_ctxsize,
464         .extsize = crypto_shash_extsize,
465         .init = crypto_init_shash_ops,
466         .init_tfm = crypto_shash_init_tfm,
467 #ifdef CONFIG_PROC_FS
468         .show = crypto_shash_show,
469 #endif
470         .maskclear = ~CRYPTO_ALG_TYPE_MASK,
471         .maskset = CRYPTO_ALG_TYPE_MASK,
472         .type = CRYPTO_ALG_TYPE_SHASH,
473         .tfmsize = offsetof(struct crypto_shash, base),
474 };
475
476 struct crypto_shash *crypto_alloc_shash(const char *alg_name, u32 type,
477                                         u32 mask)
478 {
479         return crypto_alloc_tfm(alg_name, &crypto_shash_type, type, mask);
480 }
481 EXPORT_SYMBOL_GPL(crypto_alloc_shash);
482
483 int crypto_register_shash(struct shash_alg *alg)
484 {
485         struct crypto_alg *base = &alg->base;
486
487         if (alg->digestsize > PAGE_SIZE / 8 ||
488             alg->descsize > PAGE_SIZE / 8)
489                 return -EINVAL;
490
491         base->cra_type = &crypto_shash_type;
492         base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
493         base->cra_flags |= CRYPTO_ALG_TYPE_SHASH;
494
495         return crypto_register_alg(base);
496 }
497 EXPORT_SYMBOL_GPL(crypto_register_shash);
498
499 int crypto_unregister_shash(struct shash_alg *alg)
500 {
501         return crypto_unregister_alg(&alg->base);
502 }
503 EXPORT_SYMBOL_GPL(crypto_unregister_shash);
504
505 MODULE_LICENSE("GPL");
506 MODULE_DESCRIPTION("Synchronous cryptographic hash type");