source: src/linux/universal/linux-3.18/crypto/ahash.c @ 31885

Last change on this file since 31885 was 31885, checked in by brainslayer, 5 weeks ago

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1/*
2 * Asynchronous Cryptographic Hash operations.
3 *
4 * This is the asynchronous version of hash.c with notification of
5 * completion via a callback.
6 *
7 * Copyright (c) 2008 Loc Ho <lho@amcc.com>
8 *
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.
13 *
14 */
15
16#include <crypto/internal/hash.h>
17#include <crypto/scatterwalk.h>
18#include <linux/bug.h>
19#include <linux/err.h>
20#include <linux/kernel.h>
21#include <linux/module.h>
22#include <linux/sched.h>
23#include <linux/slab.h>
24#include <linux/seq_file.h>
25#include <linux/cryptouser.h>
26#include <net/netlink.h>
27
28#include "internal.h"
29
30struct ahash_request_priv {
31        crypto_completion_t complete;
32        void *data;
33        u8 *result;
34        u32 flags;
35        void *ubuf[] CRYPTO_MINALIGN_ATTR;
36};
37
38static inline struct ahash_alg *crypto_ahash_alg(struct crypto_ahash *hash)
39{
40        return container_of(crypto_hash_alg_common(hash), struct ahash_alg,
41                            halg);
42}
43
44static int hash_walk_next(struct crypto_hash_walk *walk)
45{
46        unsigned int alignmask = walk->alignmask;
47        unsigned int offset = walk->offset;
48        unsigned int nbytes = min(walk->entrylen,
49                                  ((unsigned int)(PAGE_SIZE)) - offset);
50
51        if (walk->flags & CRYPTO_ALG_ASYNC)
52                walk->data = kmap(walk->pg);
53        else
54                walk->data = kmap_atomic(walk->pg);
55        walk->data += offset;
56
57        if (offset & alignmask) {
58                unsigned int unaligned = alignmask + 1 - (offset & alignmask);
59                if (nbytes > unaligned)
60                        nbytes = unaligned;
61        }
62
63        walk->entrylen -= nbytes;
64        return nbytes;
65}
66
67static int hash_walk_new_entry(struct crypto_hash_walk *walk)
68{
69        struct scatterlist *sg;
70
71        sg = walk->sg;
72        walk->offset = sg->offset;
73        walk->pg = sg_page(walk->sg) + (walk->offset >> PAGE_SHIFT);
74        walk->offset = offset_in_page(walk->offset);
75        walk->entrylen = sg->length;
76
77        if (walk->entrylen > walk->total)
78                walk->entrylen = walk->total;
79        walk->total -= walk->entrylen;
80
81        return hash_walk_next(walk);
82}
83
84int crypto_hash_walk_done(struct crypto_hash_walk *walk, int err)
85{
86        unsigned int alignmask = walk->alignmask;
87        unsigned int nbytes = walk->entrylen;
88
89        walk->data -= walk->offset;
90
91        if (nbytes && walk->offset & alignmask && !err) {
92                walk->offset = ALIGN(walk->offset, alignmask + 1);
93                walk->data += walk->offset;
94
95                nbytes = min(nbytes,
96                             ((unsigned int)(PAGE_SIZE)) - walk->offset);
97                walk->entrylen -= nbytes;
98
99                return nbytes;
100        }
101
102        if (walk->flags & CRYPTO_ALG_ASYNC)
103                kunmap(walk->pg);
104        else {
105                kunmap_atomic(walk->data);
106                /*
107                 * The may sleep test only makes sense for sync users.
108                 * Async users don't need to sleep here anyway.
109                 */
110                crypto_yield(walk->flags);
111        }
112
113        if (err)
114                return err;
115
116        if (nbytes) {
117                walk->offset = 0;
118                walk->pg++;
119                return hash_walk_next(walk);
120        }
121
122        if (!walk->total)
123                return 0;
124
125        walk->sg = scatterwalk_sg_next(walk->sg);
126
127        return hash_walk_new_entry(walk);
128}
129EXPORT_SYMBOL_GPL(crypto_hash_walk_done);
130
131int crypto_hash_walk_first(struct ahash_request *req,
132                           struct crypto_hash_walk *walk)
133{
134        walk->total = req->nbytes;
135
136        if (!walk->total) {
137                walk->entrylen = 0;
138                return 0;
139        }
140
141        walk->alignmask = crypto_ahash_alignmask(crypto_ahash_reqtfm(req));
142        walk->sg = req->src;
143        walk->flags = req->base.flags & CRYPTO_TFM_REQ_MASK;
144
145        return hash_walk_new_entry(walk);
146}
147EXPORT_SYMBOL_GPL(crypto_hash_walk_first);
148
149int crypto_ahash_walk_first(struct ahash_request *req,
150                            struct crypto_hash_walk *walk)
151{
152        walk->total = req->nbytes;
153
154        if (!walk->total) {
155                walk->entrylen = 0;
156                return 0;
157        }
158
159        walk->alignmask = crypto_ahash_alignmask(crypto_ahash_reqtfm(req));
160        walk->sg = req->src;
161        walk->flags = req->base.flags & CRYPTO_TFM_REQ_MASK;
162        walk->flags |= CRYPTO_ALG_ASYNC;
163
164        BUILD_BUG_ON(CRYPTO_TFM_REQ_MASK & CRYPTO_ALG_ASYNC);
165
166        return hash_walk_new_entry(walk);
167}
168EXPORT_SYMBOL_GPL(crypto_ahash_walk_first);
169
170int crypto_hash_walk_first_compat(struct hash_desc *hdesc,
171                                  struct crypto_hash_walk *walk,
172                                  struct scatterlist *sg, unsigned int len)
173{
174        walk->total = len;
175
176        if (!walk->total) {
177                walk->entrylen = 0;
178                return 0;
179        }
180
181        walk->alignmask = crypto_hash_alignmask(hdesc->tfm);
182        walk->sg = sg;
183        walk->flags = hdesc->flags & CRYPTO_TFM_REQ_MASK;
184
185        return hash_walk_new_entry(walk);
186}
187
188static int ahash_setkey_unaligned(struct crypto_ahash *tfm, const u8 *key,
189                                unsigned int keylen)
190{
191        unsigned long alignmask = crypto_ahash_alignmask(tfm);
192        int ret;
193        u8 *buffer, *alignbuffer;
194        unsigned long absize;
195
196        absize = keylen + alignmask;
197        buffer = kmalloc(absize, GFP_KERNEL);
198        if (!buffer)
199                return -ENOMEM;
200
201        alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
202        memcpy(alignbuffer, key, keylen);
203        ret = tfm->setkey(tfm, alignbuffer, keylen);
204        kzfree(buffer);
205        return ret;
206}
207
208int crypto_ahash_setkey(struct crypto_ahash *tfm, const u8 *key,
209                        unsigned int keylen)
210{
211        unsigned long alignmask = crypto_ahash_alignmask(tfm);
212
213        if ((unsigned long)key & alignmask)
214                return ahash_setkey_unaligned(tfm, key, keylen);
215
216        return tfm->setkey(tfm, key, keylen);
217}
218EXPORT_SYMBOL_GPL(crypto_ahash_setkey);
219
220static int ahash_nosetkey(struct crypto_ahash *tfm, const u8 *key,
221                          unsigned int keylen)
222{
223        return -ENOSYS;
224}
225
226static inline unsigned int ahash_align_buffer_size(unsigned len,
227                                                   unsigned long mask)
228{
229        return len + (mask & ~(crypto_tfm_ctx_alignment() - 1));
230}
231
232static int ahash_save_req(struct ahash_request *req, crypto_completion_t cplt)
233{
234        struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
235        unsigned long alignmask = crypto_ahash_alignmask(tfm);
236        unsigned int ds = crypto_ahash_digestsize(tfm);
237        struct ahash_request_priv *priv;
238
239        priv = kmalloc(sizeof(*priv) + ahash_align_buffer_size(ds, alignmask),
240                       (req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP) ?
241                       GFP_KERNEL : GFP_ATOMIC);
242        if (!priv)
243                return -ENOMEM;
244
245        /*
246         * WARNING: Voodoo programming below!
247         *
248         * The code below is obscure and hard to understand, thus explanation
249         * is necessary. See include/crypto/hash.h and include/linux/crypto.h
250         * to understand the layout of structures used here!
251         *
252         * The code here will replace portions of the ORIGINAL request with
253         * pointers to new code and buffers so the hashing operation can store
254         * the result in aligned buffer. We will call the modified request
255         * an ADJUSTED request.
256         *
257         * The newly mangled request will look as such:
258         *
259         * req {
260         *   .result        = ADJUSTED[new aligned buffer]
261         *   .base.complete = ADJUSTED[pointer to completion function]
262         *   .base.data     = ADJUSTED[*req (pointer to self)]
263         *   .priv          = ADJUSTED[new priv] {
264         *           .result   = ORIGINAL(result)
265         *           .complete = ORIGINAL(base.complete)
266         *           .data     = ORIGINAL(base.data)
267         *   }
268         */
269
270        priv->result = req->result;
271        priv->complete = req->base.complete;
272        priv->data = req->base.data;
273        priv->flags = req->base.flags;
274
275        /*
276         * WARNING: We do not backup req->priv here! The req->priv
277         *          is for internal use of the Crypto API and the
278         *          user must _NOT_ _EVER_ depend on it's content!
279         */
280
281        req->result = PTR_ALIGN((u8 *)priv->ubuf, alignmask + 1);
282        req->base.complete = cplt;
283        req->base.data = req;
284        req->priv = priv;
285
286        return 0;
287}
288
289static void ahash_restore_req(struct ahash_request *req, int err)
290{
291        struct ahash_request_priv *priv = req->priv;
292
293        if (!err)
294                memcpy(priv->result, req->result,
295                       crypto_ahash_digestsize(crypto_ahash_reqtfm(req)));
296
297        /* Restore the original crypto request. */
298        req->result = priv->result;
299
300        ahash_request_set_callback(req, priv->flags,
301                                   priv->complete, priv->data);
302        req->priv = NULL;
303
304        /* Free the req->priv.priv from the ADJUSTED request. */
305        kzfree(priv);
306}
307
308static void ahash_notify_einprogress(struct ahash_request *req)
309{
310        struct ahash_request_priv *priv = req->priv;
311        struct crypto_async_request oreq;
312
313        oreq.data = priv->data;
314
315        priv->complete(&oreq, -EINPROGRESS);
316}
317
318static void ahash_op_unaligned_done(struct crypto_async_request *req, int err)
319{
320        struct ahash_request *areq = req->data;
321
322        if (err == -EINPROGRESS) {
323                ahash_notify_einprogress(areq);
324                return;
325        }
326
327        /*
328         * Restore the original request, see ahash_op_unaligned() for what
329         * goes where.
330         *
331         * The "struct ahash_request *req" here is in fact the "req.base"
332         * from the ADJUSTED request from ahash_op_unaligned(), thus as it
333         * is a pointer to self, it is also the ADJUSTED "req" .
334         */
335
336        /* First copy req->result into req->priv.result */
337        ahash_restore_req(areq, err);
338
339        /* Complete the ORIGINAL request. */
340        areq->base.complete(&areq->base, err);
341}
342
343static int ahash_op_unaligned(struct ahash_request *req,
344                              int (*op)(struct ahash_request *))
345{
346        int err;
347
348        err = ahash_save_req(req, ahash_op_unaligned_done);
349        if (err)
350                return err;
351
352        err = op(req);
353        if (err == -EINPROGRESS ||
354            (err == -EBUSY && (ahash_request_flags(req) &
355                               CRYPTO_TFM_REQ_MAY_BACKLOG)))
356                return err;
357
358        ahash_restore_req(req, err);
359
360        return err;
361}
362
363static int crypto_ahash_op(struct ahash_request *req,
364                           int (*op)(struct ahash_request *))
365{
366        struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
367        unsigned long alignmask = crypto_ahash_alignmask(tfm);
368
369        if ((unsigned long)req->result & alignmask)
370                return ahash_op_unaligned(req, op);
371
372        return op(req);
373}
374
375int crypto_ahash_final(struct ahash_request *req)
376{
377        return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->final);
378}
379EXPORT_SYMBOL_GPL(crypto_ahash_final);
380
381int crypto_ahash_finup(struct ahash_request *req)
382{
383        return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->finup);
384}
385EXPORT_SYMBOL_GPL(crypto_ahash_finup);
386
387int crypto_ahash_digest(struct ahash_request *req)
388{
389        return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->digest);
390}
391EXPORT_SYMBOL_GPL(crypto_ahash_digest);
392
393static void ahash_def_finup_done2(struct crypto_async_request *req, int err)
394{
395        struct ahash_request *areq = req->data;
396
397        if (err == -EINPROGRESS)
398                return;
399
400        ahash_restore_req(areq, err);
401
402        areq->base.complete(&areq->base, err);
403}
404
405static int ahash_def_finup_finish1(struct ahash_request *req, int err)
406{
407        if (err)
408                goto out;
409
410        req->base.complete = ahash_def_finup_done2;
411
412        err = crypto_ahash_reqtfm(req)->final(req);
413        if (err == -EINPROGRESS ||
414            (err == -EBUSY && (ahash_request_flags(req) &
415                               CRYPTO_TFM_REQ_MAY_BACKLOG)))
416                return err;
417
418out:
419        ahash_restore_req(req, err);
420        return err;
421}
422
423static void ahash_def_finup_done1(struct crypto_async_request *req, int err)
424{
425        struct ahash_request *areq = req->data;
426
427        if (err == -EINPROGRESS) {
428                ahash_notify_einprogress(areq);
429                return;
430        }
431
432        areq->base.flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
433
434        err = ahash_def_finup_finish1(areq, err);
435        if (areq->priv)
436                return;
437
438        areq->base.complete(&areq->base, err);
439}
440
441static int ahash_def_finup(struct ahash_request *req)
442{
443        struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
444        int err;
445
446        err = ahash_save_req(req, ahash_def_finup_done1);
447        if (err)
448                return err;
449
450        err = tfm->update(req);
451        if (err == -EINPROGRESS ||
452            (err == -EBUSY && (ahash_request_flags(req) &
453                               CRYPTO_TFM_REQ_MAY_BACKLOG)))
454                return err;
455
456        return ahash_def_finup_finish1(req, err);
457}
458
459static int ahash_no_export(struct ahash_request *req, void *out)
460{
461        return -ENOSYS;
462}
463
464static int ahash_no_import(struct ahash_request *req, const void *in)
465{
466        return -ENOSYS;
467}
468
469static int crypto_ahash_init_tfm(struct crypto_tfm *tfm)
470{
471        struct crypto_ahash *hash = __crypto_ahash_cast(tfm);
472        struct ahash_alg *alg = crypto_ahash_alg(hash);
473
474        hash->setkey = ahash_nosetkey;
475        hash->has_setkey = false;
476        hash->export = ahash_no_export;
477        hash->import = ahash_no_import;
478
479        if (tfm->__crt_alg->cra_type != &crypto_ahash_type)
480                return crypto_init_shash_ops_async(tfm);
481
482        hash->init = alg->init;
483        hash->update = alg->update;
484        hash->final = alg->final;
485        hash->finup = alg->finup ?: ahash_def_finup;
486        hash->digest = alg->digest;
487
488        if (alg->setkey) {
489                hash->setkey = alg->setkey;
490                hash->has_setkey = true;
491        }
492        if (alg->export)
493                hash->export = alg->export;
494        if (alg->import)
495                hash->import = alg->import;
496
497        return 0;
498}
499
500static unsigned int crypto_ahash_extsize(struct crypto_alg *alg)
501{
502        if (alg->cra_type == &crypto_ahash_type)
503                return alg->cra_ctxsize;
504
505        return sizeof(struct crypto_shash *);
506}
507
508#ifdef CONFIG_NET
509static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
510{
511        struct crypto_report_hash rhash;
512
513        strncpy(rhash.type, "ahash", sizeof(rhash.type));
514
515        rhash.blocksize = alg->cra_blocksize;
516        rhash.digestsize = __crypto_hash_alg_common(alg)->digestsize;
517
518        if (nla_put(skb, CRYPTOCFGA_REPORT_HASH,
519                    sizeof(struct crypto_report_hash), &rhash))
520                goto nla_put_failure;
521        return 0;
522
523nla_put_failure:
524        return -EMSGSIZE;
525}
526#else
527static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
528{
529        return -ENOSYS;
530}
531#endif
532
533static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
534        __attribute__ ((unused));
535static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
536{
537        seq_printf(m, "type         : ahash\n");
538        seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
539                                             "yes" : "no");
540        seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
541        seq_printf(m, "digestsize   : %u\n",
542                   __crypto_hash_alg_common(alg)->digestsize);
543}
544
545const struct crypto_type crypto_ahash_type = {
546        .extsize = crypto_ahash_extsize,
547        .init_tfm = crypto_ahash_init_tfm,
548#ifdef CONFIG_PROC_FS
549        .show = crypto_ahash_show,
550#endif
551        .report = crypto_ahash_report,
552        .maskclear = ~CRYPTO_ALG_TYPE_MASK,
553        .maskset = CRYPTO_ALG_TYPE_AHASH_MASK,
554        .type = CRYPTO_ALG_TYPE_AHASH,
555        .tfmsize = offsetof(struct crypto_ahash, base),
556};
557EXPORT_SYMBOL_GPL(crypto_ahash_type);
558
559struct crypto_ahash *crypto_alloc_ahash(const char *alg_name, u32 type,
560                                        u32 mask)
561{
562        return crypto_alloc_tfm(alg_name, &crypto_ahash_type, type, mask);
563}
564EXPORT_SYMBOL_GPL(crypto_alloc_ahash);
565
566static int ahash_prepare_alg(struct ahash_alg *alg)
567{
568        struct crypto_alg *base = &alg->halg.base;
569
570        if (alg->halg.digestsize > PAGE_SIZE / 8 ||
571            alg->halg.statesize > PAGE_SIZE / 8 ||
572            alg->halg.statesize == 0)
573                return -EINVAL;
574
575        base->cra_type = &crypto_ahash_type;
576        base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
577        base->cra_flags |= CRYPTO_ALG_TYPE_AHASH;
578
579        return 0;
580}
581
582int crypto_register_ahash(struct ahash_alg *alg)
583{
584        struct crypto_alg *base = &alg->halg.base;
585        int err;
586
587        err = ahash_prepare_alg(alg);
588        if (err)
589                return err;
590
591        return crypto_register_alg(base);
592}
593EXPORT_SYMBOL_GPL(crypto_register_ahash);
594
595int crypto_unregister_ahash(struct ahash_alg *alg)
596{
597        return crypto_unregister_alg(&alg->halg.base);
598}
599EXPORT_SYMBOL_GPL(crypto_unregister_ahash);
600
601int ahash_register_instance(struct crypto_template *tmpl,
602                            struct ahash_instance *inst)
603{
604        int err;
605
606        err = ahash_prepare_alg(&inst->alg);
607        if (err)
608                return err;
609
610        return crypto_register_instance(tmpl, ahash_crypto_instance(inst));
611}
612EXPORT_SYMBOL_GPL(ahash_register_instance);
613
614void ahash_free_instance(struct crypto_instance *inst)
615{
616        crypto_drop_spawn(crypto_instance_ctx(inst));
617        kfree(ahash_instance(inst));
618}
619EXPORT_SYMBOL_GPL(ahash_free_instance);
620
621int crypto_init_ahash_spawn(struct crypto_ahash_spawn *spawn,
622                            struct hash_alg_common *alg,
623                            struct crypto_instance *inst)
624{
625        return crypto_init_spawn2(&spawn->base, &alg->base, inst,
626                                  &crypto_ahash_type);
627}
628EXPORT_SYMBOL_GPL(crypto_init_ahash_spawn);
629
630struct hash_alg_common *ahash_attr_alg(struct rtattr *rta, u32 type, u32 mask)
631{
632        struct crypto_alg *alg;
633
634        alg = crypto_attr_alg2(rta, &crypto_ahash_type, type, mask);
635        return IS_ERR(alg) ? ERR_CAST(alg) : __crypto_hash_alg_common(alg);
636}
637EXPORT_SYMBOL_GPL(ahash_attr_alg);
638
639MODULE_LICENSE("GPL");
640MODULE_DESCRIPTION("Asynchronous cryptographic hash type");
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