Root/crypto/ahash.c

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    void *ubuf[] CRYPTO_MINALIGN_ATTR;
35};
36
37static inline struct ahash_alg *crypto_ahash_alg(struct crypto_ahash *hash)
38{
39    return container_of(crypto_hash_alg_common(hash), struct ahash_alg,
40                halg);
41}
42
43static int hash_walk_next(struct crypto_hash_walk *walk)
44{
45    unsigned int alignmask = walk->alignmask;
46    unsigned int offset = walk->offset;
47    unsigned int nbytes = min(walk->entrylen,
48                  ((unsigned int)(PAGE_SIZE)) - offset);
49
50    if (walk->flags & CRYPTO_ALG_ASYNC)
51        walk->data = kmap(walk->pg);
52    else
53        walk->data = kmap_atomic(walk->pg);
54    walk->data += offset;
55
56    if (offset & alignmask) {
57        unsigned int unaligned = alignmask + 1 - (offset & alignmask);
58        if (nbytes > unaligned)
59            nbytes = unaligned;
60    }
61
62    walk->entrylen -= nbytes;
63    return nbytes;
64}
65
66static int hash_walk_new_entry(struct crypto_hash_walk *walk)
67{
68    struct scatterlist *sg;
69
70    sg = walk->sg;
71    walk->pg = sg_page(sg);
72    walk->offset = sg->offset;
73    walk->entrylen = sg->length;
74
75    if (walk->entrylen > walk->total)
76        walk->entrylen = walk->total;
77    walk->total -= walk->entrylen;
78
79    return hash_walk_next(walk);
80}
81
82int crypto_hash_walk_done(struct crypto_hash_walk *walk, int err)
83{
84    unsigned int alignmask = walk->alignmask;
85    unsigned int nbytes = walk->entrylen;
86
87    walk->data -= walk->offset;
88
89    if (nbytes && walk->offset & alignmask && !err) {
90        walk->offset = ALIGN(walk->offset, alignmask + 1);
91        walk->data += walk->offset;
92
93        nbytes = min(nbytes,
94                 ((unsigned int)(PAGE_SIZE)) - walk->offset);
95        walk->entrylen -= nbytes;
96
97        return nbytes;
98    }
99
100    if (walk->flags & CRYPTO_ALG_ASYNC)
101        kunmap(walk->pg);
102    else {
103        kunmap_atomic(walk->data);
104        /*
105         * The may sleep test only makes sense for sync users.
106         * Async users don't need to sleep here anyway.
107         */
108        crypto_yield(walk->flags);
109    }
110
111    if (err)
112        return err;
113
114    if (nbytes) {
115        walk->offset = 0;
116        walk->pg++;
117        return hash_walk_next(walk);
118    }
119
120    if (!walk->total)
121        return 0;
122
123    walk->sg = scatterwalk_sg_next(walk->sg);
124
125    return hash_walk_new_entry(walk);
126}
127EXPORT_SYMBOL_GPL(crypto_hash_walk_done);
128
129int crypto_hash_walk_first(struct ahash_request *req,
130               struct crypto_hash_walk *walk)
131{
132    walk->total = req->nbytes;
133
134    if (!walk->total) {
135        walk->entrylen = 0;
136        return 0;
137    }
138
139    walk->alignmask = crypto_ahash_alignmask(crypto_ahash_reqtfm(req));
140    walk->sg = req->src;
141    walk->flags = req->base.flags & CRYPTO_TFM_REQ_MASK;
142
143    return hash_walk_new_entry(walk);
144}
145EXPORT_SYMBOL_GPL(crypto_hash_walk_first);
146
147int crypto_ahash_walk_first(struct ahash_request *req,
148                struct crypto_hash_walk *walk)
149{
150    walk->total = req->nbytes;
151
152    if (!walk->total) {
153        walk->entrylen = 0;
154        return 0;
155    }
156
157    walk->alignmask = crypto_ahash_alignmask(crypto_ahash_reqtfm(req));
158    walk->sg = req->src;
159    walk->flags = req->base.flags & CRYPTO_TFM_REQ_MASK;
160    walk->flags |= CRYPTO_ALG_ASYNC;
161
162    BUILD_BUG_ON(CRYPTO_TFM_REQ_MASK & CRYPTO_ALG_ASYNC);
163
164    return hash_walk_new_entry(walk);
165}
166EXPORT_SYMBOL_GPL(crypto_ahash_walk_first);
167
168int crypto_hash_walk_first_compat(struct hash_desc *hdesc,
169                  struct crypto_hash_walk *walk,
170                  struct scatterlist *sg, unsigned int len)
171{
172    walk->total = len;
173
174    if (!walk->total) {
175        walk->entrylen = 0;
176        return 0;
177    }
178
179    walk->alignmask = crypto_hash_alignmask(hdesc->tfm);
180    walk->sg = sg;
181    walk->flags = hdesc->flags & CRYPTO_TFM_REQ_MASK;
182
183    return hash_walk_new_entry(walk);
184}
185
186static int ahash_setkey_unaligned(struct crypto_ahash *tfm, const u8 *key,
187                unsigned int keylen)
188{
189    unsigned long alignmask = crypto_ahash_alignmask(tfm);
190    int ret;
191    u8 *buffer, *alignbuffer;
192    unsigned long absize;
193
194    absize = keylen + alignmask;
195    buffer = kmalloc(absize, GFP_KERNEL);
196    if (!buffer)
197        return -ENOMEM;
198
199    alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
200    memcpy(alignbuffer, key, keylen);
201    ret = tfm->setkey(tfm, alignbuffer, keylen);
202    kzfree(buffer);
203    return ret;
204}
205
206int crypto_ahash_setkey(struct crypto_ahash *tfm, const u8 *key,
207            unsigned int keylen)
208{
209    unsigned long alignmask = crypto_ahash_alignmask(tfm);
210
211    if ((unsigned long)key & alignmask)
212        return ahash_setkey_unaligned(tfm, key, keylen);
213
214    return tfm->setkey(tfm, key, keylen);
215}
216EXPORT_SYMBOL_GPL(crypto_ahash_setkey);
217
218static int ahash_nosetkey(struct crypto_ahash *tfm, const u8 *key,
219              unsigned int keylen)
220{
221    return -ENOSYS;
222}
223
224static inline unsigned int ahash_align_buffer_size(unsigned len,
225                           unsigned long mask)
226{
227    return len + (mask & ~(crypto_tfm_ctx_alignment() - 1));
228}
229
230static int ahash_save_req(struct ahash_request *req, crypto_completion_t cplt)
231{
232    struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
233    unsigned long alignmask = crypto_ahash_alignmask(tfm);
234    unsigned int ds = crypto_ahash_digestsize(tfm);
235    struct ahash_request_priv *priv;
236
237    priv = kmalloc(sizeof(*priv) + ahash_align_buffer_size(ds, alignmask),
238               (req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP) ?
239               GFP_KERNEL : GFP_ATOMIC);
240    if (!priv)
241        return -ENOMEM;
242
243    /*
244     * WARNING: Voodoo programming below!
245     *
246     * The code below is obscure and hard to understand, thus explanation
247     * is necessary. See include/crypto/hash.h and include/linux/crypto.h
248     * to understand the layout of structures used here!
249     *
250     * The code here will replace portions of the ORIGINAL request with
251     * pointers to new code and buffers so the hashing operation can store
252     * the result in aligned buffer. We will call the modified request
253     * an ADJUSTED request.
254     *
255     * The newly mangled request will look as such:
256     *
257     * req {
258     * .result = ADJUSTED[new aligned buffer]
259     * .base.complete = ADJUSTED[pointer to completion function]
260     * .base.data = ADJUSTED[*req (pointer to self)]
261     * .priv = ADJUSTED[new priv] {
262     * .result = ORIGINAL(result)
263     * .complete = ORIGINAL(base.complete)
264     * .data = ORIGINAL(base.data)
265     * }
266     */
267
268    priv->result = req->result;
269    priv->complete = req->base.complete;
270    priv->data = req->base.data;
271    /*
272     * WARNING: We do not backup req->priv here! The req->priv
273     * is for internal use of the Crypto API and the
274     * user must _NOT_ _EVER_ depend on it's content!
275     */
276
277    req->result = PTR_ALIGN((u8 *)priv->ubuf, alignmask + 1);
278    req->base.complete = cplt;
279    req->base.data = req;
280    req->priv = priv;
281
282    return 0;
283}
284
285static void ahash_restore_req(struct ahash_request *req)
286{
287    struct ahash_request_priv *priv = req->priv;
288
289    /* Restore the original crypto request. */
290    req->result = priv->result;
291    req->base.complete = priv->complete;
292    req->base.data = priv->data;
293    req->priv = NULL;
294
295    /* Free the req->priv.priv from the ADJUSTED request. */
296    kzfree(priv);
297}
298
299static void ahash_op_unaligned_finish(struct ahash_request *req, int err)
300{
301    struct ahash_request_priv *priv = req->priv;
302
303    if (err == -EINPROGRESS)
304        return;
305
306    if (!err)
307        memcpy(priv->result, req->result,
308               crypto_ahash_digestsize(crypto_ahash_reqtfm(req)));
309
310    ahash_restore_req(req);
311}
312
313static void ahash_op_unaligned_done(struct crypto_async_request *req, int err)
314{
315    struct ahash_request *areq = req->data;
316
317    /*
318     * Restore the original request, see ahash_op_unaligned() for what
319     * goes where.
320     *
321     * The "struct ahash_request *req" here is in fact the "req.base"
322     * from the ADJUSTED request from ahash_op_unaligned(), thus as it
323     * is a pointer to self, it is also the ADJUSTED "req" .
324     */
325
326    /* First copy req->result into req->priv.result */
327    ahash_op_unaligned_finish(areq, err);
328
329    /* Complete the ORIGINAL request. */
330    areq->base.complete(&areq->base, err);
331}
332
333static int ahash_op_unaligned(struct ahash_request *req,
334                  int (*op)(struct ahash_request *))
335{
336    int err;
337
338    err = ahash_save_req(req, ahash_op_unaligned_done);
339    if (err)
340        return err;
341
342    err = op(req);
343    ahash_op_unaligned_finish(req, err);
344
345    return err;
346}
347
348static int crypto_ahash_op(struct ahash_request *req,
349               int (*op)(struct ahash_request *))
350{
351    struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
352    unsigned long alignmask = crypto_ahash_alignmask(tfm);
353
354    if ((unsigned long)req->result & alignmask)
355        return ahash_op_unaligned(req, op);
356
357    return op(req);
358}
359
360int crypto_ahash_final(struct ahash_request *req)
361{
362    return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->final);
363}
364EXPORT_SYMBOL_GPL(crypto_ahash_final);
365
366int crypto_ahash_finup(struct ahash_request *req)
367{
368    return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->finup);
369}
370EXPORT_SYMBOL_GPL(crypto_ahash_finup);
371
372int crypto_ahash_digest(struct ahash_request *req)
373{
374    return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->digest);
375}
376EXPORT_SYMBOL_GPL(crypto_ahash_digest);
377
378static void ahash_def_finup_finish2(struct ahash_request *req, int err)
379{
380    struct ahash_request_priv *priv = req->priv;
381
382    if (err == -EINPROGRESS)
383        return;
384
385    if (!err)
386        memcpy(priv->result, req->result,
387               crypto_ahash_digestsize(crypto_ahash_reqtfm(req)));
388
389    ahash_restore_req(req);
390}
391
392static void ahash_def_finup_done2(struct crypto_async_request *req, int err)
393{
394    struct ahash_request *areq = req->data;
395
396    ahash_def_finup_finish2(areq, err);
397
398    areq->base.complete(&areq->base, err);
399}
400
401static int ahash_def_finup_finish1(struct ahash_request *req, int err)
402{
403    if (err)
404        goto out;
405
406    req->base.complete = ahash_def_finup_done2;
407    req->base.flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
408    err = crypto_ahash_reqtfm(req)->final(req);
409
410out:
411    ahash_def_finup_finish2(req, err);
412    return err;
413}
414
415static void ahash_def_finup_done1(struct crypto_async_request *req, int err)
416{
417    struct ahash_request *areq = req->data;
418
419    err = ahash_def_finup_finish1(areq, err);
420
421    areq->base.complete(&areq->base, err);
422}
423
424static int ahash_def_finup(struct ahash_request *req)
425{
426    struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
427    int err;
428
429    err = ahash_save_req(req, ahash_def_finup_done1);
430    if (err)
431        return err;
432
433    err = tfm->update(req);
434    return ahash_def_finup_finish1(req, err);
435}
436
437static int ahash_no_export(struct ahash_request *req, void *out)
438{
439    return -ENOSYS;
440}
441
442static int ahash_no_import(struct ahash_request *req, const void *in)
443{
444    return -ENOSYS;
445}
446
447static int crypto_ahash_init_tfm(struct crypto_tfm *tfm)
448{
449    struct crypto_ahash *hash = __crypto_ahash_cast(tfm);
450    struct ahash_alg *alg = crypto_ahash_alg(hash);
451
452    hash->setkey = ahash_nosetkey;
453    hash->export = ahash_no_export;
454    hash->import = ahash_no_import;
455
456    if (tfm->__crt_alg->cra_type != &crypto_ahash_type)
457        return crypto_init_shash_ops_async(tfm);
458
459    hash->init = alg->init;
460    hash->update = alg->update;
461    hash->final = alg->final;
462    hash->finup = alg->finup ?: ahash_def_finup;
463    hash->digest = alg->digest;
464
465    if (alg->setkey)
466        hash->setkey = alg->setkey;
467    if (alg->export)
468        hash->export = alg->export;
469    if (alg->import)
470        hash->import = alg->import;
471
472    return 0;
473}
474
475static unsigned int crypto_ahash_extsize(struct crypto_alg *alg)
476{
477    if (alg->cra_type == &crypto_ahash_type)
478        return alg->cra_ctxsize;
479
480    return sizeof(struct crypto_shash *);
481}
482
483#ifdef CONFIG_NET
484static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
485{
486    struct crypto_report_hash rhash;
487
488    strncpy(rhash.type, "ahash", sizeof(rhash.type));
489
490    rhash.blocksize = alg->cra_blocksize;
491    rhash.digestsize = __crypto_hash_alg_common(alg)->digestsize;
492
493    if (nla_put(skb, CRYPTOCFGA_REPORT_HASH,
494            sizeof(struct crypto_report_hash), &rhash))
495        goto nla_put_failure;
496    return 0;
497
498nla_put_failure:
499    return -EMSGSIZE;
500}
501#else
502static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
503{
504    return -ENOSYS;
505}
506#endif
507
508static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
509    __attribute__ ((unused));
510static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
511{
512    seq_printf(m, "type : ahash\n");
513    seq_printf(m, "async : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
514                         "yes" : "no");
515    seq_printf(m, "blocksize : %u\n", alg->cra_blocksize);
516    seq_printf(m, "digestsize : %u\n",
517           __crypto_hash_alg_common(alg)->digestsize);
518}
519
520const struct crypto_type crypto_ahash_type = {
521    .extsize = crypto_ahash_extsize,
522    .init_tfm = crypto_ahash_init_tfm,
523#ifdef CONFIG_PROC_FS
524    .show = crypto_ahash_show,
525#endif
526    .report = crypto_ahash_report,
527    .maskclear = ~CRYPTO_ALG_TYPE_MASK,
528    .maskset = CRYPTO_ALG_TYPE_AHASH_MASK,
529    .type = CRYPTO_ALG_TYPE_AHASH,
530    .tfmsize = offsetof(struct crypto_ahash, base),
531};
532EXPORT_SYMBOL_GPL(crypto_ahash_type);
533
534struct crypto_ahash *crypto_alloc_ahash(const char *alg_name, u32 type,
535                    u32 mask)
536{
537    return crypto_alloc_tfm(alg_name, &crypto_ahash_type, type, mask);
538}
539EXPORT_SYMBOL_GPL(crypto_alloc_ahash);
540
541static int ahash_prepare_alg(struct ahash_alg *alg)
542{
543    struct crypto_alg *base = &alg->halg.base;
544
545    if (alg->halg.digestsize > PAGE_SIZE / 8 ||
546        alg->halg.statesize > PAGE_SIZE / 8)
547        return -EINVAL;
548
549    base->cra_type = &crypto_ahash_type;
550    base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
551    base->cra_flags |= CRYPTO_ALG_TYPE_AHASH;
552
553    return 0;
554}
555
556int crypto_register_ahash(struct ahash_alg *alg)
557{
558    struct crypto_alg *base = &alg->halg.base;
559    int err;
560
561    err = ahash_prepare_alg(alg);
562    if (err)
563        return err;
564
565    return crypto_register_alg(base);
566}
567EXPORT_SYMBOL_GPL(crypto_register_ahash);
568
569int crypto_unregister_ahash(struct ahash_alg *alg)
570{
571    return crypto_unregister_alg(&alg->halg.base);
572}
573EXPORT_SYMBOL_GPL(crypto_unregister_ahash);
574
575int ahash_register_instance(struct crypto_template *tmpl,
576                struct ahash_instance *inst)
577{
578    int err;
579
580    err = ahash_prepare_alg(&inst->alg);
581    if (err)
582        return err;
583
584    return crypto_register_instance(tmpl, ahash_crypto_instance(inst));
585}
586EXPORT_SYMBOL_GPL(ahash_register_instance);
587
588void ahash_free_instance(struct crypto_instance *inst)
589{
590    crypto_drop_spawn(crypto_instance_ctx(inst));
591    kfree(ahash_instance(inst));
592}
593EXPORT_SYMBOL_GPL(ahash_free_instance);
594
595int crypto_init_ahash_spawn(struct crypto_ahash_spawn *spawn,
596                struct hash_alg_common *alg,
597                struct crypto_instance *inst)
598{
599    return crypto_init_spawn2(&spawn->base, &alg->base, inst,
600                  &crypto_ahash_type);
601}
602EXPORT_SYMBOL_GPL(crypto_init_ahash_spawn);
603
604struct hash_alg_common *ahash_attr_alg(struct rtattr *rta, u32 type, u32 mask)
605{
606    struct crypto_alg *alg;
607
608    alg = crypto_attr_alg2(rta, &crypto_ahash_type, type, mask);
609    return IS_ERR(alg) ? ERR_CAST(alg) : __crypto_hash_alg_common(alg);
610}
611EXPORT_SYMBOL_GPL(ahash_attr_alg);
612
613MODULE_LICENSE("GPL");
614MODULE_DESCRIPTION("Asynchronous cryptographic hash type");
615

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