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/err.h>
19#include <linux/kernel.h>
20#include <linux/module.h>
21#include <linux/sched.h>
22#include <linux/slab.h>
23#include <linux/seq_file.h>
24#include <linux/cryptouser.h>
25#include <net/netlink.h>
26
27#include "internal.h"
28
29struct ahash_request_priv {
30    crypto_completion_t complete;
31    void *data;
32    u8 *result;
33    void *ubuf[] CRYPTO_MINALIGN_ATTR;
34};
35
36static inline struct ahash_alg *crypto_ahash_alg(struct crypto_ahash *hash)
37{
38    return container_of(crypto_hash_alg_common(hash), struct ahash_alg,
39                halg);
40}
41
42static int hash_walk_next(struct crypto_hash_walk *walk)
43{
44    unsigned int alignmask = walk->alignmask;
45    unsigned int offset = walk->offset;
46    unsigned int nbytes = min(walk->entrylen,
47                  ((unsigned int)(PAGE_SIZE)) - offset);
48
49    walk->data = kmap_atomic(walk->pg);
50    walk->data += offset;
51
52    if (offset & alignmask) {
53        unsigned int unaligned = alignmask + 1 - (offset & alignmask);
54        if (nbytes > unaligned)
55            nbytes = unaligned;
56    }
57
58    walk->entrylen -= nbytes;
59    return nbytes;
60}
61
62static int hash_walk_new_entry(struct crypto_hash_walk *walk)
63{
64    struct scatterlist *sg;
65
66    sg = walk->sg;
67    walk->pg = sg_page(sg);
68    walk->offset = sg->offset;
69    walk->entrylen = sg->length;
70
71    if (walk->entrylen > walk->total)
72        walk->entrylen = walk->total;
73    walk->total -= walk->entrylen;
74
75    return hash_walk_next(walk);
76}
77
78int crypto_hash_walk_done(struct crypto_hash_walk *walk, int err)
79{
80    unsigned int alignmask = walk->alignmask;
81    unsigned int nbytes = walk->entrylen;
82
83    walk->data -= walk->offset;
84
85    if (nbytes && walk->offset & alignmask && !err) {
86        walk->offset = ALIGN(walk->offset, alignmask + 1);
87        walk->data += walk->offset;
88
89        nbytes = min(nbytes,
90                 ((unsigned int)(PAGE_SIZE)) - walk->offset);
91        walk->entrylen -= nbytes;
92
93        return nbytes;
94    }
95
96    kunmap_atomic(walk->data);
97    crypto_yield(walk->flags);
98
99    if (err)
100        return err;
101
102    if (nbytes) {
103        walk->offset = 0;
104        walk->pg++;
105        return hash_walk_next(walk);
106    }
107
108    if (!walk->total)
109        return 0;
110
111    walk->sg = scatterwalk_sg_next(walk->sg);
112
113    return hash_walk_new_entry(walk);
114}
115EXPORT_SYMBOL_GPL(crypto_hash_walk_done);
116
117int crypto_hash_walk_first(struct ahash_request *req,
118               struct crypto_hash_walk *walk)
119{
120    walk->total = req->nbytes;
121
122    if (!walk->total)
123        return 0;
124
125    walk->alignmask = crypto_ahash_alignmask(crypto_ahash_reqtfm(req));
126    walk->sg = req->src;
127    walk->flags = req->base.flags;
128
129    return hash_walk_new_entry(walk);
130}
131EXPORT_SYMBOL_GPL(crypto_hash_walk_first);
132
133int crypto_hash_walk_first_compat(struct hash_desc *hdesc,
134                  struct crypto_hash_walk *walk,
135                  struct scatterlist *sg, unsigned int len)
136{
137    walk->total = len;
138
139    if (!walk->total)
140        return 0;
141
142    walk->alignmask = crypto_hash_alignmask(hdesc->tfm);
143    walk->sg = sg;
144    walk->flags = hdesc->flags;
145
146    return hash_walk_new_entry(walk);
147}
148
149static int ahash_setkey_unaligned(struct crypto_ahash *tfm, const u8 *key,
150                unsigned int keylen)
151{
152    unsigned long alignmask = crypto_ahash_alignmask(tfm);
153    int ret;
154    u8 *buffer, *alignbuffer;
155    unsigned long absize;
156
157    absize = keylen + alignmask;
158    buffer = kmalloc(absize, GFP_KERNEL);
159    if (!buffer)
160        return -ENOMEM;
161
162    alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
163    memcpy(alignbuffer, key, keylen);
164    ret = tfm->setkey(tfm, alignbuffer, keylen);
165    kzfree(buffer);
166    return ret;
167}
168
169int crypto_ahash_setkey(struct crypto_ahash *tfm, const u8 *key,
170            unsigned int keylen)
171{
172    unsigned long alignmask = crypto_ahash_alignmask(tfm);
173
174    if ((unsigned long)key & alignmask)
175        return ahash_setkey_unaligned(tfm, key, keylen);
176
177    return tfm->setkey(tfm, key, keylen);
178}
179EXPORT_SYMBOL_GPL(crypto_ahash_setkey);
180
181static int ahash_nosetkey(struct crypto_ahash *tfm, const u8 *key,
182              unsigned int keylen)
183{
184    return -ENOSYS;
185}
186
187static inline unsigned int ahash_align_buffer_size(unsigned len,
188                           unsigned long mask)
189{
190    return len + (mask & ~(crypto_tfm_ctx_alignment() - 1));
191}
192
193static int ahash_save_req(struct ahash_request *req, crypto_completion_t cplt)
194{
195    struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
196    unsigned long alignmask = crypto_ahash_alignmask(tfm);
197    unsigned int ds = crypto_ahash_digestsize(tfm);
198    struct ahash_request_priv *priv;
199
200    priv = kmalloc(sizeof(*priv) + ahash_align_buffer_size(ds, alignmask),
201               (req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP) ?
202               GFP_KERNEL : GFP_ATOMIC);
203    if (!priv)
204        return -ENOMEM;
205
206    /*
207     * WARNING: Voodoo programming below!
208     *
209     * The code below is obscure and hard to understand, thus explanation
210     * is necessary. See include/crypto/hash.h and include/linux/crypto.h
211     * to understand the layout of structures used here!
212     *
213     * The code here will replace portions of the ORIGINAL request with
214     * pointers to new code and buffers so the hashing operation can store
215     * the result in aligned buffer. We will call the modified request
216     * an ADJUSTED request.
217     *
218     * The newly mangled request will look as such:
219     *
220     * req {
221     * .result = ADJUSTED[new aligned buffer]
222     * .base.complete = ADJUSTED[pointer to completion function]
223     * .base.data = ADJUSTED[*req (pointer to self)]
224     * .priv = ADJUSTED[new priv] {
225     * .result = ORIGINAL(result)
226     * .complete = ORIGINAL(base.complete)
227     * .data = ORIGINAL(base.data)
228     * }
229     */
230
231    priv->result = req->result;
232    priv->complete = req->base.complete;
233    priv->data = req->base.data;
234    /*
235     * WARNING: We do not backup req->priv here! The req->priv
236     * is for internal use of the Crypto API and the
237     * user must _NOT_ _EVER_ depend on it's content!
238     */
239
240    req->result = PTR_ALIGN((u8 *)priv->ubuf, alignmask + 1);
241    req->base.complete = cplt;
242    req->base.data = req;
243    req->priv = priv;
244
245    return 0;
246}
247
248static void ahash_restore_req(struct ahash_request *req)
249{
250    struct ahash_request_priv *priv = req->priv;
251
252    /* Restore the original crypto request. */
253    req->result = priv->result;
254    req->base.complete = priv->complete;
255    req->base.data = priv->data;
256    req->priv = NULL;
257
258    /* Free the req->priv.priv from the ADJUSTED request. */
259    kzfree(priv);
260}
261
262static void ahash_op_unaligned_finish(struct ahash_request *req, int err)
263{
264    struct ahash_request_priv *priv = req->priv;
265
266    if (err == -EINPROGRESS)
267        return;
268
269    if (!err)
270        memcpy(priv->result, req->result,
271               crypto_ahash_digestsize(crypto_ahash_reqtfm(req)));
272
273    ahash_restore_req(req);
274}
275
276static void ahash_op_unaligned_done(struct crypto_async_request *req, int err)
277{
278    struct ahash_request *areq = req->data;
279
280    /*
281     * Restore the original request, see ahash_op_unaligned() for what
282     * goes where.
283     *
284     * The "struct ahash_request *req" here is in fact the "req.base"
285     * from the ADJUSTED request from ahash_op_unaligned(), thus as it
286     * is a pointer to self, it is also the ADJUSTED "req" .
287     */
288
289    /* First copy req->result into req->priv.result */
290    ahash_op_unaligned_finish(areq, err);
291
292    /* Complete the ORIGINAL request. */
293    areq->base.complete(&areq->base, err);
294}
295
296static int ahash_op_unaligned(struct ahash_request *req,
297                  int (*op)(struct ahash_request *))
298{
299    int err;
300
301    err = ahash_save_req(req, ahash_op_unaligned_done);
302    if (err)
303        return err;
304
305    err = op(req);
306    ahash_op_unaligned_finish(req, err);
307
308    return err;
309}
310
311static int crypto_ahash_op(struct ahash_request *req,
312               int (*op)(struct ahash_request *))
313{
314    struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
315    unsigned long alignmask = crypto_ahash_alignmask(tfm);
316
317    if ((unsigned long)req->result & alignmask)
318        return ahash_op_unaligned(req, op);
319
320    return op(req);
321}
322
323int crypto_ahash_final(struct ahash_request *req)
324{
325    return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->final);
326}
327EXPORT_SYMBOL_GPL(crypto_ahash_final);
328
329int crypto_ahash_finup(struct ahash_request *req)
330{
331    return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->finup);
332}
333EXPORT_SYMBOL_GPL(crypto_ahash_finup);
334
335int crypto_ahash_digest(struct ahash_request *req)
336{
337    return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->digest);
338}
339EXPORT_SYMBOL_GPL(crypto_ahash_digest);
340
341static void ahash_def_finup_finish2(struct ahash_request *req, int err)
342{
343    struct ahash_request_priv *priv = req->priv;
344
345    if (err == -EINPROGRESS)
346        return;
347
348    if (!err)
349        memcpy(priv->result, req->result,
350               crypto_ahash_digestsize(crypto_ahash_reqtfm(req)));
351
352    ahash_restore_req(req);
353}
354
355static void ahash_def_finup_done2(struct crypto_async_request *req, int err)
356{
357    struct ahash_request *areq = req->data;
358
359    ahash_def_finup_finish2(areq, err);
360
361    areq->base.complete(&areq->base, err);
362}
363
364static int ahash_def_finup_finish1(struct ahash_request *req, int err)
365{
366    if (err)
367        goto out;
368
369    req->base.complete = ahash_def_finup_done2;
370    req->base.flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
371    err = crypto_ahash_reqtfm(req)->final(req);
372
373out:
374    ahash_def_finup_finish2(req, err);
375    return err;
376}
377
378static void ahash_def_finup_done1(struct crypto_async_request *req, int err)
379{
380    struct ahash_request *areq = req->data;
381
382    err = ahash_def_finup_finish1(areq, err);
383
384    areq->base.complete(&areq->base, err);
385}
386
387static int ahash_def_finup(struct ahash_request *req)
388{
389    struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
390    int err;
391
392    err = ahash_save_req(req, ahash_def_finup_done1);
393    if (err)
394        return err;
395
396    err = tfm->update(req);
397    return ahash_def_finup_finish1(req, err);
398}
399
400static int ahash_no_export(struct ahash_request *req, void *out)
401{
402    return -ENOSYS;
403}
404
405static int ahash_no_import(struct ahash_request *req, const void *in)
406{
407    return -ENOSYS;
408}
409
410static int crypto_ahash_init_tfm(struct crypto_tfm *tfm)
411{
412    struct crypto_ahash *hash = __crypto_ahash_cast(tfm);
413    struct ahash_alg *alg = crypto_ahash_alg(hash);
414
415    hash->setkey = ahash_nosetkey;
416    hash->export = ahash_no_export;
417    hash->import = ahash_no_import;
418
419    if (tfm->__crt_alg->cra_type != &crypto_ahash_type)
420        return crypto_init_shash_ops_async(tfm);
421
422    hash->init = alg->init;
423    hash->update = alg->update;
424    hash->final = alg->final;
425    hash->finup = alg->finup ?: ahash_def_finup;
426    hash->digest = alg->digest;
427
428    if (alg->setkey)
429        hash->setkey = alg->setkey;
430    if (alg->export)
431        hash->export = alg->export;
432    if (alg->import)
433        hash->import = alg->import;
434
435    return 0;
436}
437
438static unsigned int crypto_ahash_extsize(struct crypto_alg *alg)
439{
440    if (alg->cra_type == &crypto_ahash_type)
441        return alg->cra_ctxsize;
442
443    return sizeof(struct crypto_shash *);
444}
445
446#ifdef CONFIG_NET
447static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
448{
449    struct crypto_report_hash rhash;
450
451    strncpy(rhash.type, "ahash", sizeof(rhash.type));
452
453    rhash.blocksize = alg->cra_blocksize;
454    rhash.digestsize = __crypto_hash_alg_common(alg)->digestsize;
455
456    if (nla_put(skb, CRYPTOCFGA_REPORT_HASH,
457            sizeof(struct crypto_report_hash), &rhash))
458        goto nla_put_failure;
459    return 0;
460
461nla_put_failure:
462    return -EMSGSIZE;
463}
464#else
465static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
466{
467    return -ENOSYS;
468}
469#endif
470
471static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
472    __attribute__ ((unused));
473static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
474{
475    seq_printf(m, "type : ahash\n");
476    seq_printf(m, "async : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
477                         "yes" : "no");
478    seq_printf(m, "blocksize : %u\n", alg->cra_blocksize);
479    seq_printf(m, "digestsize : %u\n",
480           __crypto_hash_alg_common(alg)->digestsize);
481}
482
483const struct crypto_type crypto_ahash_type = {
484    .extsize = crypto_ahash_extsize,
485    .init_tfm = crypto_ahash_init_tfm,
486#ifdef CONFIG_PROC_FS
487    .show = crypto_ahash_show,
488#endif
489    .report = crypto_ahash_report,
490    .maskclear = ~CRYPTO_ALG_TYPE_MASK,
491    .maskset = CRYPTO_ALG_TYPE_AHASH_MASK,
492    .type = CRYPTO_ALG_TYPE_AHASH,
493    .tfmsize = offsetof(struct crypto_ahash, base),
494};
495EXPORT_SYMBOL_GPL(crypto_ahash_type);
496
497struct crypto_ahash *crypto_alloc_ahash(const char *alg_name, u32 type,
498                    u32 mask)
499{
500    return crypto_alloc_tfm(alg_name, &crypto_ahash_type, type, mask);
501}
502EXPORT_SYMBOL_GPL(crypto_alloc_ahash);
503
504static int ahash_prepare_alg(struct ahash_alg *alg)
505{
506    struct crypto_alg *base = &alg->halg.base;
507
508    if (alg->halg.digestsize > PAGE_SIZE / 8 ||
509        alg->halg.statesize > PAGE_SIZE / 8)
510        return -EINVAL;
511
512    base->cra_type = &crypto_ahash_type;
513    base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
514    base->cra_flags |= CRYPTO_ALG_TYPE_AHASH;
515
516    return 0;
517}
518
519int crypto_register_ahash(struct ahash_alg *alg)
520{
521    struct crypto_alg *base = &alg->halg.base;
522    int err;
523
524    err = ahash_prepare_alg(alg);
525    if (err)
526        return err;
527
528    return crypto_register_alg(base);
529}
530EXPORT_SYMBOL_GPL(crypto_register_ahash);
531
532int crypto_unregister_ahash(struct ahash_alg *alg)
533{
534    return crypto_unregister_alg(&alg->halg.base);
535}
536EXPORT_SYMBOL_GPL(crypto_unregister_ahash);
537
538int ahash_register_instance(struct crypto_template *tmpl,
539                struct ahash_instance *inst)
540{
541    int err;
542
543    err = ahash_prepare_alg(&inst->alg);
544    if (err)
545        return err;
546
547    return crypto_register_instance(tmpl, ahash_crypto_instance(inst));
548}
549EXPORT_SYMBOL_GPL(ahash_register_instance);
550
551void ahash_free_instance(struct crypto_instance *inst)
552{
553    crypto_drop_spawn(crypto_instance_ctx(inst));
554    kfree(ahash_instance(inst));
555}
556EXPORT_SYMBOL_GPL(ahash_free_instance);
557
558int crypto_init_ahash_spawn(struct crypto_ahash_spawn *spawn,
559                struct hash_alg_common *alg,
560                struct crypto_instance *inst)
561{
562    return crypto_init_spawn2(&spawn->base, &alg->base, inst,
563                  &crypto_ahash_type);
564}
565EXPORT_SYMBOL_GPL(crypto_init_ahash_spawn);
566
567struct hash_alg_common *ahash_attr_alg(struct rtattr *rta, u32 type, u32 mask)
568{
569    struct crypto_alg *alg;
570
571    alg = crypto_attr_alg2(rta, &crypto_ahash_type, type, mask);
572    return IS_ERR(alg) ? ERR_CAST(alg) : __crypto_hash_alg_common(alg);
573}
574EXPORT_SYMBOL_GPL(ahash_attr_alg);
575
576MODULE_LICENSE("GPL");
577MODULE_DESCRIPTION("Asynchronous cryptographic hash type");
578

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