Root/crypto/aead.c

1/*
2 * AEAD: Authenticated Encryption with Associated Data
3 *
4 * This file provides API support for AEAD algorithms.
5 *
6 * Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au>
7 *
8 * This program is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public License as published by the Free
10 * Software Foundation; either version 2 of the License, or (at your option)
11 * any later version.
12 *
13 */
14
15#include <crypto/internal/aead.h>
16#include <linux/err.h>
17#include <linux/init.h>
18#include <linux/kernel.h>
19#include <linux/module.h>
20#include <linux/rtnetlink.h>
21#include <linux/sched.h>
22#include <linux/slab.h>
23#include <linux/seq_file.h>
24
25#include "internal.h"
26
27static int setkey_unaligned(struct crypto_aead *tfm, const u8 *key,
28                unsigned int keylen)
29{
30    struct aead_alg *aead = crypto_aead_alg(tfm);
31    unsigned long alignmask = crypto_aead_alignmask(tfm);
32    int ret;
33    u8 *buffer, *alignbuffer;
34    unsigned long absize;
35
36    absize = keylen + alignmask;
37    buffer = kmalloc(absize, GFP_ATOMIC);
38    if (!buffer)
39        return -ENOMEM;
40
41    alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
42    memcpy(alignbuffer, key, keylen);
43    ret = aead->setkey(tfm, alignbuffer, keylen);
44    memset(alignbuffer, 0, keylen);
45    kfree(buffer);
46    return ret;
47}
48
49static int setkey(struct crypto_aead *tfm, const u8 *key, unsigned int keylen)
50{
51    struct aead_alg *aead = crypto_aead_alg(tfm);
52    unsigned long alignmask = crypto_aead_alignmask(tfm);
53
54    if ((unsigned long)key & alignmask)
55        return setkey_unaligned(tfm, key, keylen);
56
57    return aead->setkey(tfm, key, keylen);
58}
59
60int crypto_aead_setauthsize(struct crypto_aead *tfm, unsigned int authsize)
61{
62    struct aead_tfm *crt = crypto_aead_crt(tfm);
63    int err;
64
65    if (authsize > crypto_aead_alg(tfm)->maxauthsize)
66        return -EINVAL;
67
68    if (crypto_aead_alg(tfm)->setauthsize) {
69        err = crypto_aead_alg(tfm)->setauthsize(crt->base, authsize);
70        if (err)
71            return err;
72    }
73
74    crypto_aead_crt(crt->base)->authsize = authsize;
75    crt->authsize = authsize;
76    return 0;
77}
78EXPORT_SYMBOL_GPL(crypto_aead_setauthsize);
79
80static unsigned int crypto_aead_ctxsize(struct crypto_alg *alg, u32 type,
81                    u32 mask)
82{
83    return alg->cra_ctxsize;
84}
85
86static int no_givcrypt(struct aead_givcrypt_request *req)
87{
88    return -ENOSYS;
89}
90
91static int crypto_init_aead_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
92{
93    struct aead_alg *alg = &tfm->__crt_alg->cra_aead;
94    struct aead_tfm *crt = &tfm->crt_aead;
95
96    if (max(alg->maxauthsize, alg->ivsize) > PAGE_SIZE / 8)
97        return -EINVAL;
98
99    crt->setkey = tfm->__crt_alg->cra_flags & CRYPTO_ALG_GENIV ?
100              alg->setkey : setkey;
101    crt->encrypt = alg->encrypt;
102    crt->decrypt = alg->decrypt;
103    crt->givencrypt = alg->givencrypt ?: no_givcrypt;
104    crt->givdecrypt = alg->givdecrypt ?: no_givcrypt;
105    crt->base = __crypto_aead_cast(tfm);
106    crt->ivsize = alg->ivsize;
107    crt->authsize = alg->maxauthsize;
108
109    return 0;
110}
111
112static void crypto_aead_show(struct seq_file *m, struct crypto_alg *alg)
113    __attribute__ ((unused));
114static void crypto_aead_show(struct seq_file *m, struct crypto_alg *alg)
115{
116    struct aead_alg *aead = &alg->cra_aead;
117
118    seq_printf(m, "type : aead\n");
119    seq_printf(m, "async : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
120                         "yes" : "no");
121    seq_printf(m, "blocksize : %u\n", alg->cra_blocksize);
122    seq_printf(m, "ivsize : %u\n", aead->ivsize);
123    seq_printf(m, "maxauthsize : %u\n", aead->maxauthsize);
124    seq_printf(m, "geniv : %s\n", aead->geniv ?: "<built-in>");
125}
126
127const struct crypto_type crypto_aead_type = {
128    .ctxsize = crypto_aead_ctxsize,
129    .init = crypto_init_aead_ops,
130#ifdef CONFIG_PROC_FS
131    .show = crypto_aead_show,
132#endif
133};
134EXPORT_SYMBOL_GPL(crypto_aead_type);
135
136static int aead_null_givencrypt(struct aead_givcrypt_request *req)
137{
138    return crypto_aead_encrypt(&req->areq);
139}
140
141static int aead_null_givdecrypt(struct aead_givcrypt_request *req)
142{
143    return crypto_aead_decrypt(&req->areq);
144}
145
146static int crypto_init_nivaead_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
147{
148    struct aead_alg *alg = &tfm->__crt_alg->cra_aead;
149    struct aead_tfm *crt = &tfm->crt_aead;
150
151    if (max(alg->maxauthsize, alg->ivsize) > PAGE_SIZE / 8)
152        return -EINVAL;
153
154    crt->setkey = setkey;
155    crt->encrypt = alg->encrypt;
156    crt->decrypt = alg->decrypt;
157    if (!alg->ivsize) {
158        crt->givencrypt = aead_null_givencrypt;
159        crt->givdecrypt = aead_null_givdecrypt;
160    }
161    crt->base = __crypto_aead_cast(tfm);
162    crt->ivsize = alg->ivsize;
163    crt->authsize = alg->maxauthsize;
164
165    return 0;
166}
167
168static void crypto_nivaead_show(struct seq_file *m, struct crypto_alg *alg)
169    __attribute__ ((unused));
170static void crypto_nivaead_show(struct seq_file *m, struct crypto_alg *alg)
171{
172    struct aead_alg *aead = &alg->cra_aead;
173
174    seq_printf(m, "type : nivaead\n");
175    seq_printf(m, "async : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
176                         "yes" : "no");
177    seq_printf(m, "blocksize : %u\n", alg->cra_blocksize);
178    seq_printf(m, "ivsize : %u\n", aead->ivsize);
179    seq_printf(m, "maxauthsize : %u\n", aead->maxauthsize);
180    seq_printf(m, "geniv : %s\n", aead->geniv);
181}
182
183const struct crypto_type crypto_nivaead_type = {
184    .ctxsize = crypto_aead_ctxsize,
185    .init = crypto_init_nivaead_ops,
186#ifdef CONFIG_PROC_FS
187    .show = crypto_nivaead_show,
188#endif
189};
190EXPORT_SYMBOL_GPL(crypto_nivaead_type);
191
192static int crypto_grab_nivaead(struct crypto_aead_spawn *spawn,
193                   const char *name, u32 type, u32 mask)
194{
195    struct crypto_alg *alg;
196    int err;
197
198    type &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
199    type |= CRYPTO_ALG_TYPE_AEAD;
200    mask |= CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV;
201
202    alg = crypto_alg_mod_lookup(name, type, mask);
203    if (IS_ERR(alg))
204        return PTR_ERR(alg);
205
206    err = crypto_init_spawn(&spawn->base, alg, spawn->base.inst, mask);
207    crypto_mod_put(alg);
208    return err;
209}
210
211struct crypto_instance *aead_geniv_alloc(struct crypto_template *tmpl,
212                     struct rtattr **tb, u32 type,
213                     u32 mask)
214{
215    const char *name;
216    struct crypto_aead_spawn *spawn;
217    struct crypto_attr_type *algt;
218    struct crypto_instance *inst;
219    struct crypto_alg *alg;
220    int err;
221
222    algt = crypto_get_attr_type(tb);
223    err = PTR_ERR(algt);
224    if (IS_ERR(algt))
225        return ERR_PTR(err);
226
227    if ((algt->type ^ (CRYPTO_ALG_TYPE_AEAD | CRYPTO_ALG_GENIV)) &
228        algt->mask)
229        return ERR_PTR(-EINVAL);
230
231    name = crypto_attr_alg_name(tb[1]);
232    err = PTR_ERR(name);
233    if (IS_ERR(name))
234        return ERR_PTR(err);
235
236    inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
237    if (!inst)
238        return ERR_PTR(-ENOMEM);
239
240    spawn = crypto_instance_ctx(inst);
241
242    /* Ignore async algorithms if necessary. */
243    mask |= crypto_requires_sync(algt->type, algt->mask);
244
245    crypto_set_aead_spawn(spawn, inst);
246    err = crypto_grab_nivaead(spawn, name, type, mask);
247    if (err)
248        goto err_free_inst;
249
250    alg = crypto_aead_spawn_alg(spawn);
251
252    err = -EINVAL;
253    if (!alg->cra_aead.ivsize)
254        goto err_drop_alg;
255
256    /*
257     * This is only true if we're constructing an algorithm with its
258     * default IV generator. For the default generator we elide the
259     * template name and double-check the IV generator.
260     */
261    if (algt->mask & CRYPTO_ALG_GENIV) {
262        if (strcmp(tmpl->name, alg->cra_aead.geniv))
263            goto err_drop_alg;
264
265        memcpy(inst->alg.cra_name, alg->cra_name, CRYPTO_MAX_ALG_NAME);
266        memcpy(inst->alg.cra_driver_name, alg->cra_driver_name,
267               CRYPTO_MAX_ALG_NAME);
268    } else {
269        err = -ENAMETOOLONG;
270        if (snprintf(inst->alg.cra_name, CRYPTO_MAX_ALG_NAME,
271                 "%s(%s)", tmpl->name, alg->cra_name) >=
272            CRYPTO_MAX_ALG_NAME)
273            goto err_drop_alg;
274        if (snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME,
275                 "%s(%s)", tmpl->name, alg->cra_driver_name) >=
276            CRYPTO_MAX_ALG_NAME)
277            goto err_drop_alg;
278    }
279
280    inst->alg.cra_flags = CRYPTO_ALG_TYPE_AEAD | CRYPTO_ALG_GENIV;
281    inst->alg.cra_flags |= alg->cra_flags & CRYPTO_ALG_ASYNC;
282    inst->alg.cra_priority = alg->cra_priority;
283    inst->alg.cra_blocksize = alg->cra_blocksize;
284    inst->alg.cra_alignmask = alg->cra_alignmask;
285    inst->alg.cra_type = &crypto_aead_type;
286
287    inst->alg.cra_aead.ivsize = alg->cra_aead.ivsize;
288    inst->alg.cra_aead.maxauthsize = alg->cra_aead.maxauthsize;
289    inst->alg.cra_aead.geniv = alg->cra_aead.geniv;
290
291    inst->alg.cra_aead.setkey = alg->cra_aead.setkey;
292    inst->alg.cra_aead.setauthsize = alg->cra_aead.setauthsize;
293    inst->alg.cra_aead.encrypt = alg->cra_aead.encrypt;
294    inst->alg.cra_aead.decrypt = alg->cra_aead.decrypt;
295
296out:
297    return inst;
298
299err_drop_alg:
300    crypto_drop_aead(spawn);
301err_free_inst:
302    kfree(inst);
303    inst = ERR_PTR(err);
304    goto out;
305}
306EXPORT_SYMBOL_GPL(aead_geniv_alloc);
307
308void aead_geniv_free(struct crypto_instance *inst)
309{
310    crypto_drop_aead(crypto_instance_ctx(inst));
311    kfree(inst);
312}
313EXPORT_SYMBOL_GPL(aead_geniv_free);
314
315int aead_geniv_init(struct crypto_tfm *tfm)
316{
317    struct crypto_instance *inst = (void *)tfm->__crt_alg;
318    struct crypto_aead *aead;
319
320    aead = crypto_spawn_aead(crypto_instance_ctx(inst));
321    if (IS_ERR(aead))
322        return PTR_ERR(aead);
323
324    tfm->crt_aead.base = aead;
325    tfm->crt_aead.reqsize += crypto_aead_reqsize(aead);
326
327    return 0;
328}
329EXPORT_SYMBOL_GPL(aead_geniv_init);
330
331void aead_geniv_exit(struct crypto_tfm *tfm)
332{
333    crypto_free_aead(tfm->crt_aead.base);
334}
335EXPORT_SYMBOL_GPL(aead_geniv_exit);
336
337static int crypto_nivaead_default(struct crypto_alg *alg, u32 type, u32 mask)
338{
339    struct rtattr *tb[3];
340    struct {
341        struct rtattr attr;
342        struct crypto_attr_type data;
343    } ptype;
344    struct {
345        struct rtattr attr;
346        struct crypto_attr_alg data;
347    } palg;
348    struct crypto_template *tmpl;
349    struct crypto_instance *inst;
350    struct crypto_alg *larval;
351    const char *geniv;
352    int err;
353
354    larval = crypto_larval_lookup(alg->cra_driver_name,
355                      CRYPTO_ALG_TYPE_AEAD | CRYPTO_ALG_GENIV,
356                      CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
357    err = PTR_ERR(larval);
358    if (IS_ERR(larval))
359        goto out;
360
361    err = -EAGAIN;
362    if (!crypto_is_larval(larval))
363        goto drop_larval;
364
365    ptype.attr.rta_len = sizeof(ptype);
366    ptype.attr.rta_type = CRYPTOA_TYPE;
367    ptype.data.type = type | CRYPTO_ALG_GENIV;
368    /* GENIV tells the template that we're making a default geniv. */
369    ptype.data.mask = mask | CRYPTO_ALG_GENIV;
370    tb[0] = &ptype.attr;
371
372    palg.attr.rta_len = sizeof(palg);
373    palg.attr.rta_type = CRYPTOA_ALG;
374    /* Must use the exact name to locate ourselves. */
375    memcpy(palg.data.name, alg->cra_driver_name, CRYPTO_MAX_ALG_NAME);
376    tb[1] = &palg.attr;
377
378    tb[2] = NULL;
379
380    geniv = alg->cra_aead.geniv;
381
382    tmpl = crypto_lookup_template(geniv);
383    err = -ENOENT;
384    if (!tmpl)
385        goto kill_larval;
386
387    inst = tmpl->alloc(tb);
388    err = PTR_ERR(inst);
389    if (IS_ERR(inst))
390        goto put_tmpl;
391
392    if ((err = crypto_register_instance(tmpl, inst))) {
393        tmpl->free(inst);
394        goto put_tmpl;
395    }
396
397    /* Redo the lookup to use the instance we just registered. */
398    err = -EAGAIN;
399
400put_tmpl:
401    crypto_tmpl_put(tmpl);
402kill_larval:
403    crypto_larval_kill(larval);
404drop_larval:
405    crypto_mod_put(larval);
406out:
407    crypto_mod_put(alg);
408    return err;
409}
410
411static struct crypto_alg *crypto_lookup_aead(const char *name, u32 type,
412                         u32 mask)
413{
414    struct crypto_alg *alg;
415
416    alg = crypto_alg_mod_lookup(name, type, mask);
417    if (IS_ERR(alg))
418        return alg;
419
420    if (alg->cra_type == &crypto_aead_type)
421        return alg;
422
423    if (!alg->cra_aead.ivsize)
424        return alg;
425
426    crypto_mod_put(alg);
427    alg = crypto_alg_mod_lookup(name, type | CRYPTO_ALG_TESTED,
428                    mask & ~CRYPTO_ALG_TESTED);
429    if (IS_ERR(alg))
430        return alg;
431
432    if (alg->cra_type == &crypto_aead_type) {
433        if ((alg->cra_flags ^ type ^ ~mask) & CRYPTO_ALG_TESTED) {
434            crypto_mod_put(alg);
435            alg = ERR_PTR(-ENOENT);
436        }
437        return alg;
438    }
439
440    BUG_ON(!alg->cra_aead.ivsize);
441
442    return ERR_PTR(crypto_nivaead_default(alg, type, mask));
443}
444
445int crypto_grab_aead(struct crypto_aead_spawn *spawn, const char *name,
446             u32 type, u32 mask)
447{
448    struct crypto_alg *alg;
449    int err;
450
451    type &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
452    type |= CRYPTO_ALG_TYPE_AEAD;
453    mask &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
454    mask |= CRYPTO_ALG_TYPE_MASK;
455
456    alg = crypto_lookup_aead(name, type, mask);
457    if (IS_ERR(alg))
458        return PTR_ERR(alg);
459
460    err = crypto_init_spawn(&spawn->base, alg, spawn->base.inst, mask);
461    crypto_mod_put(alg);
462    return err;
463}
464EXPORT_SYMBOL_GPL(crypto_grab_aead);
465
466struct crypto_aead *crypto_alloc_aead(const char *alg_name, u32 type, u32 mask)
467{
468    struct crypto_tfm *tfm;
469    int err;
470
471    type &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
472    type |= CRYPTO_ALG_TYPE_AEAD;
473    mask &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
474    mask |= CRYPTO_ALG_TYPE_MASK;
475
476    for (;;) {
477        struct crypto_alg *alg;
478
479        alg = crypto_lookup_aead(alg_name, type, mask);
480        if (IS_ERR(alg)) {
481            err = PTR_ERR(alg);
482            goto err;
483        }
484
485        tfm = __crypto_alloc_tfm(alg, type, mask);
486        if (!IS_ERR(tfm))
487            return __crypto_aead_cast(tfm);
488
489        crypto_mod_put(alg);
490        err = PTR_ERR(tfm);
491
492err:
493        if (err != -EAGAIN)
494            break;
495        if (signal_pending(current)) {
496            err = -EINTR;
497            break;
498        }
499    }
500
501    return ERR_PTR(err);
502}
503EXPORT_SYMBOL_GPL(crypto_alloc_aead);
504
505MODULE_LICENSE("GPL");
506MODULE_DESCRIPTION("Authenticated Encryption with Associated Data (AEAD)");
507

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