Root/crypto/ccm.c

1/*
2 * CCM: Counter with CBC-MAC
3 *
4 * (C) Copyright IBM Corp. 2007 - Joy Latten <latten@us.ibm.com>
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/internal/aead.h>
14#include <crypto/internal/skcipher.h>
15#include <crypto/scatterwalk.h>
16#include <linux/err.h>
17#include <linux/init.h>
18#include <linux/kernel.h>
19#include <linux/module.h>
20#include <linux/slab.h>
21
22#include "internal.h"
23
24struct ccm_instance_ctx {
25    struct crypto_skcipher_spawn ctr;
26    struct crypto_spawn cipher;
27};
28
29struct crypto_ccm_ctx {
30    struct crypto_cipher *cipher;
31    struct crypto_ablkcipher *ctr;
32};
33
34struct crypto_rfc4309_ctx {
35    struct crypto_aead *child;
36    u8 nonce[3];
37};
38
39struct crypto_ccm_req_priv_ctx {
40    u8 odata[16];
41    u8 idata[16];
42    u8 auth_tag[16];
43    u32 ilen;
44    u32 flags;
45    struct scatterlist src[2];
46    struct scatterlist dst[2];
47    struct ablkcipher_request abreq;
48};
49
50static inline struct crypto_ccm_req_priv_ctx *crypto_ccm_reqctx(
51    struct aead_request *req)
52{
53    unsigned long align = crypto_aead_alignmask(crypto_aead_reqtfm(req));
54
55    return (void *)PTR_ALIGN((u8 *)aead_request_ctx(req), align + 1);
56}
57
58static int set_msg_len(u8 *block, unsigned int msglen, int csize)
59{
60    __be32 data;
61
62    memset(block, 0, csize);
63    block += csize;
64
65    if (csize >= 4)
66        csize = 4;
67    else if (msglen > (1 << (8 * csize)))
68        return -EOVERFLOW;
69
70    data = cpu_to_be32(msglen);
71    memcpy(block - csize, (u8 *)&data + 4 - csize, csize);
72
73    return 0;
74}
75
76static int crypto_ccm_setkey(struct crypto_aead *aead, const u8 *key,
77                 unsigned int keylen)
78{
79    struct crypto_ccm_ctx *ctx = crypto_aead_ctx(aead);
80    struct crypto_ablkcipher *ctr = ctx->ctr;
81    struct crypto_cipher *tfm = ctx->cipher;
82    int err = 0;
83
84    crypto_ablkcipher_clear_flags(ctr, CRYPTO_TFM_REQ_MASK);
85    crypto_ablkcipher_set_flags(ctr, crypto_aead_get_flags(aead) &
86                    CRYPTO_TFM_REQ_MASK);
87    err = crypto_ablkcipher_setkey(ctr, key, keylen);
88    crypto_aead_set_flags(aead, crypto_ablkcipher_get_flags(ctr) &
89                  CRYPTO_TFM_RES_MASK);
90    if (err)
91        goto out;
92
93    crypto_cipher_clear_flags(tfm, CRYPTO_TFM_REQ_MASK);
94    crypto_cipher_set_flags(tfm, crypto_aead_get_flags(aead) &
95                    CRYPTO_TFM_REQ_MASK);
96    err = crypto_cipher_setkey(tfm, key, keylen);
97    crypto_aead_set_flags(aead, crypto_cipher_get_flags(tfm) &
98                  CRYPTO_TFM_RES_MASK);
99
100out:
101    return err;
102}
103
104static int crypto_ccm_setauthsize(struct crypto_aead *tfm,
105                  unsigned int authsize)
106{
107    switch (authsize) {
108    case 4:
109    case 6:
110    case 8:
111    case 10:
112    case 12:
113    case 14:
114    case 16:
115        break;
116    default:
117        return -EINVAL;
118    }
119
120    return 0;
121}
122
123static int format_input(u8 *info, struct aead_request *req,
124            unsigned int cryptlen)
125{
126    struct crypto_aead *aead = crypto_aead_reqtfm(req);
127    unsigned int lp = req->iv[0];
128    unsigned int l = lp + 1;
129    unsigned int m;
130
131    m = crypto_aead_authsize(aead);
132
133    memcpy(info, req->iv, 16);
134
135    /* format control info per RFC 3610 and
136     * NIST Special Publication 800-38C
137     */
138    *info |= (8 * ((m - 2) / 2));
139    if (req->assoclen)
140        *info |= 64;
141
142    return set_msg_len(info + 16 - l, cryptlen, l);
143}
144
145static int format_adata(u8 *adata, unsigned int a)
146{
147    int len = 0;
148
149    /* add control info for associated data
150     * RFC 3610 and NIST Special Publication 800-38C
151     */
152    if (a < 65280) {
153        *(__be16 *)adata = cpu_to_be16(a);
154        len = 2;
155    } else {
156        *(__be16 *)adata = cpu_to_be16(0xfffe);
157        *(__be32 *)&adata[2] = cpu_to_be32(a);
158        len = 6;
159    }
160
161    return len;
162}
163
164static void compute_mac(struct crypto_cipher *tfm, u8 *data, int n,
165               struct crypto_ccm_req_priv_ctx *pctx)
166{
167    unsigned int bs = 16;
168    u8 *odata = pctx->odata;
169    u8 *idata = pctx->idata;
170    int datalen, getlen;
171
172    datalen = n;
173
174    /* first time in here, block may be partially filled. */
175    getlen = bs - pctx->ilen;
176    if (datalen >= getlen) {
177        memcpy(idata + pctx->ilen, data, getlen);
178        crypto_xor(odata, idata, bs);
179        crypto_cipher_encrypt_one(tfm, odata, odata);
180        datalen -= getlen;
181        data += getlen;
182        pctx->ilen = 0;
183    }
184
185    /* now encrypt rest of data */
186    while (datalen >= bs) {
187        crypto_xor(odata, data, bs);
188        crypto_cipher_encrypt_one(tfm, odata, odata);
189
190        datalen -= bs;
191        data += bs;
192    }
193
194    /* check and see if there's leftover data that wasn't
195     * enough to fill a block.
196     */
197    if (datalen) {
198        memcpy(idata + pctx->ilen, data, datalen);
199        pctx->ilen += datalen;
200    }
201}
202
203static void get_data_to_compute(struct crypto_cipher *tfm,
204                   struct crypto_ccm_req_priv_ctx *pctx,
205                   struct scatterlist *sg, unsigned int len)
206{
207    struct scatter_walk walk;
208    u8 *data_src;
209    int n;
210
211    scatterwalk_start(&walk, sg);
212
213    while (len) {
214        n = scatterwalk_clamp(&walk, len);
215        if (!n) {
216            scatterwalk_start(&walk, sg_next(walk.sg));
217            n = scatterwalk_clamp(&walk, len);
218        }
219        data_src = scatterwalk_map(&walk);
220
221        compute_mac(tfm, data_src, n, pctx);
222        len -= n;
223
224        scatterwalk_unmap(data_src);
225        scatterwalk_advance(&walk, n);
226        scatterwalk_done(&walk, 0, len);
227        if (len)
228            crypto_yield(pctx->flags);
229    }
230
231    /* any leftover needs padding and then encrypted */
232    if (pctx->ilen) {
233        int padlen;
234        u8 *odata = pctx->odata;
235        u8 *idata = pctx->idata;
236
237        padlen = 16 - pctx->ilen;
238        memset(idata + pctx->ilen, 0, padlen);
239        crypto_xor(odata, idata, 16);
240        crypto_cipher_encrypt_one(tfm, odata, odata);
241        pctx->ilen = 0;
242    }
243}
244
245static int crypto_ccm_auth(struct aead_request *req, struct scatterlist *plain,
246               unsigned int cryptlen)
247{
248    struct crypto_aead *aead = crypto_aead_reqtfm(req);
249    struct crypto_ccm_ctx *ctx = crypto_aead_ctx(aead);
250    struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req);
251    struct crypto_cipher *cipher = ctx->cipher;
252    unsigned int assoclen = req->assoclen;
253    u8 *odata = pctx->odata;
254    u8 *idata = pctx->idata;
255    int err;
256
257    /* format control data for input */
258    err = format_input(odata, req, cryptlen);
259    if (err)
260        goto out;
261
262    /* encrypt first block to use as start in computing mac */
263    crypto_cipher_encrypt_one(cipher, odata, odata);
264
265    /* format associated data and compute into mac */
266    if (assoclen) {
267        pctx->ilen = format_adata(idata, assoclen);
268        get_data_to_compute(cipher, pctx, req->assoc, req->assoclen);
269    } else {
270        pctx->ilen = 0;
271    }
272
273    /* compute plaintext into mac */
274    if (cryptlen)
275        get_data_to_compute(cipher, pctx, plain, cryptlen);
276
277out:
278    return err;
279}
280
281static void crypto_ccm_encrypt_done(struct crypto_async_request *areq, int err)
282{
283    struct aead_request *req = areq->data;
284    struct crypto_aead *aead = crypto_aead_reqtfm(req);
285    struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req);
286    u8 *odata = pctx->odata;
287
288    if (!err)
289        scatterwalk_map_and_copy(odata, req->dst, req->cryptlen,
290                     crypto_aead_authsize(aead), 1);
291    aead_request_complete(req, err);
292}
293
294static inline int crypto_ccm_check_iv(const u8 *iv)
295{
296    /* 2 <= L <= 8, so 1 <= L' <= 7. */
297    if (1 > iv[0] || iv[0] > 7)
298        return -EINVAL;
299
300    return 0;
301}
302
303static int crypto_ccm_encrypt(struct aead_request *req)
304{
305    struct crypto_aead *aead = crypto_aead_reqtfm(req);
306    struct crypto_ccm_ctx *ctx = crypto_aead_ctx(aead);
307    struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req);
308    struct ablkcipher_request *abreq = &pctx->abreq;
309    struct scatterlist *dst;
310    unsigned int cryptlen = req->cryptlen;
311    u8 *odata = pctx->odata;
312    u8 *iv = req->iv;
313    int err;
314
315    err = crypto_ccm_check_iv(iv);
316    if (err)
317        return err;
318
319    pctx->flags = aead_request_flags(req);
320
321    err = crypto_ccm_auth(req, req->src, cryptlen);
322    if (err)
323        return err;
324
325     /* Note: rfc 3610 and NIST 800-38C require counter of
326     * zero to encrypt auth tag.
327     */
328    memset(iv + 15 - iv[0], 0, iv[0] + 1);
329
330    sg_init_table(pctx->src, 2);
331    sg_set_buf(pctx->src, odata, 16);
332    scatterwalk_sg_chain(pctx->src, 2, req->src);
333
334    dst = pctx->src;
335    if (req->src != req->dst) {
336        sg_init_table(pctx->dst, 2);
337        sg_set_buf(pctx->dst, odata, 16);
338        scatterwalk_sg_chain(pctx->dst, 2, req->dst);
339        dst = pctx->dst;
340    }
341
342    ablkcipher_request_set_tfm(abreq, ctx->ctr);
343    ablkcipher_request_set_callback(abreq, pctx->flags,
344                    crypto_ccm_encrypt_done, req);
345    ablkcipher_request_set_crypt(abreq, pctx->src, dst, cryptlen + 16, iv);
346    err = crypto_ablkcipher_encrypt(abreq);
347    if (err)
348        return err;
349
350    /* copy authtag to end of dst */
351    scatterwalk_map_and_copy(odata, req->dst, cryptlen,
352                 crypto_aead_authsize(aead), 1);
353    return err;
354}
355
356static void crypto_ccm_decrypt_done(struct crypto_async_request *areq,
357                   int err)
358{
359    struct aead_request *req = areq->data;
360    struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req);
361    struct crypto_aead *aead = crypto_aead_reqtfm(req);
362    unsigned int authsize = crypto_aead_authsize(aead);
363    unsigned int cryptlen = req->cryptlen - authsize;
364
365    if (!err) {
366        err = crypto_ccm_auth(req, req->dst, cryptlen);
367        if (!err && crypto_memneq(pctx->auth_tag, pctx->odata, authsize))
368            err = -EBADMSG;
369    }
370    aead_request_complete(req, err);
371}
372
373static int crypto_ccm_decrypt(struct aead_request *req)
374{
375    struct crypto_aead *aead = crypto_aead_reqtfm(req);
376    struct crypto_ccm_ctx *ctx = crypto_aead_ctx(aead);
377    struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req);
378    struct ablkcipher_request *abreq = &pctx->abreq;
379    struct scatterlist *dst;
380    unsigned int authsize = crypto_aead_authsize(aead);
381    unsigned int cryptlen = req->cryptlen;
382    u8 *authtag = pctx->auth_tag;
383    u8 *odata = pctx->odata;
384    u8 *iv = req->iv;
385    int err;
386
387    if (cryptlen < authsize)
388        return -EINVAL;
389    cryptlen -= authsize;
390
391    err = crypto_ccm_check_iv(iv);
392    if (err)
393        return err;
394
395    pctx->flags = aead_request_flags(req);
396
397    scatterwalk_map_and_copy(authtag, req->src, cryptlen, authsize, 0);
398
399    memset(iv + 15 - iv[0], 0, iv[0] + 1);
400
401    sg_init_table(pctx->src, 2);
402    sg_set_buf(pctx->src, authtag, 16);
403    scatterwalk_sg_chain(pctx->src, 2, req->src);
404
405    dst = pctx->src;
406    if (req->src != req->dst) {
407        sg_init_table(pctx->dst, 2);
408        sg_set_buf(pctx->dst, authtag, 16);
409        scatterwalk_sg_chain(pctx->dst, 2, req->dst);
410        dst = pctx->dst;
411    }
412
413    ablkcipher_request_set_tfm(abreq, ctx->ctr);
414    ablkcipher_request_set_callback(abreq, pctx->flags,
415                    crypto_ccm_decrypt_done, req);
416    ablkcipher_request_set_crypt(abreq, pctx->src, dst, cryptlen + 16, iv);
417    err = crypto_ablkcipher_decrypt(abreq);
418    if (err)
419        return err;
420
421    err = crypto_ccm_auth(req, req->dst, cryptlen);
422    if (err)
423        return err;
424
425    /* verify */
426    if (crypto_memneq(authtag, odata, authsize))
427        return -EBADMSG;
428
429    return err;
430}
431
432static int crypto_ccm_init_tfm(struct crypto_tfm *tfm)
433{
434    struct crypto_instance *inst = (void *)tfm->__crt_alg;
435    struct ccm_instance_ctx *ictx = crypto_instance_ctx(inst);
436    struct crypto_ccm_ctx *ctx = crypto_tfm_ctx(tfm);
437    struct crypto_cipher *cipher;
438    struct crypto_ablkcipher *ctr;
439    unsigned long align;
440    int err;
441
442    cipher = crypto_spawn_cipher(&ictx->cipher);
443    if (IS_ERR(cipher))
444        return PTR_ERR(cipher);
445
446    ctr = crypto_spawn_skcipher(&ictx->ctr);
447    err = PTR_ERR(ctr);
448    if (IS_ERR(ctr))
449        goto err_free_cipher;
450
451    ctx->cipher = cipher;
452    ctx->ctr = ctr;
453
454    align = crypto_tfm_alg_alignmask(tfm);
455    align &= ~(crypto_tfm_ctx_alignment() - 1);
456    tfm->crt_aead.reqsize = align +
457                sizeof(struct crypto_ccm_req_priv_ctx) +
458                crypto_ablkcipher_reqsize(ctr);
459
460    return 0;
461
462err_free_cipher:
463    crypto_free_cipher(cipher);
464    return err;
465}
466
467static void crypto_ccm_exit_tfm(struct crypto_tfm *tfm)
468{
469    struct crypto_ccm_ctx *ctx = crypto_tfm_ctx(tfm);
470
471    crypto_free_cipher(ctx->cipher);
472    crypto_free_ablkcipher(ctx->ctr);
473}
474
475static struct crypto_instance *crypto_ccm_alloc_common(struct rtattr **tb,
476                               const char *full_name,
477                               const char *ctr_name,
478                               const char *cipher_name)
479{
480    struct crypto_attr_type *algt;
481    struct crypto_instance *inst;
482    struct crypto_alg *ctr;
483    struct crypto_alg *cipher;
484    struct ccm_instance_ctx *ictx;
485    int err;
486
487    algt = crypto_get_attr_type(tb);
488    if (IS_ERR(algt))
489        return ERR_CAST(algt);
490
491    if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
492        return ERR_PTR(-EINVAL);
493
494    cipher = crypto_alg_mod_lookup(cipher_name, CRYPTO_ALG_TYPE_CIPHER,
495                       CRYPTO_ALG_TYPE_MASK);
496    if (IS_ERR(cipher))
497        return ERR_CAST(cipher);
498
499    err = -EINVAL;
500    if (cipher->cra_blocksize != 16)
501        goto out_put_cipher;
502
503    inst = kzalloc(sizeof(*inst) + sizeof(*ictx), GFP_KERNEL);
504    err = -ENOMEM;
505    if (!inst)
506        goto out_put_cipher;
507
508    ictx = crypto_instance_ctx(inst);
509
510    err = crypto_init_spawn(&ictx->cipher, cipher, inst,
511                CRYPTO_ALG_TYPE_MASK);
512    if (err)
513        goto err_free_inst;
514
515    crypto_set_skcipher_spawn(&ictx->ctr, inst);
516    err = crypto_grab_skcipher(&ictx->ctr, ctr_name, 0,
517                   crypto_requires_sync(algt->type,
518                            algt->mask));
519    if (err)
520        goto err_drop_cipher;
521
522    ctr = crypto_skcipher_spawn_alg(&ictx->ctr);
523
524    /* Not a stream cipher? */
525    err = -EINVAL;
526    if (ctr->cra_blocksize != 1)
527        goto err_drop_ctr;
528
529    /* We want the real thing! */
530    if (ctr->cra_ablkcipher.ivsize != 16)
531        goto err_drop_ctr;
532
533    err = -ENAMETOOLONG;
534    if (snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME,
535             "ccm_base(%s,%s)", ctr->cra_driver_name,
536             cipher->cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
537        goto err_drop_ctr;
538
539    memcpy(inst->alg.cra_name, full_name, CRYPTO_MAX_ALG_NAME);
540
541    inst->alg.cra_flags = CRYPTO_ALG_TYPE_AEAD;
542    inst->alg.cra_flags |= ctr->cra_flags & CRYPTO_ALG_ASYNC;
543    inst->alg.cra_priority = cipher->cra_priority + ctr->cra_priority;
544    inst->alg.cra_blocksize = 1;
545    inst->alg.cra_alignmask = cipher->cra_alignmask | ctr->cra_alignmask |
546                  (__alignof__(u32) - 1);
547    inst->alg.cra_type = &crypto_aead_type;
548    inst->alg.cra_aead.ivsize = 16;
549    inst->alg.cra_aead.maxauthsize = 16;
550    inst->alg.cra_ctxsize = sizeof(struct crypto_ccm_ctx);
551    inst->alg.cra_init = crypto_ccm_init_tfm;
552    inst->alg.cra_exit = crypto_ccm_exit_tfm;
553    inst->alg.cra_aead.setkey = crypto_ccm_setkey;
554    inst->alg.cra_aead.setauthsize = crypto_ccm_setauthsize;
555    inst->alg.cra_aead.encrypt = crypto_ccm_encrypt;
556    inst->alg.cra_aead.decrypt = crypto_ccm_decrypt;
557
558out:
559    crypto_mod_put(cipher);
560    return inst;
561
562err_drop_ctr:
563    crypto_drop_skcipher(&ictx->ctr);
564err_drop_cipher:
565    crypto_drop_spawn(&ictx->cipher);
566err_free_inst:
567    kfree(inst);
568out_put_cipher:
569    inst = ERR_PTR(err);
570    goto out;
571}
572
573static struct crypto_instance *crypto_ccm_alloc(struct rtattr **tb)
574{
575    const char *cipher_name;
576    char ctr_name[CRYPTO_MAX_ALG_NAME];
577    char full_name[CRYPTO_MAX_ALG_NAME];
578
579    cipher_name = crypto_attr_alg_name(tb[1]);
580    if (IS_ERR(cipher_name))
581        return ERR_CAST(cipher_name);
582
583    if (snprintf(ctr_name, CRYPTO_MAX_ALG_NAME, "ctr(%s)",
584             cipher_name) >= CRYPTO_MAX_ALG_NAME)
585        return ERR_PTR(-ENAMETOOLONG);
586
587    if (snprintf(full_name, CRYPTO_MAX_ALG_NAME, "ccm(%s)", cipher_name) >=
588        CRYPTO_MAX_ALG_NAME)
589        return ERR_PTR(-ENAMETOOLONG);
590
591    return crypto_ccm_alloc_common(tb, full_name, ctr_name, cipher_name);
592}
593
594static void crypto_ccm_free(struct crypto_instance *inst)
595{
596    struct ccm_instance_ctx *ctx = crypto_instance_ctx(inst);
597
598    crypto_drop_spawn(&ctx->cipher);
599    crypto_drop_skcipher(&ctx->ctr);
600    kfree(inst);
601}
602
603static struct crypto_template crypto_ccm_tmpl = {
604    .name = "ccm",
605    .alloc = crypto_ccm_alloc,
606    .free = crypto_ccm_free,
607    .module = THIS_MODULE,
608};
609
610static struct crypto_instance *crypto_ccm_base_alloc(struct rtattr **tb)
611{
612    const char *ctr_name;
613    const char *cipher_name;
614    char full_name[CRYPTO_MAX_ALG_NAME];
615
616    ctr_name = crypto_attr_alg_name(tb[1]);
617    if (IS_ERR(ctr_name))
618        return ERR_CAST(ctr_name);
619
620    cipher_name = crypto_attr_alg_name(tb[2]);
621    if (IS_ERR(cipher_name))
622        return ERR_CAST(cipher_name);
623
624    if (snprintf(full_name, CRYPTO_MAX_ALG_NAME, "ccm_base(%s,%s)",
625             ctr_name, cipher_name) >= CRYPTO_MAX_ALG_NAME)
626        return ERR_PTR(-ENAMETOOLONG);
627
628    return crypto_ccm_alloc_common(tb, full_name, ctr_name, cipher_name);
629}
630
631static struct crypto_template crypto_ccm_base_tmpl = {
632    .name = "ccm_base",
633    .alloc = crypto_ccm_base_alloc,
634    .free = crypto_ccm_free,
635    .module = THIS_MODULE,
636};
637
638static int crypto_rfc4309_setkey(struct crypto_aead *parent, const u8 *key,
639                 unsigned int keylen)
640{
641    struct crypto_rfc4309_ctx *ctx = crypto_aead_ctx(parent);
642    struct crypto_aead *child = ctx->child;
643    int err;
644
645    if (keylen < 3)
646        return -EINVAL;
647
648    keylen -= 3;
649    memcpy(ctx->nonce, key + keylen, 3);
650
651    crypto_aead_clear_flags(child, CRYPTO_TFM_REQ_MASK);
652    crypto_aead_set_flags(child, crypto_aead_get_flags(parent) &
653                     CRYPTO_TFM_REQ_MASK);
654    err = crypto_aead_setkey(child, key, keylen);
655    crypto_aead_set_flags(parent, crypto_aead_get_flags(child) &
656                      CRYPTO_TFM_RES_MASK);
657
658    return err;
659}
660
661static int crypto_rfc4309_setauthsize(struct crypto_aead *parent,
662                      unsigned int authsize)
663{
664    struct crypto_rfc4309_ctx *ctx = crypto_aead_ctx(parent);
665
666    switch (authsize) {
667    case 8:
668    case 12:
669    case 16:
670        break;
671    default:
672        return -EINVAL;
673    }
674
675    return crypto_aead_setauthsize(ctx->child, authsize);
676}
677
678static struct aead_request *crypto_rfc4309_crypt(struct aead_request *req)
679{
680    struct aead_request *subreq = aead_request_ctx(req);
681    struct crypto_aead *aead = crypto_aead_reqtfm(req);
682    struct crypto_rfc4309_ctx *ctx = crypto_aead_ctx(aead);
683    struct crypto_aead *child = ctx->child;
684    u8 *iv = PTR_ALIGN((u8 *)(subreq + 1) + crypto_aead_reqsize(child),
685               crypto_aead_alignmask(child) + 1);
686
687    /* L' */
688    iv[0] = 3;
689
690    memcpy(iv + 1, ctx->nonce, 3);
691    memcpy(iv + 4, req->iv, 8);
692
693    aead_request_set_tfm(subreq, child);
694    aead_request_set_callback(subreq, req->base.flags, req->base.complete,
695                  req->base.data);
696    aead_request_set_crypt(subreq, req->src, req->dst, req->cryptlen, iv);
697    aead_request_set_assoc(subreq, req->assoc, req->assoclen);
698
699    return subreq;
700}
701
702static int crypto_rfc4309_encrypt(struct aead_request *req)
703{
704    req = crypto_rfc4309_crypt(req);
705
706    return crypto_aead_encrypt(req);
707}
708
709static int crypto_rfc4309_decrypt(struct aead_request *req)
710{
711    req = crypto_rfc4309_crypt(req);
712
713    return crypto_aead_decrypt(req);
714}
715
716static int crypto_rfc4309_init_tfm(struct crypto_tfm *tfm)
717{
718    struct crypto_instance *inst = (void *)tfm->__crt_alg;
719    struct crypto_aead_spawn *spawn = crypto_instance_ctx(inst);
720    struct crypto_rfc4309_ctx *ctx = crypto_tfm_ctx(tfm);
721    struct crypto_aead *aead;
722    unsigned long align;
723
724    aead = crypto_spawn_aead(spawn);
725    if (IS_ERR(aead))
726        return PTR_ERR(aead);
727
728    ctx->child = aead;
729
730    align = crypto_aead_alignmask(aead);
731    align &= ~(crypto_tfm_ctx_alignment() - 1);
732    tfm->crt_aead.reqsize = sizeof(struct aead_request) +
733                ALIGN(crypto_aead_reqsize(aead),
734                      crypto_tfm_ctx_alignment()) +
735                align + 16;
736
737    return 0;
738}
739
740static void crypto_rfc4309_exit_tfm(struct crypto_tfm *tfm)
741{
742    struct crypto_rfc4309_ctx *ctx = crypto_tfm_ctx(tfm);
743
744    crypto_free_aead(ctx->child);
745}
746
747static struct crypto_instance *crypto_rfc4309_alloc(struct rtattr **tb)
748{
749    struct crypto_attr_type *algt;
750    struct crypto_instance *inst;
751    struct crypto_aead_spawn *spawn;
752    struct crypto_alg *alg;
753    const char *ccm_name;
754    int err;
755
756    algt = crypto_get_attr_type(tb);
757    if (IS_ERR(algt))
758        return ERR_CAST(algt);
759
760    if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
761        return ERR_PTR(-EINVAL);
762
763    ccm_name = crypto_attr_alg_name(tb[1]);
764    if (IS_ERR(ccm_name))
765        return ERR_CAST(ccm_name);
766
767    inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
768    if (!inst)
769        return ERR_PTR(-ENOMEM);
770
771    spawn = crypto_instance_ctx(inst);
772    crypto_set_aead_spawn(spawn, inst);
773    err = crypto_grab_aead(spawn, ccm_name, 0,
774                   crypto_requires_sync(algt->type, algt->mask));
775    if (err)
776        goto out_free_inst;
777
778    alg = crypto_aead_spawn_alg(spawn);
779
780    err = -EINVAL;
781
782    /* We only support 16-byte blocks. */
783    if (alg->cra_aead.ivsize != 16)
784        goto out_drop_alg;
785
786    /* Not a stream cipher? */
787    if (alg->cra_blocksize != 1)
788        goto out_drop_alg;
789
790    err = -ENAMETOOLONG;
791    if (snprintf(inst->alg.cra_name, CRYPTO_MAX_ALG_NAME,
792             "rfc4309(%s)", alg->cra_name) >= CRYPTO_MAX_ALG_NAME ||
793        snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME,
794             "rfc4309(%s)", alg->cra_driver_name) >=
795        CRYPTO_MAX_ALG_NAME)
796        goto out_drop_alg;
797
798    inst->alg.cra_flags = CRYPTO_ALG_TYPE_AEAD;
799    inst->alg.cra_flags |= alg->cra_flags & CRYPTO_ALG_ASYNC;
800    inst->alg.cra_priority = alg->cra_priority;
801    inst->alg.cra_blocksize = 1;
802    inst->alg.cra_alignmask = alg->cra_alignmask;
803    inst->alg.cra_type = &crypto_nivaead_type;
804
805    inst->alg.cra_aead.ivsize = 8;
806    inst->alg.cra_aead.maxauthsize = 16;
807
808    inst->alg.cra_ctxsize = sizeof(struct crypto_rfc4309_ctx);
809
810    inst->alg.cra_init = crypto_rfc4309_init_tfm;
811    inst->alg.cra_exit = crypto_rfc4309_exit_tfm;
812
813    inst->alg.cra_aead.setkey = crypto_rfc4309_setkey;
814    inst->alg.cra_aead.setauthsize = crypto_rfc4309_setauthsize;
815    inst->alg.cra_aead.encrypt = crypto_rfc4309_encrypt;
816    inst->alg.cra_aead.decrypt = crypto_rfc4309_decrypt;
817
818    inst->alg.cra_aead.geniv = "seqiv";
819
820out:
821    return inst;
822
823out_drop_alg:
824    crypto_drop_aead(spawn);
825out_free_inst:
826    kfree(inst);
827    inst = ERR_PTR(err);
828    goto out;
829}
830
831static void crypto_rfc4309_free(struct crypto_instance *inst)
832{
833    crypto_drop_spawn(crypto_instance_ctx(inst));
834    kfree(inst);
835}
836
837static struct crypto_template crypto_rfc4309_tmpl = {
838    .name = "rfc4309",
839    .alloc = crypto_rfc4309_alloc,
840    .free = crypto_rfc4309_free,
841    .module = THIS_MODULE,
842};
843
844static int __init crypto_ccm_module_init(void)
845{
846    int err;
847
848    err = crypto_register_template(&crypto_ccm_base_tmpl);
849    if (err)
850        goto out;
851
852    err = crypto_register_template(&crypto_ccm_tmpl);
853    if (err)
854        goto out_undo_base;
855
856    err = crypto_register_template(&crypto_rfc4309_tmpl);
857    if (err)
858        goto out_undo_ccm;
859
860out:
861    return err;
862
863out_undo_ccm:
864    crypto_unregister_template(&crypto_ccm_tmpl);
865out_undo_base:
866    crypto_unregister_template(&crypto_ccm_base_tmpl);
867    goto out;
868}
869
870static void __exit crypto_ccm_module_exit(void)
871{
872    crypto_unregister_template(&crypto_rfc4309_tmpl);
873    crypto_unregister_template(&crypto_ccm_tmpl);
874    crypto_unregister_template(&crypto_ccm_base_tmpl);
875}
876
877module_init(crypto_ccm_module_init);
878module_exit(crypto_ccm_module_exit);
879
880MODULE_LICENSE("GPL");
881MODULE_DESCRIPTION("Counter with CBC MAC");
882MODULE_ALIAS("ccm_base");
883MODULE_ALIAS("rfc4309");
884

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