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, 0);
220
221        compute_mac(tfm, data_src, n, pctx);
222        len -= n;
223
224        scatterwalk_unmap(data_src, 0);
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    get_data_to_compute(cipher, pctx, plain, cryptlen);
275
276out:
277    return err;
278}
279
280static void crypto_ccm_encrypt_done(struct crypto_async_request *areq, int err)
281{
282    struct aead_request *req = areq->data;
283    struct crypto_aead *aead = crypto_aead_reqtfm(req);
284    struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req);
285    u8 *odata = pctx->odata;
286
287    if (!err)
288        scatterwalk_map_and_copy(odata, req->dst, req->cryptlen,
289                     crypto_aead_authsize(aead), 1);
290    aead_request_complete(req, err);
291}
292
293static inline int crypto_ccm_check_iv(const u8 *iv)
294{
295    /* 2 <= L <= 8, so 1 <= L' <= 7. */
296    if (1 > iv[0] || iv[0] > 7)
297        return -EINVAL;
298
299    return 0;
300}
301
302static int crypto_ccm_encrypt(struct aead_request *req)
303{
304    struct crypto_aead *aead = crypto_aead_reqtfm(req);
305    struct crypto_ccm_ctx *ctx = crypto_aead_ctx(aead);
306    struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req);
307    struct ablkcipher_request *abreq = &pctx->abreq;
308    struct scatterlist *dst;
309    unsigned int cryptlen = req->cryptlen;
310    u8 *odata = pctx->odata;
311    u8 *iv = req->iv;
312    int err;
313
314    err = crypto_ccm_check_iv(iv);
315    if (err)
316        return err;
317
318    pctx->flags = aead_request_flags(req);
319
320    err = crypto_ccm_auth(req, req->src, cryptlen);
321    if (err)
322        return err;
323
324     /* Note: rfc 3610 and NIST 800-38C require counter of
325     * zero to encrypt auth tag.
326     */
327    memset(iv + 15 - iv[0], 0, iv[0] + 1);
328
329    sg_init_table(pctx->src, 2);
330    sg_set_buf(pctx->src, odata, 16);
331    scatterwalk_sg_chain(pctx->src, 2, req->src);
332
333    dst = pctx->src;
334    if (req->src != req->dst) {
335        sg_init_table(pctx->dst, 2);
336        sg_set_buf(pctx->dst, odata, 16);
337        scatterwalk_sg_chain(pctx->dst, 2, req->dst);
338        dst = pctx->dst;
339    }
340
341    ablkcipher_request_set_tfm(abreq, ctx->ctr);
342    ablkcipher_request_set_callback(abreq, pctx->flags,
343                    crypto_ccm_encrypt_done, req);
344    ablkcipher_request_set_crypt(abreq, pctx->src, dst, cryptlen + 16, iv);
345    err = crypto_ablkcipher_encrypt(abreq);
346    if (err)
347        return err;
348
349    /* copy authtag to end of dst */
350    scatterwalk_map_and_copy(odata, req->dst, cryptlen,
351                 crypto_aead_authsize(aead), 1);
352    return err;
353}
354
355static void crypto_ccm_decrypt_done(struct crypto_async_request *areq,
356                   int err)
357{
358    struct aead_request *req = areq->data;
359    struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req);
360    struct crypto_aead *aead = crypto_aead_reqtfm(req);
361    unsigned int authsize = crypto_aead_authsize(aead);
362    unsigned int cryptlen = req->cryptlen - authsize;
363
364    if (!err) {
365        err = crypto_ccm_auth(req, req->dst, cryptlen);
366        if (!err && memcmp(pctx->auth_tag, pctx->odata, authsize))
367            err = -EBADMSG;
368    }
369    aead_request_complete(req, err);
370}
371
372static int crypto_ccm_decrypt(struct aead_request *req)
373{
374    struct crypto_aead *aead = crypto_aead_reqtfm(req);
375    struct crypto_ccm_ctx *ctx = crypto_aead_ctx(aead);
376    struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req);
377    struct ablkcipher_request *abreq = &pctx->abreq;
378    struct scatterlist *dst;
379    unsigned int authsize = crypto_aead_authsize(aead);
380    unsigned int cryptlen = req->cryptlen;
381    u8 *authtag = pctx->auth_tag;
382    u8 *odata = pctx->odata;
383    u8 *iv = req->iv;
384    int err;
385
386    if (cryptlen < authsize)
387        return -EINVAL;
388    cryptlen -= authsize;
389
390    err = crypto_ccm_check_iv(iv);
391    if (err)
392        return err;
393
394    pctx->flags = aead_request_flags(req);
395
396    scatterwalk_map_and_copy(authtag, req->src, cryptlen, authsize, 0);
397
398    memset(iv + 15 - iv[0], 0, iv[0] + 1);
399
400    sg_init_table(pctx->src, 2);
401    sg_set_buf(pctx->src, authtag, 16);
402    scatterwalk_sg_chain(pctx->src, 2, req->src);
403
404    dst = pctx->src;
405    if (req->src != req->dst) {
406        sg_init_table(pctx->dst, 2);
407        sg_set_buf(pctx->dst, authtag, 16);
408        scatterwalk_sg_chain(pctx->dst, 2, req->dst);
409        dst = pctx->dst;
410    }
411
412    ablkcipher_request_set_tfm(abreq, ctx->ctr);
413    ablkcipher_request_set_callback(abreq, pctx->flags,
414                    crypto_ccm_decrypt_done, req);
415    ablkcipher_request_set_crypt(abreq, pctx->src, dst, cryptlen + 16, iv);
416    err = crypto_ablkcipher_decrypt(abreq);
417    if (err)
418        return err;
419
420    err = crypto_ccm_auth(req, req->dst, cryptlen);
421    if (err)
422        return err;
423
424    /* verify */
425    if (memcmp(authtag, odata, authsize))
426        return -EBADMSG;
427
428    return err;
429}
430
431static int crypto_ccm_init_tfm(struct crypto_tfm *tfm)
432{
433    struct crypto_instance *inst = (void *)tfm->__crt_alg;
434    struct ccm_instance_ctx *ictx = crypto_instance_ctx(inst);
435    struct crypto_ccm_ctx *ctx = crypto_tfm_ctx(tfm);
436    struct crypto_cipher *cipher;
437    struct crypto_ablkcipher *ctr;
438    unsigned long align;
439    int err;
440
441    cipher = crypto_spawn_cipher(&ictx->cipher);
442    if (IS_ERR(cipher))
443        return PTR_ERR(cipher);
444
445    ctr = crypto_spawn_skcipher(&ictx->ctr);
446    err = PTR_ERR(ctr);
447    if (IS_ERR(ctr))
448        goto err_free_cipher;
449
450    ctx->cipher = cipher;
451    ctx->ctr = ctr;
452
453    align = crypto_tfm_alg_alignmask(tfm);
454    align &= ~(crypto_tfm_ctx_alignment() - 1);
455    tfm->crt_aead.reqsize = align +
456                sizeof(struct crypto_ccm_req_priv_ctx) +
457                crypto_ablkcipher_reqsize(ctr);
458
459    return 0;
460
461err_free_cipher:
462    crypto_free_cipher(cipher);
463    return err;
464}
465
466static void crypto_ccm_exit_tfm(struct crypto_tfm *tfm)
467{
468    struct crypto_ccm_ctx *ctx = crypto_tfm_ctx(tfm);
469
470    crypto_free_cipher(ctx->cipher);
471    crypto_free_ablkcipher(ctx->ctr);
472}
473
474static struct crypto_instance *crypto_ccm_alloc_common(struct rtattr **tb,
475                               const char *full_name,
476                               const char *ctr_name,
477                               const char *cipher_name)
478{
479    struct crypto_attr_type *algt;
480    struct crypto_instance *inst;
481    struct crypto_alg *ctr;
482    struct crypto_alg *cipher;
483    struct ccm_instance_ctx *ictx;
484    int err;
485
486    algt = crypto_get_attr_type(tb);
487    err = PTR_ERR(algt);
488    if (IS_ERR(algt))
489        return ERR_PTR(err);
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    err = PTR_ERR(cipher);
497    if (IS_ERR(cipher))
498        return ERR_PTR(err);
499
500    err = -EINVAL;
501    if (cipher->cra_blocksize != 16)
502        goto out_put_cipher;
503
504    inst = kzalloc(sizeof(*inst) + sizeof(*ictx), GFP_KERNEL);
505    err = -ENOMEM;
506    if (!inst)
507        goto out_put_cipher;
508
509    ictx = crypto_instance_ctx(inst);
510
511    err = crypto_init_spawn(&ictx->cipher, cipher, inst,
512                CRYPTO_ALG_TYPE_MASK);
513    if (err)
514        goto err_free_inst;
515
516    crypto_set_skcipher_spawn(&ictx->ctr, inst);
517    err = crypto_grab_skcipher(&ictx->ctr, ctr_name, 0,
518                   crypto_requires_sync(algt->type,
519                            algt->mask));
520    if (err)
521        goto err_drop_cipher;
522
523    ctr = crypto_skcipher_spawn_alg(&ictx->ctr);
524
525    /* Not a stream cipher? */
526    err = -EINVAL;
527    if (ctr->cra_blocksize != 1)
528        goto err_drop_ctr;
529
530    /* We want the real thing! */
531    if (ctr->cra_ablkcipher.ivsize != 16)
532        goto err_drop_ctr;
533
534    err = -ENAMETOOLONG;
535    if (snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME,
536             "ccm_base(%s,%s)", ctr->cra_driver_name,
537             cipher->cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
538        goto err_drop_ctr;
539
540    memcpy(inst->alg.cra_name, full_name, CRYPTO_MAX_ALG_NAME);
541
542    inst->alg.cra_flags = CRYPTO_ALG_TYPE_AEAD;
543    inst->alg.cra_flags |= ctr->cra_flags & CRYPTO_ALG_ASYNC;
544    inst->alg.cra_priority = cipher->cra_priority + ctr->cra_priority;
545    inst->alg.cra_blocksize = 1;
546    inst->alg.cra_alignmask = cipher->cra_alignmask | ctr->cra_alignmask |
547                  (__alignof__(u32) - 1);
548    inst->alg.cra_type = &crypto_aead_type;
549    inst->alg.cra_aead.ivsize = 16;
550    inst->alg.cra_aead.maxauthsize = 16;
551    inst->alg.cra_ctxsize = sizeof(struct crypto_ccm_ctx);
552    inst->alg.cra_init = crypto_ccm_init_tfm;
553    inst->alg.cra_exit = crypto_ccm_exit_tfm;
554    inst->alg.cra_aead.setkey = crypto_ccm_setkey;
555    inst->alg.cra_aead.setauthsize = crypto_ccm_setauthsize;
556    inst->alg.cra_aead.encrypt = crypto_ccm_encrypt;
557    inst->alg.cra_aead.decrypt = crypto_ccm_decrypt;
558
559out:
560    crypto_mod_put(cipher);
561    return inst;
562
563err_drop_ctr:
564    crypto_drop_skcipher(&ictx->ctr);
565err_drop_cipher:
566    crypto_drop_spawn(&ictx->cipher);
567err_free_inst:
568    kfree(inst);
569out_put_cipher:
570    inst = ERR_PTR(err);
571    goto out;
572}
573
574static struct crypto_instance *crypto_ccm_alloc(struct rtattr **tb)
575{
576    int err;
577    const char *cipher_name;
578    char ctr_name[CRYPTO_MAX_ALG_NAME];
579    char full_name[CRYPTO_MAX_ALG_NAME];
580
581    cipher_name = crypto_attr_alg_name(tb[1]);
582    err = PTR_ERR(cipher_name);
583    if (IS_ERR(cipher_name))
584        return ERR_PTR(err);
585
586    if (snprintf(ctr_name, CRYPTO_MAX_ALG_NAME, "ctr(%s)",
587             cipher_name) >= CRYPTO_MAX_ALG_NAME)
588        return ERR_PTR(-ENAMETOOLONG);
589
590    if (snprintf(full_name, CRYPTO_MAX_ALG_NAME, "ccm(%s)", cipher_name) >=
591        CRYPTO_MAX_ALG_NAME)
592        return ERR_PTR(-ENAMETOOLONG);
593
594    return crypto_ccm_alloc_common(tb, full_name, ctr_name, cipher_name);
595}
596
597static void crypto_ccm_free(struct crypto_instance *inst)
598{
599    struct ccm_instance_ctx *ctx = crypto_instance_ctx(inst);
600
601    crypto_drop_spawn(&ctx->cipher);
602    crypto_drop_skcipher(&ctx->ctr);
603    kfree(inst);
604}
605
606static struct crypto_template crypto_ccm_tmpl = {
607    .name = "ccm",
608    .alloc = crypto_ccm_alloc,
609    .free = crypto_ccm_free,
610    .module = THIS_MODULE,
611};
612
613static struct crypto_instance *crypto_ccm_base_alloc(struct rtattr **tb)
614{
615    int err;
616    const char *ctr_name;
617    const char *cipher_name;
618    char full_name[CRYPTO_MAX_ALG_NAME];
619
620    ctr_name = crypto_attr_alg_name(tb[1]);
621    err = PTR_ERR(ctr_name);
622    if (IS_ERR(ctr_name))
623        return ERR_PTR(err);
624
625    cipher_name = crypto_attr_alg_name(tb[2]);
626    err = PTR_ERR(cipher_name);
627    if (IS_ERR(cipher_name))
628        return ERR_PTR(err);
629
630    if (snprintf(full_name, CRYPTO_MAX_ALG_NAME, "ccm_base(%s,%s)",
631             ctr_name, cipher_name) >= CRYPTO_MAX_ALG_NAME)
632        return ERR_PTR(-ENAMETOOLONG);
633
634    return crypto_ccm_alloc_common(tb, full_name, ctr_name, cipher_name);
635}
636
637static struct crypto_template crypto_ccm_base_tmpl = {
638    .name = "ccm_base",
639    .alloc = crypto_ccm_base_alloc,
640    .free = crypto_ccm_free,
641    .module = THIS_MODULE,
642};
643
644static int crypto_rfc4309_setkey(struct crypto_aead *parent, const u8 *key,
645                 unsigned int keylen)
646{
647    struct crypto_rfc4309_ctx *ctx = crypto_aead_ctx(parent);
648    struct crypto_aead *child = ctx->child;
649    int err;
650
651    if (keylen < 3)
652        return -EINVAL;
653
654    keylen -= 3;
655    memcpy(ctx->nonce, key + keylen, 3);
656
657    crypto_aead_clear_flags(child, CRYPTO_TFM_REQ_MASK);
658    crypto_aead_set_flags(child, crypto_aead_get_flags(parent) &
659                     CRYPTO_TFM_REQ_MASK);
660    err = crypto_aead_setkey(child, key, keylen);
661    crypto_aead_set_flags(parent, crypto_aead_get_flags(child) &
662                      CRYPTO_TFM_RES_MASK);
663
664    return err;
665}
666
667static int crypto_rfc4309_setauthsize(struct crypto_aead *parent,
668                      unsigned int authsize)
669{
670    struct crypto_rfc4309_ctx *ctx = crypto_aead_ctx(parent);
671
672    switch (authsize) {
673    case 8:
674    case 12:
675    case 16:
676        break;
677    default:
678        return -EINVAL;
679    }
680
681    return crypto_aead_setauthsize(ctx->child, authsize);
682}
683
684static struct aead_request *crypto_rfc4309_crypt(struct aead_request *req)
685{
686    struct aead_request *subreq = aead_request_ctx(req);
687    struct crypto_aead *aead = crypto_aead_reqtfm(req);
688    struct crypto_rfc4309_ctx *ctx = crypto_aead_ctx(aead);
689    struct crypto_aead *child = ctx->child;
690    u8 *iv = PTR_ALIGN((u8 *)(subreq + 1) + crypto_aead_reqsize(child),
691               crypto_aead_alignmask(child) + 1);
692
693    /* L' */
694    iv[0] = 3;
695
696    memcpy(iv + 1, ctx->nonce, 3);
697    memcpy(iv + 4, req->iv, 8);
698
699    aead_request_set_tfm(subreq, child);
700    aead_request_set_callback(subreq, req->base.flags, req->base.complete,
701                  req->base.data);
702    aead_request_set_crypt(subreq, req->src, req->dst, req->cryptlen, iv);
703    aead_request_set_assoc(subreq, req->assoc, req->assoclen);
704
705    return subreq;
706}
707
708static int crypto_rfc4309_encrypt(struct aead_request *req)
709{
710    req = crypto_rfc4309_crypt(req);
711
712    return crypto_aead_encrypt(req);
713}
714
715static int crypto_rfc4309_decrypt(struct aead_request *req)
716{
717    req = crypto_rfc4309_crypt(req);
718
719    return crypto_aead_decrypt(req);
720}
721
722static int crypto_rfc4309_init_tfm(struct crypto_tfm *tfm)
723{
724    struct crypto_instance *inst = (void *)tfm->__crt_alg;
725    struct crypto_aead_spawn *spawn = crypto_instance_ctx(inst);
726    struct crypto_rfc4309_ctx *ctx = crypto_tfm_ctx(tfm);
727    struct crypto_aead *aead;
728    unsigned long align;
729
730    aead = crypto_spawn_aead(spawn);
731    if (IS_ERR(aead))
732        return PTR_ERR(aead);
733
734    ctx->child = aead;
735
736    align = crypto_aead_alignmask(aead);
737    align &= ~(crypto_tfm_ctx_alignment() - 1);
738    tfm->crt_aead.reqsize = sizeof(struct aead_request) +
739                ALIGN(crypto_aead_reqsize(aead),
740                      crypto_tfm_ctx_alignment()) +
741                align + 16;
742
743    return 0;
744}
745
746static void crypto_rfc4309_exit_tfm(struct crypto_tfm *tfm)
747{
748    struct crypto_rfc4309_ctx *ctx = crypto_tfm_ctx(tfm);
749
750    crypto_free_aead(ctx->child);
751}
752
753static struct crypto_instance *crypto_rfc4309_alloc(struct rtattr **tb)
754{
755    struct crypto_attr_type *algt;
756    struct crypto_instance *inst;
757    struct crypto_aead_spawn *spawn;
758    struct crypto_alg *alg;
759    const char *ccm_name;
760    int err;
761
762    algt = crypto_get_attr_type(tb);
763    err = PTR_ERR(algt);
764    if (IS_ERR(algt))
765        return ERR_PTR(err);
766
767    if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
768        return ERR_PTR(-EINVAL);
769
770    ccm_name = crypto_attr_alg_name(tb[1]);
771    err = PTR_ERR(ccm_name);
772    if (IS_ERR(ccm_name))
773        return ERR_PTR(err);
774
775    inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
776    if (!inst)
777        return ERR_PTR(-ENOMEM);
778
779    spawn = crypto_instance_ctx(inst);
780    crypto_set_aead_spawn(spawn, inst);
781    err = crypto_grab_aead(spawn, ccm_name, 0,
782                   crypto_requires_sync(algt->type, algt->mask));
783    if (err)
784        goto out_free_inst;
785
786    alg = crypto_aead_spawn_alg(spawn);
787
788    err = -EINVAL;
789
790    /* We only support 16-byte blocks. */
791    if (alg->cra_aead.ivsize != 16)
792        goto out_drop_alg;
793
794    /* Not a stream cipher? */
795    if (alg->cra_blocksize != 1)
796        goto out_drop_alg;
797
798    err = -ENAMETOOLONG;
799    if (snprintf(inst->alg.cra_name, CRYPTO_MAX_ALG_NAME,
800             "rfc4309(%s)", alg->cra_name) >= CRYPTO_MAX_ALG_NAME ||
801        snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME,
802             "rfc4309(%s)", alg->cra_driver_name) >=
803        CRYPTO_MAX_ALG_NAME)
804        goto out_drop_alg;
805
806    inst->alg.cra_flags = CRYPTO_ALG_TYPE_AEAD;
807    inst->alg.cra_flags |= alg->cra_flags & CRYPTO_ALG_ASYNC;
808    inst->alg.cra_priority = alg->cra_priority;
809    inst->alg.cra_blocksize = 1;
810    inst->alg.cra_alignmask = alg->cra_alignmask;
811    inst->alg.cra_type = &crypto_nivaead_type;
812
813    inst->alg.cra_aead.ivsize = 8;
814    inst->alg.cra_aead.maxauthsize = 16;
815
816    inst->alg.cra_ctxsize = sizeof(struct crypto_rfc4309_ctx);
817
818    inst->alg.cra_init = crypto_rfc4309_init_tfm;
819    inst->alg.cra_exit = crypto_rfc4309_exit_tfm;
820
821    inst->alg.cra_aead.setkey = crypto_rfc4309_setkey;
822    inst->alg.cra_aead.setauthsize = crypto_rfc4309_setauthsize;
823    inst->alg.cra_aead.encrypt = crypto_rfc4309_encrypt;
824    inst->alg.cra_aead.decrypt = crypto_rfc4309_decrypt;
825
826    inst->alg.cra_aead.geniv = "seqiv";
827
828out:
829    return inst;
830
831out_drop_alg:
832    crypto_drop_aead(spawn);
833out_free_inst:
834    kfree(inst);
835    inst = ERR_PTR(err);
836    goto out;
837}
838
839static void crypto_rfc4309_free(struct crypto_instance *inst)
840{
841    crypto_drop_spawn(crypto_instance_ctx(inst));
842    kfree(inst);
843}
844
845static struct crypto_template crypto_rfc4309_tmpl = {
846    .name = "rfc4309",
847    .alloc = crypto_rfc4309_alloc,
848    .free = crypto_rfc4309_free,
849    .module = THIS_MODULE,
850};
851
852static int __init crypto_ccm_module_init(void)
853{
854    int err;
855
856    err = crypto_register_template(&crypto_ccm_base_tmpl);
857    if (err)
858        goto out;
859
860    err = crypto_register_template(&crypto_ccm_tmpl);
861    if (err)
862        goto out_undo_base;
863
864    err = crypto_register_template(&crypto_rfc4309_tmpl);
865    if (err)
866        goto out_undo_ccm;
867
868out:
869    return err;
870
871out_undo_ccm:
872    crypto_unregister_template(&crypto_ccm_tmpl);
873out_undo_base:
874    crypto_unregister_template(&crypto_ccm_base_tmpl);
875    goto out;
876}
877
878static void __exit crypto_ccm_module_exit(void)
879{
880    crypto_unregister_template(&crypto_rfc4309_tmpl);
881    crypto_unregister_template(&crypto_ccm_tmpl);
882    crypto_unregister_template(&crypto_ccm_base_tmpl);
883}
884
885module_init(crypto_ccm_module_init);
886module_exit(crypto_ccm_module_exit);
887
888MODULE_LICENSE("GPL");
889MODULE_DESCRIPTION("Counter with CBC MAC");
890MODULE_ALIAS("ccm_base");
891MODULE_ALIAS("rfc4309");
892

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