Version:  2.0.40 2.2.26 2.4.37 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 4.10

Linux/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 
 24 struct ccm_instance_ctx {
 25         struct crypto_skcipher_spawn ctr;
 26         struct crypto_spawn cipher;
 27 };
 28 
 29 struct crypto_ccm_ctx {
 30         struct crypto_cipher *cipher;
 31         struct crypto_skcipher *ctr;
 32 };
 33 
 34 struct crypto_rfc4309_ctx {
 35         struct crypto_aead *child;
 36         u8 nonce[3];
 37 };
 38 
 39 struct crypto_rfc4309_req_ctx {
 40         struct scatterlist src[3];
 41         struct scatterlist dst[3];
 42         struct aead_request subreq;
 43 };
 44 
 45 struct crypto_ccm_req_priv_ctx {
 46         u8 odata[16];
 47         u8 idata[16];
 48         u8 auth_tag[16];
 49         u32 ilen;
 50         u32 flags;
 51         struct scatterlist src[3];
 52         struct scatterlist dst[3];
 53         struct skcipher_request skreq;
 54 };
 55 
 56 static inline struct crypto_ccm_req_priv_ctx *crypto_ccm_reqctx(
 57         struct aead_request *req)
 58 {
 59         unsigned long align = crypto_aead_alignmask(crypto_aead_reqtfm(req));
 60 
 61         return (void *)PTR_ALIGN((u8 *)aead_request_ctx(req), align + 1);
 62 }
 63 
 64 static int set_msg_len(u8 *block, unsigned int msglen, int csize)
 65 {
 66         __be32 data;
 67 
 68         memset(block, 0, csize);
 69         block += csize;
 70 
 71         if (csize >= 4)
 72                 csize = 4;
 73         else if (msglen > (1 << (8 * csize)))
 74                 return -EOVERFLOW;
 75 
 76         data = cpu_to_be32(msglen);
 77         memcpy(block - csize, (u8 *)&data + 4 - csize, csize);
 78 
 79         return 0;
 80 }
 81 
 82 static int crypto_ccm_setkey(struct crypto_aead *aead, const u8 *key,
 83                              unsigned int keylen)
 84 {
 85         struct crypto_ccm_ctx *ctx = crypto_aead_ctx(aead);
 86         struct crypto_skcipher *ctr = ctx->ctr;
 87         struct crypto_cipher *tfm = ctx->cipher;
 88         int err = 0;
 89 
 90         crypto_skcipher_clear_flags(ctr, CRYPTO_TFM_REQ_MASK);
 91         crypto_skcipher_set_flags(ctr, crypto_aead_get_flags(aead) &
 92                                        CRYPTO_TFM_REQ_MASK);
 93         err = crypto_skcipher_setkey(ctr, key, keylen);
 94         crypto_aead_set_flags(aead, crypto_skcipher_get_flags(ctr) &
 95                               CRYPTO_TFM_RES_MASK);
 96         if (err)
 97                 goto out;
 98 
 99         crypto_cipher_clear_flags(tfm, CRYPTO_TFM_REQ_MASK);
100         crypto_cipher_set_flags(tfm, crypto_aead_get_flags(aead) &
101                                     CRYPTO_TFM_REQ_MASK);
102         err = crypto_cipher_setkey(tfm, key, keylen);
103         crypto_aead_set_flags(aead, crypto_cipher_get_flags(tfm) &
104                               CRYPTO_TFM_RES_MASK);
105 
106 out:
107         return err;
108 }
109 
110 static int crypto_ccm_setauthsize(struct crypto_aead *tfm,
111                                   unsigned int authsize)
112 {
113         switch (authsize) {
114         case 4:
115         case 6:
116         case 8:
117         case 10:
118         case 12:
119         case 14:
120         case 16:
121                 break;
122         default:
123                 return -EINVAL;
124         }
125 
126         return 0;
127 }
128 
129 static int format_input(u8 *info, struct aead_request *req,
130                         unsigned int cryptlen)
131 {
132         struct crypto_aead *aead = crypto_aead_reqtfm(req);
133         unsigned int lp = req->iv[0];
134         unsigned int l = lp + 1;
135         unsigned int m;
136 
137         m = crypto_aead_authsize(aead);
138 
139         memcpy(info, req->iv, 16);
140 
141         /* format control info per RFC 3610 and
142          * NIST Special Publication 800-38C
143          */
144         *info |= (8 * ((m - 2) / 2));
145         if (req->assoclen)
146                 *info |= 64;
147 
148         return set_msg_len(info + 16 - l, cryptlen, l);
149 }
150 
151 static int format_adata(u8 *adata, unsigned int a)
152 {
153         int len = 0;
154 
155         /* add control info for associated data
156          * RFC 3610 and NIST Special Publication 800-38C
157          */
158         if (a < 65280) {
159                 *(__be16 *)adata = cpu_to_be16(a);
160                 len = 2;
161         } else  {
162                 *(__be16 *)adata = cpu_to_be16(0xfffe);
163                 *(__be32 *)&adata[2] = cpu_to_be32(a);
164                 len = 6;
165         }
166 
167         return len;
168 }
169 
170 static void compute_mac(struct crypto_cipher *tfm, u8 *data, int n,
171                        struct crypto_ccm_req_priv_ctx *pctx)
172 {
173         unsigned int bs = 16;
174         u8 *odata = pctx->odata;
175         u8 *idata = pctx->idata;
176         int datalen, getlen;
177 
178         datalen = n;
179 
180         /* first time in here, block may be partially filled. */
181         getlen = bs - pctx->ilen;
182         if (datalen >= getlen) {
183                 memcpy(idata + pctx->ilen, data, getlen);
184                 crypto_xor(odata, idata, bs);
185                 crypto_cipher_encrypt_one(tfm, odata, odata);
186                 datalen -= getlen;
187                 data += getlen;
188                 pctx->ilen = 0;
189         }
190 
191         /* now encrypt rest of data */
192         while (datalen >= bs) {
193                 crypto_xor(odata, data, bs);
194                 crypto_cipher_encrypt_one(tfm, odata, odata);
195 
196                 datalen -= bs;
197                 data += bs;
198         }
199 
200         /* check and see if there's leftover data that wasn't
201          * enough to fill a block.
202          */
203         if (datalen) {
204                 memcpy(idata + pctx->ilen, data, datalen);
205                 pctx->ilen += datalen;
206         }
207 }
208 
209 static void get_data_to_compute(struct crypto_cipher *tfm,
210                                struct crypto_ccm_req_priv_ctx *pctx,
211                                struct scatterlist *sg, unsigned int len)
212 {
213         struct scatter_walk walk;
214         u8 *data_src;
215         int n;
216 
217         scatterwalk_start(&walk, sg);
218 
219         while (len) {
220                 n = scatterwalk_clamp(&walk, len);
221                 if (!n) {
222                         scatterwalk_start(&walk, sg_next(walk.sg));
223                         n = scatterwalk_clamp(&walk, len);
224                 }
225                 data_src = scatterwalk_map(&walk);
226 
227                 compute_mac(tfm, data_src, n, pctx);
228                 len -= n;
229 
230                 scatterwalk_unmap(data_src);
231                 scatterwalk_advance(&walk, n);
232                 scatterwalk_done(&walk, 0, len);
233                 if (len)
234                         crypto_yield(pctx->flags);
235         }
236 
237         /* any leftover needs padding and then encrypted */
238         if (pctx->ilen) {
239                 int padlen;
240                 u8 *odata = pctx->odata;
241                 u8 *idata = pctx->idata;
242 
243                 padlen = 16 - pctx->ilen;
244                 memset(idata + pctx->ilen, 0, padlen);
245                 crypto_xor(odata, idata, 16);
246                 crypto_cipher_encrypt_one(tfm, odata, odata);
247                 pctx->ilen = 0;
248         }
249 }
250 
251 static int crypto_ccm_auth(struct aead_request *req, struct scatterlist *plain,
252                            unsigned int cryptlen)
253 {
254         struct crypto_aead *aead = crypto_aead_reqtfm(req);
255         struct crypto_ccm_ctx *ctx = crypto_aead_ctx(aead);
256         struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req);
257         struct crypto_cipher *cipher = ctx->cipher;
258         unsigned int assoclen = req->assoclen;
259         u8 *odata = pctx->odata;
260         u8 *idata = pctx->idata;
261         int err;
262 
263         /* format control data for input */
264         err = format_input(odata, req, cryptlen);
265         if (err)
266                 goto out;
267 
268         /* encrypt first block to use as start in computing mac  */
269         crypto_cipher_encrypt_one(cipher, odata, odata);
270 
271         /* format associated data and compute into mac */
272         if (assoclen) {
273                 pctx->ilen = format_adata(idata, assoclen);
274                 get_data_to_compute(cipher, pctx, req->src, req->assoclen);
275         } else {
276                 pctx->ilen = 0;
277         }
278 
279         /* compute plaintext into mac */
280         if (cryptlen)
281                 get_data_to_compute(cipher, pctx, plain, cryptlen);
282 
283 out:
284         return err;
285 }
286 
287 static void crypto_ccm_encrypt_done(struct crypto_async_request *areq, int err)
288 {
289         struct aead_request *req = areq->data;
290         struct crypto_aead *aead = crypto_aead_reqtfm(req);
291         struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req);
292         u8 *odata = pctx->odata;
293 
294         if (!err)
295                 scatterwalk_map_and_copy(odata, req->dst,
296                                          req->assoclen + req->cryptlen,
297                                          crypto_aead_authsize(aead), 1);
298         aead_request_complete(req, err);
299 }
300 
301 static inline int crypto_ccm_check_iv(const u8 *iv)
302 {
303         /* 2 <= L <= 8, so 1 <= L' <= 7. */
304         if (1 > iv[0] || iv[0] > 7)
305                 return -EINVAL;
306 
307         return 0;
308 }
309 
310 static int crypto_ccm_init_crypt(struct aead_request *req, u8 *tag)
311 {
312         struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req);
313         struct scatterlist *sg;
314         u8 *iv = req->iv;
315         int err;
316 
317         err = crypto_ccm_check_iv(iv);
318         if (err)
319                 return err;
320 
321         pctx->flags = aead_request_flags(req);
322 
323          /* Note: rfc 3610 and NIST 800-38C require counter of
324          * zero to encrypt auth tag.
325          */
326         memset(iv + 15 - iv[0], 0, iv[0] + 1);
327 
328         sg_init_table(pctx->src, 3);
329         sg_set_buf(pctx->src, tag, 16);
330         sg = scatterwalk_ffwd(pctx->src + 1, req->src, req->assoclen);
331         if (sg != pctx->src + 1)
332                 sg_chain(pctx->src, 2, sg);
333 
334         if (req->src != req->dst) {
335                 sg_init_table(pctx->dst, 3);
336                 sg_set_buf(pctx->dst, tag, 16);
337                 sg = scatterwalk_ffwd(pctx->dst + 1, req->dst, req->assoclen);
338                 if (sg != pctx->dst + 1)
339                         sg_chain(pctx->dst, 2, sg);
340         }
341 
342         return 0;
343 }
344 
345 static int crypto_ccm_encrypt(struct aead_request *req)
346 {
347         struct crypto_aead *aead = crypto_aead_reqtfm(req);
348         struct crypto_ccm_ctx *ctx = crypto_aead_ctx(aead);
349         struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req);
350         struct skcipher_request *skreq = &pctx->skreq;
351         struct scatterlist *dst;
352         unsigned int cryptlen = req->cryptlen;
353         u8 *odata = pctx->odata;
354         u8 *iv = req->iv;
355         int err;
356 
357         err = crypto_ccm_init_crypt(req, odata);
358         if (err)
359                 return err;
360 
361         err = crypto_ccm_auth(req, sg_next(pctx->src), cryptlen);
362         if (err)
363                 return err;
364 
365         dst = pctx->src;
366         if (req->src != req->dst)
367                 dst = pctx->dst;
368 
369         skcipher_request_set_tfm(skreq, ctx->ctr);
370         skcipher_request_set_callback(skreq, pctx->flags,
371                                       crypto_ccm_encrypt_done, req);
372         skcipher_request_set_crypt(skreq, pctx->src, dst, cryptlen + 16, iv);
373         err = crypto_skcipher_encrypt(skreq);
374         if (err)
375                 return err;
376 
377         /* copy authtag to end of dst */
378         scatterwalk_map_and_copy(odata, sg_next(dst), cryptlen,
379                                  crypto_aead_authsize(aead), 1);
380         return err;
381 }
382 
383 static void crypto_ccm_decrypt_done(struct crypto_async_request *areq,
384                                    int err)
385 {
386         struct aead_request *req = areq->data;
387         struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req);
388         struct crypto_aead *aead = crypto_aead_reqtfm(req);
389         unsigned int authsize = crypto_aead_authsize(aead);
390         unsigned int cryptlen = req->cryptlen - authsize;
391         struct scatterlist *dst;
392 
393         pctx->flags = 0;
394 
395         dst = sg_next(req->src == req->dst ? pctx->src : pctx->dst);
396 
397         if (!err) {
398                 err = crypto_ccm_auth(req, dst, cryptlen);
399                 if (!err && crypto_memneq(pctx->auth_tag, pctx->odata, authsize))
400                         err = -EBADMSG;
401         }
402         aead_request_complete(req, err);
403 }
404 
405 static int crypto_ccm_decrypt(struct aead_request *req)
406 {
407         struct crypto_aead *aead = crypto_aead_reqtfm(req);
408         struct crypto_ccm_ctx *ctx = crypto_aead_ctx(aead);
409         struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req);
410         struct skcipher_request *skreq = &pctx->skreq;
411         struct scatterlist *dst;
412         unsigned int authsize = crypto_aead_authsize(aead);
413         unsigned int cryptlen = req->cryptlen;
414         u8 *authtag = pctx->auth_tag;
415         u8 *odata = pctx->odata;
416         u8 *iv = req->iv;
417         int err;
418 
419         cryptlen -= authsize;
420 
421         err = crypto_ccm_init_crypt(req, authtag);
422         if (err)
423                 return err;
424 
425         scatterwalk_map_and_copy(authtag, sg_next(pctx->src), cryptlen,
426                                  authsize, 0);
427 
428         dst = pctx->src;
429         if (req->src != req->dst)
430                 dst = pctx->dst;
431 
432         skcipher_request_set_tfm(skreq, ctx->ctr);
433         skcipher_request_set_callback(skreq, pctx->flags,
434                                       crypto_ccm_decrypt_done, req);
435         skcipher_request_set_crypt(skreq, pctx->src, dst, cryptlen + 16, iv);
436         err = crypto_skcipher_decrypt(skreq);
437         if (err)
438                 return err;
439 
440         err = crypto_ccm_auth(req, sg_next(dst), cryptlen);
441         if (err)
442                 return err;
443 
444         /* verify */
445         if (crypto_memneq(authtag, odata, authsize))
446                 return -EBADMSG;
447 
448         return err;
449 }
450 
451 static int crypto_ccm_init_tfm(struct crypto_aead *tfm)
452 {
453         struct aead_instance *inst = aead_alg_instance(tfm);
454         struct ccm_instance_ctx *ictx = aead_instance_ctx(inst);
455         struct crypto_ccm_ctx *ctx = crypto_aead_ctx(tfm);
456         struct crypto_cipher *cipher;
457         struct crypto_skcipher *ctr;
458         unsigned long align;
459         int err;
460 
461         cipher = crypto_spawn_cipher(&ictx->cipher);
462         if (IS_ERR(cipher))
463                 return PTR_ERR(cipher);
464 
465         ctr = crypto_spawn_skcipher(&ictx->ctr);
466         err = PTR_ERR(ctr);
467         if (IS_ERR(ctr))
468                 goto err_free_cipher;
469 
470         ctx->cipher = cipher;
471         ctx->ctr = ctr;
472 
473         align = crypto_aead_alignmask(tfm);
474         align &= ~(crypto_tfm_ctx_alignment() - 1);
475         crypto_aead_set_reqsize(
476                 tfm,
477                 align + sizeof(struct crypto_ccm_req_priv_ctx) +
478                 crypto_skcipher_reqsize(ctr));
479 
480         return 0;
481 
482 err_free_cipher:
483         crypto_free_cipher(cipher);
484         return err;
485 }
486 
487 static void crypto_ccm_exit_tfm(struct crypto_aead *tfm)
488 {
489         struct crypto_ccm_ctx *ctx = crypto_aead_ctx(tfm);
490 
491         crypto_free_cipher(ctx->cipher);
492         crypto_free_skcipher(ctx->ctr);
493 }
494 
495 static void crypto_ccm_free(struct aead_instance *inst)
496 {
497         struct ccm_instance_ctx *ctx = aead_instance_ctx(inst);
498 
499         crypto_drop_spawn(&ctx->cipher);
500         crypto_drop_skcipher(&ctx->ctr);
501         kfree(inst);
502 }
503 
504 static int crypto_ccm_create_common(struct crypto_template *tmpl,
505                                     struct rtattr **tb,
506                                     const char *full_name,
507                                     const char *ctr_name,
508                                     const char *cipher_name)
509 {
510         struct crypto_attr_type *algt;
511         struct aead_instance *inst;
512         struct skcipher_alg *ctr;
513         struct crypto_alg *cipher;
514         struct ccm_instance_ctx *ictx;
515         int err;
516 
517         algt = crypto_get_attr_type(tb);
518         if (IS_ERR(algt))
519                 return PTR_ERR(algt);
520 
521         if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
522                 return -EINVAL;
523 
524         cipher = crypto_alg_mod_lookup(cipher_name,  CRYPTO_ALG_TYPE_CIPHER,
525                                        CRYPTO_ALG_TYPE_MASK);
526         if (IS_ERR(cipher))
527                 return PTR_ERR(cipher);
528 
529         err = -EINVAL;
530         if (cipher->cra_blocksize != 16)
531                 goto out_put_cipher;
532 
533         inst = kzalloc(sizeof(*inst) + sizeof(*ictx), GFP_KERNEL);
534         err = -ENOMEM;
535         if (!inst)
536                 goto out_put_cipher;
537 
538         ictx = aead_instance_ctx(inst);
539 
540         err = crypto_init_spawn(&ictx->cipher, cipher,
541                                 aead_crypto_instance(inst),
542                                 CRYPTO_ALG_TYPE_MASK);
543         if (err)
544                 goto err_free_inst;
545 
546         crypto_set_skcipher_spawn(&ictx->ctr, aead_crypto_instance(inst));
547         err = crypto_grab_skcipher(&ictx->ctr, ctr_name, 0,
548                                    crypto_requires_sync(algt->type,
549                                                         algt->mask));
550         if (err)
551                 goto err_drop_cipher;
552 
553         ctr = crypto_spawn_skcipher_alg(&ictx->ctr);
554 
555         /* Not a stream cipher? */
556         err = -EINVAL;
557         if (ctr->base.cra_blocksize != 1)
558                 goto err_drop_ctr;
559 
560         /* We want the real thing! */
561         if (crypto_skcipher_alg_ivsize(ctr) != 16)
562                 goto err_drop_ctr;
563 
564         err = -ENAMETOOLONG;
565         if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
566                      "ccm_base(%s,%s)", ctr->base.cra_driver_name,
567                      cipher->cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
568                 goto err_drop_ctr;
569 
570         memcpy(inst->alg.base.cra_name, full_name, CRYPTO_MAX_ALG_NAME);
571 
572         inst->alg.base.cra_flags = ctr->base.cra_flags & CRYPTO_ALG_ASYNC;
573         inst->alg.base.cra_priority = (cipher->cra_priority +
574                                        ctr->base.cra_priority) / 2;
575         inst->alg.base.cra_blocksize = 1;
576         inst->alg.base.cra_alignmask = cipher->cra_alignmask |
577                                        ctr->base.cra_alignmask |
578                                        (__alignof__(u32) - 1);
579         inst->alg.ivsize = 16;
580         inst->alg.chunksize = crypto_skcipher_alg_chunksize(ctr);
581         inst->alg.maxauthsize = 16;
582         inst->alg.base.cra_ctxsize = sizeof(struct crypto_ccm_ctx);
583         inst->alg.init = crypto_ccm_init_tfm;
584         inst->alg.exit = crypto_ccm_exit_tfm;
585         inst->alg.setkey = crypto_ccm_setkey;
586         inst->alg.setauthsize = crypto_ccm_setauthsize;
587         inst->alg.encrypt = crypto_ccm_encrypt;
588         inst->alg.decrypt = crypto_ccm_decrypt;
589 
590         inst->free = crypto_ccm_free;
591 
592         err = aead_register_instance(tmpl, inst);
593         if (err)
594                 goto err_drop_ctr;
595 
596 out_put_cipher:
597         crypto_mod_put(cipher);
598         return err;
599 
600 err_drop_ctr:
601         crypto_drop_skcipher(&ictx->ctr);
602 err_drop_cipher:
603         crypto_drop_spawn(&ictx->cipher);
604 err_free_inst:
605         kfree(inst);
606         goto out_put_cipher;
607 }
608 
609 static int crypto_ccm_create(struct crypto_template *tmpl, struct rtattr **tb)
610 {
611         const char *cipher_name;
612         char ctr_name[CRYPTO_MAX_ALG_NAME];
613         char full_name[CRYPTO_MAX_ALG_NAME];
614 
615         cipher_name = crypto_attr_alg_name(tb[1]);
616         if (IS_ERR(cipher_name))
617                 return PTR_ERR(cipher_name);
618 
619         if (snprintf(ctr_name, CRYPTO_MAX_ALG_NAME, "ctr(%s)",
620                      cipher_name) >= CRYPTO_MAX_ALG_NAME)
621                 return -ENAMETOOLONG;
622 
623         if (snprintf(full_name, CRYPTO_MAX_ALG_NAME, "ccm(%s)", cipher_name) >=
624             CRYPTO_MAX_ALG_NAME)
625                 return -ENAMETOOLONG;
626 
627         return crypto_ccm_create_common(tmpl, tb, full_name, ctr_name,
628                                         cipher_name);
629 }
630 
631 static struct crypto_template crypto_ccm_tmpl = {
632         .name = "ccm",
633         .create = crypto_ccm_create,
634         .module = THIS_MODULE,
635 };
636 
637 static int crypto_ccm_base_create(struct crypto_template *tmpl,
638                                   struct rtattr **tb)
639 {
640         const char *ctr_name;
641         const char *cipher_name;
642         char full_name[CRYPTO_MAX_ALG_NAME];
643 
644         ctr_name = crypto_attr_alg_name(tb[1]);
645         if (IS_ERR(ctr_name))
646                 return PTR_ERR(ctr_name);
647 
648         cipher_name = crypto_attr_alg_name(tb[2]);
649         if (IS_ERR(cipher_name))
650                 return PTR_ERR(cipher_name);
651 
652         if (snprintf(full_name, CRYPTO_MAX_ALG_NAME, "ccm_base(%s,%s)",
653                      ctr_name, cipher_name) >= CRYPTO_MAX_ALG_NAME)
654                 return -ENAMETOOLONG;
655 
656         return crypto_ccm_create_common(tmpl, tb, full_name, ctr_name,
657                                         cipher_name);
658 }
659 
660 static struct crypto_template crypto_ccm_base_tmpl = {
661         .name = "ccm_base",
662         .create = crypto_ccm_base_create,
663         .module = THIS_MODULE,
664 };
665 
666 static int crypto_rfc4309_setkey(struct crypto_aead *parent, const u8 *key,
667                                  unsigned int keylen)
668 {
669         struct crypto_rfc4309_ctx *ctx = crypto_aead_ctx(parent);
670         struct crypto_aead *child = ctx->child;
671         int err;
672 
673         if (keylen < 3)
674                 return -EINVAL;
675 
676         keylen -= 3;
677         memcpy(ctx->nonce, key + keylen, 3);
678 
679         crypto_aead_clear_flags(child, CRYPTO_TFM_REQ_MASK);
680         crypto_aead_set_flags(child, crypto_aead_get_flags(parent) &
681                                      CRYPTO_TFM_REQ_MASK);
682         err = crypto_aead_setkey(child, key, keylen);
683         crypto_aead_set_flags(parent, crypto_aead_get_flags(child) &
684                                       CRYPTO_TFM_RES_MASK);
685 
686         return err;
687 }
688 
689 static int crypto_rfc4309_setauthsize(struct crypto_aead *parent,
690                                       unsigned int authsize)
691 {
692         struct crypto_rfc4309_ctx *ctx = crypto_aead_ctx(parent);
693 
694         switch (authsize) {
695         case 8:
696         case 12:
697         case 16:
698                 break;
699         default:
700                 return -EINVAL;
701         }
702 
703         return crypto_aead_setauthsize(ctx->child, authsize);
704 }
705 
706 static struct aead_request *crypto_rfc4309_crypt(struct aead_request *req)
707 {
708         struct crypto_rfc4309_req_ctx *rctx = aead_request_ctx(req);
709         struct aead_request *subreq = &rctx->subreq;
710         struct crypto_aead *aead = crypto_aead_reqtfm(req);
711         struct crypto_rfc4309_ctx *ctx = crypto_aead_ctx(aead);
712         struct crypto_aead *child = ctx->child;
713         struct scatterlist *sg;
714         u8 *iv = PTR_ALIGN((u8 *)(subreq + 1) + crypto_aead_reqsize(child),
715                            crypto_aead_alignmask(child) + 1);
716 
717         /* L' */
718         iv[0] = 3;
719 
720         memcpy(iv + 1, ctx->nonce, 3);
721         memcpy(iv + 4, req->iv, 8);
722 
723         scatterwalk_map_and_copy(iv + 16, req->src, 0, req->assoclen - 8, 0);
724 
725         sg_init_table(rctx->src, 3);
726         sg_set_buf(rctx->src, iv + 16, req->assoclen - 8);
727         sg = scatterwalk_ffwd(rctx->src + 1, req->src, req->assoclen);
728         if (sg != rctx->src + 1)
729                 sg_chain(rctx->src, 2, sg);
730 
731         if (req->src != req->dst) {
732                 sg_init_table(rctx->dst, 3);
733                 sg_set_buf(rctx->dst, iv + 16, req->assoclen - 8);
734                 sg = scatterwalk_ffwd(rctx->dst + 1, req->dst, req->assoclen);
735                 if (sg != rctx->dst + 1)
736                         sg_chain(rctx->dst, 2, sg);
737         }
738 
739         aead_request_set_tfm(subreq, child);
740         aead_request_set_callback(subreq, req->base.flags, req->base.complete,
741                                   req->base.data);
742         aead_request_set_crypt(subreq, rctx->src,
743                                req->src == req->dst ? rctx->src : rctx->dst,
744                                req->cryptlen, iv);
745         aead_request_set_ad(subreq, req->assoclen - 8);
746 
747         return subreq;
748 }
749 
750 static int crypto_rfc4309_encrypt(struct aead_request *req)
751 {
752         if (req->assoclen != 16 && req->assoclen != 20)
753                 return -EINVAL;
754 
755         req = crypto_rfc4309_crypt(req);
756 
757         return crypto_aead_encrypt(req);
758 }
759 
760 static int crypto_rfc4309_decrypt(struct aead_request *req)
761 {
762         if (req->assoclen != 16 && req->assoclen != 20)
763                 return -EINVAL;
764 
765         req = crypto_rfc4309_crypt(req);
766 
767         return crypto_aead_decrypt(req);
768 }
769 
770 static int crypto_rfc4309_init_tfm(struct crypto_aead *tfm)
771 {
772         struct aead_instance *inst = aead_alg_instance(tfm);
773         struct crypto_aead_spawn *spawn = aead_instance_ctx(inst);
774         struct crypto_rfc4309_ctx *ctx = crypto_aead_ctx(tfm);
775         struct crypto_aead *aead;
776         unsigned long align;
777 
778         aead = crypto_spawn_aead(spawn);
779         if (IS_ERR(aead))
780                 return PTR_ERR(aead);
781 
782         ctx->child = aead;
783 
784         align = crypto_aead_alignmask(aead);
785         align &= ~(crypto_tfm_ctx_alignment() - 1);
786         crypto_aead_set_reqsize(
787                 tfm,
788                 sizeof(struct crypto_rfc4309_req_ctx) +
789                 ALIGN(crypto_aead_reqsize(aead), crypto_tfm_ctx_alignment()) +
790                 align + 32);
791 
792         return 0;
793 }
794 
795 static void crypto_rfc4309_exit_tfm(struct crypto_aead *tfm)
796 {
797         struct crypto_rfc4309_ctx *ctx = crypto_aead_ctx(tfm);
798 
799         crypto_free_aead(ctx->child);
800 }
801 
802 static void crypto_rfc4309_free(struct aead_instance *inst)
803 {
804         crypto_drop_aead(aead_instance_ctx(inst));
805         kfree(inst);
806 }
807 
808 static int crypto_rfc4309_create(struct crypto_template *tmpl,
809                                  struct rtattr **tb)
810 {
811         struct crypto_attr_type *algt;
812         struct aead_instance *inst;
813         struct crypto_aead_spawn *spawn;
814         struct aead_alg *alg;
815         const char *ccm_name;
816         int err;
817 
818         algt = crypto_get_attr_type(tb);
819         if (IS_ERR(algt))
820                 return PTR_ERR(algt);
821 
822         if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
823                 return -EINVAL;
824 
825         ccm_name = crypto_attr_alg_name(tb[1]);
826         if (IS_ERR(ccm_name))
827                 return PTR_ERR(ccm_name);
828 
829         inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
830         if (!inst)
831                 return -ENOMEM;
832 
833         spawn = aead_instance_ctx(inst);
834         crypto_set_aead_spawn(spawn, aead_crypto_instance(inst));
835         err = crypto_grab_aead(spawn, ccm_name, 0,
836                                crypto_requires_sync(algt->type, algt->mask));
837         if (err)
838                 goto out_free_inst;
839 
840         alg = crypto_spawn_aead_alg(spawn);
841 
842         err = -EINVAL;
843 
844         /* We only support 16-byte blocks. */
845         if (crypto_aead_alg_ivsize(alg) != 16)
846                 goto out_drop_alg;
847 
848         /* Not a stream cipher? */
849         if (alg->base.cra_blocksize != 1)
850                 goto out_drop_alg;
851 
852         err = -ENAMETOOLONG;
853         if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
854                      "rfc4309(%s)", alg->base.cra_name) >=
855             CRYPTO_MAX_ALG_NAME ||
856             snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
857                      "rfc4309(%s)", alg->base.cra_driver_name) >=
858             CRYPTO_MAX_ALG_NAME)
859                 goto out_drop_alg;
860 
861         inst->alg.base.cra_flags = alg->base.cra_flags & CRYPTO_ALG_ASYNC;
862         inst->alg.base.cra_priority = alg->base.cra_priority;
863         inst->alg.base.cra_blocksize = 1;
864         inst->alg.base.cra_alignmask = alg->base.cra_alignmask;
865 
866         inst->alg.ivsize = 8;
867         inst->alg.chunksize = crypto_aead_alg_chunksize(alg);
868         inst->alg.maxauthsize = 16;
869 
870         inst->alg.base.cra_ctxsize = sizeof(struct crypto_rfc4309_ctx);
871 
872         inst->alg.init = crypto_rfc4309_init_tfm;
873         inst->alg.exit = crypto_rfc4309_exit_tfm;
874 
875         inst->alg.setkey = crypto_rfc4309_setkey;
876         inst->alg.setauthsize = crypto_rfc4309_setauthsize;
877         inst->alg.encrypt = crypto_rfc4309_encrypt;
878         inst->alg.decrypt = crypto_rfc4309_decrypt;
879 
880         inst->free = crypto_rfc4309_free;
881 
882         err = aead_register_instance(tmpl, inst);
883         if (err)
884                 goto out_drop_alg;
885 
886 out:
887         return err;
888 
889 out_drop_alg:
890         crypto_drop_aead(spawn);
891 out_free_inst:
892         kfree(inst);
893         goto out;
894 }
895 
896 static struct crypto_template crypto_rfc4309_tmpl = {
897         .name = "rfc4309",
898         .create = crypto_rfc4309_create,
899         .module = THIS_MODULE,
900 };
901 
902 static int __init crypto_ccm_module_init(void)
903 {
904         int err;
905 
906         err = crypto_register_template(&crypto_ccm_base_tmpl);
907         if (err)
908                 goto out;
909 
910         err = crypto_register_template(&crypto_ccm_tmpl);
911         if (err)
912                 goto out_undo_base;
913 
914         err = crypto_register_template(&crypto_rfc4309_tmpl);
915         if (err)
916                 goto out_undo_ccm;
917 
918 out:
919         return err;
920 
921 out_undo_ccm:
922         crypto_unregister_template(&crypto_ccm_tmpl);
923 out_undo_base:
924         crypto_unregister_template(&crypto_ccm_base_tmpl);
925         goto out;
926 }
927 
928 static void __exit crypto_ccm_module_exit(void)
929 {
930         crypto_unregister_template(&crypto_rfc4309_tmpl);
931         crypto_unregister_template(&crypto_ccm_tmpl);
932         crypto_unregister_template(&crypto_ccm_base_tmpl);
933 }
934 
935 module_init(crypto_ccm_module_init);
936 module_exit(crypto_ccm_module_exit);
937 
938 MODULE_LICENSE("GPL");
939 MODULE_DESCRIPTION("Counter with CBC MAC");
940 MODULE_ALIAS_CRYPTO("ccm_base");
941 MODULE_ALIAS_CRYPTO("rfc4309");
942 MODULE_ALIAS_CRYPTO("ccm");
943 

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