ccm.c

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    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_ablkcipher *ctr;
   32 };
   33 
   34 struct crypto_rfc4309_ctx {
   35         struct crypto_aead *child;
   36         u8 nonce[3];
   37 };
   38 
   39 struct 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 
   50 static 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 
   58 static 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 
   76 static 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 
  100 out:
  101         return err;
  102 }
  103 
  104 static 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 
  123 static 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 
  145 static 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 
  164 static 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 
  203 static 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 
  245 static 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 
  276 out:
  277         return err;
  278 }
  279 
  280 static 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 
  293 static 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 
  302 static 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 
  355 static 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 
  372 static 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 
  431 static 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 
  461 err_free_cipher:
  462         crypto_free_cipher(cipher);
  463         return err;
  464 }
  465 
  466 static 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 
  474 static 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 
  559 out:
  560         crypto_mod_put(cipher);
  561         return inst;
  562 
  563 err_drop_ctr:
  564         crypto_drop_skcipher(&ictx->ctr);
  565 err_drop_cipher:
  566         crypto_drop_spawn(&ictx->cipher);
  567 err_free_inst:
  568         kfree(inst);
  569 out_put_cipher:
  570         inst = ERR_PTR(err);
  571         goto out;
  572 }
  573 
  574 static 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 
  597 static 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 
  606 static 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 
  613 static 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 
  637 static 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 
  644 static 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 
  667 static 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 
  684 static 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 
  708 static int crypto_rfc4309_encrypt(struct aead_request *req)
  709 {
  710         req = crypto_rfc4309_crypt(req);
  711 
  712         return crypto_aead_encrypt(req);
  713 }
  714 
  715 static int crypto_rfc4309_decrypt(struct aead_request *req)
  716 {
  717         req = crypto_rfc4309_crypt(req);
  718 
  719         return crypto_aead_decrypt(req);
  720 }
  721 
  722 static 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 
  746 static 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 
  753 static 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 
  828 out:
  829         return inst;
  830 
  831 out_drop_alg:
  832         crypto_drop_aead(spawn);
  833 out_free_inst:
  834         kfree(inst);
  835         inst = ERR_PTR(err);
  836         goto out;
  837 }
  838 
  839 static void crypto_rfc4309_free(struct crypto_instance *inst)
  840 {
  841         crypto_drop_spawn(crypto_instance_ctx(inst));
  842         kfree(inst);
  843 }
  844 
  845 static 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 
  852 static 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 
  868 out:
  869         return err;
  870 
  871 out_undo_ccm:
  872         crypto_unregister_template(&crypto_ccm_tmpl);
  873 out_undo_base:
  874         crypto_unregister_template(&crypto_ccm_base_tmpl);
  875         goto out;
  876 }
  877 
  878 static 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 
  885 module_init(crypto_ccm_module_init);
  886 module_exit(crypto_ccm_module_exit);
  887 
  888 MODULE_LICENSE("GPL");
  889 MODULE_DESCRIPTION("Counter with CBC MAC");
  890 MODULE_ALIAS("ccm_base");
  891 MODULE_ALIAS("rfc4309");
Cache object: 496d8294a7735ddf71e1cea584dc569f
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FreeBSD/Linux Kernel Cross Reference sys/crypto/ccm.c

FreeBSD/Linux Kernel Cross Reference
sys/crypto/ccm.c
