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root/crypto/ccm.c

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DEFINITIONS

This source file includes following definitions.
  1. crypto_ccm_reqctx
  2. set_msg_len
  3. crypto_ccm_setkey
  4. crypto_ccm_setauthsize
  5. format_input
  6. format_adata
  7. compute_mac
  8. get_data_to_compute
  9. crypto_ccm_auth
  10. crypto_ccm_encrypt_done
  11. crypto_ccm_check_iv
  12. crypto_ccm_encrypt
  13. crypto_ccm_decrypt_done
  14. crypto_ccm_decrypt
  15. crypto_ccm_init_tfm
  16. crypto_ccm_exit_tfm
  17. crypto_ccm_alloc_common
  18. crypto_ccm_alloc
  19. crypto_ccm_free
  20. crypto_ccm_base_alloc
  21. crypto_rfc4309_setkey
  22. crypto_rfc4309_setauthsize
  23. crypto_rfc4309_crypt
  24. crypto_rfc4309_encrypt
  25. crypto_rfc4309_decrypt
  26. crypto_rfc4309_init_tfm
  27. crypto_rfc4309_exit_tfm
  28. crypto_rfc4309_alloc
  29. crypto_rfc4309_free
  30. crypto_ccm_module_init
  31. crypto_ccm_module_exit

/*
 * CCM: Counter with CBC-MAC
 *
 * (C) Copyright IBM Corp. 2007 - Joy Latten <latten@us.ibm.com>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version.
 *
 */

#include <crypto/internal/aead.h>
#include <crypto/internal/skcipher.h>
#include <crypto/scatterwalk.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>

#include "internal.h"

struct ccm_instance_ctx {
        struct crypto_skcipher_spawn ctr;
        struct crypto_spawn cipher;
};

struct crypto_ccm_ctx {
        struct crypto_cipher *cipher;
        struct crypto_ablkcipher *ctr;
};

struct crypto_rfc4309_ctx {
        struct crypto_aead *child;
        u8 nonce[3];
};

struct crypto_ccm_req_priv_ctx {
        u8 odata[16];
        u8 idata[16];
        u8 auth_tag[16];
        u32 ilen;
        u32 flags;
        struct scatterlist src[2];
        struct scatterlist dst[2];
        struct ablkcipher_request abreq;
};

static inline struct crypto_ccm_req_priv_ctx *crypto_ccm_reqctx(
        struct aead_request *req)
{
        unsigned long align = crypto_aead_alignmask(crypto_aead_reqtfm(req));

        return (void *)PTR_ALIGN((u8 *)aead_request_ctx(req), align + 1);
}

static int set_msg_len(u8 *block, unsigned int msglen, int csize)
{
        __be32 data;

        memset(block, 0, csize);
        block += csize;

        if (csize >= 4)
                csize = 4;
        else if (msglen > (1 << (8 * csize)))
                return -EOVERFLOW;

        data = cpu_to_be32(msglen);
        memcpy(block - csize, (u8 *)&data + 4 - csize, csize);

        return 0;
}

static int crypto_ccm_setkey(struct crypto_aead *aead, const u8 *key,
                             unsigned int keylen)
{
        struct crypto_ccm_ctx *ctx = crypto_aead_ctx(aead);
        struct crypto_ablkcipher *ctr = ctx->ctr;
        struct crypto_cipher *tfm = ctx->cipher;
        int err = 0;

        crypto_ablkcipher_clear_flags(ctr, CRYPTO_TFM_REQ_MASK);
        crypto_ablkcipher_set_flags(ctr, crypto_aead_get_flags(aead) &
                                    CRYPTO_TFM_REQ_MASK);
        err = crypto_ablkcipher_setkey(ctr, key, keylen);
        crypto_aead_set_flags(aead, crypto_ablkcipher_get_flags(ctr) &
                              CRYPTO_TFM_RES_MASK);
        if (err)
                goto out;

        crypto_cipher_clear_flags(tfm, CRYPTO_TFM_REQ_MASK);
        crypto_cipher_set_flags(tfm, crypto_aead_get_flags(aead) &
                                    CRYPTO_TFM_REQ_MASK);
        err = crypto_cipher_setkey(tfm, key, keylen);
        crypto_aead_set_flags(aead, crypto_cipher_get_flags(tfm) &
                              CRYPTO_TFM_RES_MASK);

out:
        return err;
}

static int crypto_ccm_setauthsize(struct crypto_aead *tfm,
                                  unsigned int authsize)
{
        switch (authsize) {
        case 4:
        case 6:
        case 8:
        case 10:
        case 12:
        case 14:
        case 16:
                break;
        default:
                return -EINVAL;
        }

        return 0;
}

static int format_input(u8 *info, struct aead_request *req,
                        unsigned int cryptlen)
{
        struct crypto_aead *aead = crypto_aead_reqtfm(req);
        unsigned int lp = req->iv[0];
        unsigned int l = lp + 1;
        unsigned int m;

        m = crypto_aead_authsize(aead);

        memcpy(info, req->iv, 16);

        /* format control info per RFC 3610 and
         * NIST Special Publication 800-38C
         */
        *info |= (8 * ((m - 2) / 2));
        if (req->assoclen)
                *info |= 64;

        return set_msg_len(info + 16 - l, cryptlen, l);
}

static int format_adata(u8 *adata, unsigned int a)
{
        int len = 0;

        /* add control info for associated data
         * RFC 3610 and NIST Special Publication 800-38C
         */
        if (a < 65280) {
                *(__be16 *)adata = cpu_to_be16(a);
                len = 2;
        } else  {
                *(__be16 *)adata = cpu_to_be16(0xfffe);
                *(__be32 *)&adata[2] = cpu_to_be32(a);
                len = 6;
        }

        return len;
}

static void compute_mac(struct crypto_cipher *tfm, u8 *data, int n,
                       struct crypto_ccm_req_priv_ctx *pctx)
{
        unsigned int bs = 16;
        u8 *odata = pctx->odata;
        u8 *idata = pctx->idata;
        int datalen, getlen;

        datalen = n;

        /* first time in here, block may be partially filled. */
        getlen = bs - pctx->ilen;
        if (datalen >= getlen) {
                memcpy(idata + pctx->ilen, data, getlen);
                crypto_xor(odata, idata, bs);
                crypto_cipher_encrypt_one(tfm, odata, odata);
                datalen -= getlen;
                data += getlen;
                pctx->ilen = 0;
        }

        /* now encrypt rest of data */
        while (datalen >= bs) {
                crypto_xor(odata, data, bs);
                crypto_cipher_encrypt_one(tfm, odata, odata);

                datalen -= bs;
                data += bs;
        }

        /* check and see if there's leftover data that wasn't
         * enough to fill a block.
         */
        if (datalen) {
                memcpy(idata + pctx->ilen, data, datalen);
                pctx->ilen += datalen;
        }
}

static void get_data_to_compute(struct crypto_cipher *tfm,
                               struct crypto_ccm_req_priv_ctx *pctx,
                               struct scatterlist *sg, unsigned int len)
{
        struct scatter_walk walk;
        u8 *data_src;
        int n;

        scatterwalk_start(&walk, sg);

        while (len) {
                n = scatterwalk_clamp(&walk, len);
                if (!n) {
                        scatterwalk_start(&walk, sg_next(walk.sg));
                        n = scatterwalk_clamp(&walk, len);
                }
                data_src = scatterwalk_map(&walk, 0);

                compute_mac(tfm, data_src, n, pctx);
                len -= n;

                scatterwalk_unmap(data_src, 0);
                scatterwalk_advance(&walk, n);
                scatterwalk_done(&walk, 0, len);
                if (len)
                        crypto_yield(pctx->flags);
        }

        /* any leftover needs padding and then encrypted */
        if (pctx->ilen) {
                int padlen;
                u8 *odata = pctx->odata;
                u8 *idata = pctx->idata;

                padlen = 16 - pctx->ilen;
                memset(idata + pctx->ilen, 0, padlen);
                crypto_xor(odata, idata, 16);
                crypto_cipher_encrypt_one(tfm, odata, odata);
                pctx->ilen = 0;
        }
}

static int crypto_ccm_auth(struct aead_request *req, struct scatterlist *plain,
                           unsigned int cryptlen)
{
        struct crypto_aead *aead = crypto_aead_reqtfm(req);
        struct crypto_ccm_ctx *ctx = crypto_aead_ctx(aead);
        struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req);
        struct crypto_cipher *cipher = ctx->cipher;
        unsigned int assoclen = req->assoclen;
        u8 *odata = pctx->odata;
        u8 *idata = pctx->idata;
        int err;

        /* format control data for input */
        err = format_input(odata, req, cryptlen);
        if (err)
                goto out;

        /* encrypt first block to use as start in computing mac  */
        crypto_cipher_encrypt_one(cipher, odata, odata);

        /* format associated data and compute into mac */
        if (assoclen) {
                pctx->ilen = format_adata(idata, assoclen);
                get_data_to_compute(cipher, pctx, req->assoc, req->assoclen);
        }

        /* compute plaintext into mac */
        get_data_to_compute(cipher, pctx, plain, cryptlen);

out:
        return err;
}

static void crypto_ccm_encrypt_done(struct crypto_async_request *areq, int err)
{
        struct aead_request *req = areq->data;
        struct crypto_aead *aead = crypto_aead_reqtfm(req);
        struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req);
        u8 *odata = pctx->odata;

        if (!err)
                scatterwalk_map_and_copy(odata, req->dst, req->cryptlen,
                                         crypto_aead_authsize(aead), 1);
        aead_request_complete(req, err);
}

static inline int crypto_ccm_check_iv(const u8 *iv)
{
        /* 2 <= L <= 8, so 1 <= L' <= 7. */
        if (1 > iv[0] || iv[0] > 7)
                return -EINVAL;

        return 0;
}

static int crypto_ccm_encrypt(struct aead_request *req)
{
        struct crypto_aead *aead = crypto_aead_reqtfm(req);
        struct crypto_ccm_ctx *ctx = crypto_aead_ctx(aead);
        struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req);
        struct ablkcipher_request *abreq = &pctx->abreq;
        struct scatterlist *dst;
        unsigned int cryptlen = req->cryptlen;
        u8 *odata = pctx->odata;
        u8 *iv = req->iv;
        int err;

        err = crypto_ccm_check_iv(iv);
        if (err)
                return err;

        pctx->flags = aead_request_flags(req);

        err = crypto_ccm_auth(req, req->src, cryptlen);
        if (err)
                return err;

         /* Note: rfc 3610 and NIST 800-38C require counter of
         * zero to encrypt auth tag.
         */
        memset(iv + 15 - iv[0], 0, iv[0] + 1);

        sg_init_table(pctx->src, 2);
        sg_set_buf(pctx->src, odata, 16);
        scatterwalk_sg_chain(pctx->src, 2, req->src);

        dst = pctx->src;
        if (req->src != req->dst) {
                sg_init_table(pctx->dst, 2);
                sg_set_buf(pctx->dst, odata, 16);
                scatterwalk_sg_chain(pctx->dst, 2, req->dst);
                dst = pctx->dst;
        }

        ablkcipher_request_set_tfm(abreq, ctx->ctr);
        ablkcipher_request_set_callback(abreq, pctx->flags,
                                        crypto_ccm_encrypt_done, req);
        ablkcipher_request_set_crypt(abreq, pctx->src, dst, cryptlen + 16, iv);
        err = crypto_ablkcipher_encrypt(abreq);
        if (err)
                return err;

        /* copy authtag to end of dst */
        scatterwalk_map_and_copy(odata, req->dst, cryptlen,
                                 crypto_aead_authsize(aead), 1);
        return err;
}

static void crypto_ccm_decrypt_done(struct crypto_async_request *areq,
                                   int err)
{
        struct aead_request *req = areq->data;
        struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req);
        struct crypto_aead *aead = crypto_aead_reqtfm(req);
        unsigned int authsize = crypto_aead_authsize(aead);
        unsigned int cryptlen = req->cryptlen - authsize;

        if (!err) {
                err = crypto_ccm_auth(req, req->dst, cryptlen);
                if (!err && memcmp(pctx->auth_tag, pctx->odata, authsize))
                        err = -EBADMSG;
        }
        aead_request_complete(req, err);
}

static int crypto_ccm_decrypt(struct aead_request *req)
{
        struct crypto_aead *aead = crypto_aead_reqtfm(req);
        struct crypto_ccm_ctx *ctx = crypto_aead_ctx(aead);
        struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req);
        struct ablkcipher_request *abreq = &pctx->abreq;
        struct scatterlist *dst;
        unsigned int authsize = crypto_aead_authsize(aead);
        unsigned int cryptlen = req->cryptlen;
        u8 *authtag = pctx->auth_tag;
        u8 *odata = pctx->odata;
        u8 *iv = req->iv;
        int err;

        if (cryptlen < authsize)
                return -EINVAL;
        cryptlen -= authsize;

        err = crypto_ccm_check_iv(iv);
        if (err)
                return err;

        pctx->flags = aead_request_flags(req);

        scatterwalk_map_and_copy(authtag, req->src, cryptlen, authsize, 0);

        memset(iv + 15 - iv[0], 0, iv[0] + 1);

        sg_init_table(pctx->src, 2);
        sg_set_buf(pctx->src, authtag, 16);
        scatterwalk_sg_chain(pctx->src, 2, req->src);

        dst = pctx->src;
        if (req->src != req->dst) {
                sg_init_table(pctx->dst, 2);
                sg_set_buf(pctx->dst, authtag, 16);
                scatterwalk_sg_chain(pctx->dst, 2, req->dst);
                dst = pctx->dst;
        }

        ablkcipher_request_set_tfm(abreq, ctx->ctr);
        ablkcipher_request_set_callback(abreq, pctx->flags,
                                        crypto_ccm_decrypt_done, req);
        ablkcipher_request_set_crypt(abreq, pctx->src, dst, cryptlen + 16, iv);
        err = crypto_ablkcipher_decrypt(abreq);
        if (err)
                return err;

        err = crypto_ccm_auth(req, req->dst, cryptlen);
        if (err)
                return err;

        /* verify */
        if (memcmp(authtag, odata, authsize))
                return -EBADMSG;

        return err;
}

static int crypto_ccm_init_tfm(struct crypto_tfm *tfm)
{
        struct crypto_instance *inst = (void *)tfm->__crt_alg;
        struct ccm_instance_ctx *ictx = crypto_instance_ctx(inst);
        struct crypto_ccm_ctx *ctx = crypto_tfm_ctx(tfm);
        struct crypto_cipher *cipher;
        struct crypto_ablkcipher *ctr;
        unsigned long align;
        int err;

        cipher = crypto_spawn_cipher(&ictx->cipher);
        if (IS_ERR(cipher))
                return PTR_ERR(cipher);

        ctr = crypto_spawn_skcipher(&ictx->ctr);
        err = PTR_ERR(ctr);
        if (IS_ERR(ctr))
                goto err_free_cipher;

        ctx->cipher = cipher;
        ctx->ctr = ctr;

        align = crypto_tfm_alg_alignmask(tfm);
        align &= ~(crypto_tfm_ctx_alignment() - 1);
        tfm->crt_aead.reqsize = align +
                                sizeof(struct crypto_ccm_req_priv_ctx) +
                                crypto_ablkcipher_reqsize(ctr);

        return 0;

err_free_cipher:
        crypto_free_cipher(cipher);
        return err;
}

static void crypto_ccm_exit_tfm(struct crypto_tfm *tfm)
{
        struct crypto_ccm_ctx *ctx = crypto_tfm_ctx(tfm);

        crypto_free_cipher(ctx->cipher);
        crypto_free_ablkcipher(ctx->ctr);
}

static struct crypto_instance *crypto_ccm_alloc_common(struct rtattr **tb,
                                                       const char *full_name,
                                                       const char *ctr_name,
                                                       const char *cipher_name)
{
        struct crypto_attr_type *algt;
        struct crypto_instance *inst;
        struct crypto_alg *ctr;
        struct crypto_alg *cipher;
        struct ccm_instance_ctx *ictx;
        int err;

        algt = crypto_get_attr_type(tb);
        err = PTR_ERR(algt);
        if (IS_ERR(algt))
                return ERR_PTR(err);

        if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
                return ERR_PTR(-EINVAL);

        cipher = crypto_alg_mod_lookup(cipher_name,  CRYPTO_ALG_TYPE_CIPHER,
                                       CRYPTO_ALG_TYPE_MASK);
        err = PTR_ERR(cipher);
        if (IS_ERR(cipher))
                return ERR_PTR(err);

        err = -EINVAL;
        if (cipher->cra_blocksize != 16)
                goto out_put_cipher;

        inst = kzalloc(sizeof(*inst) + sizeof(*ictx), GFP_KERNEL);
        err = -ENOMEM;
        if (!inst)
                goto out_put_cipher;

        ictx = crypto_instance_ctx(inst);

        err = crypto_init_spawn(&ictx->cipher, cipher, inst,
                                CRYPTO_ALG_TYPE_MASK);
        if (err)
                goto err_free_inst;

        crypto_set_skcipher_spawn(&ictx->ctr, inst);
        err = crypto_grab_skcipher(&ictx->ctr, ctr_name, 0,
                                   crypto_requires_sync(algt->type,
                                                        algt->mask));
        if (err)
                goto err_drop_cipher;

        ctr = crypto_skcipher_spawn_alg(&ictx->ctr);

        /* Not a stream cipher? */
        err = -EINVAL;
        if (ctr->cra_blocksize != 1)
                goto err_drop_ctr;

        /* We want the real thing! */
        if (ctr->cra_ablkcipher.ivsize != 16)
                goto err_drop_ctr;

        err = -ENAMETOOLONG;
        if (snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME,
                     "ccm_base(%s,%s)", ctr->cra_driver_name,
                     cipher->cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
                goto err_drop_ctr;

        memcpy(inst->alg.cra_name, full_name, CRYPTO_MAX_ALG_NAME);

        inst->alg.cra_flags = CRYPTO_ALG_TYPE_AEAD;
        inst->alg.cra_flags |= ctr->cra_flags & CRYPTO_ALG_ASYNC;
        inst->alg.cra_priority = cipher->cra_priority + ctr->cra_priority;
        inst->alg.cra_blocksize = 1;
        inst->alg.cra_alignmask = cipher->cra_alignmask | ctr->cra_alignmask |
                                  (__alignof__(u32) - 1);
        inst->alg.cra_type = &crypto_aead_type;
        inst->alg.cra_aead.ivsize = 16;
        inst->alg.cra_aead.maxauthsize = 16;
        inst->alg.cra_ctxsize = sizeof(struct crypto_ccm_ctx);
        inst->alg.cra_init = crypto_ccm_init_tfm;
        inst->alg.cra_exit = crypto_ccm_exit_tfm;
        inst->alg.cra_aead.setkey = crypto_ccm_setkey;
        inst->alg.cra_aead.setauthsize = crypto_ccm_setauthsize;
        inst->alg.cra_aead.encrypt = crypto_ccm_encrypt;
        inst->alg.cra_aead.decrypt = crypto_ccm_decrypt;

out:
        crypto_mod_put(cipher);
        return inst;

err_drop_ctr:
        crypto_drop_skcipher(&ictx->ctr);
err_drop_cipher:
        crypto_drop_spawn(&ictx->cipher);
err_free_inst:
        kfree(inst);
out_put_cipher:
        inst = ERR_PTR(err);
        goto out;
}

static struct crypto_instance *crypto_ccm_alloc(struct rtattr **tb)
{
        int err;
        const char *cipher_name;
        char ctr_name[CRYPTO_MAX_ALG_NAME];
        char full_name[CRYPTO_MAX_ALG_NAME];

        cipher_name = crypto_attr_alg_name(tb[1]);
        err = PTR_ERR(cipher_name);
        if (IS_ERR(cipher_name))
                return ERR_PTR(err);

        if (snprintf(ctr_name, CRYPTO_MAX_ALG_NAME, "ctr(%s)",
                     cipher_name) >= CRYPTO_MAX_ALG_NAME)
                return ERR_PTR(-ENAMETOOLONG);

        if (snprintf(full_name, CRYPTO_MAX_ALG_NAME, "ccm(%s)", cipher_name) >=
            CRYPTO_MAX_ALG_NAME)
                return ERR_PTR(-ENAMETOOLONG);

        return crypto_ccm_alloc_common(tb, full_name, ctr_name, cipher_name);
}

static void crypto_ccm_free(struct crypto_instance *inst)
{
        struct ccm_instance_ctx *ctx = crypto_instance_ctx(inst);

        crypto_drop_spawn(&ctx->cipher);
        crypto_drop_skcipher(&ctx->ctr);
        kfree(inst);
}

static struct crypto_template crypto_ccm_tmpl = {
        .name = "ccm",
        .alloc = crypto_ccm_alloc,
        .free = crypto_ccm_free,
        .module = THIS_MODULE,
};

static struct crypto_instance *crypto_ccm_base_alloc(struct rtattr **tb)
{
        int err;
        const char *ctr_name;
        const char *cipher_name;
        char full_name[CRYPTO_MAX_ALG_NAME];

        ctr_name = crypto_attr_alg_name(tb[1]);
        err = PTR_ERR(ctr_name);
        if (IS_ERR(ctr_name))
                return ERR_PTR(err);

        cipher_name = crypto_attr_alg_name(tb[2]);
        err = PTR_ERR(cipher_name);
        if (IS_ERR(cipher_name))
                return ERR_PTR(err);

        if (snprintf(full_name, CRYPTO_MAX_ALG_NAME, "ccm_base(%s,%s)",
                     ctr_name, cipher_name) >= CRYPTO_MAX_ALG_NAME)
                return ERR_PTR(-ENAMETOOLONG);

        return crypto_ccm_alloc_common(tb, full_name, ctr_name, cipher_name);
}

static struct crypto_template crypto_ccm_base_tmpl = {
        .name = "ccm_base",
        .alloc = crypto_ccm_base_alloc,
        .free = crypto_ccm_free,
        .module = THIS_MODULE,
};

static int crypto_rfc4309_setkey(struct crypto_aead *parent, const u8 *key,
                                 unsigned int keylen)
{
        struct crypto_rfc4309_ctx *ctx = crypto_aead_ctx(parent);
        struct crypto_aead *child = ctx->child;
        int err;

        if (keylen < 3)
                return -EINVAL;

        keylen -= 3;
        memcpy(ctx->nonce, key + keylen, 3);

        crypto_aead_clear_flags(child, CRYPTO_TFM_REQ_MASK);
        crypto_aead_set_flags(child, crypto_aead_get_flags(parent) &
                                     CRYPTO_TFM_REQ_MASK);
        err = crypto_aead_setkey(child, key, keylen);
        crypto_aead_set_flags(parent, crypto_aead_get_flags(child) &
                                      CRYPTO_TFM_RES_MASK);

        return err;
}

static int crypto_rfc4309_setauthsize(struct crypto_aead *parent,
                                      unsigned int authsize)
{
        struct crypto_rfc4309_ctx *ctx = crypto_aead_ctx(parent);

        switch (authsize) {
        case 8:
        case 12:
        case 16:
                break;
        default:
                return -EINVAL;
        }

        return crypto_aead_setauthsize(ctx->child, authsize);
}

static struct aead_request *crypto_rfc4309_crypt(struct aead_request *req)
{
        struct aead_request *subreq = aead_request_ctx(req);
        struct crypto_aead *aead = crypto_aead_reqtfm(req);
        struct crypto_rfc4309_ctx *ctx = crypto_aead_ctx(aead);
        struct crypto_aead *child = ctx->child;
        u8 *iv = PTR_ALIGN((u8 *)(subreq + 1) + crypto_aead_reqsize(child),
                           crypto_aead_alignmask(child) + 1);

        /* L' */
        iv[0] = 3;

        memcpy(iv + 1, ctx->nonce, 3);
        memcpy(iv + 4, req->iv, 8);

        aead_request_set_tfm(subreq, child);
        aead_request_set_callback(subreq, req->base.flags, req->base.complete,
                                  req->base.data);
        aead_request_set_crypt(subreq, req->src, req->dst, req->cryptlen, iv);
        aead_request_set_assoc(subreq, req->assoc, req->assoclen);

        return subreq;
}

static int crypto_rfc4309_encrypt(struct aead_request *req)
{
        req = crypto_rfc4309_crypt(req);

        return crypto_aead_encrypt(req);
}

static int crypto_rfc4309_decrypt(struct aead_request *req)
{
        req = crypto_rfc4309_crypt(req);

        return crypto_aead_decrypt(req);
}

static int crypto_rfc4309_init_tfm(struct crypto_tfm *tfm)
{
        struct crypto_instance *inst = (void *)tfm->__crt_alg;
        struct crypto_aead_spawn *spawn = crypto_instance_ctx(inst);
        struct crypto_rfc4309_ctx *ctx = crypto_tfm_ctx(tfm);
        struct crypto_aead *aead;
        unsigned long align;

        aead = crypto_spawn_aead(spawn);
        if (IS_ERR(aead))
                return PTR_ERR(aead);

        ctx->child = aead;

        align = crypto_aead_alignmask(aead);
        align &= ~(crypto_tfm_ctx_alignment() - 1);
        tfm->crt_aead.reqsize = sizeof(struct aead_request) +
                                ALIGN(crypto_aead_reqsize(aead),
                                      crypto_tfm_ctx_alignment()) +
                                align + 16;

        return 0;
}

static void crypto_rfc4309_exit_tfm(struct crypto_tfm *tfm)
{
        struct crypto_rfc4309_ctx *ctx = crypto_tfm_ctx(tfm);

        crypto_free_aead(ctx->child);
}

static struct crypto_instance *crypto_rfc4309_alloc(struct rtattr **tb)
{
        struct crypto_attr_type *algt;
        struct crypto_instance *inst;
        struct crypto_aead_spawn *spawn;
        struct crypto_alg *alg;
        const char *ccm_name;
        int err;

        algt = crypto_get_attr_type(tb);
        err = PTR_ERR(algt);
        if (IS_ERR(algt))
                return ERR_PTR(err);

        if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
                return ERR_PTR(-EINVAL);

        ccm_name = crypto_attr_alg_name(tb[1]);
        err = PTR_ERR(ccm_name);
        if (IS_ERR(ccm_name))
                return ERR_PTR(err);

        inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
        if (!inst)
                return ERR_PTR(-ENOMEM);

        spawn = crypto_instance_ctx(inst);
        crypto_set_aead_spawn(spawn, inst);
        err = crypto_grab_aead(spawn, ccm_name, 0,
                               crypto_requires_sync(algt->type, algt->mask));
        if (err)
                goto out_free_inst;

        alg = crypto_aead_spawn_alg(spawn);

        err = -EINVAL;

        /* We only support 16-byte blocks. */
        if (alg->cra_aead.ivsize != 16)
                goto out_drop_alg;

        /* Not a stream cipher? */
        if (alg->cra_blocksize != 1)
                goto out_drop_alg;

        err = -ENAMETOOLONG;
        if (snprintf(inst->alg.cra_name, CRYPTO_MAX_ALG_NAME,
                     "rfc4309(%s)", alg->cra_name) >= CRYPTO_MAX_ALG_NAME ||
            snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME,
                     "rfc4309(%s)", alg->cra_driver_name) >=
            CRYPTO_MAX_ALG_NAME)
                goto out_drop_alg;

        inst->alg.cra_flags = CRYPTO_ALG_TYPE_AEAD;
        inst->alg.cra_flags |= alg->cra_flags & CRYPTO_ALG_ASYNC;
        inst->alg.cra_priority = alg->cra_priority;
        inst->alg.cra_blocksize = 1;
        inst->alg.cra_alignmask = alg->cra_alignmask;
        inst->alg.cra_type = &crypto_nivaead_type;

        inst->alg.cra_aead.ivsize = 8;
        inst->alg.cra_aead.maxauthsize = 16;

        inst->alg.cra_ctxsize = sizeof(struct crypto_rfc4309_ctx);

        inst->alg.cra_init = crypto_rfc4309_init_tfm;
        inst->alg.cra_exit = crypto_rfc4309_exit_tfm;

        inst->alg.cra_aead.setkey = crypto_rfc4309_setkey;
        inst->alg.cra_aead.setauthsize = crypto_rfc4309_setauthsize;
        inst->alg.cra_aead.encrypt = crypto_rfc4309_encrypt;
        inst->alg.cra_aead.decrypt = crypto_rfc4309_decrypt;

        inst->alg.cra_aead.geniv = "seqiv";

out:
        return inst;

out_drop_alg:
        crypto_drop_aead(spawn);
out_free_inst:
        kfree(inst);
        inst = ERR_PTR(err);
        goto out;
}

static void crypto_rfc4309_free(struct crypto_instance *inst)
{
        crypto_drop_spawn(crypto_instance_ctx(inst));
        kfree(inst);
}

static struct crypto_template crypto_rfc4309_tmpl = {
        .name = "rfc4309",
        .alloc = crypto_rfc4309_alloc,
        .free = crypto_rfc4309_free,
        .module = THIS_MODULE,
};

static int __init crypto_ccm_module_init(void)
{
        int err;

        err = crypto_register_template(&crypto_ccm_base_tmpl);
        if (err)
                goto out;

        err = crypto_register_template(&crypto_ccm_tmpl);
        if (err)
                goto out_undo_base;

        err = crypto_register_template(&crypto_rfc4309_tmpl);
        if (err)
                goto out_undo_ccm;

out:
        return err;

out_undo_ccm:
        crypto_unregister_template(&crypto_ccm_tmpl);
out_undo_base:
        crypto_unregister_template(&crypto_ccm_base_tmpl);
        goto out;
}

static void __exit crypto_ccm_module_exit(void)
{
        crypto_unregister_template(&crypto_rfc4309_tmpl);
        crypto_unregister_template(&crypto_ccm_tmpl);
        crypto_unregister_template(&crypto_ccm_base_tmpl);
}

module_init(crypto_ccm_module_init);
module_exit(crypto_ccm_module_exit);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Counter with CBC MAC");
MODULE_ALIAS("ccm_base");
MODULE_ALIAS("rfc4309");

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