+static int crypto_rfc3686_setkey(struct crypto_tfm *parent, const u8 *key,
+ unsigned int keylen)
+{
+ struct crypto_rfc3686_ctx *ctx = crypto_tfm_ctx(parent);
+ struct crypto_blkcipher *child = ctx->child;
+ int err;
+
+ /* the nonce is stored in bytes at end of key */
+ if (keylen < CTR_RFC3686_NONCE_SIZE)
+ return -EINVAL;
+
+ memcpy(ctx->nonce, key + (keylen - CTR_RFC3686_NONCE_SIZE),
+ CTR_RFC3686_NONCE_SIZE);
+
+ keylen -= CTR_RFC3686_NONCE_SIZE;
+
+ crypto_blkcipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
+ crypto_blkcipher_set_flags(child, crypto_tfm_get_flags(parent) &
+ CRYPTO_TFM_REQ_MASK);
+ err = crypto_blkcipher_setkey(child, key, keylen);
+ crypto_tfm_set_flags(parent, crypto_blkcipher_get_flags(child) &
+ CRYPTO_TFM_RES_MASK);
+
+ return err;
+}
+
+static int crypto_rfc3686_crypt(struct blkcipher_desc *desc,
+ struct scatterlist *dst,
+ struct scatterlist *src, unsigned int nbytes)
+{
+ struct crypto_blkcipher *tfm = desc->tfm;
+ struct crypto_rfc3686_ctx *ctx = crypto_blkcipher_ctx(tfm);
+ struct crypto_blkcipher *child = ctx->child;
+ unsigned long alignmask = crypto_blkcipher_alignmask(tfm);
+ u8 ivblk[CTR_RFC3686_BLOCK_SIZE + alignmask];
+ u8 *iv = PTR_ALIGN(ivblk + 0, alignmask + 1);
+ u8 *info = desc->info;
+ int err;
+
+ /* set up counter block */
+ memcpy(iv, ctx->nonce, CTR_RFC3686_NONCE_SIZE);
+ memcpy(iv + CTR_RFC3686_NONCE_SIZE, info, CTR_RFC3686_IV_SIZE);
+
+ /* initialize counter portion of counter block */
+ *(__be32 *)(iv + CTR_RFC3686_NONCE_SIZE + CTR_RFC3686_IV_SIZE) =
+ cpu_to_be32(1);
+
+ desc->tfm = child;
+ desc->info = iv;
+ err = crypto_blkcipher_encrypt_iv(desc, dst, src, nbytes);
+ desc->tfm = tfm;
+ desc->info = info;
+
+ return err;
+}
+
+static int crypto_rfc3686_init_tfm(struct crypto_tfm *tfm)
+{
+ struct crypto_instance *inst = (void *)tfm->__crt_alg;
+ struct crypto_spawn *spawn = crypto_instance_ctx(inst);
+ struct crypto_rfc3686_ctx *ctx = crypto_tfm_ctx(tfm);
+ struct crypto_blkcipher *cipher;
+
+ cipher = crypto_spawn_blkcipher(spawn);
+ if (IS_ERR(cipher))
+ return PTR_ERR(cipher);
+
+ ctx->child = cipher;
+
+ return 0;
+}
+
+static void crypto_rfc3686_exit_tfm(struct crypto_tfm *tfm)
+{
+ struct crypto_rfc3686_ctx *ctx = crypto_tfm_ctx(tfm);
+
+ crypto_free_blkcipher(ctx->child);
+}
+
+static struct crypto_instance *crypto_rfc3686_alloc(struct rtattr **tb)
+{
+ struct crypto_instance *inst;
+ struct crypto_alg *alg;
+ int err;
+
+ err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_BLKCIPHER);
+ if (err)
+ return ERR_PTR(err);
+
+ alg = crypto_attr_alg(tb[1], CRYPTO_ALG_TYPE_BLKCIPHER,
+ CRYPTO_ALG_TYPE_MASK);
+ err = PTR_ERR(alg);
+ if (IS_ERR(alg))
+ return ERR_PTR(err);
+
+ /* We only support 16-byte blocks. */
+ err = -EINVAL;
+ if (alg->cra_blkcipher.ivsize != CTR_RFC3686_BLOCK_SIZE)
+ goto out_put_alg;
+
+ /* Not a stream cipher? */
+ if (alg->cra_blocksize != 1)
+ goto out_put_alg;
+
+ inst = crypto_alloc_instance("rfc3686", alg);
+ if (IS_ERR(inst))
+ goto out;
+
+ inst->alg.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER;
+ inst->alg.cra_priority = alg->cra_priority;
+ inst->alg.cra_blocksize = 1;
+ inst->alg.cra_alignmask = alg->cra_alignmask;
+ inst->alg.cra_type = &crypto_blkcipher_type;
+
+ inst->alg.cra_blkcipher.ivsize = CTR_RFC3686_IV_SIZE;
+ inst->alg.cra_blkcipher.min_keysize = alg->cra_blkcipher.min_keysize
+ + CTR_RFC3686_NONCE_SIZE;
+ inst->alg.cra_blkcipher.max_keysize = alg->cra_blkcipher.max_keysize
+ + CTR_RFC3686_NONCE_SIZE;
+
+ inst->alg.cra_blkcipher.geniv = "seqiv";
+
+ inst->alg.cra_ctxsize = sizeof(struct crypto_rfc3686_ctx);
+
+ inst->alg.cra_init = crypto_rfc3686_init_tfm;
+ inst->alg.cra_exit = crypto_rfc3686_exit_tfm;
+
+ inst->alg.cra_blkcipher.setkey = crypto_rfc3686_setkey;
+ inst->alg.cra_blkcipher.encrypt = crypto_rfc3686_crypt;
+ inst->alg.cra_blkcipher.decrypt = crypto_rfc3686_crypt;
+
+out:
+ crypto_mod_put(alg);
+ return inst;
+
+out_put_alg:
+ inst = ERR_PTR(err);
+ goto out;
+}
+
+static struct crypto_template crypto_rfc3686_tmpl = {
+ .name = "rfc3686",
+ .alloc = crypto_rfc3686_alloc,
+ .free = crypto_ctr_free,
+ .module = THIS_MODULE,
+};
+