crypto: ctr - convert to skcipher API
Convert the CTR template from the deprecated "blkcipher" API to the "skcipher" API, taking advantage of skcipher_alloc_instance_simple() to simplify it considerably. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Eric Biggers
Herbert Xu
parent
03b8302dda
commit
11f14630c4
160
crypto/ctr.c
160
crypto/ctr.c
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@ -17,14 +17,8 @@
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/random.h>
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#include <linux/scatterlist.h>
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#include <linux/slab.h>
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struct crypto_ctr_ctx {
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struct crypto_cipher *child;
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};
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struct crypto_rfc3686_ctx {
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struct crypto_skcipher *child;
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u8 nonce[CTR_RFC3686_NONCE_SIZE];
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@ -35,24 +29,7 @@ struct crypto_rfc3686_req_ctx {
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struct skcipher_request subreq CRYPTO_MINALIGN_ATTR;
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};
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static int crypto_ctr_setkey(struct crypto_tfm *parent, const u8 *key,
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unsigned int keylen)
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{
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struct crypto_ctr_ctx *ctx = crypto_tfm_ctx(parent);
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struct crypto_cipher *child = ctx->child;
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int err;
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crypto_cipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
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crypto_cipher_set_flags(child, crypto_tfm_get_flags(parent) &
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CRYPTO_TFM_REQ_MASK);
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err = crypto_cipher_setkey(child, key, keylen);
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crypto_tfm_set_flags(parent, crypto_cipher_get_flags(child) &
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CRYPTO_TFM_RES_MASK);
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return err;
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}
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static void crypto_ctr_crypt_final(struct blkcipher_walk *walk,
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static void crypto_ctr_crypt_final(struct skcipher_walk *walk,
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struct crypto_cipher *tfm)
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{
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unsigned int bsize = crypto_cipher_blocksize(tfm);
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@ -70,7 +47,7 @@ static void crypto_ctr_crypt_final(struct blkcipher_walk *walk,
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crypto_inc(ctrblk, bsize);
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}
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static int crypto_ctr_crypt_segment(struct blkcipher_walk *walk,
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static int crypto_ctr_crypt_segment(struct skcipher_walk *walk,
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struct crypto_cipher *tfm)
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{
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void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =
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@ -96,7 +73,7 @@ static int crypto_ctr_crypt_segment(struct blkcipher_walk *walk,
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return nbytes;
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}
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static int crypto_ctr_crypt_inplace(struct blkcipher_walk *walk,
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static int crypto_ctr_crypt_inplace(struct skcipher_walk *walk,
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struct crypto_cipher *tfm)
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{
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void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =
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@ -123,135 +100,80 @@ static int crypto_ctr_crypt_inplace(struct blkcipher_walk *walk,
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return nbytes;
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}
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static int crypto_ctr_crypt(struct blkcipher_desc *desc,
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struct scatterlist *dst, struct scatterlist *src,
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unsigned int nbytes)
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static int crypto_ctr_crypt(struct skcipher_request *req)
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{
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struct blkcipher_walk walk;
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struct crypto_blkcipher *tfm = desc->tfm;
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struct crypto_ctr_ctx *ctx = crypto_blkcipher_ctx(tfm);
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struct crypto_cipher *child = ctx->child;
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unsigned int bsize = crypto_cipher_blocksize(child);
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struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
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struct crypto_cipher *cipher = skcipher_cipher_simple(tfm);
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const unsigned int bsize = crypto_cipher_blocksize(cipher);
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struct skcipher_walk walk;
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unsigned int nbytes;
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int err;
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blkcipher_walk_init(&walk, dst, src, nbytes);
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err = blkcipher_walk_virt_block(desc, &walk, bsize);
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err = skcipher_walk_virt(&walk, req, false);
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while (walk.nbytes >= bsize) {
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if (walk.src.virt.addr == walk.dst.virt.addr)
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nbytes = crypto_ctr_crypt_inplace(&walk, child);
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nbytes = crypto_ctr_crypt_inplace(&walk, cipher);
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else
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nbytes = crypto_ctr_crypt_segment(&walk, child);
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nbytes = crypto_ctr_crypt_segment(&walk, cipher);
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err = blkcipher_walk_done(desc, &walk, nbytes);
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err = skcipher_walk_done(&walk, nbytes);
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}
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if (walk.nbytes) {
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crypto_ctr_crypt_final(&walk, child);
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err = blkcipher_walk_done(desc, &walk, 0);
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crypto_ctr_crypt_final(&walk, cipher);
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err = skcipher_walk_done(&walk, 0);
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}
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return err;
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}
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static int crypto_ctr_init_tfm(struct crypto_tfm *tfm)
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static int crypto_ctr_create(struct crypto_template *tmpl, struct rtattr **tb)
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{
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struct crypto_instance *inst = (void *)tfm->__crt_alg;
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struct crypto_spawn *spawn = crypto_instance_ctx(inst);
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struct crypto_ctr_ctx *ctx = crypto_tfm_ctx(tfm);
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struct crypto_cipher *cipher;
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cipher = crypto_spawn_cipher(spawn);
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if (IS_ERR(cipher))
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return PTR_ERR(cipher);
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ctx->child = cipher;
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return 0;
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}
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static void crypto_ctr_exit_tfm(struct crypto_tfm *tfm)
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{
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struct crypto_ctr_ctx *ctx = crypto_tfm_ctx(tfm);
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crypto_free_cipher(ctx->child);
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}
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static struct crypto_instance *crypto_ctr_alloc(struct rtattr **tb)
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{
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struct crypto_instance *inst;
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struct crypto_attr_type *algt;
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struct skcipher_instance *inst;
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struct crypto_alg *alg;
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u32 mask;
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int err;
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err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_BLKCIPHER);
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if (err)
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return ERR_PTR(err);
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algt = crypto_get_attr_type(tb);
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if (IS_ERR(algt))
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return ERR_CAST(algt);
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mask = CRYPTO_ALG_TYPE_MASK |
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crypto_requires_off(algt->type, algt->mask,
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CRYPTO_ALG_NEED_FALLBACK);
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alg = crypto_attr_alg(tb[1], CRYPTO_ALG_TYPE_CIPHER, mask);
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if (IS_ERR(alg))
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return ERR_CAST(alg);
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inst = skcipher_alloc_instance_simple(tmpl, tb, &alg);
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if (IS_ERR(inst))
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return PTR_ERR(inst);
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/* Block size must be >= 4 bytes. */
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err = -EINVAL;
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if (alg->cra_blocksize < 4)
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goto out_put_alg;
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goto out_free_inst;
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/* If this is false we'd fail the alignment of crypto_inc. */
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if (alg->cra_blocksize % 4)
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goto out_put_alg;
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goto out_free_inst;
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inst = crypto_alloc_instance("ctr", alg);
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if (IS_ERR(inst))
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goto out;
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/* CTR mode is a stream cipher. */
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inst->alg.base.cra_blocksize = 1;
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inst->alg.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER;
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inst->alg.cra_priority = alg->cra_priority;
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inst->alg.cra_blocksize = 1;
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inst->alg.cra_alignmask = alg->cra_alignmask;
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inst->alg.cra_type = &crypto_blkcipher_type;
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/*
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* To simplify the implementation, configure the skcipher walk to only
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* give a partial block at the very end, never earlier.
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*/
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inst->alg.chunksize = alg->cra_blocksize;
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inst->alg.cra_blkcipher.ivsize = alg->cra_blocksize;
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inst->alg.cra_blkcipher.min_keysize = alg->cra_cipher.cia_min_keysize;
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inst->alg.cra_blkcipher.max_keysize = alg->cra_cipher.cia_max_keysize;
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inst->alg.encrypt = crypto_ctr_crypt;
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inst->alg.decrypt = crypto_ctr_crypt;
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inst->alg.cra_ctxsize = sizeof(struct crypto_ctr_ctx);
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inst->alg.cra_init = crypto_ctr_init_tfm;
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inst->alg.cra_exit = crypto_ctr_exit_tfm;
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inst->alg.cra_blkcipher.setkey = crypto_ctr_setkey;
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inst->alg.cra_blkcipher.encrypt = crypto_ctr_crypt;
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inst->alg.cra_blkcipher.decrypt = crypto_ctr_crypt;
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out:
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crypto_mod_put(alg);
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return inst;
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err = skcipher_register_instance(tmpl, inst);
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if (err)
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goto out_free_inst;
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goto out_put_alg;
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out_free_inst:
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inst->free(inst);
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out_put_alg:
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inst = ERR_PTR(err);
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goto out;
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}
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static void crypto_ctr_free(struct crypto_instance *inst)
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{
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crypto_drop_spawn(crypto_instance_ctx(inst));
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kfree(inst);
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crypto_mod_put(alg);
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return err;
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}
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static struct crypto_template crypto_ctr_tmpl = {
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.name = "ctr",
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.alloc = crypto_ctr_alloc,
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.free = crypto_ctr_free,
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.create = crypto_ctr_create,
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.module = THIS_MODULE,
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};
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@ -480,6 +402,6 @@ module_init(crypto_ctr_module_init);
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module_exit(crypto_ctr_module_exit);
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("CTR Counter block mode");
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MODULE_DESCRIPTION("CTR block cipher mode of operation");
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MODULE_ALIAS_CRYPTO("rfc3686");
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MODULE_ALIAS_CRYPTO("ctr");
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