From: Eric Biggers <ebiggers@xxxxxxxxxx>
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@xxxxxxxxxx>
---
crypto/ctr.c | 160 +++++++++++++--------------------------------------
1 file changed, 41 insertions(+), 119 deletions(-)
diff --git a/crypto/ctr.c b/crypto/ctr.c
index 30f3946efc6da..4c743a96faa49 100644
--- a/crypto/ctr.c
+++ b/crypto/ctr.c
@@ -17,14 +17,8 @@
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
-#include <linux/random.h>
-#include <linux/scatterlist.h>
#include <linux/slab.h>
-struct crypto_ctr_ctx {
- struct crypto_cipher *child;
-};
-
struct crypto_rfc3686_ctx {
struct crypto_skcipher *child;
u8 nonce[CTR_RFC3686_NONCE_SIZE];
@@ -35,24 +29,7 @@ struct crypto_rfc3686_req_ctx {
struct skcipher_request subreq CRYPTO_MINALIGN_ATTR;
};
-static int crypto_ctr_setkey(struct crypto_tfm *parent, const u8 *key,
- unsigned int keylen)
-{
- struct crypto_ctr_ctx *ctx = crypto_tfm_ctx(parent);
- struct crypto_cipher *child = ctx->child;
- int err;
-
- crypto_cipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
- crypto_cipher_set_flags(child, crypto_tfm_get_flags(parent) &
- CRYPTO_TFM_REQ_MASK);
- err = crypto_cipher_setkey(child, key, keylen);
- crypto_tfm_set_flags(parent, crypto_cipher_get_flags(child) &
- CRYPTO_TFM_RES_MASK);
-
- return err;
-}
-
-static void crypto_ctr_crypt_final(struct blkcipher_walk *walk,
+static void crypto_ctr_crypt_final(struct skcipher_walk *walk,
struct crypto_cipher *tfm)
{
unsigned int bsize = crypto_cipher_blocksize(tfm);
@@ -70,7 +47,7 @@ static void crypto_ctr_crypt_final(struct blkcipher_walk *walk,
crypto_inc(ctrblk, bsize);
}
-static int crypto_ctr_crypt_segment(struct blkcipher_walk *walk,
+static int crypto_ctr_crypt_segment(struct skcipher_walk *walk,
struct crypto_cipher *tfm)
{
void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =
@@ -96,7 +73,7 @@ static int crypto_ctr_crypt_segment(struct blkcipher_walk *walk,
return nbytes;
}
-static int crypto_ctr_crypt_inplace(struct blkcipher_walk *walk,
+static int crypto_ctr_crypt_inplace(struct skcipher_walk *walk,
struct crypto_cipher *tfm)
{
void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =
@@ -123,135 +100,80 @@ static int crypto_ctr_crypt_inplace(struct blkcipher_walk *walk,
return nbytes;
}
-static int crypto_ctr_crypt(struct blkcipher_desc *desc,
- struct scatterlist *dst, struct scatterlist *src,
- unsigned int nbytes)
+static int crypto_ctr_crypt(struct skcipher_request *req)
{
- struct blkcipher_walk walk;
- struct crypto_blkcipher *tfm = desc->tfm;
- struct crypto_ctr_ctx *ctx = crypto_blkcipher_ctx(tfm);
- struct crypto_cipher *child = ctx->child;
- unsigned int bsize = crypto_cipher_blocksize(child);
+ struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
+ struct crypto_cipher *cipher = skcipher_cipher_simple(tfm);
+ const unsigned int bsize = crypto_cipher_blocksize(cipher);
+ struct skcipher_walk walk;
+ unsigned int nbytes;
int err;
- blkcipher_walk_init(&walk, dst, src, nbytes);
- err = blkcipher_walk_virt_block(desc, &walk, bsize);
+ err = skcipher_walk_virt(&walk, req, false);
while (walk.nbytes >= bsize) {
if (walk.src.virt.addr == walk.dst.virt.addr)
- nbytes = crypto_ctr_crypt_inplace(&walk, child);
+ nbytes = crypto_ctr_crypt_inplace(&walk, cipher);
else
- nbytes = crypto_ctr_crypt_segment(&walk, child);
+ nbytes = crypto_ctr_crypt_segment(&walk, cipher);
- err = blkcipher_walk_done(desc, &walk, nbytes);
+ err = skcipher_walk_done(&walk, nbytes);
}
if (walk.nbytes) {
- crypto_ctr_crypt_final(&walk, child);
- err = blkcipher_walk_done(desc, &walk, 0);
+ crypto_ctr_crypt_final(&walk, cipher);
+ err = skcipher_walk_done(&walk, 0);
}
return err;
}
-static int crypto_ctr_init_tfm(struct crypto_tfm *tfm)
+static int crypto_ctr_create(struct crypto_template *tmpl, struct rtattr **tb)
{
- struct crypto_instance *inst = (void *)tfm->__crt_alg;
- struct crypto_spawn *spawn = crypto_instance_ctx(inst);
- struct crypto_ctr_ctx *ctx = crypto_tfm_ctx(tfm);
- struct crypto_cipher *cipher;
-
- cipher = crypto_spawn_cipher(spawn);
- if (IS_ERR(cipher))
- return PTR_ERR(cipher);
-
- ctx->child = cipher;
-
- return 0;
-}
-
-static void crypto_ctr_exit_tfm(struct crypto_tfm *tfm)
-{
- struct crypto_ctr_ctx *ctx = crypto_tfm_ctx(tfm);
-
- crypto_free_cipher(ctx->child);
-}
-
-static struct crypto_instance *crypto_ctr_alloc(struct rtattr **tb)
-{
- struct crypto_instance *inst;
- struct crypto_attr_type *algt;
+ struct skcipher_instance *inst;
struct crypto_alg *alg;
- u32 mask;
int err;
- err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_BLKCIPHER);
- if (err)
- return ERR_PTR(err);
-
- algt = crypto_get_attr_type(tb);
- if (IS_ERR(algt))
- return ERR_CAST(algt);
-
- mask = CRYPTO_ALG_TYPE_MASK |
- crypto_requires_off(algt->type, algt->mask,
- CRYPTO_ALG_NEED_FALLBACK);
-
- alg = crypto_attr_alg(tb[1], CRYPTO_ALG_TYPE_CIPHER, mask);
- if (IS_ERR(alg))
- return ERR_CAST(alg);
+ inst = skcipher_alloc_instance_simple(tmpl, tb, &alg);
+ if (IS_ERR(inst))
+ return PTR_ERR(inst);
/* Block size must be >= 4 bytes. */
err = -EINVAL;
if (alg->cra_blocksize < 4)
- goto out_put_alg;
+ goto out_free_inst;
/* If this is false we'd fail the alignment of crypto_inc. */
if (alg->cra_blocksize % 4)
- goto out_put_alg;
-
- inst = crypto_alloc_instance("ctr", 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;
+ goto out_free_inst;
- inst->alg.cra_blkcipher.ivsize = alg->cra_blocksize;
- inst->alg.cra_blkcipher.min_keysize = alg->cra_cipher.cia_min_keysize;
- inst->alg.cra_blkcipher.max_keysize = alg->cra_cipher.cia_max_keysize;
-
- inst->alg.cra_ctxsize = sizeof(struct crypto_ctr_ctx);
+ /* CTR mode is a stream cipher. */
+ inst->alg.base.cra_blocksize = 1;
- inst->alg.cra_init = crypto_ctr_init_tfm;
- inst->alg.cra_exit = crypto_ctr_exit_tfm;
+ /*
+ * To simplify the implementation, configure the skcipher walk to only
+ * give a partial block at the very end, never earlier.
+ */
+ inst->alg.chunksize = alg->cra_blocksize;
- inst->alg.cra_blkcipher.setkey = crypto_ctr_setkey;
- inst->alg.cra_blkcipher.encrypt = crypto_ctr_crypt;
- inst->alg.cra_blkcipher.decrypt = crypto_ctr_crypt;
+ inst->alg.encrypt = crypto_ctr_crypt;
+ inst->alg.decrypt = crypto_ctr_crypt;
-out:
- crypto_mod_put(alg);
- return inst;
+ err = skcipher_register_instance(tmpl, inst);
+ if (err)
+ goto out_free_inst;
+ goto out_put_alg;
+out_free_inst:
+ inst->free(inst);
out_put_alg:
- inst = ERR_PTR(err);
- goto out;
-}
-
-static void crypto_ctr_free(struct crypto_instance *inst)
-{
- crypto_drop_spawn(crypto_instance_ctx(inst));
- kfree(inst);
+ crypto_mod_put(alg);
+ return err;
}
static struct crypto_template crypto_ctr_tmpl = {
.name = "ctr",
- .alloc = crypto_ctr_alloc,
- .free = crypto_ctr_free,
+ .create = crypto_ctr_create,
.module = THIS_MODULE,
};
@@ -480,6 +402,6 @@ module_init(crypto_ctr_module_init);
module_exit(crypto_ctr_module_exit);
MODULE_LICENSE("GPL");
-MODULE_DESCRIPTION("CTR Counter block mode");
+MODULE_DESCRIPTION("CTR block cipher mode of operation");
MODULE_ALIAS_CRYPTO("rfc3686");
MODULE_ALIAS_CRYPTO("ctr");
--
2.20.1
