[v3 PATCH 14/16] crypto: cbc - Convert to skcipher

Herbert Xu
2016-11-22T12:08:54Z

This patch converts cbc over to the skcipher interface. It also
rearranges the code to allow it to be reused by drivers.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
---

crypto/cbc.c | 242 +++++++++++++++++++++++++++++++++--------------------------
1 file changed, 138 insertions(+), 104 deletions(-)

diff --git a/crypto/cbc.c b/crypto/cbc.c
index 780ee27..6539b38 100644
--- a/crypto/cbc.c
+++ b/crypto/cbc.c
@@ -10,42 +10,39 @@
*
*/

-#include <crypto/algapi.h>
+#include <crypto/internal/skcipher.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/log2.h>
#include <linux/module.h>
-#include <linux/scatterlist.h>
#include <linux/slab.h>

struct crypto_cbc_ctx {
struct crypto_cipher *child;
};

-static int crypto_cbc_setkey(struct crypto_tfm *parent, const u8 *key,
+static int crypto_cbc_setkey(struct crypto_skcipher *parent, const u8 *key,
unsigned int keylen)
{
- struct crypto_cbc_ctx *ctx = crypto_tfm_ctx(parent);
+ struct crypto_cbc_ctx *ctx = crypto_skcipher_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_cipher_set_flags(child, crypto_skcipher_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);
+ crypto_skcipher_set_flags(parent, crypto_cipher_get_flags(child) &
+ CRYPTO_TFM_RES_MASK);
return err;
}

-static int crypto_cbc_encrypt_segment(struct blkcipher_desc *desc,
- struct blkcipher_walk *walk,
- struct crypto_cipher *tfm)
+static inline int crypto_cbc_encrypt_segment(
+ struct skcipher_walk *walk, struct crypto_skcipher *tfm,
+ void (*fn)(struct crypto_skcipher *, const u8 *, u8 *))
{
- void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =
- crypto_cipher_alg(tfm)->cia_encrypt;
- int bsize = crypto_cipher_blocksize(tfm);
+ unsigned int bsize = crypto_skcipher_blocksize(tfm);
unsigned int nbytes = walk->nbytes;
u8 *src = walk->src.virt.addr;
u8 *dst = walk->dst.virt.addr;
@@ -53,7 +50,7 @@ static int crypto_cbc_encrypt_segment(struct blkcipher_desc *desc,

do {
crypto_xor(iv, src, bsize);
- fn(crypto_cipher_tfm(tfm), dst, iv);
+ fn(tfm, iv, dst);
memcpy(iv, dst, bsize);

src += bsize;
@@ -63,20 +60,18 @@ static int crypto_cbc_encrypt_segment(struct blkcipher_desc *desc,
return nbytes;
}

-static int crypto_cbc_encrypt_inplace(struct blkcipher_desc *desc,
- struct blkcipher_walk *walk,
- struct crypto_cipher *tfm)
+static inline int crypto_cbc_encrypt_inplace(
+ struct skcipher_walk *walk, struct crypto_skcipher *tfm,
+ void (*fn)(struct crypto_skcipher *, const u8 *, u8 *))
{
- void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =
- crypto_cipher_alg(tfm)->cia_encrypt;
- int bsize = crypto_cipher_blocksize(tfm);
+ unsigned int bsize = crypto_skcipher_blocksize(tfm);
unsigned int nbytes = walk->nbytes;
u8 *src = walk->src.virt.addr;
u8 *iv = walk->iv;

do {
crypto_xor(src, iv, bsize);
- fn(crypto_cipher_tfm(tfm), src, src);
+ fn(tfm, src, src);
iv = src;

src += bsize;
@@ -87,44 +82,52 @@ static int crypto_cbc_encrypt_inplace(struct blkcipher_desc *desc,
return nbytes;
}

-static int crypto_cbc_encrypt(struct blkcipher_desc *desc,
- struct scatterlist *dst, struct scatterlist *src,
- unsigned int nbytes)
+static inline int crypto_cbc_encrypt_walk(struct skcipher_request *req,
+ void (*fn)(struct crypto_skcipher *,
+ const u8 *, u8 *))
{
- struct blkcipher_walk walk;
- struct crypto_blkcipher *tfm = desc->tfm;
- struct crypto_cbc_ctx *ctx = crypto_blkcipher_ctx(tfm);
- struct crypto_cipher *child = ctx->child;
+ struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
+ struct skcipher_walk walk;
int err;

- blkcipher_walk_init(&walk, dst, src, nbytes);
- err = blkcipher_walk_virt(desc, &walk);
+ err = skcipher_walk_virt(&walk, req, false);

- while ((nbytes = walk.nbytes)) {
+ while (walk.nbytes) {
if (walk.src.virt.addr == walk.dst.virt.addr)
- nbytes = crypto_cbc_encrypt_inplace(desc, &walk, child);
+ err = crypto_cbc_encrypt_inplace(&walk, tfm, fn);
else
- nbytes = crypto_cbc_encrypt_segment(desc, &walk, child);
- err = blkcipher_walk_done(desc, &walk, nbytes);
+ err = crypto_cbc_encrypt_segment(&walk, tfm, fn);
+ err = skcipher_walk_done(&walk, err);
}

return err;
}

-static int crypto_cbc_decrypt_segment(struct blkcipher_desc *desc,
- struct blkcipher_walk *walk,
- struct crypto_cipher *tfm)
+static inline void crypto_cbc_encrypt_one(struct crypto_skcipher *tfm,
+ const u8 *src, u8 *dst)
+{
+ struct crypto_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
+
+ crypto_cipher_encrypt_one(ctx->child, dst, src);
+}
+
+static int crypto_cbc_encrypt(struct skcipher_request *req)
{
- void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =
- crypto_cipher_alg(tfm)->cia_decrypt;
- int bsize = crypto_cipher_blocksize(tfm);
+ return crypto_cbc_encrypt_walk(req, crypto_cbc_encrypt_one);
+}
+
+static inline int crypto_cbc_decrypt_segment(
+ struct skcipher_walk *walk, struct crypto_skcipher *tfm,
+ void (*fn)(struct crypto_skcipher *, const u8 *, u8 *))
+{
+ unsigned int bsize = crypto_skcipher_blocksize(tfm);
unsigned int nbytes = walk->nbytes;
u8 *src = walk->src.virt.addr;
u8 *dst = walk->dst.virt.addr;
u8 *iv = walk->iv;

do {
- fn(crypto_cipher_tfm(tfm), dst, src);
+ fn(tfm, src, dst);
crypto_xor(dst, iv, bsize);
iv = src;

@@ -137,13 +140,11 @@ static int crypto_cbc_decrypt_segment(struct blkcipher_desc *desc,
return nbytes;
}

-static int crypto_cbc_decrypt_inplace(struct blkcipher_desc *desc,
- struct blkcipher_walk *walk,
- struct crypto_cipher *tfm)
+static inline int crypto_cbc_decrypt_inplace(
+ struct skcipher_walk *walk, struct crypto_skcipher *tfm,
+ void (*fn)(struct crypto_skcipher *, const u8 *, u8 *))
{
- void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =
- crypto_cipher_alg(tfm)->cia_decrypt;
- int bsize = crypto_cipher_blocksize(tfm);
+ unsigned int bsize = crypto_skcipher_blocksize(tfm);
unsigned int nbytes = walk->nbytes;
u8 *src = walk->src.virt.addr;
u8 last_iv[bsize];
@@ -153,7 +154,7 @@ static int crypto_cbc_decrypt_inplace(struct blkcipher_desc *desc,
memcpy(last_iv, src, bsize);

for (;;) {
- fn(crypto_cipher_tfm(tfm), src, src);
+ fn(tfm, src, src);
if ((nbytes -= bsize) < bsize)
break;
crypto_xor(src, src - bsize, bsize);
@@ -166,35 +167,46 @@ static int crypto_cbc_decrypt_inplace(struct blkcipher_desc *desc,
return nbytes;
}

-static int crypto_cbc_decrypt(struct blkcipher_desc *desc,
- struct scatterlist *dst, struct scatterlist *src,
- unsigned int nbytes)
+static inline int crypto_cbc_decrypt_blocks(
+ struct skcipher_walk *walk, struct crypto_skcipher *tfm,
+ void (*fn)(struct crypto_skcipher *, const u8 *, u8 *))
{
- struct blkcipher_walk walk;
- struct crypto_blkcipher *tfm = desc->tfm;
- struct crypto_cbc_ctx *ctx = crypto_blkcipher_ctx(tfm);
- struct crypto_cipher *child = ctx->child;
+ if (walk->src.virt.addr == walk->dst.virt.addr)
+ return crypto_cbc_decrypt_inplace(walk, tfm, fn);
+ else
+ return crypto_cbc_decrypt_segment(walk, tfm, fn);
+}
+
+static inline void crypto_cbc_decrypt_one(struct crypto_skcipher *tfm,
+ const u8 *src, u8 *dst)
+{
+ struct crypto_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
+
+ crypto_cipher_decrypt_one(ctx->child, dst, src);
+}
+
+static int crypto_cbc_decrypt(struct skcipher_request *req)
+{
+ struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
+ struct skcipher_walk walk;
int err;

- blkcipher_walk_init(&walk, dst, src, nbytes);
- err = blkcipher_walk_virt(desc, &walk);
+ err = skcipher_walk_virt(&walk, req, false);

- while ((nbytes = walk.nbytes)) {
- if (walk.src.virt.addr == walk.dst.virt.addr)
- nbytes = crypto_cbc_decrypt_inplace(desc, &walk, child);
- else
- nbytes = crypto_cbc_decrypt_segment(desc, &walk, child);
- err = blkcipher_walk_done(desc, &walk, nbytes);
+ while (walk.nbytes) {
+ err = crypto_cbc_decrypt_blocks(&walk, tfm,
+ crypto_cbc_decrypt_one);
+ err = skcipher_walk_done(&walk, err);
}

return err;
}

-static int crypto_cbc_init_tfm(struct crypto_tfm *tfm)
+static int crypto_cbc_init_tfm(struct crypto_skcipher *tfm)
{
- struct crypto_instance *inst = (void *)tfm->__crt_alg;
- struct crypto_spawn *spawn = crypto_instance_ctx(inst);
- struct crypto_cbc_ctx *ctx = crypto_tfm_ctx(tfm);
+ struct skcipher_instance *inst = skcipher_alg_instance(tfm);
+ struct crypto_spawn *spawn = skcipher_instance_ctx(inst);
+ struct crypto_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
struct crypto_cipher *cipher;

cipher = crypto_spawn_cipher(spawn);
@@ -205,72 +217,94 @@ static int crypto_cbc_init_tfm(struct crypto_tfm *tfm)
return 0;
}

-static void crypto_cbc_exit_tfm(struct crypto_tfm *tfm)
+static void crypto_cbc_exit_tfm(struct crypto_skcipher *tfm)
{
- struct crypto_cbc_ctx *ctx = crypto_tfm_ctx(tfm);
+ struct crypto_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
+
crypto_free_cipher(ctx->child);
}

-static struct crypto_instance *crypto_cbc_alloc(struct rtattr **tb)
+static void crypto_cbc_free(struct skcipher_instance *inst)
{
- struct crypto_instance *inst;
+ crypto_drop_skcipher(skcipher_instance_ctx(inst));
+ kfree(inst);
+}
+
+static int crypto_cbc_create(struct crypto_template *tmpl, struct rtattr **tb)
+{
+ struct skcipher_instance *inst;
+ struct crypto_spawn *spawn;
struct crypto_alg *alg;
int err;

- err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_BLKCIPHER);
+ err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SKCIPHER);
if (err)
- return ERR_PTR(err);
+ return err;
+
+ inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
+ if (!inst)
+ return -ENOMEM;

alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER,
CRYPTO_ALG_TYPE_MASK);
+ err = PTR_ERR(alg);
if (IS_ERR(alg))
- return ERR_CAST(alg);
+ goto err_free_inst;

- inst = ERR_PTR(-EINVAL);
- if (!is_power_of_2(alg->cra_blocksize))
- goto out_put_alg;
+ spawn = skcipher_instance_ctx(inst);
+ err = crypto_init_spawn(spawn, alg, skcipher_crypto_instance(inst),
+ CRYPTO_ALG_TYPE_MASK);
+ crypto_mod_put(alg);
+ if (err)
+ goto err_free_inst;
+
+ err = crypto_inst_setname(skcipher_crypto_instance(inst), "cbc", alg);
+ if (err)
+ goto err_drop_spawn;

- inst = crypto_alloc_instance("cbc", alg);
- if (IS_ERR(inst))
- goto out_put_alg;
+ err = -EINVAL;
+ if (!is_power_of_2(alg->cra_blocksize))
+ goto err_drop_spawn;

- inst->alg.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER;
- inst->alg.cra_priority = alg->cra_priority;
- inst->alg.cra_blocksize = alg->cra_blocksize;
- inst->alg.cra_alignmask = alg->cra_alignmask;
- inst->alg.cra_type = &crypto_blkcipher_type;
+ inst->alg.base.cra_priority = alg->cra_priority;
+ inst->alg.base.cra_blocksize = alg->cra_blocksize;
+ inst->alg.base.cra_alignmask = alg->cra_alignmask;

/* We access the data as u32s when xoring. */
- inst->alg.cra_alignmask |= __alignof__(u32) - 1;
+ inst->alg.base.cra_alignmask |= __alignof__(u32) - 1;

- 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.ivsize = alg->cra_blocksize;
+ inst->alg.min_keysize = alg->cra_cipher.cia_min_keysize;
+ inst->alg.max_keysize = alg->cra_cipher.cia_max_keysize;

- inst->alg.cra_ctxsize = sizeof(struct crypto_cbc_ctx);
+ inst->alg.base.cra_ctxsize = sizeof(struct crypto_cbc_ctx);

- inst->alg.cra_init = crypto_cbc_init_tfm;
- inst->alg.cra_exit = crypto_cbc_exit_tfm;
+ inst->alg.init = crypto_cbc_init_tfm;
+ inst->alg.exit = crypto_cbc_exit_tfm;

- inst->alg.cra_blkcipher.setkey = crypto_cbc_setkey;
- inst->alg.cra_blkcipher.encrypt = crypto_cbc_encrypt;
- inst->alg.cra_blkcipher.decrypt = crypto_cbc_decrypt;
+ inst->alg.setkey = crypto_cbc_setkey;
+ inst->alg.encrypt = crypto_cbc_encrypt;
+ inst->alg.decrypt = crypto_cbc_decrypt;

-out_put_alg:
- crypto_mod_put(alg);
- return inst;
-}
+ inst->free = crypto_cbc_free;

-static void crypto_cbc_free(struct crypto_instance *inst)
-{
- crypto_drop_spawn(crypto_instance_ctx(inst));
+ err = skcipher_register_instance(tmpl, inst);
+ if (err)
+ goto err_drop_spawn;
+
+out:
+ return err;
+
+err_drop_spawn:
+ crypto_drop_spawn(spawn);
+err_free_inst:
kfree(inst);
+ goto out;
}

static struct crypto_template crypto_cbc_tmpl = {
.name = "cbc",
- .alloc = crypto_cbc_alloc,
- .free = crypto_cbc_free,
+ .create = crypto_cbc_create,
.module = THIS_MODULE,
};