From: Eric Biggers <ebiggers@xxxxxxxxxx>
The majority of skcipher templates (including both the existing ones and
the ones remaining to be converted from the "blkcipher" API) just wrap a
single block cipher algorithm. This includes cbc, cfb, ctr, ecb, kw,
ofb, and pcbc. Add a helper function skcipher_alloc_instance_simple()
that handles allocating an skcipher instance for this common case.
Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx>
---
crypto/skcipher.c | 131 +++++++++++++++++++++++++++++
include/crypto/internal/skcipher.h | 15 ++++
2 files changed, 146 insertions(+)
diff --git a/crypto/skcipher.c b/crypto/skcipher.c
index 2a969296bc248..040ae6377b32b 100644
--- a/crypto/skcipher.c
+++ b/crypto/skcipher.c
@@ -1058,5 +1058,136 @@ int skcipher_register_instance(struct crypto_template *tmpl,
}
EXPORT_SYMBOL_GPL(skcipher_register_instance);
+static int skcipher_setkey_simple(struct crypto_skcipher *tfm, const u8 *key,
+ unsigned int keylen)
+{
+ struct crypto_cipher *cipher = skcipher_cipher_simple(tfm);
+ int err;
+
+ crypto_cipher_clear_flags(cipher, CRYPTO_TFM_REQ_MASK);
+ crypto_cipher_set_flags(cipher, crypto_skcipher_get_flags(tfm) &
+ CRYPTO_TFM_REQ_MASK);
+ err = crypto_cipher_setkey(cipher, key, keylen);
+ crypto_skcipher_set_flags(tfm, crypto_cipher_get_flags(cipher) &
+ CRYPTO_TFM_RES_MASK);
+ return err;
+}
+
+static int skcipher_init_tfm_simple(struct crypto_skcipher *tfm)
+{
+ struct skcipher_instance *inst = skcipher_alg_instance(tfm);
+ struct crypto_spawn *spawn = skcipher_instance_ctx(inst);
+ struct skcipher_ctx_simple *ctx = crypto_skcipher_ctx(tfm);
+ struct crypto_cipher *cipher;
+
+ cipher = crypto_spawn_cipher(spawn);
+ if (IS_ERR(cipher))
+ return PTR_ERR(cipher);
+
+ ctx->cipher = cipher;
+ return 0;
+}
+
+static void skcipher_exit_tfm_simple(struct crypto_skcipher *tfm)
+{
+ struct skcipher_ctx_simple *ctx = crypto_skcipher_ctx(tfm);
+
+ crypto_free_cipher(ctx->cipher);
+}
+
+static void skcipher_free_instance_simple(struct skcipher_instance *inst)
+{
+ crypto_drop_spawn(skcipher_instance_ctx(inst));
+ kfree(inst);
+}
+
+/**
+ * skcipher_alloc_instance_simple - allocate instance of simple block cipher mode
+ *
+ * Allocate an skcipher_instance for a simple block cipher mode of operation,
+ * e.g. cbc or ecb. The instance context will have just a single crypto_spawn,
+ * that for the underlying cipher. The {min,max}_keysize, ivsize, blocksize,
+ * alignmask, and priority are set from the underlying cipher but can be
+ * overridden if needed. The tfm context defaults to skcipher_ctx_simple, and
+ * default ->setkey(), ->init(), and ->exit() methods are installed.
+ *
+ * @tmpl: the template being instantiated
+ * @tb: the template parameters
+ * @cipher_alg_ret: on success, a pointer to the underlying cipher algorithm is
+ * returned here. It must be dropped with crypto_mod_put().
+ *
+ * Return: a pointer to the new instance, or an ERR_PTR(). The caller still
+ * needs to register the instance.
+ */
+struct skcipher_instance *
+skcipher_alloc_instance_simple(struct crypto_template *tmpl, struct rtattr **tb,
+ struct crypto_alg **cipher_alg_ret)
+{
+ struct crypto_attr_type *algt;
+ struct crypto_alg *cipher_alg;
+ struct skcipher_instance *inst;
+ struct crypto_spawn *spawn;
+ u32 mask;
+ int err;
+
+ algt = crypto_get_attr_type(tb);
+ if (IS_ERR(algt))
+ return ERR_CAST(algt);
+
+ if ((algt->type ^ CRYPTO_ALG_TYPE_SKCIPHER) & algt->mask)
+ return ERR_PTR(-EINVAL);
+
+ mask = CRYPTO_ALG_TYPE_MASK |
+ crypto_requires_off(algt->type, algt->mask,
+ CRYPTO_ALG_NEED_FALLBACK);
+
+ cipher_alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER, mask);
+ if (IS_ERR(cipher_alg))
+ return ERR_CAST(cipher_alg);
+
+ inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
+ if (!inst) {
+ err = -ENOMEM;
+ goto err_put_cipher_alg;
+ }
+ spawn = skcipher_instance_ctx(inst);
+
+ err = crypto_inst_setname(skcipher_crypto_instance(inst), tmpl->name,
+ cipher_alg);
+ if (err)
+ goto err_free_inst;
+
+ err = crypto_init_spawn(spawn, cipher_alg,
+ skcipher_crypto_instance(inst),
+ CRYPTO_ALG_TYPE_MASK);
+ if (err)
+ goto err_free_inst;
+ inst->free = skcipher_free_instance_simple;
+
+ /* Default algorithm properties, can be overridden */
+ inst->alg.base.cra_blocksize = cipher_alg->cra_blocksize;
+ inst->alg.base.cra_alignmask = cipher_alg->cra_alignmask;
+ inst->alg.base.cra_priority = cipher_alg->cra_priority;
+ inst->alg.min_keysize = cipher_alg->cra_cipher.cia_min_keysize;
+ inst->alg.max_keysize = cipher_alg->cra_cipher.cia_max_keysize;
+ inst->alg.ivsize = cipher_alg->cra_blocksize;
+
+ /* Use skcipher_ctx_simple by default, can be overridden */
+ inst->alg.base.cra_ctxsize = sizeof(struct skcipher_ctx_simple);
+ inst->alg.setkey = skcipher_setkey_simple;
+ inst->alg.init = skcipher_init_tfm_simple;
+ inst->alg.exit = skcipher_exit_tfm_simple;
+
+ *cipher_alg_ret = cipher_alg;
+ return inst;
+
+err_free_inst:
+ kfree(inst);
+err_put_cipher_alg:
+ crypto_mod_put(cipher_alg);
+ return ERR_PTR(err);
+}
+EXPORT_SYMBOL_GPL(skcipher_alloc_instance_simple);
+
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Symmetric key cipher type");
diff --git a/include/crypto/internal/skcipher.h b/include/crypto/internal/skcipher.h
index 453e867b4bd92..9de6032209cb1 100644
--- a/include/crypto/internal/skcipher.h
+++ b/include/crypto/internal/skcipher.h
@@ -205,5 +205,20 @@ static inline unsigned int crypto_skcipher_alg_max_keysize(
return alg->max_keysize;
}
+/* Helpers for simple block cipher modes of operation */
+struct skcipher_ctx_simple {
+ struct crypto_cipher *cipher; /* underlying block cipher */
+};
+static inline struct crypto_cipher *
+skcipher_cipher_simple(struct crypto_skcipher *tfm)
+{
+ struct skcipher_ctx_simple *ctx = crypto_skcipher_ctx(tfm);
+
+ return ctx->cipher;
+}
+struct skcipher_instance *
+skcipher_alloc_instance_simple(struct crypto_template *tmpl, struct rtattr **tb,
+ struct crypto_alg **cipher_alg_ret);
+
#endif /* _CRYPTO_INTERNAL_SKCIPHER_H */
--
2.20.1
