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-rw-r--r--include/crypto/dh.h58
-rw-r--r--include/crypto/ecdh.h58
-rw-r--r--include/crypto/kpp.h15
3 files changed, 128 insertions, 3 deletions
diff --git a/include/crypto/dh.h b/include/crypto/dh.h
index 5102a8f282e6..6b424ad3482e 100644
--- a/include/crypto/dh.h
+++ b/include/crypto/dh.h
@@ -13,6 +13,27 @@
#ifndef _CRYPTO_DH_
#define _CRYPTO_DH_
+/**
+ * DOC: DH Helper Functions
+ *
+ * To use DH with the KPP cipher API, the following data structure and
+ * functions should be used.
+ *
+ * To use DH with KPP, the following functions should be used to operate on
+ * a DH private key. The packet private key that can be set with
+ * the KPP API function call of crypto_kpp_set_secret.
+ */
+
+/**
+ * struct dh - define a DH private key
+ *
+ * @key: Private DH key
+ * @p: Diffie-Hellman parameter P
+ * @g: Diffie-Hellman generator G
+ * @key_size: Size of the private DH key
+ * @p_size: Size of DH parameter P
+ * @g_size: Size of DH generator G
+ */
struct dh {
void *key;
void *p;
@@ -22,8 +43,45 @@ struct dh {
unsigned int g_size;
};
+/**
+ * crypto_dh_key_len() - Obtain the size of the private DH key
+ * @params: private DH key
+ *
+ * This function returns the packet DH key size. A caller can use that
+ * with the provided DH private key reference to obtain the required
+ * memory size to hold a packet key.
+ *
+ * Return: size of the key in bytes
+ */
int crypto_dh_key_len(const struct dh *params);
+
+/**
+ * crypto_dh_encode_key() - encode the private key
+ * @buf: Buffer allocated by the caller to hold the packet DH
+ * private key. The buffer should be at least crypto_dh_key_len
+ * bytes in size.
+ * @len: Length of the packet private key buffer
+ * @params: Buffer with the caller-specified private key
+ *
+ * The DH implementations operate on a packet representation of the private
+ * key.
+ *
+ * Return: -EINVAL if buffer has insufficient size, 0 on success
+ */
int crypto_dh_encode_key(char *buf, unsigned int len, const struct dh *params);
+
+/**
+ * crypto_dh_decode_key() - decode a private key
+ * @buf: Buffer holding a packet key that should be decoded
+ * @len: Lenth of the packet private key buffer
+ * @params: Buffer allocated by the caller that is filled with the
+ * unpacket DH private key.
+ *
+ * The unpacking obtains the private key by pointing @p to the correct location
+ * in @buf. Thus, both pointers refer to the same memory.
+ *
+ * Return: -EINVAL if buffer has insufficient size, 0 on success
+ */
int crypto_dh_decode_key(const char *buf, unsigned int len, struct dh *params);
#endif
diff --git a/include/crypto/ecdh.h b/include/crypto/ecdh.h
index 84bad548d194..03a64f62ba7a 100644
--- a/include/crypto/ecdh.h
+++ b/include/crypto/ecdh.h
@@ -13,18 +13,76 @@
#ifndef _CRYPTO_ECDH_
#define _CRYPTO_ECDH_
+/**
+ * DOC: ECDH Helper Functions
+ *
+ * To use ECDH with the KPP cipher API, the following data structure and
+ * functions should be used.
+ *
+ * The ECC curves known to the ECDH implementation are specified in this
+ * header file.
+ *
+ * To use ECDH with KPP, the following functions should be used to operate on
+ * an ECDH private key. The packet private key that can be set with
+ * the KPP API function call of crypto_kpp_set_secret.
+ */
+
/* Curves IDs */
#define ECC_CURVE_NIST_P192 0x0001
#define ECC_CURVE_NIST_P256 0x0002
+/**
+ * struct ecdh - define an ECDH private key
+ *
+ * @curve_id: ECC curve the key is based on.
+ * @key: Private ECDH key
+ * @key_size: Size of the private ECDH key
+ */
struct ecdh {
unsigned short curve_id;
char *key;
unsigned short key_size;
};
+/**
+ * crypto_ecdh_key_len() - Obtain the size of the private ECDH key
+ * @params: private ECDH key
+ *
+ * This function returns the packet ECDH key size. A caller can use that
+ * with the provided ECDH private key reference to obtain the required
+ * memory size to hold a packet key.
+ *
+ * Return: size of the key in bytes
+ */
int crypto_ecdh_key_len(const struct ecdh *params);
+
+/**
+ * crypto_ecdh_encode_key() - encode the private key
+ * @buf: Buffer allocated by the caller to hold the packet ECDH
+ * private key. The buffer should be at least crypto_ecdh_key_len
+ * bytes in size.
+ * @len: Length of the packet private key buffer
+ * @p: Buffer with the caller-specified private key
+ *
+ * The ECDH implementations operate on a packet representation of the private
+ * key.
+ *
+ * Return: -EINVAL if buffer has insufficient size, 0 on success
+ */
int crypto_ecdh_encode_key(char *buf, unsigned int len, const struct ecdh *p);
+
+/**
+ * crypto_ecdh_decode_key() - decode a private key
+ * @buf: Buffer holding a packet key that should be decoded
+ * @len: Lenth of the packet private key buffer
+ * @p: Buffer allocated by the caller that is filled with the
+ * unpacket ECDH private key.
+ *
+ * The unpacking obtains the private key by pointing @p to the correct location
+ * in @buf. Thus, both pointers refer to the same memory.
+ *
+ * Return: -EINVAL if buffer has insufficient size, 0 on success
+ */
int crypto_ecdh_decode_key(const char *buf, unsigned int len, struct ecdh *p);
#endif
diff --git a/include/crypto/kpp.h b/include/crypto/kpp.h
index 30791f75c180..4307a2f2365f 100644
--- a/include/crypto/kpp.h
+++ b/include/crypto/kpp.h
@@ -71,7 +71,7 @@ struct crypto_kpp {
*
* @reqsize: Request context size required by algorithm
* implementation
- * @base Common crypto API algorithm data structure
+ * @base: Common crypto API algorithm data structure
*/
struct kpp_alg {
int (*set_secret)(struct crypto_kpp *tfm, void *buffer,
@@ -89,7 +89,7 @@ struct kpp_alg {
};
/**
- * DOC: Generic Key-agreement Protocol Primitevs API
+ * DOC: Generic Key-agreement Protocol Primitives API
*
* The KPP API is used with the algorithm type
* CRYPTO_ALG_TYPE_KPP (listed as type "kpp" in /proc/crypto)
@@ -264,6 +264,12 @@ struct kpp_secret {
* Function invokes the specific kpp operation for a given alg.
*
* @tfm: tfm handle
+ * @buffer: Buffer holding the packet representation of the private
+ * key. The structure of the packet key depends on the particular
+ * KPP implementation. Packing and unpacking helpers are provided
+ * for ECDH and DH (see the respective header files for those
+ * implementations).
+ * @len: Length of the packet private key buffer.
*
* Return: zero on success; error code in case of error
*/
@@ -279,7 +285,10 @@ static inline int crypto_kpp_set_secret(struct crypto_kpp *tfm, void *buffer,
* crypto_kpp_generate_public_key() - Invoke kpp operation
*
* Function invokes the specific kpp operation for generating the public part
- * for a given kpp algorithm
+ * for a given kpp algorithm.
+ *
+ * To generate a private key, the caller should use a random number generator.
+ * The output of the requested length serves as the private key.
*
* @req: kpp key request
*