/*
* Key-agreement Protocol Primitives (KPP)
*
* Copyright (c) 2016, Intel Corporation
* Authors: Salvatore Benedetto <salvatore.benedetto@intel.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the Free
* Software Foundation; either version 2 of the License, or (at your option)
* any later version.
*
*/
#ifndef _CRYPTO_KPP_
#define _CRYPTO_KPP_
#include <linux/crypto.h>
/**
* struct kpp_request
*
* @base: Common attributes for async crypto requests
* @src: Source data
* @dst: Destination data
* @src_len: Size of the input buffer
* @dst_len: Size of the output buffer. It needs to be at least
* as big as the expected result depending on the operation
* After operation it will be updated with the actual size of the
* result. In case of error where the dst sgl size was insufficient,
* it will be updated to the size required for the operation.
* @__ctx: Start of private context data
*/
struct kpp_request {
struct crypto_async_request base;
struct scatterlist *src;
struct scatterlist *dst;
unsigned int src_len;
unsigned int dst_len;
void *__ctx[] CRYPTO_MINALIGN_ATTR;
};
/**
* struct crypto_kpp - user-instantiated object which encapsulate
* algorithms and core processing logic
*
* @base: Common crypto API algorithm data structure
*/
struct crypto_kpp {
struct crypto_tfm base;
};
/**
* struct kpp_alg - generic key-agreement protocol primitives
*
* @set_secret: Function invokes the protocol specific function to
* store the secret private key along with parameters.
* The implementation knows how to decode the buffer
* @generate_public_key: Function generate the public key to be sent to the
* counterpart. In case of error, where output is not big
* enough req->dst_len will be updated to the size
* required
* @compute_shared_secret: Function compute the shared secret as defined by
* the algorithm. The result is given back to the user.
* In case of error, where output is not big enough,
* req->dst_len will be updated to the size required
* @max_size: Function returns the size of the output buffer
* @init: Initialize the object. This is called only once at
* instantiation time. In case the cryptographic hardware
* needs to be initialized. Software fallback should be
* put in place here.
* @exit: Undo everything @init did.
*
* @reqsize: Request context size required by algorithm
* implementation
* @base: Common crypto API algorithm data structure
*/
struct kpp_alg {
int (*set_secret)(struct crypto_kpp *tfm, const void *buffer,
unsigned int len);
int (*generate_public_key)(struct kpp_request *req);
int (*compute_shared_secret)(struct kpp_request *req);
unsigned int (*max_size)(struct crypto_kpp *tfm);
int (*init)(struct crypto_kpp *tfm);
void (*exit)(struct crypto_kpp *tfm);
unsigned int reqsize;
struct crypto_alg base;
};
/**
* 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)
*/
/**
* crypto_alloc_kpp() - allocate KPP tfm handle
* @alg_name: is the name of the kpp algorithm (e.g. "dh", "ecdh")
* @type: specifies the type of the algorithm
* @mask: specifies the mask for the algorithm
*
* Allocate a handle for kpp algorithm. The returned struct crypto_kpp
* is required for any following API invocation
*
* Return: allocated handle in case of success; IS_ERR() is true in case of
* an error, PTR_ERR() returns the error code.
*/
struct crypto_kpp *crypto_alloc_kpp(const char *alg_name, u32 type, u32 mask);
static inline struct crypto_tfm *crypto_kpp_tfm(struct crypto_kpp *tfm)
{
return &tfm->base;
}
static inline struct kpp_alg *__crypto_kpp_alg(struct crypto_alg *alg)
{
return container_of(alg, struct kpp_alg, base);
}
static inline struct crypto_kpp *__crypto_kpp_tfm(struct crypto_tfm *tfm)
{
return container_of(tfm, struct crypto_kpp, base);
}
static inline struct kpp_alg *crypto_kpp_alg(struct crypto_kpp *tfm)
{
return __crypto_kpp_alg(crypto_kpp_tfm(tfm)->__crt_alg);
}
static inline unsigned int crypto_kpp_reqsize(struct crypto_kpp *tfm)
{
return crypto_kpp_alg(tfm)->reqsize;
}
static inline void kpp_request_set_tfm(struct kpp_request *req,
struct crypto_kpp *tfm)
{
req->base.tfm = crypto_kpp_tfm(tfm);
}
static inline struct crypto_kpp *crypto_kpp_reqtfm(struct kpp_request *req)
{
return __crypto_kpp_tfm(req->base.tfm);
}
static inline u32 crypto_kpp_get_flags(struct crypto_kpp *tfm)
{
return crypto_tfm_get_flags(crypto_kpp_tfm(tfm));
}
static inline void crypto_kpp_set_flags(struct crypto_kpp *tfm, u32 flags)
{
crypto_tfm_set_flags(crypto_kpp_tfm(tfm), flags);
}
/**
* crypto_free_kpp() - free KPP tfm handle
*
* @tfm: KPP tfm handle allocated with crypto_alloc_kpp()
*/
static inline void crypto_free_kpp(struct crypto_kpp *tfm)
{
crypto_destroy_tfm(tfm, crypto_kpp_tfm(tfm));
}
/**
* kpp_request_alloc() - allocates kpp request
*
* @tfm: KPP tfm handle allocated with crypto_alloc_kpp()
* @gfp: allocation flags
*
* Return: allocated handle in case of success or NULL in case of an error.
*/
static inline struct kpp_request *kpp_request_alloc(struct crypto_kpp *tfm,
gfp_t gfp)
{
struct kpp_request *req;
req = kmalloc(sizeof(*req) + crypto_kpp_reqsize(tfm), gfp);
if (likely(req))
kpp_request_set_tfm(req, tfm);
return req;
}
/**
* kpp_request_free() - zeroize and free kpp request
*
* @req: request to free
*/
static inline void kpp_request_free(struct kpp_request *req)
{
kzfree(req);
}
/**
* kpp_request_set_callback() - Sets an asynchronous callback.
*
* Callback will be called when an asynchronous operation on a given
* request is finished.
*
* @req: request that the callback will be set for
* @flgs: specify for instance if the operation may backlog
* @cmpl: callback which will be called
* @data: private data used by the caller
*/
static inline void kpp_request_set_callback(struct kpp_request *req,
u32 flgs,
crypto_completion_t cmpl,
void *data)
{
req->base.complete = cmpl;
req->base.data = data;
req->base.flags = flgs;
}
/**
* kpp_request_set_input() - Sets input buffer
*
* Sets parameters required by generate_public_key
*
* @req: kpp request
* @input: ptr to input scatter list
* @input_len: size of the input scatter list
*/
static inline void kpp_request_set_input(struct kpp_request *req,
struct scatterlist *input,
unsigned int input_len)
{
req->src = input;
req->src_len = input_len;
}
/**
* kpp_request_set_output() - Sets output buffer
*
* Sets parameters required by kpp operation
*
* @req: kpp request
* @output: ptr to output scatter list
* @output_len: size of the output scatter list
*/
static inline void kpp_request_set_output(struct kpp_request *req,
struct scatterlist *output,
unsigned int output_len)
{
req->dst = output;
req->dst_len = output_len;
}
enum {
CRYPTO_KPP_SECRET_TYPE_UNKNOWN,
CRYPTO_KPP_SECRET_TYPE_DH,
CRYPTO_KPP_SECRET_TYPE_ECDH,
};
/**
* struct kpp_secret - small header for packing secret buffer
*
* @type: define type of secret. Each kpp type will define its own
* @len: specify the len of the secret, include the header, that
* follows the struct
*/
struct kpp_secret {
unsigned short type;
unsigned short len;
};
/**
* crypto_kpp_set_secret() - Invoke kpp operation
*
* 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
*/
static inline int crypto_kpp_set_secret(struct crypto_kpp *tfm,
const void *buffer, unsigned int len)
{
struct kpp_alg *alg = crypto_kpp_alg(tfm);
return alg->set_secret(tfm, buffer, len);
}
/**
* crypto_kpp_generate_public_key() - Invoke kpp operation
*
* Function invokes the specific kpp operation for generating the public part
* 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
*
* Return: zero on success; error code in case of error
*/
static inline int crypto_kpp_generate_public_key(struct kpp_request *req)
{
struct crypto_kpp *tfm = crypto_kpp_reqtfm(req);
struct kpp_alg *alg = crypto_kpp_alg(tfm);
return alg->generate_public_key(req);
}
/**
* crypto_kpp_compute_shared_secret() - Invoke kpp operation
*
* Function invokes the specific kpp operation for computing the shared secret
* for a given kpp algorithm.
*
* @req: kpp key request
*
* Return: zero on success; error code in case of error
*/
static inline int crypto_kpp_compute_shared_secret(struct kpp_request *req)
{
struct crypto_kpp *tfm = crypto_kpp_reqtfm(req);
struct kpp_alg *alg = crypto_kpp_alg(tfm);
return alg->compute_shared_secret(req);
}
/**
* crypto_kpp_maxsize() - Get len for output buffer
*
* Function returns the output buffer size required for a given key.
* Function assumes that the key is already set in the transformation. If this
* function is called without a setkey or with a failed setkey, you will end up
* in a NULL dereference.
*
* @tfm: KPP tfm handle allocated with crypto_alloc_kpp()
*/
static inline unsigned int crypto_kpp_maxsize(struct crypto_kpp *tfm)
{
struct kpp_alg *alg = crypto_kpp_alg(tfm);
return alg->max_size(tfm);
}
#endif
