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