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1/* SPDX-License-Identifier: GPL-2.0-or-later */2/*3 * Key-agreement Protocol Primitives (KPP)4 *5 * Copyright (c) 2016, Intel Corporation6 * Authors: Salvatore Benedetto <salvatore.benedetto@intel.com>7 */8 9#ifndef _CRYPTO_KPP_10#define _CRYPTO_KPP_11 12#include <linux/atomic.h>13#include <linux/container_of.h>14#include <linux/crypto.h>15#include <linux/slab.h>16 17/**18 * struct kpp_request19 *20 * @base: Common attributes for async crypto requests21 * @src: Source data22 * @dst: Destination data23 * @src_len: Size of the input buffer24 * @dst_len: Size of the output buffer. It needs to be at least25 * as big as the expected result depending on the operation26 * After operation it will be updated with the actual size of the27 * result. In case of error where the dst sgl size was insufficient,28 * it will be updated to the size required for the operation.29 * @__ctx: Start of private context data30 */31struct kpp_request {32 struct crypto_async_request base;33 struct scatterlist *src;34 struct scatterlist *dst;35 unsigned int src_len;36 unsigned int dst_len;37 void *__ctx[] CRYPTO_MINALIGN_ATTR;38};39 40/**41 * struct crypto_kpp - user-instantiated object which encapsulate42 * algorithms and core processing logic43 *44 * @reqsize: Request context size required by algorithm45 * implementation46 * @base: Common crypto API algorithm data structure47 */48struct crypto_kpp {49 unsigned int reqsize;50 51 struct crypto_tfm base;52};53 54/**55 * struct kpp_alg - generic key-agreement protocol primitives56 *57 * @set_secret: Function invokes the protocol specific function to58 * store the secret private key along with parameters.59 * The implementation knows how to decode the buffer60 * @generate_public_key: Function generate the public key to be sent to the61 * counterpart. In case of error, where output is not big62 * enough req->dst_len will be updated to the size63 * required64 * @compute_shared_secret: Function compute the shared secret as defined by65 * the algorithm. The result is given back to the user.66 * In case of error, where output is not big enough,67 * req->dst_len will be updated to the size required68 * @max_size: Function returns the size of the output buffer69 * @init: Initialize the object. This is called only once at70 * instantiation time. In case the cryptographic hardware71 * needs to be initialized. Software fallback should be72 * put in place here.73 * @exit: Undo everything @init did.74 *75 * @base: Common crypto API algorithm data structure76 */77struct kpp_alg {78 int (*set_secret)(struct crypto_kpp *tfm, const void *buffer,79 unsigned int len);80 int (*generate_public_key)(struct kpp_request *req);81 int (*compute_shared_secret)(struct kpp_request *req);82 83 unsigned int (*max_size)(struct crypto_kpp *tfm);84 85 int (*init)(struct crypto_kpp *tfm);86 void (*exit)(struct crypto_kpp *tfm);87 88 struct crypto_alg base;89};90 91/**92 * DOC: Generic Key-agreement Protocol Primitives API93 *94 * The KPP API is used with the algorithm type95 * CRYPTO_ALG_TYPE_KPP (listed as type "kpp" in /proc/crypto)96 */97 98/**99 * crypto_alloc_kpp() - allocate KPP tfm handle100 * @alg_name: is the name of the kpp algorithm (e.g. "dh", "ecdh")101 * @type: specifies the type of the algorithm102 * @mask: specifies the mask for the algorithm103 *104 * Allocate a handle for kpp algorithm. The returned struct crypto_kpp105 * is required for any following API invocation106 *107 * Return: allocated handle in case of success; IS_ERR() is true in case of108 * an error, PTR_ERR() returns the error code.109 */110struct crypto_kpp *crypto_alloc_kpp(const char *alg_name, u32 type, u32 mask);111 112int crypto_has_kpp(const char *alg_name, u32 type, u32 mask);113 114static inline struct crypto_tfm *crypto_kpp_tfm(struct crypto_kpp *tfm)115{116 return &tfm->base;117}118 119static inline struct kpp_alg *__crypto_kpp_alg(struct crypto_alg *alg)120{121 return container_of(alg, struct kpp_alg, base);122}123 124static inline struct crypto_kpp *__crypto_kpp_tfm(struct crypto_tfm *tfm)125{126 return container_of(tfm, struct crypto_kpp, base);127}128 129static inline struct kpp_alg *crypto_kpp_alg(struct crypto_kpp *tfm)130{131 return __crypto_kpp_alg(crypto_kpp_tfm(tfm)->__crt_alg);132}133 134static inline unsigned int crypto_kpp_reqsize(struct crypto_kpp *tfm)135{136 return tfm->reqsize;137}138 139static inline void kpp_request_set_tfm(struct kpp_request *req,140 struct crypto_kpp *tfm)141{142 req->base.tfm = crypto_kpp_tfm(tfm);143}144 145static inline struct crypto_kpp *crypto_kpp_reqtfm(struct kpp_request *req)146{147 return __crypto_kpp_tfm(req->base.tfm);148}149 150static inline u32 crypto_kpp_get_flags(struct crypto_kpp *tfm)151{152 return crypto_tfm_get_flags(crypto_kpp_tfm(tfm));153}154 155static inline void crypto_kpp_set_flags(struct crypto_kpp *tfm, u32 flags)156{157 crypto_tfm_set_flags(crypto_kpp_tfm(tfm), flags);158}159 160/**161 * crypto_free_kpp() - free KPP tfm handle162 *163 * @tfm: KPP tfm handle allocated with crypto_alloc_kpp()164 *165 * If @tfm is a NULL or error pointer, this function does nothing.166 */167static inline void crypto_free_kpp(struct crypto_kpp *tfm)168{169 crypto_destroy_tfm(tfm, crypto_kpp_tfm(tfm));170}171 172/**173 * kpp_request_alloc() - allocates kpp request174 *175 * @tfm: KPP tfm handle allocated with crypto_alloc_kpp()176 * @gfp: allocation flags177 *178 * Return: allocated handle in case of success or NULL in case of an error.179 */180static inline struct kpp_request *kpp_request_alloc(struct crypto_kpp *tfm,181 gfp_t gfp)182{183 struct kpp_request *req;184 185 req = kmalloc(sizeof(*req) + crypto_kpp_reqsize(tfm), gfp);186 if (likely(req))187 kpp_request_set_tfm(req, tfm);188 189 return req;190}191 192/**193 * kpp_request_free() - zeroize and free kpp request194 *195 * @req: request to free196 */197static inline void kpp_request_free(struct kpp_request *req)198{199 kfree_sensitive(req);200}201 202/**203 * kpp_request_set_callback() - Sets an asynchronous callback.204 *205 * Callback will be called when an asynchronous operation on a given206 * request is finished.207 *208 * @req: request that the callback will be set for209 * @flgs: specify for instance if the operation may backlog210 * @cmpl: callback which will be called211 * @data: private data used by the caller212 */213static inline void kpp_request_set_callback(struct kpp_request *req,214 u32 flgs,215 crypto_completion_t cmpl,216 void *data)217{218 req->base.complete = cmpl;219 req->base.data = data;220 req->base.flags = flgs;221}222 223/**224 * kpp_request_set_input() - Sets input buffer225 *226 * Sets parameters required by generate_public_key227 *228 * @req: kpp request229 * @input: ptr to input scatter list230 * @input_len: size of the input scatter list231 */232static inline void kpp_request_set_input(struct kpp_request *req,233 struct scatterlist *input,234 unsigned int input_len)235{236 req->src = input;237 req->src_len = input_len;238}239 240/**241 * kpp_request_set_output() - Sets output buffer242 *243 * Sets parameters required by kpp operation244 *245 * @req: kpp request246 * @output: ptr to output scatter list247 * @output_len: size of the output scatter list248 */249static inline void kpp_request_set_output(struct kpp_request *req,250 struct scatterlist *output,251 unsigned int output_len)252{253 req->dst = output;254 req->dst_len = output_len;255}256 257enum {258 CRYPTO_KPP_SECRET_TYPE_UNKNOWN,259 CRYPTO_KPP_SECRET_TYPE_DH,260 CRYPTO_KPP_SECRET_TYPE_ECDH,261};262 263/**264 * struct kpp_secret - small header for packing secret buffer265 *266 * @type: define type of secret. Each kpp type will define its own267 * @len: specify the len of the secret, include the header, that268 * follows the struct269 */270struct kpp_secret {271 unsigned short type;272 unsigned short len;273};274 275/**276 * crypto_kpp_set_secret() - Invoke kpp operation277 *278 * Function invokes the specific kpp operation for a given alg.279 *280 * @tfm: tfm handle281 * @buffer: Buffer holding the packet representation of the private282 * key. The structure of the packet key depends on the particular283 * KPP implementation. Packing and unpacking helpers are provided284 * for ECDH and DH (see the respective header files for those285 * implementations).286 * @len: Length of the packet private key buffer.287 *288 * Return: zero on success; error code in case of error289 */290static inline int crypto_kpp_set_secret(struct crypto_kpp *tfm,291 const void *buffer, unsigned int len)292{293 return crypto_kpp_alg(tfm)->set_secret(tfm, buffer, len);294}295 296/**297 * crypto_kpp_generate_public_key() - Invoke kpp operation298 *299 * Function invokes the specific kpp operation for generating the public part300 * for a given kpp algorithm.301 *302 * To generate a private key, the caller should use a random number generator.303 * The output of the requested length serves as the private key.304 *305 * @req: kpp key request306 *307 * Return: zero on success; error code in case of error308 */309static inline int crypto_kpp_generate_public_key(struct kpp_request *req)310{311 struct crypto_kpp *tfm = crypto_kpp_reqtfm(req);312 313 return crypto_kpp_alg(tfm)->generate_public_key(req);314}315 316/**317 * crypto_kpp_compute_shared_secret() - Invoke kpp operation318 *319 * Function invokes the specific kpp operation for computing the shared secret320 * for a given kpp algorithm.321 *322 * @req: kpp key request323 *324 * Return: zero on success; error code in case of error325 */326static inline int crypto_kpp_compute_shared_secret(struct kpp_request *req)327{328 struct crypto_kpp *tfm = crypto_kpp_reqtfm(req);329 330 return crypto_kpp_alg(tfm)->compute_shared_secret(req);331}332 333/**334 * crypto_kpp_maxsize() - Get len for output buffer335 *336 * Function returns the output buffer size required for a given key.337 * Function assumes that the key is already set in the transformation. If this338 * function is called without a setkey or with a failed setkey, you will end up339 * in a NULL dereference.340 *341 * @tfm: KPP tfm handle allocated with crypto_alloc_kpp()342 */343static inline unsigned int crypto_kpp_maxsize(struct crypto_kpp *tfm)344{345 struct kpp_alg *alg = crypto_kpp_alg(tfm);346 347 return alg->max_size(tfm);348}349 350#endif351