1 /* SPDX-License-Identifier: GPL-2.0-or-later */ 2 /* 3 * Key-agreement Protocol Primitives (KPP) 4 * 5 * Copyright (c) 2016, Intel Corporation 6 * Authors: Salvatore Benedetto <salvatore.benedetto@intel.com> 7 */ 8 9 #ifndef _CRYPTO_KPP_ 10 #define _CRYPTO_KPP_ 11 #include <linux/crypto.h> 12 13 /** 14 * struct kpp_request 15 * 16 * @base: Common attributes for async crypto requests 17 * @src: Source data 18 * @dst: Destination data 19 * @src_len: Size of the input buffer 20 * @dst_len: Size of the output buffer. It needs to be at least 21 * as big as the expected result depending on the operation 22 * After operation it will be updated with the actual size of the 23 * result. In case of error where the dst sgl size was insufficient, 24 * it will be updated to the size required for the operation. 25 * @__ctx: Start of private context data 26 */ 27 struct kpp_request { 28 struct crypto_async_request base; 29 struct scatterlist *src; 30 struct scatterlist *dst; 31 unsigned int src_len; 32 unsigned int dst_len; 33 void *__ctx[] CRYPTO_MINALIGN_ATTR; 34 }; 35 36 /** 37 * struct crypto_kpp - user-instantiated object which encapsulate 38 * algorithms and core processing logic 39 * 40 * @reqsize: Request context size required by algorithm 41 * implementation 42 * @base: Common crypto API algorithm data structure 43 */ 44 struct crypto_kpp { 45 unsigned int reqsize; 46 47 struct crypto_tfm base; 48 }; 49 50 /** 51 * struct kpp_alg - generic key-agreement protocol primitives 52 * 53 * @set_secret: Function invokes the protocol specific function to 54 * store the secret private key along with parameters. 55 * The implementation knows how to decode the buffer 56 * @generate_public_key: Function generate the public key to be sent to the 57 * counterpart. In case of error, where output is not big 58 * enough req->dst_len will be updated to the size 59 * required 60 * @compute_shared_secret: Function compute the shared secret as defined by 61 * the algorithm. The result is given back to the user. 62 * In case of error, where output is not big enough, 63 * req->dst_len will be updated to the size required 64 * @max_size: Function returns the size of the output buffer 65 * @init: Initialize the object. This is called only once at 66 * instantiation time. In case the cryptographic hardware 67 * needs to be initialized. Software fallback should be 68 * put in place here. 69 * @exit: Undo everything @init did. 70 * 71 * @base: Common crypto API algorithm data structure 72 */ 73 struct kpp_alg { 74 int (*set_secret)(struct crypto_kpp *tfm, const void *buffer, 75 unsigned int len); 76 int (*generate_public_key)(struct kpp_request *req); 77 int (*compute_shared_secret)(struct kpp_request *req); 78 79 unsigned int (*max_size)(struct crypto_kpp *tfm); 80 81 int (*init)(struct crypto_kpp *tfm); 82 void (*exit)(struct crypto_kpp *tfm); 83 84 struct crypto_alg base; 85 }; 86 87 /** 88 * DOC: Generic Key-agreement Protocol Primitives API 89 * 90 * The KPP API is used with the algorithm type 91 * CRYPTO_ALG_TYPE_KPP (listed as type "kpp" in /proc/crypto) 92 */ 93 94 /** 95 * crypto_alloc_kpp() - allocate KPP tfm handle 96 * @alg_name: is the name of the kpp algorithm (e.g. "dh", "ecdh") 97 * @type: specifies the type of the algorithm 98 * @mask: specifies the mask for the algorithm 99 * 100 * Allocate a handle for kpp algorithm. The returned struct crypto_kpp 101 * is required for any following API invocation 102 * 103 * Return: allocated handle in case of success; IS_ERR() is true in case of 104 * an error, PTR_ERR() returns the error code. 105 */ 106 struct crypto_kpp *crypto_alloc_kpp(const char *alg_name, u32 type, u32 mask); 107 108 int crypto_has_kpp(const char *alg_name, u32 type, u32 mask); 109 110 static inline struct crypto_tfm *crypto_kpp_tfm(struct crypto_kpp *tfm) 111 { 112 return &tfm->base; 113 } 114 115 static inline struct kpp_alg *__crypto_kpp_alg(struct crypto_alg *alg) 116 { 117 return container_of(alg, struct kpp_alg, base); 118 } 119 120 static inline struct crypto_kpp *__crypto_kpp_tfm(struct crypto_tfm *tfm) 121 { 122 return container_of(tfm, struct crypto_kpp, base); 123 } 124 125 static inline struct kpp_alg *crypto_kpp_alg(struct crypto_kpp *tfm) 126 { 127 return __crypto_kpp_alg(crypto_kpp_tfm(tfm)->__crt_alg); 128 } 129 130 static inline unsigned int crypto_kpp_reqsize(struct crypto_kpp *tfm) 131 { 132 return tfm->reqsize; 133 } 134 135 static inline void kpp_request_set_tfm(struct kpp_request *req, 136 struct crypto_kpp *tfm) 137 { 138 req->base.tfm = crypto_kpp_tfm(tfm); 139 } 140 141 static inline struct crypto_kpp *crypto_kpp_reqtfm(struct kpp_request *req) 142 { 143 return __crypto_kpp_tfm(req->base.tfm); 144 } 145 146 static inline u32 crypto_kpp_get_flags(struct crypto_kpp *tfm) 147 { 148 return crypto_tfm_get_flags(crypto_kpp_tfm(tfm)); 149 } 150 151 static inline void crypto_kpp_set_flags(struct crypto_kpp *tfm, u32 flags) 152 { 153 crypto_tfm_set_flags(crypto_kpp_tfm(tfm), flags); 154 } 155 156 /** 157 * crypto_free_kpp() - free KPP tfm handle 158 * 159 * @tfm: KPP tfm handle allocated with crypto_alloc_kpp() 160 * 161 * If @tfm is a NULL or error pointer, this function does nothing. 162 */ 163 static inline void crypto_free_kpp(struct crypto_kpp *tfm) 164 { 165 crypto_destroy_tfm(tfm, crypto_kpp_tfm(tfm)); 166 } 167 168 /** 169 * kpp_request_alloc() - allocates kpp request 170 * 171 * @tfm: KPP tfm handle allocated with crypto_alloc_kpp() 172 * @gfp: allocation flags 173 * 174 * Return: allocated handle in case of success or NULL in case of an error. 175 */ 176 static inline struct kpp_request *kpp_request_alloc(struct crypto_kpp *tfm, 177 gfp_t gfp) 178 { 179 struct kpp_request *req; 180 181 req = kmalloc(sizeof(*req) + crypto_kpp_reqsize(tfm), gfp); 182 if (likely(req)) 183 kpp_request_set_tfm(req, tfm); 184 185 return req; 186 } 187 188 /** 189 * kpp_request_free() - zeroize and free kpp request 190 * 191 * @req: request to free 192 */ 193 static inline void kpp_request_free(struct kpp_request *req) 194 { 195 kfree_sensitive(req); 196 } 197 198 /** 199 * kpp_request_set_callback() - Sets an asynchronous callback. 200 * 201 * Callback will be called when an asynchronous operation on a given 202 * request is finished. 203 * 204 * @req: request that the callback will be set for 205 * @flgs: specify for instance if the operation may backlog 206 * @cmpl: callback which will be called 207 * @data: private data used by the caller 208 */ 209 static inline void kpp_request_set_callback(struct kpp_request *req, 210 u32 flgs, 211 crypto_completion_t cmpl, 212 void *data) 213 { 214 req->base.complete = cmpl; 215 req->base.data = data; 216 req->base.flags = flgs; 217 } 218 219 /** 220 * kpp_request_set_input() - Sets input buffer 221 * 222 * Sets parameters required by generate_public_key 223 * 224 * @req: kpp request 225 * @input: ptr to input scatter list 226 * @input_len: size of the input scatter list 227 */ 228 static inline void kpp_request_set_input(struct kpp_request *req, 229 struct scatterlist *input, 230 unsigned int input_len) 231 { 232 req->src = input; 233 req->src_len = input_len; 234 } 235 236 /** 237 * kpp_request_set_output() - Sets output buffer 238 * 239 * Sets parameters required by kpp operation 240 * 241 * @req: kpp request 242 * @output: ptr to output scatter list 243 * @output_len: size of the output scatter list 244 */ 245 static inline void kpp_request_set_output(struct kpp_request *req, 246 struct scatterlist *output, 247 unsigned int output_len) 248 { 249 req->dst = output; 250 req->dst_len = output_len; 251 } 252 253 enum { 254 CRYPTO_KPP_SECRET_TYPE_UNKNOWN, 255 CRYPTO_KPP_SECRET_TYPE_DH, 256 CRYPTO_KPP_SECRET_TYPE_ECDH, 257 }; 258 259 /** 260 * struct kpp_secret - small header for packing secret buffer 261 * 262 * @type: define type of secret. Each kpp type will define its own 263 * @len: specify the len of the secret, include the header, that 264 * follows the struct 265 */ 266 struct kpp_secret { 267 unsigned short type; 268 unsigned short len; 269 }; 270 271 /** 272 * crypto_kpp_set_secret() - Invoke kpp operation 273 * 274 * Function invokes the specific kpp operation for a given alg. 275 * 276 * @tfm: tfm handle 277 * @buffer: Buffer holding the packet representation of the private 278 * key. The structure of the packet key depends on the particular 279 * KPP implementation. Packing and unpacking helpers are provided 280 * for ECDH and DH (see the respective header files for those 281 * implementations). 282 * @len: Length of the packet private key buffer. 283 * 284 * Return: zero on success; error code in case of error 285 */ 286 static inline int crypto_kpp_set_secret(struct crypto_kpp *tfm, 287 const void *buffer, unsigned int len) 288 { 289 struct kpp_alg *alg = crypto_kpp_alg(tfm); 290 struct crypto_alg *calg = tfm->base.__crt_alg; 291 int ret; 292 293 crypto_stats_get(calg); 294 ret = alg->set_secret(tfm, buffer, len); 295 crypto_stats_kpp_set_secret(calg, ret); 296 return ret; 297 } 298 299 /** 300 * crypto_kpp_generate_public_key() - Invoke kpp operation 301 * 302 * Function invokes the specific kpp operation for generating the public part 303 * for a given kpp algorithm. 304 * 305 * To generate a private key, the caller should use a random number generator. 306 * The output of the requested length serves as the private key. 307 * 308 * @req: kpp key request 309 * 310 * Return: zero on success; error code in case of error 311 */ 312 static inline int crypto_kpp_generate_public_key(struct kpp_request *req) 313 { 314 struct crypto_kpp *tfm = crypto_kpp_reqtfm(req); 315 struct kpp_alg *alg = crypto_kpp_alg(tfm); 316 struct crypto_alg *calg = tfm->base.__crt_alg; 317 int ret; 318 319 crypto_stats_get(calg); 320 ret = alg->generate_public_key(req); 321 crypto_stats_kpp_generate_public_key(calg, ret); 322 return ret; 323 } 324 325 /** 326 * crypto_kpp_compute_shared_secret() - Invoke kpp operation 327 * 328 * Function invokes the specific kpp operation for computing the shared secret 329 * for a given kpp algorithm. 330 * 331 * @req: kpp key request 332 * 333 * Return: zero on success; error code in case of error 334 */ 335 static inline int crypto_kpp_compute_shared_secret(struct kpp_request *req) 336 { 337 struct crypto_kpp *tfm = crypto_kpp_reqtfm(req); 338 struct kpp_alg *alg = crypto_kpp_alg(tfm); 339 struct crypto_alg *calg = tfm->base.__crt_alg; 340 int ret; 341 342 crypto_stats_get(calg); 343 ret = alg->compute_shared_secret(req); 344 crypto_stats_kpp_compute_shared_secret(calg, ret); 345 return ret; 346 } 347 348 /** 349 * crypto_kpp_maxsize() - Get len for output buffer 350 * 351 * Function returns the output buffer size required for a given key. 352 * Function assumes that the key is already set in the transformation. If this 353 * function is called without a setkey or with a failed setkey, you will end up 354 * in a NULL dereference. 355 * 356 * @tfm: KPP tfm handle allocated with crypto_alloc_kpp() 357 */ 358 static inline unsigned int crypto_kpp_maxsize(struct crypto_kpp *tfm) 359 { 360 struct kpp_alg *alg = crypto_kpp_alg(tfm); 361 362 return alg->max_size(tfm); 363 } 364 365 #endif 366