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 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_request 19 * 20 * @base: Common attributes for async crypto requests 21 * @src: Source data 22 * @dst: Destination data 23 * @src_len: Size of the input buffer 24 * @dst_len: Size of the output buffer. It needs to be at least 25 * as big as the expected result depending on the operation 26 * After operation it will be updated with the actual size of the 27 * 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 data 30 */ 31 struct 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 encapsulate 42 * algorithms and core processing logic 43 * 44 * @reqsize: Request context size required by algorithm 45 * implementation 46 * @base: Common crypto API algorithm data structure 47 */ 48 struct crypto_kpp { 49 unsigned int reqsize; 50 51 struct crypto_tfm base; 52 }; 53 54 /* 55 * struct crypto_istat_kpp - statistics for KPP algorithm 56 * @setsecret_cnt: number of setsecrey operation 57 * @generate_public_key_cnt: number of generate_public_key operation 58 * @compute_shared_secret_cnt: number of compute_shared_secret operation 59 * @err_cnt: number of error for KPP requests 60 */ 61 struct crypto_istat_kpp { 62 atomic64_t setsecret_cnt; 63 atomic64_t generate_public_key_cnt; 64 atomic64_t compute_shared_secret_cnt; 65 atomic64_t err_cnt; 66 }; 67 68 /** 69 * struct kpp_alg - generic key-agreement protocol primitives 70 * 71 * @set_secret: Function invokes the protocol specific function to 72 * store the secret private key along with parameters. 73 * The implementation knows how to decode the buffer 74 * @generate_public_key: Function generate the public key to be sent to the 75 * counterpart. In case of error, where output is not big 76 * enough req->dst_len will be updated to the size 77 * required 78 * @compute_shared_secret: Function compute the shared secret as defined by 79 * the algorithm. The result is given back to the user. 80 * In case of error, where output is not big enough, 81 * req->dst_len will be updated to the size required 82 * @max_size: Function returns the size of the output buffer 83 * @init: Initialize the object. This is called only once at 84 * instantiation time. In case the cryptographic hardware 85 * needs to be initialized. Software fallback should be 86 * put in place here. 87 * @exit: Undo everything @init did. 88 * 89 * @base: Common crypto API algorithm data structure 90 * @stat: Statistics for KPP algorithm 91 */ 92 struct kpp_alg { 93 int (*set_secret)(struct crypto_kpp *tfm, const void *buffer, 94 unsigned int len); 95 int (*generate_public_key)(struct kpp_request *req); 96 int (*compute_shared_secret)(struct kpp_request *req); 97 98 unsigned int (*max_size)(struct crypto_kpp *tfm); 99 100 int (*init)(struct crypto_kpp *tfm); 101 void (*exit)(struct crypto_kpp *tfm); 102 103 #ifdef CONFIG_CRYPTO_STATS 104 struct crypto_istat_kpp stat; 105 #endif 106 107 struct crypto_alg base; 108 }; 109 110 /** 111 * DOC: Generic Key-agreement Protocol Primitives API 112 * 113 * The KPP API is used with the algorithm type 114 * CRYPTO_ALG_TYPE_KPP (listed as type "kpp" in /proc/crypto) 115 */ 116 117 /** 118 * crypto_alloc_kpp() - allocate KPP tfm handle 119 * @alg_name: is the name of the kpp algorithm (e.g. "dh", "ecdh") 120 * @type: specifies the type of the algorithm 121 * @mask: specifies the mask for the algorithm 122 * 123 * Allocate a handle for kpp algorithm. The returned struct crypto_kpp 124 * is required for any following API invocation 125 * 126 * Return: allocated handle in case of success; IS_ERR() is true in case of 127 * an error, PTR_ERR() returns the error code. 128 */ 129 struct crypto_kpp *crypto_alloc_kpp(const char *alg_name, u32 type, u32 mask); 130 131 int crypto_has_kpp(const char *alg_name, u32 type, u32 mask); 132 133 static inline struct crypto_tfm *crypto_kpp_tfm(struct crypto_kpp *tfm) 134 { 135 return &tfm->base; 136 } 137 138 static inline struct kpp_alg *__crypto_kpp_alg(struct crypto_alg *alg) 139 { 140 return container_of(alg, struct kpp_alg, base); 141 } 142 143 static inline struct crypto_kpp *__crypto_kpp_tfm(struct crypto_tfm *tfm) 144 { 145 return container_of(tfm, struct crypto_kpp, base); 146 } 147 148 static inline struct kpp_alg *crypto_kpp_alg(struct crypto_kpp *tfm) 149 { 150 return __crypto_kpp_alg(crypto_kpp_tfm(tfm)->__crt_alg); 151 } 152 153 static inline unsigned int crypto_kpp_reqsize(struct crypto_kpp *tfm) 154 { 155 return tfm->reqsize; 156 } 157 158 static inline void kpp_request_set_tfm(struct kpp_request *req, 159 struct crypto_kpp *tfm) 160 { 161 req->base.tfm = crypto_kpp_tfm(tfm); 162 } 163 164 static inline struct crypto_kpp *crypto_kpp_reqtfm(struct kpp_request *req) 165 { 166 return __crypto_kpp_tfm(req->base.tfm); 167 } 168 169 static inline u32 crypto_kpp_get_flags(struct crypto_kpp *tfm) 170 { 171 return crypto_tfm_get_flags(crypto_kpp_tfm(tfm)); 172 } 173 174 static inline void crypto_kpp_set_flags(struct crypto_kpp *tfm, u32 flags) 175 { 176 crypto_tfm_set_flags(crypto_kpp_tfm(tfm), flags); 177 } 178 179 /** 180 * crypto_free_kpp() - free KPP tfm handle 181 * 182 * @tfm: KPP tfm handle allocated with crypto_alloc_kpp() 183 * 184 * If @tfm is a NULL or error pointer, this function does nothing. 185 */ 186 static inline void crypto_free_kpp(struct crypto_kpp *tfm) 187 { 188 crypto_destroy_tfm(tfm, crypto_kpp_tfm(tfm)); 189 } 190 191 /** 192 * kpp_request_alloc() - allocates kpp request 193 * 194 * @tfm: KPP tfm handle allocated with crypto_alloc_kpp() 195 * @gfp: allocation flags 196 * 197 * Return: allocated handle in case of success or NULL in case of an error. 198 */ 199 static inline struct kpp_request *kpp_request_alloc(struct crypto_kpp *tfm, 200 gfp_t gfp) 201 { 202 struct kpp_request *req; 203 204 req = kmalloc(sizeof(*req) + crypto_kpp_reqsize(tfm), gfp); 205 if (likely(req)) 206 kpp_request_set_tfm(req, tfm); 207 208 return req; 209 } 210 211 /** 212 * kpp_request_free() - zeroize and free kpp request 213 * 214 * @req: request to free 215 */ 216 static inline void kpp_request_free(struct kpp_request *req) 217 { 218 kfree_sensitive(req); 219 } 220 221 /** 222 * kpp_request_set_callback() - Sets an asynchronous callback. 223 * 224 * Callback will be called when an asynchronous operation on a given 225 * request is finished. 226 * 227 * @req: request that the callback will be set for 228 * @flgs: specify for instance if the operation may backlog 229 * @cmpl: callback which will be called 230 * @data: private data used by the caller 231 */ 232 static inline void kpp_request_set_callback(struct kpp_request *req, 233 u32 flgs, 234 crypto_completion_t cmpl, 235 void *data) 236 { 237 req->base.complete = cmpl; 238 req->base.data = data; 239 req->base.flags = flgs; 240 } 241 242 /** 243 * kpp_request_set_input() - Sets input buffer 244 * 245 * Sets parameters required by generate_public_key 246 * 247 * @req: kpp request 248 * @input: ptr to input scatter list 249 * @input_len: size of the input scatter list 250 */ 251 static inline void kpp_request_set_input(struct kpp_request *req, 252 struct scatterlist *input, 253 unsigned int input_len) 254 { 255 req->src = input; 256 req->src_len = input_len; 257 } 258 259 /** 260 * kpp_request_set_output() - Sets output buffer 261 * 262 * Sets parameters required by kpp operation 263 * 264 * @req: kpp request 265 * @output: ptr to output scatter list 266 * @output_len: size of the output scatter list 267 */ 268 static inline void kpp_request_set_output(struct kpp_request *req, 269 struct scatterlist *output, 270 unsigned int output_len) 271 { 272 req->dst = output; 273 req->dst_len = output_len; 274 } 275 276 enum { 277 CRYPTO_KPP_SECRET_TYPE_UNKNOWN, 278 CRYPTO_KPP_SECRET_TYPE_DH, 279 CRYPTO_KPP_SECRET_TYPE_ECDH, 280 }; 281 282 /** 283 * struct kpp_secret - small header for packing secret buffer 284 * 285 * @type: define type of secret. Each kpp type will define its own 286 * @len: specify the len of the secret, include the header, that 287 * follows the struct 288 */ 289 struct kpp_secret { 290 unsigned short type; 291 unsigned short len; 292 }; 293 294 static inline struct crypto_istat_kpp *kpp_get_stat(struct kpp_alg *alg) 295 { 296 #ifdef CONFIG_CRYPTO_STATS 297 return &alg->stat; 298 #else 299 return NULL; 300 #endif 301 } 302 303 static inline int crypto_kpp_errstat(struct kpp_alg *alg, int err) 304 { 305 if (!IS_ENABLED(CONFIG_CRYPTO_STATS)) 306 return err; 307 308 if (err && err != -EINPROGRESS && err != -EBUSY) 309 atomic64_inc(&kpp_get_stat(alg)->err_cnt); 310 311 return err; 312 } 313 314 /** 315 * crypto_kpp_set_secret() - Invoke kpp operation 316 * 317 * Function invokes the specific kpp operation for a given alg. 318 * 319 * @tfm: tfm handle 320 * @buffer: Buffer holding the packet representation of the private 321 * key. The structure of the packet key depends on the particular 322 * KPP implementation. Packing and unpacking helpers are provided 323 * for ECDH and DH (see the respective header files for those 324 * implementations). 325 * @len: Length of the packet private key buffer. 326 * 327 * Return: zero on success; error code in case of error 328 */ 329 static inline int crypto_kpp_set_secret(struct crypto_kpp *tfm, 330 const void *buffer, unsigned int len) 331 { 332 struct kpp_alg *alg = crypto_kpp_alg(tfm); 333 334 if (IS_ENABLED(CONFIG_CRYPTO_STATS)) 335 atomic64_inc(&kpp_get_stat(alg)->setsecret_cnt); 336 337 return crypto_kpp_errstat(alg, alg->set_secret(tfm, buffer, len)); 338 } 339 340 /** 341 * crypto_kpp_generate_public_key() - Invoke kpp operation 342 * 343 * Function invokes the specific kpp operation for generating the public part 344 * for a given kpp algorithm. 345 * 346 * To generate a private key, the caller should use a random number generator. 347 * The output of the requested length serves as the private key. 348 * 349 * @req: kpp key request 350 * 351 * Return: zero on success; error code in case of error 352 */ 353 static inline int crypto_kpp_generate_public_key(struct kpp_request *req) 354 { 355 struct crypto_kpp *tfm = crypto_kpp_reqtfm(req); 356 struct kpp_alg *alg = crypto_kpp_alg(tfm); 357 358 if (IS_ENABLED(CONFIG_CRYPTO_STATS)) 359 atomic64_inc(&kpp_get_stat(alg)->generate_public_key_cnt); 360 361 return crypto_kpp_errstat(alg, alg->generate_public_key(req)); 362 } 363 364 /** 365 * crypto_kpp_compute_shared_secret() - Invoke kpp operation 366 * 367 * Function invokes the specific kpp operation for computing the shared secret 368 * for a given kpp algorithm. 369 * 370 * @req: kpp key request 371 * 372 * Return: zero on success; error code in case of error 373 */ 374 static inline int crypto_kpp_compute_shared_secret(struct kpp_request *req) 375 { 376 struct crypto_kpp *tfm = crypto_kpp_reqtfm(req); 377 struct kpp_alg *alg = crypto_kpp_alg(tfm); 378 379 if (IS_ENABLED(CONFIG_CRYPTO_STATS)) 380 atomic64_inc(&kpp_get_stat(alg)->compute_shared_secret_cnt); 381 382 return crypto_kpp_errstat(alg, alg->compute_shared_secret(req)); 383 } 384 385 /** 386 * crypto_kpp_maxsize() - Get len for output buffer 387 * 388 * Function returns the output buffer size required for a given key. 389 * Function assumes that the key is already set in the transformation. If this 390 * function is called without a setkey or with a failed setkey, you will end up 391 * in a NULL dereference. 392 * 393 * @tfm: KPP tfm handle allocated with crypto_alloc_kpp() 394 */ 395 static inline unsigned int crypto_kpp_maxsize(struct crypto_kpp *tfm) 396 { 397 struct kpp_alg *alg = crypto_kpp_alg(tfm); 398 399 return alg->max_size(tfm); 400 } 401 402 #endif 403