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