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 int crypto_has_kpp(const char *alg_name, u32 type, u32 mask); 108 109 static inline struct crypto_tfm *crypto_kpp_tfm(struct crypto_kpp *tfm) 110 { 111 return &tfm->base; 112 } 113 114 static inline struct kpp_alg *__crypto_kpp_alg(struct crypto_alg *alg) 115 { 116 return container_of(alg, struct kpp_alg, base); 117 } 118 119 static inline struct crypto_kpp *__crypto_kpp_tfm(struct crypto_tfm *tfm) 120 { 121 return container_of(tfm, struct crypto_kpp, base); 122 } 123 124 static inline struct kpp_alg *crypto_kpp_alg(struct crypto_kpp *tfm) 125 { 126 return __crypto_kpp_alg(crypto_kpp_tfm(tfm)->__crt_alg); 127 } 128 129 static inline unsigned int crypto_kpp_reqsize(struct crypto_kpp *tfm) 130 { 131 return crypto_kpp_alg(tfm)->reqsize; 132 } 133 134 static inline void kpp_request_set_tfm(struct kpp_request *req, 135 struct crypto_kpp *tfm) 136 { 137 req->base.tfm = crypto_kpp_tfm(tfm); 138 } 139 140 static inline struct crypto_kpp *crypto_kpp_reqtfm(struct kpp_request *req) 141 { 142 return __crypto_kpp_tfm(req->base.tfm); 143 } 144 145 static inline u32 crypto_kpp_get_flags(struct crypto_kpp *tfm) 146 { 147 return crypto_tfm_get_flags(crypto_kpp_tfm(tfm)); 148 } 149 150 static inline void crypto_kpp_set_flags(struct crypto_kpp *tfm, u32 flags) 151 { 152 crypto_tfm_set_flags(crypto_kpp_tfm(tfm), flags); 153 } 154 155 /** 156 * crypto_free_kpp() - free KPP tfm handle 157 * 158 * @tfm: KPP tfm handle allocated with crypto_alloc_kpp() 159 * 160 * If @tfm is a NULL or error pointer, this function does nothing. 161 */ 162 static inline void crypto_free_kpp(struct crypto_kpp *tfm) 163 { 164 crypto_destroy_tfm(tfm, crypto_kpp_tfm(tfm)); 165 } 166 167 /** 168 * kpp_request_alloc() - allocates kpp request 169 * 170 * @tfm: KPP tfm handle allocated with crypto_alloc_kpp() 171 * @gfp: allocation flags 172 * 173 * Return: allocated handle in case of success or NULL in case of an error. 174 */ 175 static inline struct kpp_request *kpp_request_alloc(struct crypto_kpp *tfm, 176 gfp_t gfp) 177 { 178 struct kpp_request *req; 179 180 req = kmalloc(sizeof(*req) + crypto_kpp_reqsize(tfm), gfp); 181 if (likely(req)) 182 kpp_request_set_tfm(req, tfm); 183 184 return req; 185 } 186 187 /** 188 * kpp_request_free() - zeroize and free kpp request 189 * 190 * @req: request to free 191 */ 192 static inline void kpp_request_free(struct kpp_request *req) 193 { 194 kfree_sensitive(req); 195 } 196 197 /** 198 * kpp_request_set_callback() - Sets an asynchronous callback. 199 * 200 * Callback will be called when an asynchronous operation on a given 201 * request is finished. 202 * 203 * @req: request that the callback will be set for 204 * @flgs: specify for instance if the operation may backlog 205 * @cmpl: callback which will be called 206 * @data: private data used by the caller 207 */ 208 static inline void kpp_request_set_callback(struct kpp_request *req, 209 u32 flgs, 210 crypto_completion_t cmpl, 211 void *data) 212 { 213 req->base.complete = cmpl; 214 req->base.data = data; 215 req->base.flags = flgs; 216 } 217 218 /** 219 * kpp_request_set_input() - Sets input buffer 220 * 221 * Sets parameters required by generate_public_key 222 * 223 * @req: kpp request 224 * @input: ptr to input scatter list 225 * @input_len: size of the input scatter list 226 */ 227 static inline void kpp_request_set_input(struct kpp_request *req, 228 struct scatterlist *input, 229 unsigned int input_len) 230 { 231 req->src = input; 232 req->src_len = input_len; 233 } 234 235 /** 236 * kpp_request_set_output() - Sets output buffer 237 * 238 * Sets parameters required by kpp operation 239 * 240 * @req: kpp request 241 * @output: ptr to output scatter list 242 * @output_len: size of the output scatter list 243 */ 244 static inline void kpp_request_set_output(struct kpp_request *req, 245 struct scatterlist *output, 246 unsigned int output_len) 247 { 248 req->dst = output; 249 req->dst_len = output_len; 250 } 251 252 enum { 253 CRYPTO_KPP_SECRET_TYPE_UNKNOWN, 254 CRYPTO_KPP_SECRET_TYPE_DH, 255 CRYPTO_KPP_SECRET_TYPE_ECDH, 256 }; 257 258 /** 259 * struct kpp_secret - small header for packing secret buffer 260 * 261 * @type: define type of secret. Each kpp type will define its own 262 * @len: specify the len of the secret, include the header, that 263 * follows the struct 264 */ 265 struct kpp_secret { 266 unsigned short type; 267 unsigned short len; 268 }; 269 270 /** 271 * crypto_kpp_set_secret() - Invoke kpp operation 272 * 273 * Function invokes the specific kpp operation for a given alg. 274 * 275 * @tfm: tfm handle 276 * @buffer: Buffer holding the packet representation of the private 277 * key. The structure of the packet key depends on the particular 278 * KPP implementation. Packing and unpacking helpers are provided 279 * for ECDH and DH (see the respective header files for those 280 * implementations). 281 * @len: Length of the packet private key buffer. 282 * 283 * Return: zero on success; error code in case of error 284 */ 285 static inline int crypto_kpp_set_secret(struct crypto_kpp *tfm, 286 const void *buffer, unsigned int len) 287 { 288 struct kpp_alg *alg = crypto_kpp_alg(tfm); 289 struct crypto_alg *calg = tfm->base.__crt_alg; 290 int ret; 291 292 crypto_stats_get(calg); 293 ret = alg->set_secret(tfm, buffer, len); 294 crypto_stats_kpp_set_secret(calg, ret); 295 return ret; 296 } 297 298 /** 299 * crypto_kpp_generate_public_key() - Invoke kpp operation 300 * 301 * Function invokes the specific kpp operation for generating the public part 302 * for a given kpp algorithm. 303 * 304 * To generate a private key, the caller should use a random number generator. 305 * The output of the requested length serves as the private key. 306 * 307 * @req: kpp key request 308 * 309 * Return: zero on success; error code in case of error 310 */ 311 static inline int crypto_kpp_generate_public_key(struct kpp_request *req) 312 { 313 struct crypto_kpp *tfm = crypto_kpp_reqtfm(req); 314 struct kpp_alg *alg = crypto_kpp_alg(tfm); 315 struct crypto_alg *calg = tfm->base.__crt_alg; 316 int ret; 317 318 crypto_stats_get(calg); 319 ret = alg->generate_public_key(req); 320 crypto_stats_kpp_generate_public_key(calg, ret); 321 return ret; 322 } 323 324 /** 325 * crypto_kpp_compute_shared_secret() - Invoke kpp operation 326 * 327 * Function invokes the specific kpp operation for computing the shared secret 328 * for a given kpp algorithm. 329 * 330 * @req: kpp key request 331 * 332 * Return: zero on success; error code in case of error 333 */ 334 static inline int crypto_kpp_compute_shared_secret(struct kpp_request *req) 335 { 336 struct crypto_kpp *tfm = crypto_kpp_reqtfm(req); 337 struct kpp_alg *alg = crypto_kpp_alg(tfm); 338 struct crypto_alg *calg = tfm->base.__crt_alg; 339 int ret; 340 341 crypto_stats_get(calg); 342 ret = alg->compute_shared_secret(req); 343 crypto_stats_kpp_compute_shared_secret(calg, ret); 344 return ret; 345 } 346 347 /** 348 * crypto_kpp_maxsize() - Get len for output buffer 349 * 350 * Function returns the output buffer size required for a given key. 351 * Function assumes that the key is already set in the transformation. If this 352 * function is called without a setkey or with a failed setkey, you will end up 353 * in a NULL dereference. 354 * 355 * @tfm: KPP tfm handle allocated with crypto_alloc_kpp() 356 */ 357 static inline unsigned int crypto_kpp_maxsize(struct crypto_kpp *tfm) 358 { 359 struct kpp_alg *alg = crypto_kpp_alg(tfm); 360 361 return alg->max_size(tfm); 362 } 363 364 #endif 365