1 /* 2 * Key-agreement Protocol Primitives (KPP) 3 * 4 * Copyright (c) 2016, Intel Corporation 5 * Authors: Salvatore Benedetto <salvatore.benedetto@intel.com> 6 * 7 * This program is free software; you can redistribute it and/or modify it 8 * under the terms of the GNU General Public License as published by the Free 9 * Software Foundation; either version 2 of the License, or (at your option) 10 * any later version. 11 * 12 */ 13 14 #ifndef _CRYPTO_KPP_ 15 #define _CRYPTO_KPP_ 16 #include <linux/crypto.h> 17 18 /** 19 * struct kpp_request 20 * 21 * @base: Common attributes for async crypto requests 22 * @src: Source data 23 * @dst: Destination data 24 * @src_len: Size of the input buffer 25 * @dst_len: Size of the output buffer. It needs to be at least 26 * as big as the expected result depending on the operation 27 * After operation it will be updated with the actual size of the 28 * result. In case of error where the dst sgl size was insufficient, 29 * it will be updated to the size required for the operation. 30 * @__ctx: Start of private context data 31 */ 32 struct kpp_request { 33 struct crypto_async_request base; 34 struct scatterlist *src; 35 struct scatterlist *dst; 36 unsigned int src_len; 37 unsigned int dst_len; 38 void *__ctx[] CRYPTO_MINALIGN_ATTR; 39 }; 40 41 /** 42 * struct crypto_kpp - user-instantiated object which encapsulate 43 * algorithms and core processing logic 44 * 45 * @base: Common crypto API algorithm data structure 46 */ 47 struct crypto_kpp { 48 struct crypto_tfm base; 49 }; 50 51 /** 52 * struct kpp_alg - generic key-agreement protocol primitives 53 * 54 * @set_secret: Function invokes the protocol specific function to 55 * store the secret private key along with parameters. 56 * The implementation knows how to decode the buffer 57 * @generate_public_key: Function generate the public key to be sent to the 58 * counterpart. In case of error, where output is not big 59 * enough req->dst_len will be updated to the size 60 * required 61 * @compute_shared_secret: Function compute the shared secret as defined by 62 * the algorithm. The result is given back to the user. 63 * In case of error, where output is not big enough, 64 * req->dst_len will be updated to the size required 65 * @max_size: Function returns the size of the output buffer 66 * @init: Initialize the object. This is called only once at 67 * instantiation time. In case the cryptographic hardware 68 * needs to be initialized. Software fallback should be 69 * put in place here. 70 * @exit: Undo everything @init did. 71 * 72 * @reqsize: Request context size required by algorithm 73 * implementation 74 * @base: Common crypto API algorithm data structure 75 */ 76 struct kpp_alg { 77 int (*set_secret)(struct crypto_kpp *tfm, const void *buffer, 78 unsigned int len); 79 int (*generate_public_key)(struct kpp_request *req); 80 int (*compute_shared_secret)(struct kpp_request *req); 81 82 unsigned int (*max_size)(struct crypto_kpp *tfm); 83 84 int (*init)(struct crypto_kpp *tfm); 85 void (*exit)(struct crypto_kpp *tfm); 86 87 unsigned int reqsize; 88 struct crypto_alg base; 89 }; 90 91 /** 92 * DOC: Generic Key-agreement Protocol Primitives API 93 * 94 * The KPP API is used with the algorithm type 95 * CRYPTO_ALG_TYPE_KPP (listed as type "kpp" in /proc/crypto) 96 */ 97 98 /** 99 * crypto_alloc_kpp() - allocate KPP tfm handle 100 * @alg_name: is the name of the kpp algorithm (e.g. "dh", "ecdh") 101 * @type: specifies the type of the algorithm 102 * @mask: specifies the mask for the algorithm 103 * 104 * Allocate a handle for kpp algorithm. The returned struct crypto_kpp 105 * is required for any following API invocation 106 * 107 * Return: allocated handle in case of success; IS_ERR() is true in case of 108 * an error, PTR_ERR() returns the error code. 109 */ 110 struct crypto_kpp *crypto_alloc_kpp(const char *alg_name, u32 type, u32 mask); 111 112 static inline struct crypto_tfm *crypto_kpp_tfm(struct crypto_kpp *tfm) 113 { 114 return &tfm->base; 115 } 116 117 static inline struct kpp_alg *__crypto_kpp_alg(struct crypto_alg *alg) 118 { 119 return container_of(alg, struct kpp_alg, base); 120 } 121 122 static inline struct crypto_kpp *__crypto_kpp_tfm(struct crypto_tfm *tfm) 123 { 124 return container_of(tfm, struct crypto_kpp, base); 125 } 126 127 static inline struct kpp_alg *crypto_kpp_alg(struct crypto_kpp *tfm) 128 { 129 return __crypto_kpp_alg(crypto_kpp_tfm(tfm)->__crt_alg); 130 } 131 132 static inline unsigned int crypto_kpp_reqsize(struct crypto_kpp *tfm) 133 { 134 return crypto_kpp_alg(tfm)->reqsize; 135 } 136 137 static inline void kpp_request_set_tfm(struct kpp_request *req, 138 struct crypto_kpp *tfm) 139 { 140 req->base.tfm = crypto_kpp_tfm(tfm); 141 } 142 143 static inline struct crypto_kpp *crypto_kpp_reqtfm(struct kpp_request *req) 144 { 145 return __crypto_kpp_tfm(req->base.tfm); 146 } 147 148 static inline u32 crypto_kpp_get_flags(struct crypto_kpp *tfm) 149 { 150 return crypto_tfm_get_flags(crypto_kpp_tfm(tfm)); 151 } 152 153 static inline void crypto_kpp_set_flags(struct crypto_kpp *tfm, u32 flags) 154 { 155 crypto_tfm_set_flags(crypto_kpp_tfm(tfm), flags); 156 } 157 158 /** 159 * crypto_free_kpp() - free KPP tfm handle 160 * 161 * @tfm: KPP tfm handle allocated with crypto_alloc_kpp() 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 kzfree(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); 290 291 return alg->set_secret(tfm, buffer, len); 292 } 293 294 /** 295 * crypto_kpp_generate_public_key() - Invoke kpp operation 296 * 297 * Function invokes the specific kpp operation for generating the public part 298 * for a given kpp algorithm. 299 * 300 * To generate a private key, the caller should use a random number generator. 301 * The output of the requested length serves as the private key. 302 * 303 * @req: kpp key request 304 * 305 * Return: zero on success; error code in case of error 306 */ 307 static inline int crypto_kpp_generate_public_key(struct kpp_request *req) 308 { 309 struct crypto_kpp *tfm = crypto_kpp_reqtfm(req); 310 struct kpp_alg *alg = crypto_kpp_alg(tfm); 311 312 return alg->generate_public_key(req); 313 } 314 315 /** 316 * crypto_kpp_compute_shared_secret() - Invoke kpp operation 317 * 318 * Function invokes the specific kpp operation for computing the shared secret 319 * for a given kpp algorithm. 320 * 321 * @req: kpp key request 322 * 323 * Return: zero on success; error code in case of error 324 */ 325 static inline int crypto_kpp_compute_shared_secret(struct kpp_request *req) 326 { 327 struct crypto_kpp *tfm = crypto_kpp_reqtfm(req); 328 struct kpp_alg *alg = crypto_kpp_alg(tfm); 329 330 return alg->compute_shared_secret(req); 331 } 332 333 /** 334 * crypto_kpp_maxsize() - Get len for output buffer 335 * 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 this 338 * function is called without a setkey or with a failed setkey, you will end up 339 * in a NULL dereference. 340 * 341 * @tfm: KPP tfm handle allocated with crypto_alloc_kpp() 342 */ 343 static 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 #endif 351