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 /** 149 * crypto_free_kpp() - free KPP tfm handle 150 * 151 * @tfm: KPP tfm handle allocated with crypto_alloc_kpp() 152 */ 153 static inline void crypto_free_kpp(struct crypto_kpp *tfm) 154 { 155 crypto_destroy_tfm(tfm, crypto_kpp_tfm(tfm)); 156 } 157 158 /** 159 * kpp_request_alloc() - allocates kpp request 160 * 161 * @tfm: KPP tfm handle allocated with crypto_alloc_kpp() 162 * @gfp: allocation flags 163 * 164 * Return: allocated handle in case of success or NULL in case of an error. 165 */ 166 static inline struct kpp_request *kpp_request_alloc(struct crypto_kpp *tfm, 167 gfp_t gfp) 168 { 169 struct kpp_request *req; 170 171 req = kmalloc(sizeof(*req) + crypto_kpp_reqsize(tfm), gfp); 172 if (likely(req)) 173 kpp_request_set_tfm(req, tfm); 174 175 return req; 176 } 177 178 /** 179 * kpp_request_free() - zeroize and free kpp request 180 * 181 * @req: request to free 182 */ 183 static inline void kpp_request_free(struct kpp_request *req) 184 { 185 kzfree(req); 186 } 187 188 /** 189 * kpp_request_set_callback() - Sets an asynchronous callback. 190 * 191 * Callback will be called when an asynchronous operation on a given 192 * request is finished. 193 * 194 * @req: request that the callback will be set for 195 * @flgs: specify for instance if the operation may backlog 196 * @cmpl: callback which will be called 197 * @data: private data used by the caller 198 */ 199 static inline void kpp_request_set_callback(struct kpp_request *req, 200 u32 flgs, 201 crypto_completion_t cmpl, 202 void *data) 203 { 204 req->base.complete = cmpl; 205 req->base.data = data; 206 req->base.flags = flgs; 207 } 208 209 /** 210 * kpp_request_set_input() - Sets input buffer 211 * 212 * Sets parameters required by generate_public_key 213 * 214 * @req: kpp request 215 * @input: ptr to input scatter list 216 * @input_len: size of the input scatter list 217 */ 218 static inline void kpp_request_set_input(struct kpp_request *req, 219 struct scatterlist *input, 220 unsigned int input_len) 221 { 222 req->src = input; 223 req->src_len = input_len; 224 } 225 226 /** 227 * kpp_request_set_output() - Sets output buffer 228 * 229 * Sets parameters required by kpp operation 230 * 231 * @req: kpp request 232 * @output: ptr to output scatter list 233 * @output_len: size of the output scatter list 234 */ 235 static inline void kpp_request_set_output(struct kpp_request *req, 236 struct scatterlist *output, 237 unsigned int output_len) 238 { 239 req->dst = output; 240 req->dst_len = output_len; 241 } 242 243 enum { 244 CRYPTO_KPP_SECRET_TYPE_UNKNOWN, 245 CRYPTO_KPP_SECRET_TYPE_DH, 246 CRYPTO_KPP_SECRET_TYPE_ECDH, 247 }; 248 249 /** 250 * struct kpp_secret - small header for packing secret buffer 251 * 252 * @type: define type of secret. Each kpp type will define its own 253 * @len: specify the len of the secret, include the header, that 254 * follows the struct 255 */ 256 struct kpp_secret { 257 unsigned short type; 258 unsigned short len; 259 }; 260 261 /** 262 * crypto_kpp_set_secret() - Invoke kpp operation 263 * 264 * Function invokes the specific kpp operation for a given alg. 265 * 266 * @tfm: tfm handle 267 * @buffer: Buffer holding the packet representation of the private 268 * key. The structure of the packet key depends on the particular 269 * KPP implementation. Packing and unpacking helpers are provided 270 * for ECDH and DH (see the respective header files for those 271 * implementations). 272 * @len: Length of the packet private key buffer. 273 * 274 * Return: zero on success; error code in case of error 275 */ 276 static inline int crypto_kpp_set_secret(struct crypto_kpp *tfm, 277 const void *buffer, unsigned int len) 278 { 279 struct kpp_alg *alg = crypto_kpp_alg(tfm); 280 281 return alg->set_secret(tfm, buffer, len); 282 } 283 284 /** 285 * crypto_kpp_generate_public_key() - Invoke kpp operation 286 * 287 * Function invokes the specific kpp operation for generating the public part 288 * for a given kpp algorithm. 289 * 290 * To generate a private key, the caller should use a random number generator. 291 * The output of the requested length serves as the private key. 292 * 293 * @req: kpp key request 294 * 295 * Return: zero on success; error code in case of error 296 */ 297 static inline int crypto_kpp_generate_public_key(struct kpp_request *req) 298 { 299 struct crypto_kpp *tfm = crypto_kpp_reqtfm(req); 300 struct kpp_alg *alg = crypto_kpp_alg(tfm); 301 302 return alg->generate_public_key(req); 303 } 304 305 /** 306 * crypto_kpp_compute_shared_secret() - Invoke kpp operation 307 * 308 * Function invokes the specific kpp operation for computing the shared secret 309 * for a given kpp algorithm. 310 * 311 * @req: kpp key request 312 * 313 * Return: zero on success; error code in case of error 314 */ 315 static inline int crypto_kpp_compute_shared_secret(struct kpp_request *req) 316 { 317 struct crypto_kpp *tfm = crypto_kpp_reqtfm(req); 318 struct kpp_alg *alg = crypto_kpp_alg(tfm); 319 320 return alg->compute_shared_secret(req); 321 } 322 323 /** 324 * crypto_kpp_maxsize() - Get len for output buffer 325 * 326 * Function returns the output buffer size required for a given key. 327 * Function assumes that the key is already set in the transformation. If this 328 * function is called without a setkey or with a failed setkey, you will end up 329 * in a NULL dereference. 330 * 331 * @tfm: KPP tfm handle allocated with crypto_alloc_kpp() 332 */ 333 static inline unsigned int crypto_kpp_maxsize(struct crypto_kpp *tfm) 334 { 335 struct kpp_alg *alg = crypto_kpp_alg(tfm); 336 337 return alg->max_size(tfm); 338 } 339 340 #endif 341