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 kpp_alg - generic key-agreement protocol primitives 56 * 57 * @set_secret: Function invokes the protocol specific function to 58 * store the secret private key along with parameters. 59 * The implementation knows how to decode the buffer 60 * @generate_public_key: Function generate the public key to be sent to the 61 * counterpart. In case of error, where output is not big 62 * enough req->dst_len will be updated to the size 63 * required 64 * @compute_shared_secret: Function compute the shared secret as defined by 65 * the algorithm. The result is given back to the user. 66 * In case of error, where output is not big enough, 67 * req->dst_len will be updated to the size required 68 * @max_size: Function returns the size of the output buffer 69 * @init: Initialize the object. This is called only once at 70 * instantiation time. In case the cryptographic hardware 71 * needs to be initialized. Software fallback should be 72 * put in place here. 73 * @exit: Undo everything @init did. 74 * 75 * @base: Common crypto API algorithm data structure 76 */ 77 struct kpp_alg { 78 int (*set_secret)(struct crypto_kpp *tfm, const void *buffer, 79 unsigned int len); 80 int (*generate_public_key)(struct kpp_request *req); 81 int (*compute_shared_secret)(struct kpp_request *req); 82 83 unsigned int (*max_size)(struct crypto_kpp *tfm); 84 85 int (*init)(struct crypto_kpp *tfm); 86 void (*exit)(struct crypto_kpp *tfm); 87 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 int crypto_has_kpp(const char *alg_name, u32 type, u32 mask); 113 114 static inline struct crypto_tfm *crypto_kpp_tfm(struct crypto_kpp *tfm) 115 { 116 return &tfm->base; 117 } 118 119 static inline struct kpp_alg *__crypto_kpp_alg(struct crypto_alg *alg) 120 { 121 return container_of(alg, struct kpp_alg, base); 122 } 123 124 static inline struct crypto_kpp *__crypto_kpp_tfm(struct crypto_tfm *tfm) 125 { 126 return container_of(tfm, struct crypto_kpp, base); 127 } 128 129 static inline struct kpp_alg *crypto_kpp_alg(struct crypto_kpp *tfm) 130 { 131 return __crypto_kpp_alg(crypto_kpp_tfm(tfm)->__crt_alg); 132 } 133 134 static inline unsigned int crypto_kpp_reqsize(struct crypto_kpp *tfm) 135 { 136 return tfm->reqsize; 137 } 138 139 static inline void kpp_request_set_tfm(struct kpp_request *req, 140 struct crypto_kpp *tfm) 141 { 142 req->base.tfm = crypto_kpp_tfm(tfm); 143 } 144 145 static inline struct crypto_kpp *crypto_kpp_reqtfm(struct kpp_request *req) 146 { 147 return __crypto_kpp_tfm(req->base.tfm); 148 } 149 150 static inline u32 crypto_kpp_get_flags(struct crypto_kpp *tfm) 151 { 152 return crypto_tfm_get_flags(crypto_kpp_tfm(tfm)); 153 } 154 155 static inline void crypto_kpp_set_flags(struct crypto_kpp *tfm, u32 flags) 156 { 157 crypto_tfm_set_flags(crypto_kpp_tfm(tfm), flags); 158 } 159 160 /** 161 * crypto_free_kpp() - free KPP tfm handle 162 * 163 * @tfm: KPP tfm handle allocated with crypto_alloc_kpp() 164 * 165 * If @tfm is a NULL or error pointer, this function does nothing. 166 */ 167 static inline void crypto_free_kpp(struct crypto_kpp *tfm) 168 { 169 crypto_destroy_tfm(tfm, crypto_kpp_tfm(tfm)); 170 } 171 172 /** 173 * kpp_request_alloc() - allocates kpp request 174 * 175 * @tfm: KPP tfm handle allocated with crypto_alloc_kpp() 176 * @gfp: allocation flags 177 * 178 * Return: allocated handle in case of success or NULL in case of an error. 179 */ 180 static inline struct kpp_request *kpp_request_alloc(struct crypto_kpp *tfm, 181 gfp_t gfp) 182 { 183 struct kpp_request *req; 184 185 req = kmalloc(sizeof(*req) + crypto_kpp_reqsize(tfm), gfp); 186 if (likely(req)) 187 kpp_request_set_tfm(req, tfm); 188 189 return req; 190 } 191 192 /** 193 * kpp_request_free() - zeroize and free kpp request 194 * 195 * @req: request to free 196 */ 197 static inline void kpp_request_free(struct kpp_request *req) 198 { 199 kfree_sensitive(req); 200 } 201 202 /** 203 * kpp_request_set_callback() - Sets an asynchronous callback. 204 * 205 * Callback will be called when an asynchronous operation on a given 206 * request is finished. 207 * 208 * @req: request that the callback will be set for 209 * @flgs: specify for instance if the operation may backlog 210 * @cmpl: callback which will be called 211 * @data: private data used by the caller 212 */ 213 static inline void kpp_request_set_callback(struct kpp_request *req, 214 u32 flgs, 215 crypto_completion_t cmpl, 216 void *data) 217 { 218 req->base.complete = cmpl; 219 req->base.data = data; 220 req->base.flags = flgs; 221 } 222 223 /** 224 * kpp_request_set_input() - Sets input buffer 225 * 226 * Sets parameters required by generate_public_key 227 * 228 * @req: kpp request 229 * @input: ptr to input scatter list 230 * @input_len: size of the input scatter list 231 */ 232 static inline void kpp_request_set_input(struct kpp_request *req, 233 struct scatterlist *input, 234 unsigned int input_len) 235 { 236 req->src = input; 237 req->src_len = input_len; 238 } 239 240 /** 241 * kpp_request_set_output() - Sets output buffer 242 * 243 * Sets parameters required by kpp operation 244 * 245 * @req: kpp request 246 * @output: ptr to output scatter list 247 * @output_len: size of the output scatter list 248 */ 249 static inline void kpp_request_set_output(struct kpp_request *req, 250 struct scatterlist *output, 251 unsigned int output_len) 252 { 253 req->dst = output; 254 req->dst_len = output_len; 255 } 256 257 enum { 258 CRYPTO_KPP_SECRET_TYPE_UNKNOWN, 259 CRYPTO_KPP_SECRET_TYPE_DH, 260 CRYPTO_KPP_SECRET_TYPE_ECDH, 261 }; 262 263 /** 264 * struct kpp_secret - small header for packing secret buffer 265 * 266 * @type: define type of secret. Each kpp type will define its own 267 * @len: specify the len of the secret, include the header, that 268 * follows the struct 269 */ 270 struct kpp_secret { 271 unsigned short type; 272 unsigned short len; 273 }; 274 275 /** 276 * crypto_kpp_set_secret() - Invoke kpp operation 277 * 278 * Function invokes the specific kpp operation for a given alg. 279 * 280 * @tfm: tfm handle 281 * @buffer: Buffer holding the packet representation of the private 282 * key. The structure of the packet key depends on the particular 283 * KPP implementation. Packing and unpacking helpers are provided 284 * for ECDH and DH (see the respective header files for those 285 * implementations). 286 * @len: Length of the packet private key buffer. 287 * 288 * Return: zero on success; error code in case of error 289 */ 290 static inline int crypto_kpp_set_secret(struct crypto_kpp *tfm, 291 const void *buffer, unsigned int len) 292 { 293 return crypto_kpp_alg(tfm)->set_secret(tfm, buffer, len); 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); 312 313 return crypto_kpp_alg(tfm)->generate_public_key(req); 314 } 315 316 /** 317 * crypto_kpp_compute_shared_secret() - Invoke kpp operation 318 * 319 * Function invokes the specific kpp operation for computing the shared secret 320 * for a given kpp algorithm. 321 * 322 * @req: kpp key request 323 * 324 * Return: zero on success; error code in case of error 325 */ 326 static inline int crypto_kpp_compute_shared_secret(struct kpp_request *req) 327 { 328 struct crypto_kpp *tfm = crypto_kpp_reqtfm(req); 329 330 return crypto_kpp_alg(tfm)->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