include/crypto/kpp.h

   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