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 thie 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, 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         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 requeried 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, void *buffer,
 277                                         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
 327  *
 328  * @tfm:        KPP tfm handle allocated with crypto_alloc_kpp()
 329  *
 330  * Return: minimum len for output buffer or error code if key hasn't been set
 331  */
 332 static inline int crypto_kpp_maxsize(struct crypto_kpp *tfm)
 333 {
 334         struct kpp_alg *alg = crypto_kpp_alg(tfm);
 335
 336         return alg->max_size(tfm);
 337 }
 338
 339 #endif