include/crypto/kpp.h

   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 #include <linux/crypto.h>
  12
  13 /**
  14  * struct kpp_request
  15  *
  16  * @base:       Common attributes for async crypto requests
  17  * @src:        Source data
  18  * @dst:        Destination data
  19  * @src_len:    Size of the input buffer
  20  * @dst_len:    Size of the output buffer. It needs to be at least
  21  *              as big as the expected result depending on the operation
  22  *              After operation it will be updated with the actual size of the
  23  *              result. In case of error where the dst sgl size was insufficient,
  24  *              it will be updated to the size required for the operation.
  25  * @__ctx:      Start of private context data
  26  */
  27 struct kpp_request {
  28         struct crypto_async_request base;
  29         struct scatterlist *src;
  30         struct scatterlist *dst;
  31         unsigned int src_len;
  32         unsigned int dst_len;
  33         void *__ctx[] CRYPTO_MINALIGN_ATTR;
  34 };
  35
  36 /**
  37  * struct crypto_kpp - user-instantiated object which encapsulate
  38  * algorithms and core processing logic
  39  *
  40  * @base:       Common crypto API algorithm data structure
  41  */
  42 struct crypto_kpp {
  43         struct crypto_tfm base;
  44 };
  45
  46 /**
  47  * struct kpp_alg - generic key-agreement protocol primitives
  48  *
  49  * @set_secret:         Function invokes the protocol specific function to
  50  *                      store the secret private key along with parameters.
  51  *                      The implementation knows how to decode the buffer
  52  * @generate_public_key: Function generate the public key to be sent to the
  53  *                      counterpart. In case of error, where output is not big
  54  *                      enough req->dst_len will be updated to the size
  55  *                      required
  56  * @compute_shared_secret: Function compute the shared secret as defined by
  57  *                      the algorithm. The result is given back to the user.
  58  *                      In case of error, where output is not big enough,
  59  *                      req->dst_len will be updated to the size required
  60  * @max_size:           Function returns the size of the output buffer
  61  * @init:               Initialize the object. This is called only once at
  62  *                      instantiation time. In case the cryptographic hardware
  63  *                      needs to be initialized. Software fallback should be
  64  *                      put in place here.
  65  * @exit:               Undo everything @init did.
  66  *
  67  * @reqsize:            Request context size required by algorithm
  68  *                      implementation
  69  * @base:               Common crypto API algorithm data structure
  70  */
  71 struct kpp_alg {
  72         int (*set_secret)(struct crypto_kpp *tfm, const void *buffer,
  73                           unsigned int len);
  74         int (*generate_public_key)(struct kpp_request *req);
  75         int (*compute_shared_secret)(struct kpp_request *req);
  76
  77         unsigned int (*max_size)(struct crypto_kpp *tfm);
  78
  79         int (*init)(struct crypto_kpp *tfm);
  80         void (*exit)(struct crypto_kpp *tfm);
  81
  82         unsigned int reqsize;
  83         struct crypto_alg base;
  84 };
  85
  86 /**
  87  * DOC: Generic Key-agreement Protocol Primitives API
  88  *
  89  * The KPP API is used with the algorithm type
  90  * CRYPTO_ALG_TYPE_KPP (listed as type "kpp" in /proc/crypto)
  91  */
  92
  93 /**
  94  * crypto_alloc_kpp() - allocate KPP tfm handle
  95  * @alg_name: is the name of the kpp algorithm (e.g. "dh", "ecdh")
  96  * @type: specifies the type of the algorithm
  97  * @mask: specifies the mask for the algorithm
  98  *
  99  * Allocate a handle for kpp algorithm. The returned struct crypto_kpp
 100  * is required for any following API invocation
 101  *
 102  * Return: allocated handle in case of success; IS_ERR() is true in case of
 103  *         an error, PTR_ERR() returns the error code.
 104  */
 105 struct crypto_kpp *crypto_alloc_kpp(const char *alg_name, u32 type, u32 mask);
 106
 107 static inline struct crypto_tfm *crypto_kpp_tfm(struct crypto_kpp *tfm)
 108 {
 109         return &tfm->base;
 110 }
 111
 112 static inline struct kpp_alg *__crypto_kpp_alg(struct crypto_alg *alg)
 113 {
 114         return container_of(alg, struct kpp_alg, base);
 115 }
 116
 117 static inline struct crypto_kpp *__crypto_kpp_tfm(struct crypto_tfm *tfm)
 118 {
 119         return container_of(tfm, struct crypto_kpp, base);
 120 }
 121
 122 static inline struct kpp_alg *crypto_kpp_alg(struct crypto_kpp *tfm)
 123 {
 124         return __crypto_kpp_alg(crypto_kpp_tfm(tfm)->__crt_alg);
 125 }
 126
 127 static inline unsigned int crypto_kpp_reqsize(struct crypto_kpp *tfm)
 128 {
 129         return crypto_kpp_alg(tfm)->reqsize;
 130 }
 131
 132 static inline void kpp_request_set_tfm(struct kpp_request *req,
 133                                        struct crypto_kpp *tfm)
 134 {
 135         req->base.tfm = crypto_kpp_tfm(tfm);
 136 }
 137
 138 static inline struct crypto_kpp *crypto_kpp_reqtfm(struct kpp_request *req)
 139 {
 140         return __crypto_kpp_tfm(req->base.tfm);
 141 }
 142
 143 static inline u32 crypto_kpp_get_flags(struct crypto_kpp *tfm)
 144 {
 145         return crypto_tfm_get_flags(crypto_kpp_tfm(tfm));
 146 }
 147
 148 static inline void crypto_kpp_set_flags(struct crypto_kpp *tfm, u32 flags)
 149 {
 150         crypto_tfm_set_flags(crypto_kpp_tfm(tfm), flags);
 151 }
 152
 153 /**
 154  * crypto_free_kpp() - free KPP tfm handle
 155  *
 156  * @tfm: KPP tfm handle allocated with crypto_alloc_kpp()
 157  */
 158 static inline void crypto_free_kpp(struct crypto_kpp *tfm)
 159 {
 160         crypto_destroy_tfm(tfm, crypto_kpp_tfm(tfm));
 161 }
 162
 163 /**
 164  * kpp_request_alloc() - allocates kpp request
 165  *
 166  * @tfm:        KPP tfm handle allocated with crypto_alloc_kpp()
 167  * @gfp:        allocation flags
 168  *
 169  * Return: allocated handle in case of success or NULL in case of an error.
 170  */
 171 static inline struct kpp_request *kpp_request_alloc(struct crypto_kpp *tfm,
 172                                                     gfp_t gfp)
 173 {
 174         struct kpp_request *req;
 175
 176         req = kmalloc(sizeof(*req) + crypto_kpp_reqsize(tfm), gfp);
 177         if (likely(req))
 178                 kpp_request_set_tfm(req, tfm);
 179
 180         return req;
 181 }
 182
 183 /**
 184  * kpp_request_free() - zeroize and free kpp request
 185  *
 186  * @req:        request to free
 187  */
 188 static inline void kpp_request_free(struct kpp_request *req)
 189 {
 190         kzfree(req);
 191 }
 192
 193 /**
 194  * kpp_request_set_callback() - Sets an asynchronous callback.
 195  *
 196  * Callback will be called when an asynchronous operation on a given
 197  * request is finished.
 198  *
 199  * @req:        request that the callback will be set for
 200  * @flgs:       specify for instance if the operation may backlog
 201  * @cmpl:       callback which will be called
 202  * @data:       private data used by the caller
 203  */
 204 static inline void kpp_request_set_callback(struct kpp_request *req,
 205                                             u32 flgs,
 206                                             crypto_completion_t cmpl,
 207                                             void *data)
 208 {
 209         req->base.complete = cmpl;
 210         req->base.data = data;
 211         req->base.flags = flgs;
 212 }
 213
 214 /**
 215  * kpp_request_set_input() - Sets input buffer
 216  *
 217  * Sets parameters required by generate_public_key
 218  *
 219  * @req:        kpp request
 220  * @input:      ptr to input scatter list
 221  * @input_len:  size of the input scatter list
 222  */
 223 static inline void kpp_request_set_input(struct kpp_request *req,
 224                                          struct scatterlist *input,
 225                                          unsigned int input_len)
 226 {
 227         req->src = input;
 228         req->src_len = input_len;
 229 }
 230
 231 /**
 232  * kpp_request_set_output() - Sets output buffer
 233  *
 234  * Sets parameters required by kpp operation
 235  *
 236  * @req:        kpp request
 237  * @output:     ptr to output scatter list
 238  * @output_len: size of the output scatter list
 239  */
 240 static inline void kpp_request_set_output(struct kpp_request *req,
 241                                           struct scatterlist *output,
 242                                           unsigned int output_len)
 243 {
 244         req->dst = output;
 245         req->dst_len = output_len;
 246 }
 247
 248 enum {
 249         CRYPTO_KPP_SECRET_TYPE_UNKNOWN,
 250         CRYPTO_KPP_SECRET_TYPE_DH,
 251         CRYPTO_KPP_SECRET_TYPE_ECDH,
 252 };
 253
 254 /**
 255  * struct kpp_secret - small header for packing secret buffer
 256  *
 257  * @type:       define type of secret. Each kpp type will define its own
 258  * @len:        specify the len of the secret, include the header, that
 259  *              follows the struct
 260  */
 261 struct kpp_secret {
 262         unsigned short type;
 263         unsigned short len;
 264 };
 265
 266 /**
 267  * crypto_kpp_set_secret() - Invoke kpp operation
 268  *
 269  * Function invokes the specific kpp operation for a given alg.
 270  *
 271  * @tfm:        tfm handle
 272  * @buffer:     Buffer holding the packet representation of the private
 273  *              key. The structure of the packet key depends on the particular
 274  *              KPP implementation. Packing and unpacking helpers are provided
 275  *              for ECDH and DH (see the respective header files for those
 276  *              implementations).
 277  * @len:        Length of the packet private key buffer.
 278  *
 279  * Return: zero on success; error code in case of error
 280  */
 281 static inline int crypto_kpp_set_secret(struct crypto_kpp *tfm,
 282                                         const void *buffer, unsigned int len)
 283 {
 284         struct kpp_alg *alg = crypto_kpp_alg(tfm);
 285         struct crypto_alg *calg = tfm->base.__crt_alg;
 286         int ret;
 287
 288         crypto_stats_get(calg);
 289         ret = alg->set_secret(tfm, buffer, len);
 290         crypto_stats_kpp_set_secret(calg, ret);
 291         return ret;
 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         struct crypto_alg *calg = tfm->base.__crt_alg;
 312         int ret;
 313
 314         crypto_stats_get(calg);
 315         ret = alg->generate_public_key(req);
 316         crypto_stats_kpp_generate_public_key(calg, ret);
 317         return ret;
 318 }
 319
 320 /**
 321  * crypto_kpp_compute_shared_secret() - Invoke kpp operation
 322  *
 323  * Function invokes the specific kpp operation for computing the shared secret
 324  * for a given kpp algorithm.
 325  *
 326  * @req:        kpp key request
 327  *
 328  * Return: zero on success; error code in case of error
 329  */
 330 static inline int crypto_kpp_compute_shared_secret(struct kpp_request *req)
 331 {
 332         struct crypto_kpp *tfm = crypto_kpp_reqtfm(req);
 333         struct kpp_alg *alg = crypto_kpp_alg(tfm);
 334         struct crypto_alg *calg = tfm->base.__crt_alg;
 335         int ret;
 336
 337         crypto_stats_get(calg);
 338         ret = alg->compute_shared_secret(req);
 339         crypto_stats_kpp_compute_shared_secret(calg, ret);
 340         return ret;
 341 }
 342
 343 /**
 344  * crypto_kpp_maxsize() - Get len for output buffer
 345  *
 346  * Function returns the output buffer size required for a given key.
 347  * Function assumes that the key is already set in the transformation. If this
 348  * function is called without a setkey or with a failed setkey, you will end up
 349  * in a NULL dereference.
 350  *
 351  * @tfm:        KPP tfm handle allocated with crypto_alloc_kpp()
 352  */
 353 static inline unsigned int crypto_kpp_maxsize(struct crypto_kpp *tfm)
 354 {
 355         struct kpp_alg *alg = crypto_kpp_alg(tfm);
 356
 357         return alg->max_size(tfm);
 358 }
 359
 360 #endif