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  * If @tfm is a NULL or error pointer, this function does nothing.
 159  */
 160 static inline void crypto_free_kpp(struct crypto_kpp *tfm)
 161 {
 162         crypto_destroy_tfm(tfm, crypto_kpp_tfm(tfm));
 163 }
 164
 165 /**
 166  * kpp_request_alloc() - allocates kpp request
 167  *
 168  * @tfm:        KPP tfm handle allocated with crypto_alloc_kpp()
 169  * @gfp:        allocation flags
 170  *
 171  * Return: allocated handle in case of success or NULL in case of an error.
 172  */
 173 static inline struct kpp_request *kpp_request_alloc(struct crypto_kpp *tfm,
 174                                                     gfp_t gfp)
 175 {
 176         struct kpp_request *req;
 177
 178         req = kmalloc(sizeof(*req) + crypto_kpp_reqsize(tfm), gfp);
 179         if (likely(req))
 180                 kpp_request_set_tfm(req, tfm);
 181
 182         return req;
 183 }
 184
 185 /**
 186  * kpp_request_free() - zeroize and free kpp request
 187  *
 188  * @req:        request to free
 189  */
 190 static inline void kpp_request_free(struct kpp_request *req)
 191 {
 192         kfree_sensitive(req);
 193 }
 194
 195 /**
 196  * kpp_request_set_callback() - Sets an asynchronous callback.
 197  *
 198  * Callback will be called when an asynchronous operation on a given
 199  * request is finished.
 200  *
 201  * @req:        request that the callback will be set for
 202  * @flgs:       specify for instance if the operation may backlog
 203  * @cmpl:       callback which will be called
 204  * @data:       private data used by the caller
 205  */
 206 static inline void kpp_request_set_callback(struct kpp_request *req,
 207                                             u32 flgs,
 208                                             crypto_completion_t cmpl,
 209                                             void *data)
 210 {
 211         req->base.complete = cmpl;
 212         req->base.data = data;
 213         req->base.flags = flgs;
 214 }
 215
 216 /**
 217  * kpp_request_set_input() - Sets input buffer
 218  *
 219  * Sets parameters required by generate_public_key
 220  *
 221  * @req:        kpp request
 222  * @input:      ptr to input scatter list
 223  * @input_len:  size of the input scatter list
 224  */
 225 static inline void kpp_request_set_input(struct kpp_request *req,
 226                                          struct scatterlist *input,
 227                                          unsigned int input_len)
 228 {
 229         req->src = input;
 230         req->src_len = input_len;
 231 }
 232
 233 /**
 234  * kpp_request_set_output() - Sets output buffer
 235  *
 236  * Sets parameters required by kpp operation
 237  *
 238  * @req:        kpp request
 239  * @output:     ptr to output scatter list
 240  * @output_len: size of the output scatter list
 241  */
 242 static inline void kpp_request_set_output(struct kpp_request *req,
 243                                           struct scatterlist *output,
 244                                           unsigned int output_len)
 245 {
 246         req->dst = output;
 247         req->dst_len = output_len;
 248 }
 249
 250 enum {
 251         CRYPTO_KPP_SECRET_TYPE_UNKNOWN,
 252         CRYPTO_KPP_SECRET_TYPE_DH,
 253         CRYPTO_KPP_SECRET_TYPE_ECDH,
 254 };
 255
 256 /**
 257  * struct kpp_secret - small header for packing secret buffer
 258  *
 259  * @type:       define type of secret. Each kpp type will define its own
 260  * @len:        specify the len of the secret, include the header, that
 261  *              follows the struct
 262  */
 263 struct kpp_secret {
 264         unsigned short type;
 265         unsigned short len;
 266 };
 267
 268 /**
 269  * crypto_kpp_set_secret() - Invoke kpp operation
 270  *
 271  * Function invokes the specific kpp operation for a given alg.
 272  *
 273  * @tfm:        tfm handle
 274  * @buffer:     Buffer holding the packet representation of the private
 275  *              key. The structure of the packet key depends on the particular
 276  *              KPP implementation. Packing and unpacking helpers are provided
 277  *              for ECDH and DH (see the respective header files for those
 278  *              implementations).
 279  * @len:        Length of the packet private key buffer.
 280  *
 281  * Return: zero on success; error code in case of error
 282  */
 283 static inline int crypto_kpp_set_secret(struct crypto_kpp *tfm,
 284                                         const void *buffer, unsigned int len)
 285 {
 286         struct kpp_alg *alg = crypto_kpp_alg(tfm);
 287         struct crypto_alg *calg = tfm->base.__crt_alg;
 288         int ret;
 289
 290         crypto_stats_get(calg);
 291         ret = alg->set_secret(tfm, buffer, len);
 292         crypto_stats_kpp_set_secret(calg, ret);
 293         return ret;
 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         struct kpp_alg *alg = crypto_kpp_alg(tfm);
 313         struct crypto_alg *calg = tfm->base.__crt_alg;
 314         int ret;
 315
 316         crypto_stats_get(calg);
 317         ret = alg->generate_public_key(req);
 318         crypto_stats_kpp_generate_public_key(calg, ret);
 319         return ret;
 320 }
 321
 322 /**
 323  * crypto_kpp_compute_shared_secret() - Invoke kpp operation
 324  *
 325  * Function invokes the specific kpp operation for computing the shared secret
 326  * for a given kpp algorithm.
 327  *
 328  * @req:        kpp key request
 329  *
 330  * Return: zero on success; error code in case of error
 331  */
 332 static inline int crypto_kpp_compute_shared_secret(struct kpp_request *req)
 333 {
 334         struct crypto_kpp *tfm = crypto_kpp_reqtfm(req);
 335         struct kpp_alg *alg = crypto_kpp_alg(tfm);
 336         struct crypto_alg *calg = tfm->base.__crt_alg;
 337         int ret;
 338
 339         crypto_stats_get(calg);
 340         ret = alg->compute_shared_secret(req);
 341         crypto_stats_kpp_compute_shared_secret(calg, ret);
 342         return ret;
 343 }
 344
 345 /**
 346  * crypto_kpp_maxsize() - Get len for output buffer
 347  *
 348  * Function returns the output buffer size required for a given key.
 349  * Function assumes that the key is already set in the transformation. If this
 350  * function is called without a setkey or with a failed setkey, you will end up
 351  * in a NULL dereference.
 352  *
 353  * @tfm:        KPP tfm handle allocated with crypto_alloc_kpp()
 354  */
 355 static inline unsigned int crypto_kpp_maxsize(struct crypto_kpp *tfm)
 356 {
 357         struct kpp_alg *alg = crypto_kpp_alg(tfm);
 358
 359         return alg->max_size(tfm);
 360 }
 361
 362 #endif