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 */
 27struct 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 * @reqsize:		Request context size required by algorithm
 41 *			implementation
 42 * @base:	Common crypto API algorithm data structure
 43 */
 44struct crypto_kpp {
 45	unsigned int reqsize;
 46
 47	struct crypto_tfm base;
 48};
 49
 50/**
 51 * struct kpp_alg - generic key-agreement protocol primitives
 52 *
 53 * @set_secret:		Function invokes the protocol specific function to
 54 *			store the secret private key along with parameters.
 55 *			The implementation knows how to decode the buffer
 56 * @generate_public_key: Function generate the public key to be sent to the
 57 *			counterpart. In case of error, where output is not big
 58 *			enough req->dst_len will be updated to the size
 59 *			required
 60 * @compute_shared_secret: Function compute the shared secret as defined by
 61 *			the algorithm. The result is given back to the user.
 62 *			In case of error, where output is not big enough,
 63 *			req->dst_len will be updated to the size required
 64 * @max_size:		Function returns the size of the output buffer
 65 * @init:		Initialize the object. This is called only once at
 66 *			instantiation time. In case the cryptographic hardware
 67 *			needs to be initialized. Software fallback should be
 68 *			put in place here.
 69 * @exit:		Undo everything @init did.
 70 *
 71 * @base:		Common crypto API algorithm data structure
 72 */
 73struct kpp_alg {
 74	int (*set_secret)(struct crypto_kpp *tfm, const void *buffer,
 75			  unsigned int len);
 76	int (*generate_public_key)(struct kpp_request *req);
 77	int (*compute_shared_secret)(struct kpp_request *req);
 78
 79	unsigned int (*max_size)(struct crypto_kpp *tfm);
 80
 81	int (*init)(struct crypto_kpp *tfm);
 82	void (*exit)(struct crypto_kpp *tfm);
 83
 84	struct crypto_alg base;
 85};
 86
 87/**
 88 * DOC: Generic Key-agreement Protocol Primitives API
 89 *
 90 * The KPP API is used with the algorithm type
 91 * CRYPTO_ALG_TYPE_KPP (listed as type "kpp" in /proc/crypto)
 92 */
 93
 94/**
 95 * crypto_alloc_kpp() - allocate KPP tfm handle
 96 * @alg_name: is the name of the kpp algorithm (e.g. "dh", "ecdh")
 97 * @type: specifies the type of the algorithm
 98 * @mask: specifies the mask for the algorithm
 99 *
100 * Allocate a handle for kpp algorithm. The returned struct crypto_kpp
101 * is required for any following API invocation
102 *
103 * Return: allocated handle in case of success; IS_ERR() is true in case of
104 *	   an error, PTR_ERR() returns the error code.
105 */
106struct crypto_kpp *crypto_alloc_kpp(const char *alg_name, u32 type, u32 mask);
107
108int crypto_has_kpp(const char *alg_name, u32 type, u32 mask);
109
110static inline struct crypto_tfm *crypto_kpp_tfm(struct crypto_kpp *tfm)
111{
112	return &tfm->base;
113}
114
115static inline struct kpp_alg *__crypto_kpp_alg(struct crypto_alg *alg)
116{
117	return container_of(alg, struct kpp_alg, base);
118}
119
120static inline struct crypto_kpp *__crypto_kpp_tfm(struct crypto_tfm *tfm)
121{
122	return container_of(tfm, struct crypto_kpp, base);
123}
124
125static inline struct kpp_alg *crypto_kpp_alg(struct crypto_kpp *tfm)
126{
127	return __crypto_kpp_alg(crypto_kpp_tfm(tfm)->__crt_alg);
128}
129
130static inline unsigned int crypto_kpp_reqsize(struct crypto_kpp *tfm)
131{
132	return tfm->reqsize;
133}
134
135static inline void kpp_request_set_tfm(struct kpp_request *req,
136				       struct crypto_kpp *tfm)
137{
138	req->base.tfm = crypto_kpp_tfm(tfm);
139}
140
141static inline struct crypto_kpp *crypto_kpp_reqtfm(struct kpp_request *req)
142{
143	return __crypto_kpp_tfm(req->base.tfm);
144}
145
146static inline u32 crypto_kpp_get_flags(struct crypto_kpp *tfm)
147{
148	return crypto_tfm_get_flags(crypto_kpp_tfm(tfm));
149}
150
151static inline void crypto_kpp_set_flags(struct crypto_kpp *tfm, u32 flags)
152{
153	crypto_tfm_set_flags(crypto_kpp_tfm(tfm), flags);
154}
155
156/**
157 * crypto_free_kpp() - free KPP tfm handle
158 *
159 * @tfm: KPP tfm handle allocated with crypto_alloc_kpp()
160 *
161 * If @tfm is a NULL or error pointer, this function does nothing.
162 */
163static 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 */
176static 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 */
193static inline void kpp_request_free(struct kpp_request *req)
194{
195	kfree_sensitive(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 */
209static 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 */
228static 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 */
245static 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
253enum {
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 */
266struct 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 */
286static 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	struct crypto_alg *calg = tfm->base.__crt_alg;
291	int ret;
292
293	crypto_stats_get(calg);
294	ret = alg->set_secret(tfm, buffer, len);
295	crypto_stats_kpp_set_secret(calg, ret);
296	return ret;
297}
298
299/**
300 * crypto_kpp_generate_public_key() - Invoke kpp operation
301 *
302 * Function invokes the specific kpp operation for generating the public part
303 * for a given kpp algorithm.
304 *
305 * To generate a private key, the caller should use a random number generator.
306 * The output of the requested length serves as the private key.
307 *
308 * @req:	kpp key request
309 *
310 * Return: zero on success; error code in case of error
311 */
312static inline int crypto_kpp_generate_public_key(struct kpp_request *req)
313{
314	struct crypto_kpp *tfm = crypto_kpp_reqtfm(req);
315	struct kpp_alg *alg = crypto_kpp_alg(tfm);
316	struct crypto_alg *calg = tfm->base.__crt_alg;
317	int ret;
318
319	crypto_stats_get(calg);
320	ret = alg->generate_public_key(req);
321	crypto_stats_kpp_generate_public_key(calg, ret);
322	return ret;
323}
324
325/**
326 * crypto_kpp_compute_shared_secret() - Invoke kpp operation
327 *
328 * Function invokes the specific kpp operation for computing the shared secret
329 * for a given kpp algorithm.
330 *
331 * @req:	kpp key request
332 *
333 * Return: zero on success; error code in case of error
334 */
335static inline int crypto_kpp_compute_shared_secret(struct kpp_request *req)
336{
337	struct crypto_kpp *tfm = crypto_kpp_reqtfm(req);
338	struct kpp_alg *alg = crypto_kpp_alg(tfm);
339	struct crypto_alg *calg = tfm->base.__crt_alg;
340	int ret;
341
342	crypto_stats_get(calg);
343	ret = alg->compute_shared_secret(req);
344	crypto_stats_kpp_compute_shared_secret(calg, ret);
345	return ret;
346}
347
348/**
349 * crypto_kpp_maxsize() - Get len for output buffer
350 *
351 * Function returns the output buffer size required for a given key.
352 * Function assumes that the key is already set in the transformation. If this
353 * function is called without a setkey or with a failed setkey, you will end up
354 * in a NULL dereference.
355 *
356 * @tfm:	KPP tfm handle allocated with crypto_alloc_kpp()
357 */
358static inline unsigned int crypto_kpp_maxsize(struct crypto_kpp *tfm)
359{
360	struct kpp_alg *alg = crypto_kpp_alg(tfm);
361
362	return alg->max_size(tfm);
363}
364
365#endif