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 * @base:	Common crypto API algorithm data structure
 41 */
 42struct 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 */
 71struct 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 */
105struct crypto_kpp *crypto_alloc_kpp(const char *alg_name, u32 type, u32 mask);
106
107static inline struct crypto_tfm *crypto_kpp_tfm(struct crypto_kpp *tfm)
108{
109	return &tfm->base;
110}
111
112static inline struct kpp_alg *__crypto_kpp_alg(struct crypto_alg *alg)
113{
114	return container_of(alg, struct kpp_alg, base);
115}
116
117static inline struct crypto_kpp *__crypto_kpp_tfm(struct crypto_tfm *tfm)
118{
119	return container_of(tfm, struct crypto_kpp, base);
120}
121
122static 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
127static inline unsigned int crypto_kpp_reqsize(struct crypto_kpp *tfm)
128{
129	return crypto_kpp_alg(tfm)->reqsize;
130}
131
132static 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
138static inline struct crypto_kpp *crypto_kpp_reqtfm(struct kpp_request *req)
139{
140	return __crypto_kpp_tfm(req->base.tfm);
141}
142
143static inline u32 crypto_kpp_get_flags(struct crypto_kpp *tfm)
144{
145	return crypto_tfm_get_flags(crypto_kpp_tfm(tfm));
146}
147
148static 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 */
158static 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 */
171static 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 */
188static 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 */
204static 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 */
223static 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 */
240static 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
248enum {
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 */
261struct 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 */
281static 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 */
307static 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 */
330static 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 */
353static 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