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 *
158 * If @tfm is a NULL or error pointer, this function does nothing.
159 */
160static 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 */
173static 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 */
190static 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 */
206static 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 */
225static 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 */
242static 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
250enum {
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 */
263struct 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 */
283static 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 */
309static 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 */
332static 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 */
355static 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