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
12#include <linux/atomic.h>
13#include <linux/container_of.h>
14#include <linux/crypto.h>
15#include <linux/slab.h>
16
17/**
18 * struct kpp_request
19 *
20 * @base:	Common attributes for async crypto requests
21 * @src:	Source data
22 * @dst:	Destination data
23 * @src_len:	Size of the input buffer
24 * @dst_len:	Size of the output buffer. It needs to be at least
25 *		as big as the expected result depending	on the operation
26 *		After operation it will be updated with the actual size of the
27 *		result. In case of error where the dst sgl size was insufficient,
28 *		it will be updated to the size required for the operation.
29 * @__ctx:	Start of private context data
30 */
31struct kpp_request {
32	struct crypto_async_request base;
33	struct scatterlist *src;
34	struct scatterlist *dst;
35	unsigned int src_len;
36	unsigned int dst_len;
37	void *__ctx[] CRYPTO_MINALIGN_ATTR;
38};
39
40/**
41 * struct crypto_kpp - user-instantiated object which encapsulate
42 * algorithms and core processing logic
43 *
44 * @reqsize:		Request context size required by algorithm
45 *			implementation
46 * @base:	Common crypto API algorithm data structure
47 */
48struct crypto_kpp {
49	unsigned int reqsize;
50
51	struct crypto_tfm base;
52};
53
54/*
55 * struct crypto_istat_kpp - statistics for KPP algorithm
56 * @setsecret_cnt:		number of setsecrey operation
57 * @generate_public_key_cnt:	number of generate_public_key operation
58 * @compute_shared_secret_cnt:	number of compute_shared_secret operation
59 * @err_cnt:			number of error for KPP requests
60 */
61struct crypto_istat_kpp {
62	atomic64_t setsecret_cnt;
63	atomic64_t generate_public_key_cnt;
64	atomic64_t compute_shared_secret_cnt;
65	atomic64_t err_cnt;
66};
67
68/**
69 * struct kpp_alg - generic key-agreement protocol primitives
70 *
71 * @set_secret:		Function invokes the protocol specific function to
72 *			store the secret private key along with parameters.
73 *			The implementation knows how to decode the buffer
74 * @generate_public_key: Function generate the public key to be sent to the
75 *			counterpart. In case of error, where output is not big
76 *			enough req->dst_len will be updated to the size
77 *			required
78 * @compute_shared_secret: Function compute the shared secret as defined by
79 *			the algorithm. The result is given back to the user.
80 *			In case of error, where output is not big enough,
81 *			req->dst_len will be updated to the size required
82 * @max_size:		Function returns the size of the output buffer
83 * @init:		Initialize the object. This is called only once at
84 *			instantiation time. In case the cryptographic hardware
85 *			needs to be initialized. Software fallback should be
86 *			put in place here.
87 * @exit:		Undo everything @init did.
88 *
89 * @base:		Common crypto API algorithm data structure
90 * @stat:		Statistics for KPP algorithm
91 */
92struct kpp_alg {
93	int (*set_secret)(struct crypto_kpp *tfm, const void *buffer,
94			  unsigned int len);
95	int (*generate_public_key)(struct kpp_request *req);
96	int (*compute_shared_secret)(struct kpp_request *req);
97
98	unsigned int (*max_size)(struct crypto_kpp *tfm);
99
100	int (*init)(struct crypto_kpp *tfm);
101	void (*exit)(struct crypto_kpp *tfm);
102
103#ifdef CONFIG_CRYPTO_STATS
104	struct crypto_istat_kpp stat;
105#endif
106
107	struct crypto_alg base;
108};
109
110/**
111 * DOC: Generic Key-agreement Protocol Primitives API
112 *
113 * The KPP API is used with the algorithm type
114 * CRYPTO_ALG_TYPE_KPP (listed as type "kpp" in /proc/crypto)
115 */
116
117/**
118 * crypto_alloc_kpp() - allocate KPP tfm handle
119 * @alg_name: is the name of the kpp algorithm (e.g. "dh", "ecdh")
120 * @type: specifies the type of the algorithm
121 * @mask: specifies the mask for the algorithm
122 *
123 * Allocate a handle for kpp algorithm. The returned struct crypto_kpp
124 * is required for any following API invocation
125 *
126 * Return: allocated handle in case of success; IS_ERR() is true in case of
127 *	   an error, PTR_ERR() returns the error code.
128 */
129struct crypto_kpp *crypto_alloc_kpp(const char *alg_name, u32 type, u32 mask);
130
131int crypto_has_kpp(const char *alg_name, u32 type, u32 mask);
132
133static inline struct crypto_tfm *crypto_kpp_tfm(struct crypto_kpp *tfm)
134{
135	return &tfm->base;
136}
137
138static inline struct kpp_alg *__crypto_kpp_alg(struct crypto_alg *alg)
139{
140	return container_of(alg, struct kpp_alg, base);
141}
142
143static inline struct crypto_kpp *__crypto_kpp_tfm(struct crypto_tfm *tfm)
144{
145	return container_of(tfm, struct crypto_kpp, base);
146}
147
148static inline struct kpp_alg *crypto_kpp_alg(struct crypto_kpp *tfm)
149{
150	return __crypto_kpp_alg(crypto_kpp_tfm(tfm)->__crt_alg);
151}
152
153static inline unsigned int crypto_kpp_reqsize(struct crypto_kpp *tfm)
154{
155	return tfm->reqsize;
156}
157
158static inline void kpp_request_set_tfm(struct kpp_request *req,
159				       struct crypto_kpp *tfm)
160{
161	req->base.tfm = crypto_kpp_tfm(tfm);
162}
163
164static inline struct crypto_kpp *crypto_kpp_reqtfm(struct kpp_request *req)
165{
166	return __crypto_kpp_tfm(req->base.tfm);
167}
168
169static inline u32 crypto_kpp_get_flags(struct crypto_kpp *tfm)
170{
171	return crypto_tfm_get_flags(crypto_kpp_tfm(tfm));
172}
173
174static inline void crypto_kpp_set_flags(struct crypto_kpp *tfm, u32 flags)
175{
176	crypto_tfm_set_flags(crypto_kpp_tfm(tfm), flags);
177}
178
179/**
180 * crypto_free_kpp() - free KPP tfm handle
181 *
182 * @tfm: KPP tfm handle allocated with crypto_alloc_kpp()
183 *
184 * If @tfm is a NULL or error pointer, this function does nothing.
185 */
186static inline void crypto_free_kpp(struct crypto_kpp *tfm)
187{
188	crypto_destroy_tfm(tfm, crypto_kpp_tfm(tfm));
189}
190
191/**
192 * kpp_request_alloc() - allocates kpp request
193 *
194 * @tfm:	KPP tfm handle allocated with crypto_alloc_kpp()
195 * @gfp:	allocation flags
196 *
197 * Return: allocated handle in case of success or NULL in case of an error.
198 */
199static inline struct kpp_request *kpp_request_alloc(struct crypto_kpp *tfm,
200						    gfp_t gfp)
201{
202	struct kpp_request *req;
203
204	req = kmalloc(sizeof(*req) + crypto_kpp_reqsize(tfm), gfp);
205	if (likely(req))
206		kpp_request_set_tfm(req, tfm);
207
208	return req;
209}
210
211/**
212 * kpp_request_free() - zeroize and free kpp request
213 *
214 * @req:	request to free
215 */
216static inline void kpp_request_free(struct kpp_request *req)
217{
218	kfree_sensitive(req);
219}
220
221/**
222 * kpp_request_set_callback() - Sets an asynchronous callback.
223 *
224 * Callback will be called when an asynchronous operation on a given
225 * request is finished.
226 *
227 * @req:	request that the callback will be set for
228 * @flgs:	specify for instance if the operation may backlog
229 * @cmpl:	callback which will be called
230 * @data:	private data used by the caller
231 */
232static inline void kpp_request_set_callback(struct kpp_request *req,
233					    u32 flgs,
234					    crypto_completion_t cmpl,
235					    void *data)
236{
237	req->base.complete = cmpl;
238	req->base.data = data;
239	req->base.flags = flgs;
240}
241
242/**
243 * kpp_request_set_input() - Sets input buffer
244 *
245 * Sets parameters required by generate_public_key
246 *
247 * @req:	kpp request
248 * @input:	ptr to input scatter list
249 * @input_len:	size of the input scatter list
250 */
251static inline void kpp_request_set_input(struct kpp_request *req,
252					 struct scatterlist *input,
253					 unsigned int input_len)
254{
255	req->src = input;
256	req->src_len = input_len;
257}
258
259/**
260 * kpp_request_set_output() - Sets output buffer
261 *
262 * Sets parameters required by kpp operation
263 *
264 * @req:	kpp request
265 * @output:	ptr to output scatter list
266 * @output_len:	size of the output scatter list
267 */
268static inline void kpp_request_set_output(struct kpp_request *req,
269					  struct scatterlist *output,
270					  unsigned int output_len)
271{
272	req->dst = output;
273	req->dst_len = output_len;
274}
275
276enum {
277	CRYPTO_KPP_SECRET_TYPE_UNKNOWN,
278	CRYPTO_KPP_SECRET_TYPE_DH,
279	CRYPTO_KPP_SECRET_TYPE_ECDH,
280};
281
282/**
283 * struct kpp_secret - small header for packing secret buffer
284 *
285 * @type:	define type of secret. Each kpp type will define its own
286 * @len:	specify the len of the secret, include the header, that
287 *		follows the struct
288 */
289struct kpp_secret {
290	unsigned short type;
291	unsigned short len;
292};
293
294static inline struct crypto_istat_kpp *kpp_get_stat(struct kpp_alg *alg)
295{
296#ifdef CONFIG_CRYPTO_STATS
297	return &alg->stat;
298#else
299	return NULL;
300#endif
301}
302
303static inline int crypto_kpp_errstat(struct kpp_alg *alg, int err)
304{
305	if (!IS_ENABLED(CONFIG_CRYPTO_STATS))
306		return err;
307
308	if (err && err != -EINPROGRESS && err != -EBUSY)
309		atomic64_inc(&kpp_get_stat(alg)->err_cnt);
310
311	return err;
312}
313
314/**
315 * crypto_kpp_set_secret() - Invoke kpp operation
316 *
317 * Function invokes the specific kpp operation for a given alg.
318 *
319 * @tfm:	tfm handle
320 * @buffer:	Buffer holding the packet representation of the private
321 *		key. The structure of the packet key depends on the particular
322 *		KPP implementation. Packing and unpacking helpers are provided
323 *		for ECDH and DH (see the respective header files for those
324 *		implementations).
325 * @len:	Length of the packet private key buffer.
326 *
327 * Return: zero on success; error code in case of error
328 */
329static inline int crypto_kpp_set_secret(struct crypto_kpp *tfm,
330					const void *buffer, unsigned int len)
331{
332	struct kpp_alg *alg = crypto_kpp_alg(tfm);
333
334	if (IS_ENABLED(CONFIG_CRYPTO_STATS))
335		atomic64_inc(&kpp_get_stat(alg)->setsecret_cnt);
336
337	return crypto_kpp_errstat(alg, alg->set_secret(tfm, buffer, len));
338}
339
340/**
341 * crypto_kpp_generate_public_key() - Invoke kpp operation
342 *
343 * Function invokes the specific kpp operation for generating the public part
344 * for a given kpp algorithm.
345 *
346 * To generate a private key, the caller should use a random number generator.
347 * The output of the requested length serves as the private key.
348 *
349 * @req:	kpp key request
350 *
351 * Return: zero on success; error code in case of error
352 */
353static inline int crypto_kpp_generate_public_key(struct kpp_request *req)
354{
355	struct crypto_kpp *tfm = crypto_kpp_reqtfm(req);
356	struct kpp_alg *alg = crypto_kpp_alg(tfm);
357
358	if (IS_ENABLED(CONFIG_CRYPTO_STATS))
359		atomic64_inc(&kpp_get_stat(alg)->generate_public_key_cnt);
360
361	return crypto_kpp_errstat(alg, alg->generate_public_key(req));
362}
363
364/**
365 * crypto_kpp_compute_shared_secret() - Invoke kpp operation
366 *
367 * Function invokes the specific kpp operation for computing the shared secret
368 * for a given kpp algorithm.
369 *
370 * @req:	kpp key request
371 *
372 * Return: zero on success; error code in case of error
373 */
374static inline int crypto_kpp_compute_shared_secret(struct kpp_request *req)
375{
376	struct crypto_kpp *tfm = crypto_kpp_reqtfm(req);
377	struct kpp_alg *alg = crypto_kpp_alg(tfm);
378
379	if (IS_ENABLED(CONFIG_CRYPTO_STATS))
380		atomic64_inc(&kpp_get_stat(alg)->compute_shared_secret_cnt);
381
382	return crypto_kpp_errstat(alg, alg->compute_shared_secret(req));
383}
384
385/**
386 * crypto_kpp_maxsize() - Get len for output buffer
387 *
388 * Function returns the output buffer size required for a given key.
389 * Function assumes that the key is already set in the transformation. If this
390 * function is called without a setkey or with a failed setkey, you will end up
391 * in a NULL dereference.
392 *
393 * @tfm:	KPP tfm handle allocated with crypto_alloc_kpp()
394 */
395static inline unsigned int crypto_kpp_maxsize(struct crypto_kpp *tfm)
396{
397	struct kpp_alg *alg = crypto_kpp_alg(tfm);
398
399	return alg->max_size(tfm);
400}
401
402#endif
403