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Salvatore Benedetto4e5f2c42016-06-22 17:49:13 +01001/*
2 * Key-agreement Protocol Primitives (KPP)
3 *
4 * Copyright (c) 2016, Intel Corporation
5 * Authors: Salvatore Benedetto <salvatore.benedetto@intel.com>
6 *
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU General Public License as published by the Free
9 * Software Foundation; either version 2 of the License, or (at your option)
10 * any later version.
11 *
12 */
13
14#ifndef _CRYPTO_KPP_
15#define _CRYPTO_KPP_
16#include <linux/crypto.h>
17
18/**
19 * struct kpp_request
20 *
21 * @base: Common attributes for async crypto requests
22 * @src: Source data
23 * @dst: Destination data
24 * @src_len: Size of the input buffer
25 * @dst_len: Size of the output buffer. It needs to be at least
26 * as big as the expected result depending on the operation
27 * After operation it will be updated with the actual size of the
28 * result. In case of error where the dst sgl size was insufficient,
29 * it will be updated to the size required for the operation.
30 * @__ctx: Start of private context data
31 */
32struct kpp_request {
33 struct crypto_async_request base;
34 struct scatterlist *src;
35 struct scatterlist *dst;
36 unsigned int src_len;
37 unsigned int dst_len;
38 void *__ctx[] CRYPTO_MINALIGN_ATTR;
39};
40
41/**
42 * struct crypto_kpp - user-instantiated object which encapsulate
43 * algorithms and core processing logic
44 *
45 * @base: Common crypto API algorithm data structure
46 */
47struct crypto_kpp {
48 struct crypto_tfm base;
49};
50
51/**
52 * struct kpp_alg - generic key-agreement protocol primitives
53 *
54 * @set_secret: Function invokes the protocol specific function to
55 * store the secret private key along with parameters.
56 * The implementation knows how to decode thie buffer
57 * @generate_public_key: Function generate the public key to be sent to the
58 * counterpart. In case of error, where output is not big
59 * enough req->dst_len will be updated to the size
60 * required
61 * @compute_shared_secret: Function compute the shared secret as defined by
62 * the algorithm. The result is given back to the user.
63 * In case of error, where output is not big enough,
64 * req->dst_len will be updated to the size required
65 * @max_size: Function returns the size of the output buffer
66 * @init: Initialize the object. This is called only once at
67 * instantiation time. In case the cryptographic hardware
68 * needs to be initialized. Software fallback should be
69 * put in place here.
70 * @exit: Undo everything @init did.
71 *
72 * @reqsize: Request context size required by algorithm
73 * implementation
Stephan Mueller8d23da22016-10-21 04:58:20 +020074 * @base: Common crypto API algorithm data structure
Salvatore Benedetto4e5f2c42016-06-22 17:49:13 +010075 */
76struct kpp_alg {
Eric Biggers5527dfb2017-02-24 15:46:58 -080077 int (*set_secret)(struct crypto_kpp *tfm, const void *buffer,
Salvatore Benedetto4e5f2c42016-06-22 17:49:13 +010078 unsigned int len);
79 int (*generate_public_key)(struct kpp_request *req);
80 int (*compute_shared_secret)(struct kpp_request *req);
81
82 int (*max_size)(struct crypto_kpp *tfm);
83
84 int (*init)(struct crypto_kpp *tfm);
85 void (*exit)(struct crypto_kpp *tfm);
86
87 unsigned int reqsize;
88 struct crypto_alg base;
89};
90
91/**
Stephan Mueller8d23da22016-10-21 04:58:20 +020092 * DOC: Generic Key-agreement Protocol Primitives API
Salvatore Benedetto4e5f2c42016-06-22 17:49:13 +010093 *
94 * The KPP API is used with the algorithm type
95 * CRYPTO_ALG_TYPE_KPP (listed as type "kpp" in /proc/crypto)
96 */
97
98/**
99 * crypto_alloc_kpp() - allocate KPP tfm handle
100 * @alg_name: is the name of the kpp algorithm (e.g. "dh", "ecdh")
101 * @type: specifies the type of the algorithm
102 * @mask: specifies the mask for the algorithm
103 *
104 * Allocate a handle for kpp algorithm. The returned struct crypto_kpp
105 * is requeried for any following API invocation
106 *
107 * Return: allocated handle in case of success; IS_ERR() is true in case of
108 * an error, PTR_ERR() returns the error code.
109 */
110struct crypto_kpp *crypto_alloc_kpp(const char *alg_name, u32 type, u32 mask);
111
112static inline struct crypto_tfm *crypto_kpp_tfm(struct crypto_kpp *tfm)
113{
114 return &tfm->base;
115}
116
117static inline struct kpp_alg *__crypto_kpp_alg(struct crypto_alg *alg)
118{
119 return container_of(alg, struct kpp_alg, base);
120}
121
122static inline struct crypto_kpp *__crypto_kpp_tfm(struct crypto_tfm *tfm)
123{
124 return container_of(tfm, struct crypto_kpp, base);
125}
126
127static inline struct kpp_alg *crypto_kpp_alg(struct crypto_kpp *tfm)
128{
129 return __crypto_kpp_alg(crypto_kpp_tfm(tfm)->__crt_alg);
130}
131
132static inline unsigned int crypto_kpp_reqsize(struct crypto_kpp *tfm)
133{
134 return crypto_kpp_alg(tfm)->reqsize;
135}
136
137static inline void kpp_request_set_tfm(struct kpp_request *req,
138 struct crypto_kpp *tfm)
139{
140 req->base.tfm = crypto_kpp_tfm(tfm);
141}
142
143static inline struct crypto_kpp *crypto_kpp_reqtfm(struct kpp_request *req)
144{
145 return __crypto_kpp_tfm(req->base.tfm);
146}
147
148/**
149 * crypto_free_kpp() - free KPP tfm handle
150 *
151 * @tfm: KPP tfm handle allocated with crypto_alloc_kpp()
152 */
153static inline void crypto_free_kpp(struct crypto_kpp *tfm)
154{
155 crypto_destroy_tfm(tfm, crypto_kpp_tfm(tfm));
156}
157
158/**
159 * kpp_request_alloc() - allocates kpp request
160 *
161 * @tfm: KPP tfm handle allocated with crypto_alloc_kpp()
162 * @gfp: allocation flags
163 *
164 * Return: allocated handle in case of success or NULL in case of an error.
165 */
166static inline struct kpp_request *kpp_request_alloc(struct crypto_kpp *tfm,
167 gfp_t gfp)
168{
169 struct kpp_request *req;
170
171 req = kmalloc(sizeof(*req) + crypto_kpp_reqsize(tfm), gfp);
172 if (likely(req))
173 kpp_request_set_tfm(req, tfm);
174
175 return req;
176}
177
178/**
179 * kpp_request_free() - zeroize and free kpp request
180 *
181 * @req: request to free
182 */
183static inline void kpp_request_free(struct kpp_request *req)
184{
185 kzfree(req);
186}
187
188/**
189 * kpp_request_set_callback() - Sets an asynchronous callback.
190 *
191 * Callback will be called when an asynchronous operation on a given
192 * request is finished.
193 *
194 * @req: request that the callback will be set for
195 * @flgs: specify for instance if the operation may backlog
196 * @cmpl: callback which will be called
197 * @data: private data used by the caller
198 */
199static inline void kpp_request_set_callback(struct kpp_request *req,
200 u32 flgs,
201 crypto_completion_t cmpl,
202 void *data)
203{
204 req->base.complete = cmpl;
205 req->base.data = data;
206 req->base.flags = flgs;
207}
208
209/**
210 * kpp_request_set_input() - Sets input buffer
211 *
212 * Sets parameters required by generate_public_key
213 *
214 * @req: kpp request
215 * @input: ptr to input scatter list
216 * @input_len: size of the input scatter list
217 */
218static inline void kpp_request_set_input(struct kpp_request *req,
219 struct scatterlist *input,
220 unsigned int input_len)
221{
222 req->src = input;
223 req->src_len = input_len;
224}
225
226/**
227 * kpp_request_set_output() - Sets output buffer
228 *
229 * Sets parameters required by kpp operation
230 *
231 * @req: kpp request
232 * @output: ptr to output scatter list
233 * @output_len: size of the output scatter list
234 */
235static inline void kpp_request_set_output(struct kpp_request *req,
236 struct scatterlist *output,
237 unsigned int output_len)
238{
239 req->dst = output;
240 req->dst_len = output_len;
241}
242
243enum {
244 CRYPTO_KPP_SECRET_TYPE_UNKNOWN,
Salvatore Benedetto802c7f12016-06-22 17:49:14 +0100245 CRYPTO_KPP_SECRET_TYPE_DH,
Salvatore Benedetto3c4b2392016-06-22 17:49:15 +0100246 CRYPTO_KPP_SECRET_TYPE_ECDH,
Salvatore Benedetto4e5f2c42016-06-22 17:49:13 +0100247};
248
249/**
250 * struct kpp_secret - small header for packing secret buffer
251 *
252 * @type: define type of secret. Each kpp type will define its own
253 * @len: specify the len of the secret, include the header, that
254 * follows the struct
255 */
256struct kpp_secret {
257 unsigned short type;
258 unsigned short len;
259};
260
261/**
262 * crypto_kpp_set_secret() - Invoke kpp operation
263 *
264 * Function invokes the specific kpp operation for a given alg.
265 *
266 * @tfm: tfm handle
Stephan Mueller8d23da22016-10-21 04:58:20 +0200267 * @buffer: Buffer holding the packet representation of the private
268 * key. The structure of the packet key depends on the particular
269 * KPP implementation. Packing and unpacking helpers are provided
270 * for ECDH and DH (see the respective header files for those
271 * implementations).
272 * @len: Length of the packet private key buffer.
Salvatore Benedetto4e5f2c42016-06-22 17:49:13 +0100273 *
274 * Return: zero on success; error code in case of error
275 */
Eric Biggers5527dfb2017-02-24 15:46:58 -0800276static inline int crypto_kpp_set_secret(struct crypto_kpp *tfm,
277 const void *buffer, unsigned int len)
Salvatore Benedetto4e5f2c42016-06-22 17:49:13 +0100278{
279 struct kpp_alg *alg = crypto_kpp_alg(tfm);
280
281 return alg->set_secret(tfm, buffer, len);
282}
283
284/**
285 * crypto_kpp_generate_public_key() - Invoke kpp operation
286 *
287 * Function invokes the specific kpp operation for generating the public part
Stephan Mueller8d23da22016-10-21 04:58:20 +0200288 * for a given kpp algorithm.
289 *
290 * To generate a private key, the caller should use a random number generator.
291 * The output of the requested length serves as the private key.
Salvatore Benedetto4e5f2c42016-06-22 17:49:13 +0100292 *
293 * @req: kpp key request
294 *
295 * Return: zero on success; error code in case of error
296 */
297static inline int crypto_kpp_generate_public_key(struct kpp_request *req)
298{
299 struct crypto_kpp *tfm = crypto_kpp_reqtfm(req);
300 struct kpp_alg *alg = crypto_kpp_alg(tfm);
301
302 return alg->generate_public_key(req);
303}
304
305/**
306 * crypto_kpp_compute_shared_secret() - Invoke kpp operation
307 *
308 * Function invokes the specific kpp operation for computing the shared secret
309 * for a given kpp algorithm.
310 *
311 * @req: kpp key request
312 *
313 * Return: zero on success; error code in case of error
314 */
315static inline int crypto_kpp_compute_shared_secret(struct kpp_request *req)
316{
317 struct crypto_kpp *tfm = crypto_kpp_reqtfm(req);
318 struct kpp_alg *alg = crypto_kpp_alg(tfm);
319
320 return alg->compute_shared_secret(req);
321}
322
323/**
324 * crypto_kpp_maxsize() - Get len for output buffer
325 *
326 * Function returns the output buffer size required
327 *
328 * @tfm: KPP tfm handle allocated with crypto_alloc_kpp()
329 *
330 * Return: minimum len for output buffer or error code if key hasn't been set
331 */
332static inline int crypto_kpp_maxsize(struct crypto_kpp *tfm)
333{
334 struct kpp_alg *alg = crypto_kpp_alg(tfm);
335
336 return alg->max_size(tfm);
337}
338
339#endif