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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.
Tudor-Dan Ambarusc0ca1212017-05-25 10:18:03 +030056 * The implementation knows how to decode the buffer
Salvatore Benedetto4e5f2c42016-06-22 17:49:13 +010057 * @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
Tudor-Dan Ambarusc444b8d2017-05-25 10:18:08 +030082 unsigned int (*max_size)(struct crypto_kpp *tfm);
Salvatore Benedetto4e5f2c42016-06-22 17:49:13 +010083
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
Tudor-Dan Ambarusc0ca1212017-05-25 10:18:03 +0300105 * is required for any following API invocation
Salvatore Benedetto4e5f2c42016-06-22 17:49:13 +0100106 *
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
Tudor-Dan Ambarus66d39942017-07-05 13:07:58 +0300148static inline u32 crypto_kpp_get_flags(struct crypto_kpp *tfm)
149{
150 return crypto_tfm_get_flags(crypto_kpp_tfm(tfm));
151}
152
153static inline void crypto_kpp_set_flags(struct crypto_kpp *tfm, u32 flags)
154{
155 crypto_tfm_set_flags(crypto_kpp_tfm(tfm), flags);
156}
157
Salvatore Benedetto4e5f2c42016-06-22 17:49:13 +0100158/**
159 * crypto_free_kpp() - free KPP tfm handle
160 *
161 * @tfm: KPP tfm handle allocated with crypto_alloc_kpp()
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 kzfree(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,
Salvatore Benedetto802c7f12016-06-22 17:49:14 +0100255 CRYPTO_KPP_SECRET_TYPE_DH,
Salvatore Benedetto3c4b2392016-06-22 17:49:15 +0100256 CRYPTO_KPP_SECRET_TYPE_ECDH,
Salvatore Benedetto4e5f2c42016-06-22 17:49:13 +0100257};
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
Stephan Mueller8d23da22016-10-21 04:58:20 +0200277 * @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.
Salvatore Benedetto4e5f2c42016-06-22 17:49:13 +0100283 *
284 * Return: zero on success; error code in case of error
285 */
Eric Biggers5527dfb2017-02-24 15:46:58 -0800286static inline int crypto_kpp_set_secret(struct crypto_kpp *tfm,
287 const void *buffer, unsigned int len)
Salvatore Benedetto4e5f2c42016-06-22 17:49:13 +0100288{
289 struct kpp_alg *alg = crypto_kpp_alg(tfm);
290
291 return alg->set_secret(tfm, buffer, len);
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
Stephan Mueller8d23da22016-10-21 04:58:20 +0200298 * 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.
Salvatore Benedetto4e5f2c42016-06-22 17:49:13 +0100302 *
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
312 return alg->generate_public_key(req);
313}
314
315/**
316 * crypto_kpp_compute_shared_secret() - Invoke kpp operation
317 *
318 * Function invokes the specific kpp operation for computing the shared secret
319 * for a given kpp algorithm.
320 *
321 * @req: kpp key request
322 *
323 * Return: zero on success; error code in case of error
324 */
325static inline int crypto_kpp_compute_shared_secret(struct kpp_request *req)
326{
327 struct crypto_kpp *tfm = crypto_kpp_reqtfm(req);
328 struct kpp_alg *alg = crypto_kpp_alg(tfm);
329
330 return alg->compute_shared_secret(req);
331}
332
333/**
334 * crypto_kpp_maxsize() - Get len for output buffer
335 *
Tudor-Dan Ambarusc444b8d2017-05-25 10:18:08 +0300336 * Function returns the output buffer size required for a given key.
337 * Function assumes that the key is already set in the transformation. If this
338 * function is called without a setkey or with a failed setkey, you will end up
339 * in a NULL dereference.
Salvatore Benedetto4e5f2c42016-06-22 17:49:13 +0100340 *
341 * @tfm: KPP tfm handle allocated with crypto_alloc_kpp()
Salvatore Benedetto4e5f2c42016-06-22 17:49:13 +0100342 */
Tudor-Dan Ambarusc444b8d2017-05-25 10:18:08 +0300343static inline unsigned int crypto_kpp_maxsize(struct crypto_kpp *tfm)
Salvatore Benedetto4e5f2c42016-06-22 17:49:13 +0100344{
345 struct kpp_alg *alg = crypto_kpp_alg(tfm);
346
347 return alg->max_size(tfm);
348}
349
350#endif