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