xref: /openbmc/linux/include/crypto/kpp.h (revision e8254a8e)
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  * @reqsize:		Request context size required by algorithm
41  *			implementation
42  * @base:	Common crypto API algorithm data structure
43  */
44 struct crypto_kpp {
45 	unsigned int reqsize;
46 
47 	struct crypto_tfm base;
48 };
49 
50 /**
51  * struct kpp_alg - generic key-agreement protocol primitives
52  *
53  * @set_secret:		Function invokes the protocol specific function to
54  *			store the secret private key along with parameters.
55  *			The implementation knows how to decode the buffer
56  * @generate_public_key: Function generate the public key to be sent to the
57  *			counterpart. In case of error, where output is not big
58  *			enough req->dst_len will be updated to the size
59  *			required
60  * @compute_shared_secret: Function compute the shared secret as defined by
61  *			the algorithm. The result is given back to the user.
62  *			In case of error, where output is not big enough,
63  *			req->dst_len will be updated to the size required
64  * @max_size:		Function returns the size of the output buffer
65  * @init:		Initialize the object. This is called only once at
66  *			instantiation time. In case the cryptographic hardware
67  *			needs to be initialized. Software fallback should be
68  *			put in place here.
69  * @exit:		Undo everything @init did.
70  *
71  * @base:		Common crypto API algorithm data structure
72  */
73 struct kpp_alg {
74 	int (*set_secret)(struct crypto_kpp *tfm, const void *buffer,
75 			  unsigned int len);
76 	int (*generate_public_key)(struct kpp_request *req);
77 	int (*compute_shared_secret)(struct kpp_request *req);
78 
79 	unsigned int (*max_size)(struct crypto_kpp *tfm);
80 
81 	int (*init)(struct crypto_kpp *tfm);
82 	void (*exit)(struct crypto_kpp *tfm);
83 
84 	struct crypto_alg base;
85 };
86 
87 /**
88  * DOC: Generic Key-agreement Protocol Primitives API
89  *
90  * The KPP API is used with the algorithm type
91  * CRYPTO_ALG_TYPE_KPP (listed as type "kpp" in /proc/crypto)
92  */
93 
94 /**
95  * crypto_alloc_kpp() - allocate KPP tfm handle
96  * @alg_name: is the name of the kpp algorithm (e.g. "dh", "ecdh")
97  * @type: specifies the type of the algorithm
98  * @mask: specifies the mask for the algorithm
99  *
100  * Allocate a handle for kpp algorithm. The returned struct crypto_kpp
101  * is required for any following API invocation
102  *
103  * Return: allocated handle in case of success; IS_ERR() is true in case of
104  *	   an error, PTR_ERR() returns the error code.
105  */
106 struct crypto_kpp *crypto_alloc_kpp(const char *alg_name, u32 type, u32 mask);
107 
108 int crypto_has_kpp(const char *alg_name, u32 type, u32 mask);
109 
110 static inline struct crypto_tfm *crypto_kpp_tfm(struct crypto_kpp *tfm)
111 {
112 	return &tfm->base;
113 }
114 
115 static inline struct kpp_alg *__crypto_kpp_alg(struct crypto_alg *alg)
116 {
117 	return container_of(alg, struct kpp_alg, base);
118 }
119 
120 static inline struct crypto_kpp *__crypto_kpp_tfm(struct crypto_tfm *tfm)
121 {
122 	return container_of(tfm, struct crypto_kpp, base);
123 }
124 
125 static inline struct kpp_alg *crypto_kpp_alg(struct crypto_kpp *tfm)
126 {
127 	return __crypto_kpp_alg(crypto_kpp_tfm(tfm)->__crt_alg);
128 }
129 
130 static inline unsigned int crypto_kpp_reqsize(struct crypto_kpp *tfm)
131 {
132 	return tfm->reqsize;
133 }
134 
135 static inline void kpp_request_set_tfm(struct kpp_request *req,
136 				       struct crypto_kpp *tfm)
137 {
138 	req->base.tfm = crypto_kpp_tfm(tfm);
139 }
140 
141 static inline struct crypto_kpp *crypto_kpp_reqtfm(struct kpp_request *req)
142 {
143 	return __crypto_kpp_tfm(req->base.tfm);
144 }
145 
146 static inline u32 crypto_kpp_get_flags(struct crypto_kpp *tfm)
147 {
148 	return crypto_tfm_get_flags(crypto_kpp_tfm(tfm));
149 }
150 
151 static inline void crypto_kpp_set_flags(struct crypto_kpp *tfm, u32 flags)
152 {
153 	crypto_tfm_set_flags(crypto_kpp_tfm(tfm), flags);
154 }
155 
156 /**
157  * crypto_free_kpp() - free KPP tfm handle
158  *
159  * @tfm: KPP tfm handle allocated with crypto_alloc_kpp()
160  *
161  * If @tfm is a NULL or error pointer, this function does nothing.
162  */
163 static 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  */
176 static 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  */
193 static inline void kpp_request_free(struct kpp_request *req)
194 {
195 	kfree_sensitive(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  */
209 static 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  */
228 static 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  */
245 static 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 
253 enum {
254 	CRYPTO_KPP_SECRET_TYPE_UNKNOWN,
255 	CRYPTO_KPP_SECRET_TYPE_DH,
256 	CRYPTO_KPP_SECRET_TYPE_ECDH,
257 };
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  */
266 struct 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
277  * @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.
283  *
284  * Return: zero on success; error code in case of error
285  */
286 static inline int crypto_kpp_set_secret(struct crypto_kpp *tfm,
287 					const void *buffer, unsigned int len)
288 {
289 	struct kpp_alg *alg = crypto_kpp_alg(tfm);
290 	struct crypto_alg *calg = tfm->base.__crt_alg;
291 	int ret;
292 
293 	crypto_stats_get(calg);
294 	ret = alg->set_secret(tfm, buffer, len);
295 	crypto_stats_kpp_set_secret(calg, ret);
296 	return ret;
297 }
298 
299 /**
300  * crypto_kpp_generate_public_key() - Invoke kpp operation
301  *
302  * Function invokes the specific kpp operation for generating the public part
303  * for a given kpp algorithm.
304  *
305  * To generate a private key, the caller should use a random number generator.
306  * The output of the requested length serves as the private key.
307  *
308  * @req:	kpp key request
309  *
310  * Return: zero on success; error code in case of error
311  */
312 static inline int crypto_kpp_generate_public_key(struct kpp_request *req)
313 {
314 	struct crypto_kpp *tfm = crypto_kpp_reqtfm(req);
315 	struct kpp_alg *alg = crypto_kpp_alg(tfm);
316 	struct crypto_alg *calg = tfm->base.__crt_alg;
317 	int ret;
318 
319 	crypto_stats_get(calg);
320 	ret = alg->generate_public_key(req);
321 	crypto_stats_kpp_generate_public_key(calg, ret);
322 	return ret;
323 }
324 
325 /**
326  * crypto_kpp_compute_shared_secret() - Invoke kpp operation
327  *
328  * Function invokes the specific kpp operation for computing the shared secret
329  * for a given kpp algorithm.
330  *
331  * @req:	kpp key request
332  *
333  * Return: zero on success; error code in case of error
334  */
335 static inline int crypto_kpp_compute_shared_secret(struct kpp_request *req)
336 {
337 	struct crypto_kpp *tfm = crypto_kpp_reqtfm(req);
338 	struct kpp_alg *alg = crypto_kpp_alg(tfm);
339 	struct crypto_alg *calg = tfm->base.__crt_alg;
340 	int ret;
341 
342 	crypto_stats_get(calg);
343 	ret = alg->compute_shared_secret(req);
344 	crypto_stats_kpp_compute_shared_secret(calg, ret);
345 	return ret;
346 }
347 
348 /**
349  * crypto_kpp_maxsize() - Get len for output buffer
350  *
351  * Function returns the output buffer size required for a given key.
352  * Function assumes that the key is already set in the transformation. If this
353  * function is called without a setkey or with a failed setkey, you will end up
354  * in a NULL dereference.
355  *
356  * @tfm:	KPP tfm handle allocated with crypto_alloc_kpp()
357  */
358 static inline unsigned int crypto_kpp_maxsize(struct crypto_kpp *tfm)
359 {
360 	struct kpp_alg *alg = crypto_kpp_alg(tfm);
361 
362 	return alg->max_size(tfm);
363 }
364 
365 #endif
366