xref: /linux/include/crypto/kpp.h (revision 621cde16e49b3ecf7d59a8106a20aaebfb4a59a9)
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  */
31 struct 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  */
48 struct crypto_kpp {
49 	unsigned int reqsize;
50 
51 	struct crypto_tfm base;
52 };
53 
54 /**
55  * struct kpp_alg - generic key-agreement protocol primitives
56  *
57  * @set_secret:		Function invokes the protocol specific function to
58  *			store the secret private key along with parameters.
59  *			The implementation knows how to decode the buffer
60  * @generate_public_key: Function generate the public key to be sent to the
61  *			counterpart. In case of error, where output is not big
62  *			enough req->dst_len will be updated to the size
63  *			required
64  * @compute_shared_secret: Function compute the shared secret as defined by
65  *			the algorithm. The result is given back to the user.
66  *			In case of error, where output is not big enough,
67  *			req->dst_len will be updated to the size required
68  * @max_size:		Function returns the size of the output buffer
69  * @init:		Initialize the object. This is called only once at
70  *			instantiation time. In case the cryptographic hardware
71  *			needs to be initialized. Software fallback should be
72  *			put in place here.
73  * @exit:		Undo everything @init did.
74  *
75  * @base:		Common crypto API algorithm data structure
76  */
77 struct kpp_alg {
78 	int (*set_secret)(struct crypto_kpp *tfm, const void *buffer,
79 			  unsigned int len);
80 	int (*generate_public_key)(struct kpp_request *req);
81 	int (*compute_shared_secret)(struct kpp_request *req);
82 
83 	unsigned int (*max_size)(struct crypto_kpp *tfm);
84 
85 	int (*init)(struct crypto_kpp *tfm);
86 	void (*exit)(struct crypto_kpp *tfm);
87 
88 	struct crypto_alg base;
89 };
90 
91 /**
92  * DOC: Generic Key-agreement Protocol Primitives API
93  *
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 required 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  */
110 struct crypto_kpp *crypto_alloc_kpp(const char *alg_name, u32 type, u32 mask);
111 
112 int crypto_has_kpp(const char *alg_name, u32 type, u32 mask);
113 
crypto_kpp_tfm(struct crypto_kpp * tfm)114 static inline struct crypto_tfm *crypto_kpp_tfm(struct crypto_kpp *tfm)
115 {
116 	return &tfm->base;
117 }
118 
__crypto_kpp_alg(struct crypto_alg * alg)119 static inline struct kpp_alg *__crypto_kpp_alg(struct crypto_alg *alg)
120 {
121 	return container_of(alg, struct kpp_alg, base);
122 }
123 
__crypto_kpp_tfm(struct crypto_tfm * tfm)124 static inline struct crypto_kpp *__crypto_kpp_tfm(struct crypto_tfm *tfm)
125 {
126 	return container_of(tfm, struct crypto_kpp, base);
127 }
128 
crypto_kpp_alg(struct crypto_kpp * tfm)129 static inline struct kpp_alg *crypto_kpp_alg(struct crypto_kpp *tfm)
130 {
131 	return __crypto_kpp_alg(crypto_kpp_tfm(tfm)->__crt_alg);
132 }
133 
crypto_kpp_reqsize(struct crypto_kpp * tfm)134 static inline unsigned int crypto_kpp_reqsize(struct crypto_kpp *tfm)
135 {
136 	return tfm->reqsize;
137 }
138 
kpp_request_set_tfm(struct kpp_request * req,struct crypto_kpp * tfm)139 static inline void kpp_request_set_tfm(struct kpp_request *req,
140 				       struct crypto_kpp *tfm)
141 {
142 	req->base.tfm = crypto_kpp_tfm(tfm);
143 }
144 
crypto_kpp_reqtfm(struct kpp_request * req)145 static inline struct crypto_kpp *crypto_kpp_reqtfm(struct kpp_request *req)
146 {
147 	return __crypto_kpp_tfm(req->base.tfm);
148 }
149 
crypto_kpp_get_flags(struct crypto_kpp * tfm)150 static inline u32 crypto_kpp_get_flags(struct crypto_kpp *tfm)
151 {
152 	return crypto_tfm_get_flags(crypto_kpp_tfm(tfm));
153 }
154 
crypto_kpp_set_flags(struct crypto_kpp * tfm,u32 flags)155 static inline void crypto_kpp_set_flags(struct crypto_kpp *tfm, u32 flags)
156 {
157 	crypto_tfm_set_flags(crypto_kpp_tfm(tfm), flags);
158 }
159 
160 /**
161  * crypto_free_kpp() - free KPP tfm handle
162  *
163  * @tfm: KPP tfm handle allocated with crypto_alloc_kpp()
164  *
165  * If @tfm is a NULL or error pointer, this function does nothing.
166  */
crypto_free_kpp(struct crypto_kpp * tfm)167 static inline void crypto_free_kpp(struct crypto_kpp *tfm)
168 {
169 	crypto_destroy_tfm(tfm, crypto_kpp_tfm(tfm));
170 }
171 
172 /**
173  * kpp_request_alloc() - allocates kpp request
174  *
175  * @tfm:	KPP tfm handle allocated with crypto_alloc_kpp()
176  * @gfp:	allocation flags
177  *
178  * Return: allocated handle in case of success or NULL in case of an error.
179  */
kpp_request_alloc(struct crypto_kpp * tfm,gfp_t gfp)180 static inline struct kpp_request *kpp_request_alloc(struct crypto_kpp *tfm,
181 						    gfp_t gfp)
182 {
183 	struct kpp_request *req;
184 
185 	req = kmalloc(sizeof(*req) + crypto_kpp_reqsize(tfm), gfp);
186 	if (likely(req))
187 		kpp_request_set_tfm(req, tfm);
188 
189 	return req;
190 }
191 
192 /**
193  * kpp_request_free() - zeroize and free kpp request
194  *
195  * @req:	request to free
196  */
kpp_request_free(struct kpp_request * req)197 static inline void kpp_request_free(struct kpp_request *req)
198 {
199 	kfree_sensitive(req);
200 }
201 
202 /**
203  * kpp_request_set_callback() - Sets an asynchronous callback.
204  *
205  * Callback will be called when an asynchronous operation on a given
206  * request is finished.
207  *
208  * @req:	request that the callback will be set for
209  * @flgs:	specify for instance if the operation may backlog
210  * @cmpl:	callback which will be called
211  * @data:	private data used by the caller
212  */
kpp_request_set_callback(struct kpp_request * req,u32 flgs,crypto_completion_t cmpl,void * data)213 static inline void kpp_request_set_callback(struct kpp_request *req,
214 					    u32 flgs,
215 					    crypto_completion_t cmpl,
216 					    void *data)
217 {
218 	req->base.complete = cmpl;
219 	req->base.data = data;
220 	req->base.flags = flgs;
221 }
222 
223 /**
224  * kpp_request_set_input() - Sets input buffer
225  *
226  * Sets parameters required by generate_public_key
227  *
228  * @req:	kpp request
229  * @input:	ptr to input scatter list
230  * @input_len:	size of the input scatter list
231  */
kpp_request_set_input(struct kpp_request * req,struct scatterlist * input,unsigned int input_len)232 static inline void kpp_request_set_input(struct kpp_request *req,
233 					 struct scatterlist *input,
234 					 unsigned int input_len)
235 {
236 	req->src = input;
237 	req->src_len = input_len;
238 }
239 
240 /**
241  * kpp_request_set_output() - Sets output buffer
242  *
243  * Sets parameters required by kpp operation
244  *
245  * @req:	kpp request
246  * @output:	ptr to output scatter list
247  * @output_len:	size of the output scatter list
248  */
kpp_request_set_output(struct kpp_request * req,struct scatterlist * output,unsigned int output_len)249 static inline void kpp_request_set_output(struct kpp_request *req,
250 					  struct scatterlist *output,
251 					  unsigned int output_len)
252 {
253 	req->dst = output;
254 	req->dst_len = output_len;
255 }
256 
257 enum {
258 	CRYPTO_KPP_SECRET_TYPE_UNKNOWN,
259 	CRYPTO_KPP_SECRET_TYPE_DH,
260 	CRYPTO_KPP_SECRET_TYPE_ECDH,
261 };
262 
263 /**
264  * struct kpp_secret - small header for packing secret buffer
265  *
266  * @type:	define type of secret. Each kpp type will define its own
267  * @len:	specify the len of the secret, include the header, that
268  *		follows the struct
269  */
270 struct kpp_secret {
271 	unsigned short type;
272 	unsigned short len;
273 };
274 
275 /**
276  * crypto_kpp_set_secret() - Invoke kpp operation
277  *
278  * Function invokes the specific kpp operation for a given alg.
279  *
280  * @tfm:	tfm handle
281  * @buffer:	Buffer holding the packet representation of the private
282  *		key. The structure of the packet key depends on the particular
283  *		KPP implementation. Packing and unpacking helpers are provided
284  *		for ECDH and DH (see the respective header files for those
285  *		implementations).
286  * @len:	Length of the packet private key buffer.
287  *
288  * Return: zero on success; error code in case of error
289  */
crypto_kpp_set_secret(struct crypto_kpp * tfm,const void * buffer,unsigned int len)290 static inline int crypto_kpp_set_secret(struct crypto_kpp *tfm,
291 					const void *buffer, unsigned int len)
292 {
293 	return crypto_kpp_alg(tfm)->set_secret(tfm, buffer, len);
294 }
295 
296 /**
297  * crypto_kpp_generate_public_key() - Invoke kpp operation
298  *
299  * Function invokes the specific kpp operation for generating the public part
300  * for a given kpp algorithm.
301  *
302  * To generate a private key, the caller should use a random number generator.
303  * The output of the requested length serves as the private key.
304  *
305  * @req:	kpp key request
306  *
307  * Return: zero on success; error code in case of error
308  */
crypto_kpp_generate_public_key(struct kpp_request * req)309 static inline int crypto_kpp_generate_public_key(struct kpp_request *req)
310 {
311 	struct crypto_kpp *tfm = crypto_kpp_reqtfm(req);
312 
313 	return crypto_kpp_alg(tfm)->generate_public_key(req);
314 }
315 
316 /**
317  * crypto_kpp_compute_shared_secret() - Invoke kpp operation
318  *
319  * Function invokes the specific kpp operation for computing the shared secret
320  * for a given kpp algorithm.
321  *
322  * @req:	kpp key request
323  *
324  * Return: zero on success; error code in case of error
325  */
crypto_kpp_compute_shared_secret(struct kpp_request * req)326 static inline int crypto_kpp_compute_shared_secret(struct kpp_request *req)
327 {
328 	struct crypto_kpp *tfm = crypto_kpp_reqtfm(req);
329 
330 	return crypto_kpp_alg(tfm)->compute_shared_secret(req);
331 }
332 
333 /**
334  * crypto_kpp_maxsize() - Get len for output buffer
335  *
336  * 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.
340  *
341  * @tfm:	KPP tfm handle allocated with crypto_alloc_kpp()
342  */
crypto_kpp_maxsize(struct crypto_kpp * tfm)343 static inline unsigned int crypto_kpp_maxsize(struct crypto_kpp *tfm)
344 {
345 	struct kpp_alg *alg = crypto_kpp_alg(tfm);
346 
347 	return alg->max_size(tfm);
348 }
349 
350 #endif
351