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 
crypto_kpp_tfm(struct crypto_kpp * tfm)107 static inline struct crypto_tfm *crypto_kpp_tfm(struct crypto_kpp *tfm)
108 {
109 	return &tfm->base;
110 }
111 
__crypto_kpp_alg(struct crypto_alg * alg)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 
__crypto_kpp_tfm(struct crypto_tfm * tfm)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 
crypto_kpp_alg(struct crypto_kpp * tfm)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 
crypto_kpp_reqsize(struct crypto_kpp * tfm)127 static inline unsigned int crypto_kpp_reqsize(struct crypto_kpp *tfm)
128 {
129 	return crypto_kpp_alg(tfm)->reqsize;
130 }
131 
kpp_request_set_tfm(struct kpp_request * req,struct crypto_kpp * tfm)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 
crypto_kpp_reqtfm(struct kpp_request * req)138 static inline struct crypto_kpp *crypto_kpp_reqtfm(struct kpp_request *req)
139 {
140 	return __crypto_kpp_tfm(req->base.tfm);
141 }
142 
crypto_kpp_get_flags(struct crypto_kpp * tfm)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 
crypto_kpp_set_flags(struct crypto_kpp * tfm,u32 flags)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  * If @tfm is a NULL or error pointer, this function does nothing.
159  */
crypto_free_kpp(struct crypto_kpp * tfm)160 static inline void crypto_free_kpp(struct crypto_kpp *tfm)
161 {
162 	crypto_destroy_tfm(tfm, crypto_kpp_tfm(tfm));
163 }
164 
165 /**
166  * kpp_request_alloc() - allocates kpp request
167  *
168  * @tfm:	KPP tfm handle allocated with crypto_alloc_kpp()
169  * @gfp:	allocation flags
170  *
171  * Return: allocated handle in case of success or NULL in case of an error.
172  */
kpp_request_alloc(struct crypto_kpp * tfm,gfp_t gfp)173 static inline struct kpp_request *kpp_request_alloc(struct crypto_kpp *tfm,
174 						    gfp_t gfp)
175 {
176 	struct kpp_request *req;
177 
178 	req = kmalloc(sizeof(*req) + crypto_kpp_reqsize(tfm), gfp);
179 	if (likely(req))
180 		kpp_request_set_tfm(req, tfm);
181 
182 	return req;
183 }
184 
185 /**
186  * kpp_request_free() - zeroize and free kpp request
187  *
188  * @req:	request to free
189  */
kpp_request_free(struct kpp_request * req)190 static inline void kpp_request_free(struct kpp_request *req)
191 {
192 	kfree_sensitive(req);
193 }
194 
195 /**
196  * kpp_request_set_callback() - Sets an asynchronous callback.
197  *
198  * Callback will be called when an asynchronous operation on a given
199  * request is finished.
200  *
201  * @req:	request that the callback will be set for
202  * @flgs:	specify for instance if the operation may backlog
203  * @cmpl:	callback which will be called
204  * @data:	private data used by the caller
205  */
kpp_request_set_callback(struct kpp_request * req,u32 flgs,crypto_completion_t cmpl,void * data)206 static inline void kpp_request_set_callback(struct kpp_request *req,
207 					    u32 flgs,
208 					    crypto_completion_t cmpl,
209 					    void *data)
210 {
211 	req->base.complete = cmpl;
212 	req->base.data = data;
213 	req->base.flags = flgs;
214 }
215 
216 /**
217  * kpp_request_set_input() - Sets input buffer
218  *
219  * Sets parameters required by generate_public_key
220  *
221  * @req:	kpp request
222  * @input:	ptr to input scatter list
223  * @input_len:	size of the input scatter list
224  */
kpp_request_set_input(struct kpp_request * req,struct scatterlist * input,unsigned int input_len)225 static inline void kpp_request_set_input(struct kpp_request *req,
226 					 struct scatterlist *input,
227 					 unsigned int input_len)
228 {
229 	req->src = input;
230 	req->src_len = input_len;
231 }
232 
233 /**
234  * kpp_request_set_output() - Sets output buffer
235  *
236  * Sets parameters required by kpp operation
237  *
238  * @req:	kpp request
239  * @output:	ptr to output scatter list
240  * @output_len:	size of the output scatter list
241  */
kpp_request_set_output(struct kpp_request * req,struct scatterlist * output,unsigned int output_len)242 static inline void kpp_request_set_output(struct kpp_request *req,
243 					  struct scatterlist *output,
244 					  unsigned int output_len)
245 {
246 	req->dst = output;
247 	req->dst_len = output_len;
248 }
249 
250 enum {
251 	CRYPTO_KPP_SECRET_TYPE_UNKNOWN,
252 	CRYPTO_KPP_SECRET_TYPE_DH,
253 	CRYPTO_KPP_SECRET_TYPE_ECDH,
254 };
255 
256 /**
257  * struct kpp_secret - small header for packing secret buffer
258  *
259  * @type:	define type of secret. Each kpp type will define its own
260  * @len:	specify the len of the secret, include the header, that
261  *		follows the struct
262  */
263 struct kpp_secret {
264 	unsigned short type;
265 	unsigned short len;
266 };
267 
268 /**
269  * crypto_kpp_set_secret() - Invoke kpp operation
270  *
271  * Function invokes the specific kpp operation for a given alg.
272  *
273  * @tfm:	tfm handle
274  * @buffer:	Buffer holding the packet representation of the private
275  *		key. The structure of the packet key depends on the particular
276  *		KPP implementation. Packing and unpacking helpers are provided
277  *		for ECDH and DH (see the respective header files for those
278  *		implementations).
279  * @len:	Length of the packet private key buffer.
280  *
281  * Return: zero on success; error code in case of error
282  */
crypto_kpp_set_secret(struct crypto_kpp * tfm,const void * buffer,unsigned int len)283 static inline int crypto_kpp_set_secret(struct crypto_kpp *tfm,
284 					const void *buffer, unsigned int len)
285 {
286 	struct kpp_alg *alg = crypto_kpp_alg(tfm);
287 	struct crypto_alg *calg = tfm->base.__crt_alg;
288 	int ret;
289 
290 	crypto_stats_get(calg);
291 	ret = alg->set_secret(tfm, buffer, len);
292 	crypto_stats_kpp_set_secret(calg, ret);
293 	return ret;
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 	struct kpp_alg *alg = crypto_kpp_alg(tfm);
313 	struct crypto_alg *calg = tfm->base.__crt_alg;
314 	int ret;
315 
316 	crypto_stats_get(calg);
317 	ret = alg->generate_public_key(req);
318 	crypto_stats_kpp_generate_public_key(calg, ret);
319 	return ret;
320 }
321 
322 /**
323  * crypto_kpp_compute_shared_secret() - Invoke kpp operation
324  *
325  * Function invokes the specific kpp operation for computing the shared secret
326  * for a given kpp algorithm.
327  *
328  * @req:	kpp key request
329  *
330  * Return: zero on success; error code in case of error
331  */
crypto_kpp_compute_shared_secret(struct kpp_request * req)332 static inline int crypto_kpp_compute_shared_secret(struct kpp_request *req)
333 {
334 	struct crypto_kpp *tfm = crypto_kpp_reqtfm(req);
335 	struct kpp_alg *alg = crypto_kpp_alg(tfm);
336 	struct crypto_alg *calg = tfm->base.__crt_alg;
337 	int ret;
338 
339 	crypto_stats_get(calg);
340 	ret = alg->compute_shared_secret(req);
341 	crypto_stats_kpp_compute_shared_secret(calg, ret);
342 	return ret;
343 }
344 
345 /**
346  * crypto_kpp_maxsize() - Get len for output buffer
347  *
348  * Function returns the output buffer size required for a given key.
349  * Function assumes that the key is already set in the transformation. If this
350  * function is called without a setkey or with a failed setkey, you will end up
351  * in a NULL dereference.
352  *
353  * @tfm:	KPP tfm handle allocated with crypto_alloc_kpp()
354  */
crypto_kpp_maxsize(struct crypto_kpp * tfm)355 static inline unsigned int crypto_kpp_maxsize(struct crypto_kpp *tfm)
356 {
357 	struct kpp_alg *alg = crypto_kpp_alg(tfm);
358 
359 	return alg->max_size(tfm);
360 }
361 
362 #endif
363