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 int crypto_has_kpp(const char *alg_name, u32 type, u32 mask);
108 
crypto_kpp_tfm(struct crypto_kpp * tfm)109 static inline struct crypto_tfm *crypto_kpp_tfm(struct crypto_kpp *tfm)
110 {
111 	return &tfm->base;
112 }
113 
__crypto_kpp_alg(struct crypto_alg * alg)114 static inline struct kpp_alg *__crypto_kpp_alg(struct crypto_alg *alg)
115 {
116 	return container_of(alg, struct kpp_alg, base);
117 }
118 
__crypto_kpp_tfm(struct crypto_tfm * tfm)119 static inline struct crypto_kpp *__crypto_kpp_tfm(struct crypto_tfm *tfm)
120 {
121 	return container_of(tfm, struct crypto_kpp, base);
122 }
123 
crypto_kpp_alg(struct crypto_kpp * tfm)124 static inline struct kpp_alg *crypto_kpp_alg(struct crypto_kpp *tfm)
125 {
126 	return __crypto_kpp_alg(crypto_kpp_tfm(tfm)->__crt_alg);
127 }
128 
crypto_kpp_reqsize(struct crypto_kpp * tfm)129 static inline unsigned int crypto_kpp_reqsize(struct crypto_kpp *tfm)
130 {
131 	return crypto_kpp_alg(tfm)->reqsize;
132 }
133 
kpp_request_set_tfm(struct kpp_request * req,struct crypto_kpp * tfm)134 static inline void kpp_request_set_tfm(struct kpp_request *req,
135 				       struct crypto_kpp *tfm)
136 {
137 	req->base.tfm = crypto_kpp_tfm(tfm);
138 }
139 
crypto_kpp_reqtfm(struct kpp_request * req)140 static inline struct crypto_kpp *crypto_kpp_reqtfm(struct kpp_request *req)
141 {
142 	return __crypto_kpp_tfm(req->base.tfm);
143 }
144 
crypto_kpp_get_flags(struct crypto_kpp * tfm)145 static inline u32 crypto_kpp_get_flags(struct crypto_kpp *tfm)
146 {
147 	return crypto_tfm_get_flags(crypto_kpp_tfm(tfm));
148 }
149 
crypto_kpp_set_flags(struct crypto_kpp * tfm,u32 flags)150 static inline void crypto_kpp_set_flags(struct crypto_kpp *tfm, u32 flags)
151 {
152 	crypto_tfm_set_flags(crypto_kpp_tfm(tfm), flags);
153 }
154 
155 /**
156  * crypto_free_kpp() - free KPP tfm handle
157  *
158  * @tfm: KPP tfm handle allocated with crypto_alloc_kpp()
159  *
160  * If @tfm is a NULL or error pointer, this function does nothing.
161  */
crypto_free_kpp(struct crypto_kpp * tfm)162 static inline void crypto_free_kpp(struct crypto_kpp *tfm)
163 {
164 	crypto_destroy_tfm(tfm, crypto_kpp_tfm(tfm));
165 }
166 
167 /**
168  * kpp_request_alloc() - allocates kpp request
169  *
170  * @tfm:	KPP tfm handle allocated with crypto_alloc_kpp()
171  * @gfp:	allocation flags
172  *
173  * Return: allocated handle in case of success or NULL in case of an error.
174  */
kpp_request_alloc(struct crypto_kpp * tfm,gfp_t gfp)175 static inline struct kpp_request *kpp_request_alloc(struct crypto_kpp *tfm,
176 						    gfp_t gfp)
177 {
178 	struct kpp_request *req;
179 
180 	req = kmalloc(sizeof(*req) + crypto_kpp_reqsize(tfm), gfp);
181 	if (likely(req))
182 		kpp_request_set_tfm(req, tfm);
183 
184 	return req;
185 }
186 
187 /**
188  * kpp_request_free() - zeroize and free kpp request
189  *
190  * @req:	request to free
191  */
kpp_request_free(struct kpp_request * req)192 static inline void kpp_request_free(struct kpp_request *req)
193 {
194 	kfree_sensitive(req);
195 }
196 
197 /**
198  * kpp_request_set_callback() - Sets an asynchronous callback.
199  *
200  * Callback will be called when an asynchronous operation on a given
201  * request is finished.
202  *
203  * @req:	request that the callback will be set for
204  * @flgs:	specify for instance if the operation may backlog
205  * @cmpl:	callback which will be called
206  * @data:	private data used by the caller
207  */
kpp_request_set_callback(struct kpp_request * req,u32 flgs,crypto_completion_t cmpl,void * data)208 static inline void kpp_request_set_callback(struct kpp_request *req,
209 					    u32 flgs,
210 					    crypto_completion_t cmpl,
211 					    void *data)
212 {
213 	req->base.complete = cmpl;
214 	req->base.data = data;
215 	req->base.flags = flgs;
216 }
217 
218 /**
219  * kpp_request_set_input() - Sets input buffer
220  *
221  * Sets parameters required by generate_public_key
222  *
223  * @req:	kpp request
224  * @input:	ptr to input scatter list
225  * @input_len:	size of the input scatter list
226  */
kpp_request_set_input(struct kpp_request * req,struct scatterlist * input,unsigned int input_len)227 static inline void kpp_request_set_input(struct kpp_request *req,
228 					 struct scatterlist *input,
229 					 unsigned int input_len)
230 {
231 	req->src = input;
232 	req->src_len = input_len;
233 }
234 
235 /**
236  * kpp_request_set_output() - Sets output buffer
237  *
238  * Sets parameters required by kpp operation
239  *
240  * @req:	kpp request
241  * @output:	ptr to output scatter list
242  * @output_len:	size of the output scatter list
243  */
kpp_request_set_output(struct kpp_request * req,struct scatterlist * output,unsigned int output_len)244 static inline void kpp_request_set_output(struct kpp_request *req,
245 					  struct scatterlist *output,
246 					  unsigned int output_len)
247 {
248 	req->dst = output;
249 	req->dst_len = output_len;
250 }
251 
252 enum {
253 	CRYPTO_KPP_SECRET_TYPE_UNKNOWN,
254 	CRYPTO_KPP_SECRET_TYPE_DH,
255 	CRYPTO_KPP_SECRET_TYPE_ECDH,
256 };
257 
258 /**
259  * struct kpp_secret - small header for packing secret buffer
260  *
261  * @type:	define type of secret. Each kpp type will define its own
262  * @len:	specify the len of the secret, include the header, that
263  *		follows the struct
264  */
265 struct kpp_secret {
266 	unsigned short type;
267 	unsigned short len;
268 };
269 
270 /**
271  * crypto_kpp_set_secret() - Invoke kpp operation
272  *
273  * Function invokes the specific kpp operation for a given alg.
274  *
275  * @tfm:	tfm handle
276  * @buffer:	Buffer holding the packet representation of the private
277  *		key. The structure of the packet key depends on the particular
278  *		KPP implementation. Packing and unpacking helpers are provided
279  *		for ECDH and DH (see the respective header files for those
280  *		implementations).
281  * @len:	Length of the packet private key buffer.
282  *
283  * Return: zero on success; error code in case of error
284  */
crypto_kpp_set_secret(struct crypto_kpp * tfm,const void * buffer,unsigned int len)285 static inline int crypto_kpp_set_secret(struct crypto_kpp *tfm,
286 					const void *buffer, unsigned int len)
287 {
288 	struct kpp_alg *alg = crypto_kpp_alg(tfm);
289 	struct crypto_alg *calg = tfm->base.__crt_alg;
290 	int ret;
291 
292 	crypto_stats_get(calg);
293 	ret = alg->set_secret(tfm, buffer, len);
294 	crypto_stats_kpp_set_secret(calg, ret);
295 	return ret;
296 }
297 
298 /**
299  * crypto_kpp_generate_public_key() - Invoke kpp operation
300  *
301  * Function invokes the specific kpp operation for generating the public part
302  * for a given kpp algorithm.
303  *
304  * To generate a private key, the caller should use a random number generator.
305  * The output of the requested length serves as the private key.
306  *
307  * @req:	kpp key request
308  *
309  * Return: zero on success; error code in case of error
310  */
crypto_kpp_generate_public_key(struct kpp_request * req)311 static inline int crypto_kpp_generate_public_key(struct kpp_request *req)
312 {
313 	struct crypto_kpp *tfm = crypto_kpp_reqtfm(req);
314 	struct kpp_alg *alg = crypto_kpp_alg(tfm);
315 	struct crypto_alg *calg = tfm->base.__crt_alg;
316 	int ret;
317 
318 	crypto_stats_get(calg);
319 	ret = alg->generate_public_key(req);
320 	crypto_stats_kpp_generate_public_key(calg, ret);
321 	return ret;
322 }
323 
324 /**
325  * crypto_kpp_compute_shared_secret() - Invoke kpp operation
326  *
327  * Function invokes the specific kpp operation for computing the shared secret
328  * for a given kpp algorithm.
329  *
330  * @req:	kpp key request
331  *
332  * Return: zero on success; error code in case of error
333  */
crypto_kpp_compute_shared_secret(struct kpp_request * req)334 static inline int crypto_kpp_compute_shared_secret(struct kpp_request *req)
335 {
336 	struct crypto_kpp *tfm = crypto_kpp_reqtfm(req);
337 	struct kpp_alg *alg = crypto_kpp_alg(tfm);
338 	struct crypto_alg *calg = tfm->base.__crt_alg;
339 	int ret;
340 
341 	crypto_stats_get(calg);
342 	ret = alg->compute_shared_secret(req);
343 	crypto_stats_kpp_compute_shared_secret(calg, ret);
344 	return ret;
345 }
346 
347 /**
348  * crypto_kpp_maxsize() - Get len for output buffer
349  *
350  * Function returns the output buffer size required for a given key.
351  * Function assumes that the key is already set in the transformation. If this
352  * function is called without a setkey or with a failed setkey, you will end up
353  * in a NULL dereference.
354  *
355  * @tfm:	KPP tfm handle allocated with crypto_alloc_kpp()
356  */
crypto_kpp_maxsize(struct crypto_kpp * tfm)357 static inline unsigned int crypto_kpp_maxsize(struct crypto_kpp *tfm)
358 {
359 	struct kpp_alg *alg = crypto_kpp_alg(tfm);
360 
361 	return alg->max_size(tfm);
362 }
363 
364 #endif
365