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 crypto_istat_kpp - statistics for KPP algorithm
56  * @setsecret_cnt:		number of setsecrey operation
57  * @generate_public_key_cnt:	number of generate_public_key operation
58  * @compute_shared_secret_cnt:	number of compute_shared_secret operation
59  * @err_cnt:			number of error for KPP requests
60  */
61 struct crypto_istat_kpp {
62 	atomic64_t setsecret_cnt;
63 	atomic64_t generate_public_key_cnt;
64 	atomic64_t compute_shared_secret_cnt;
65 	atomic64_t err_cnt;
66 };
67 
68 /**
69  * struct kpp_alg - generic key-agreement protocol primitives
70  *
71  * @set_secret:		Function invokes the protocol specific function to
72  *			store the secret private key along with parameters.
73  *			The implementation knows how to decode the buffer
74  * @generate_public_key: Function generate the public key to be sent to the
75  *			counterpart. In case of error, where output is not big
76  *			enough req->dst_len will be updated to the size
77  *			required
78  * @compute_shared_secret: Function compute the shared secret as defined by
79  *			the algorithm. The result is given back to the user.
80  *			In case of error, where output is not big enough,
81  *			req->dst_len will be updated to the size required
82  * @max_size:		Function returns the size of the output buffer
83  * @init:		Initialize the object. This is called only once at
84  *			instantiation time. In case the cryptographic hardware
85  *			needs to be initialized. Software fallback should be
86  *			put in place here.
87  * @exit:		Undo everything @init did.
88  *
89  * @base:		Common crypto API algorithm data structure
90  * @stat:		Statistics for KPP algorithm
91  */
92 struct kpp_alg {
93 	int (*set_secret)(struct crypto_kpp *tfm, const void *buffer,
94 			  unsigned int len);
95 	int (*generate_public_key)(struct kpp_request *req);
96 	int (*compute_shared_secret)(struct kpp_request *req);
97 
98 	unsigned int (*max_size)(struct crypto_kpp *tfm);
99 
100 	int (*init)(struct crypto_kpp *tfm);
101 	void (*exit)(struct crypto_kpp *tfm);
102 
103 #ifdef CONFIG_CRYPTO_STATS
104 	struct crypto_istat_kpp stat;
105 #endif
106 
107 	struct crypto_alg base;
108 };
109 
110 /**
111  * DOC: Generic Key-agreement Protocol Primitives API
112  *
113  * The KPP API is used with the algorithm type
114  * CRYPTO_ALG_TYPE_KPP (listed as type "kpp" in /proc/crypto)
115  */
116 
117 /**
118  * crypto_alloc_kpp() - allocate KPP tfm handle
119  * @alg_name: is the name of the kpp algorithm (e.g. "dh", "ecdh")
120  * @type: specifies the type of the algorithm
121  * @mask: specifies the mask for the algorithm
122  *
123  * Allocate a handle for kpp algorithm. The returned struct crypto_kpp
124  * is required for any following API invocation
125  *
126  * Return: allocated handle in case of success; IS_ERR() is true in case of
127  *	   an error, PTR_ERR() returns the error code.
128  */
129 struct crypto_kpp *crypto_alloc_kpp(const char *alg_name, u32 type, u32 mask);
130 
131 int crypto_has_kpp(const char *alg_name, u32 type, u32 mask);
132 
crypto_kpp_tfm(struct crypto_kpp * tfm)133 static inline struct crypto_tfm *crypto_kpp_tfm(struct crypto_kpp *tfm)
134 {
135 	return &tfm->base;
136 }
137 
__crypto_kpp_alg(struct crypto_alg * alg)138 static inline struct kpp_alg *__crypto_kpp_alg(struct crypto_alg *alg)
139 {
140 	return container_of(alg, struct kpp_alg, base);
141 }
142 
__crypto_kpp_tfm(struct crypto_tfm * tfm)143 static inline struct crypto_kpp *__crypto_kpp_tfm(struct crypto_tfm *tfm)
144 {
145 	return container_of(tfm, struct crypto_kpp, base);
146 }
147 
crypto_kpp_alg(struct crypto_kpp * tfm)148 static inline struct kpp_alg *crypto_kpp_alg(struct crypto_kpp *tfm)
149 {
150 	return __crypto_kpp_alg(crypto_kpp_tfm(tfm)->__crt_alg);
151 }
152 
crypto_kpp_reqsize(struct crypto_kpp * tfm)153 static inline unsigned int crypto_kpp_reqsize(struct crypto_kpp *tfm)
154 {
155 	return tfm->reqsize;
156 }
157 
kpp_request_set_tfm(struct kpp_request * req,struct crypto_kpp * tfm)158 static inline void kpp_request_set_tfm(struct kpp_request *req,
159 				       struct crypto_kpp *tfm)
160 {
161 	req->base.tfm = crypto_kpp_tfm(tfm);
162 }
163 
crypto_kpp_reqtfm(struct kpp_request * req)164 static inline struct crypto_kpp *crypto_kpp_reqtfm(struct kpp_request *req)
165 {
166 	return __crypto_kpp_tfm(req->base.tfm);
167 }
168 
crypto_kpp_get_flags(struct crypto_kpp * tfm)169 static inline u32 crypto_kpp_get_flags(struct crypto_kpp *tfm)
170 {
171 	return crypto_tfm_get_flags(crypto_kpp_tfm(tfm));
172 }
173 
crypto_kpp_set_flags(struct crypto_kpp * tfm,u32 flags)174 static inline void crypto_kpp_set_flags(struct crypto_kpp *tfm, u32 flags)
175 {
176 	crypto_tfm_set_flags(crypto_kpp_tfm(tfm), flags);
177 }
178 
179 /**
180  * crypto_free_kpp() - free KPP tfm handle
181  *
182  * @tfm: KPP tfm handle allocated with crypto_alloc_kpp()
183  *
184  * If @tfm is a NULL or error pointer, this function does nothing.
185  */
crypto_free_kpp(struct crypto_kpp * tfm)186 static inline void crypto_free_kpp(struct crypto_kpp *tfm)
187 {
188 	crypto_destroy_tfm(tfm, crypto_kpp_tfm(tfm));
189 }
190 
191 /**
192  * kpp_request_alloc() - allocates kpp request
193  *
194  * @tfm:	KPP tfm handle allocated with crypto_alloc_kpp()
195  * @gfp:	allocation flags
196  *
197  * Return: allocated handle in case of success or NULL in case of an error.
198  */
kpp_request_alloc(struct crypto_kpp * tfm,gfp_t gfp)199 static inline struct kpp_request *kpp_request_alloc(struct crypto_kpp *tfm,
200 						    gfp_t gfp)
201 {
202 	struct kpp_request *req;
203 
204 	req = kmalloc(sizeof(*req) + crypto_kpp_reqsize(tfm), gfp);
205 	if (likely(req))
206 		kpp_request_set_tfm(req, tfm);
207 
208 	return req;
209 }
210 
211 /**
212  * kpp_request_free() - zeroize and free kpp request
213  *
214  * @req:	request to free
215  */
kpp_request_free(struct kpp_request * req)216 static inline void kpp_request_free(struct kpp_request *req)
217 {
218 	kfree_sensitive(req);
219 }
220 
221 /**
222  * kpp_request_set_callback() - Sets an asynchronous callback.
223  *
224  * Callback will be called when an asynchronous operation on a given
225  * request is finished.
226  *
227  * @req:	request that the callback will be set for
228  * @flgs:	specify for instance if the operation may backlog
229  * @cmpl:	callback which will be called
230  * @data:	private data used by the caller
231  */
kpp_request_set_callback(struct kpp_request * req,u32 flgs,crypto_completion_t cmpl,void * data)232 static inline void kpp_request_set_callback(struct kpp_request *req,
233 					    u32 flgs,
234 					    crypto_completion_t cmpl,
235 					    void *data)
236 {
237 	req->base.complete = cmpl;
238 	req->base.data = data;
239 	req->base.flags = flgs;
240 }
241 
242 /**
243  * kpp_request_set_input() - Sets input buffer
244  *
245  * Sets parameters required by generate_public_key
246  *
247  * @req:	kpp request
248  * @input:	ptr to input scatter list
249  * @input_len:	size of the input scatter list
250  */
kpp_request_set_input(struct kpp_request * req,struct scatterlist * input,unsigned int input_len)251 static inline void kpp_request_set_input(struct kpp_request *req,
252 					 struct scatterlist *input,
253 					 unsigned int input_len)
254 {
255 	req->src = input;
256 	req->src_len = input_len;
257 }
258 
259 /**
260  * kpp_request_set_output() - Sets output buffer
261  *
262  * Sets parameters required by kpp operation
263  *
264  * @req:	kpp request
265  * @output:	ptr to output scatter list
266  * @output_len:	size of the output scatter list
267  */
kpp_request_set_output(struct kpp_request * req,struct scatterlist * output,unsigned int output_len)268 static inline void kpp_request_set_output(struct kpp_request *req,
269 					  struct scatterlist *output,
270 					  unsigned int output_len)
271 {
272 	req->dst = output;
273 	req->dst_len = output_len;
274 }
275 
276 enum {
277 	CRYPTO_KPP_SECRET_TYPE_UNKNOWN,
278 	CRYPTO_KPP_SECRET_TYPE_DH,
279 	CRYPTO_KPP_SECRET_TYPE_ECDH,
280 };
281 
282 /**
283  * struct kpp_secret - small header for packing secret buffer
284  *
285  * @type:	define type of secret. Each kpp type will define its own
286  * @len:	specify the len of the secret, include the header, that
287  *		follows the struct
288  */
289 struct kpp_secret {
290 	unsigned short type;
291 	unsigned short len;
292 };
293 
kpp_get_stat(struct kpp_alg * alg)294 static inline struct crypto_istat_kpp *kpp_get_stat(struct kpp_alg *alg)
295 {
296 #ifdef CONFIG_CRYPTO_STATS
297 	return &alg->stat;
298 #else
299 	return NULL;
300 #endif
301 }
302 
crypto_kpp_errstat(struct kpp_alg * alg,int err)303 static inline int crypto_kpp_errstat(struct kpp_alg *alg, int err)
304 {
305 	if (!IS_ENABLED(CONFIG_CRYPTO_STATS))
306 		return err;
307 
308 	if (err && err != -EINPROGRESS && err != -EBUSY)
309 		atomic64_inc(&kpp_get_stat(alg)->err_cnt);
310 
311 	return err;
312 }
313 
314 /**
315  * crypto_kpp_set_secret() - Invoke kpp operation
316  *
317  * Function invokes the specific kpp operation for a given alg.
318  *
319  * @tfm:	tfm handle
320  * @buffer:	Buffer holding the packet representation of the private
321  *		key. The structure of the packet key depends on the particular
322  *		KPP implementation. Packing and unpacking helpers are provided
323  *		for ECDH and DH (see the respective header files for those
324  *		implementations).
325  * @len:	Length of the packet private key buffer.
326  *
327  * Return: zero on success; error code in case of error
328  */
crypto_kpp_set_secret(struct crypto_kpp * tfm,const void * buffer,unsigned int len)329 static inline int crypto_kpp_set_secret(struct crypto_kpp *tfm,
330 					const void *buffer, unsigned int len)
331 {
332 	struct kpp_alg *alg = crypto_kpp_alg(tfm);
333 
334 	if (IS_ENABLED(CONFIG_CRYPTO_STATS))
335 		atomic64_inc(&kpp_get_stat(alg)->setsecret_cnt);
336 
337 	return crypto_kpp_errstat(alg, alg->set_secret(tfm, buffer, len));
338 }
339 
340 /**
341  * crypto_kpp_generate_public_key() - Invoke kpp operation
342  *
343  * Function invokes the specific kpp operation for generating the public part
344  * for a given kpp algorithm.
345  *
346  * To generate a private key, the caller should use a random number generator.
347  * The output of the requested length serves as the private key.
348  *
349  * @req:	kpp key request
350  *
351  * Return: zero on success; error code in case of error
352  */
crypto_kpp_generate_public_key(struct kpp_request * req)353 static inline int crypto_kpp_generate_public_key(struct kpp_request *req)
354 {
355 	struct crypto_kpp *tfm = crypto_kpp_reqtfm(req);
356 	struct kpp_alg *alg = crypto_kpp_alg(tfm);
357 
358 	if (IS_ENABLED(CONFIG_CRYPTO_STATS))
359 		atomic64_inc(&kpp_get_stat(alg)->generate_public_key_cnt);
360 
361 	return crypto_kpp_errstat(alg, alg->generate_public_key(req));
362 }
363 
364 /**
365  * crypto_kpp_compute_shared_secret() - Invoke kpp operation
366  *
367  * Function invokes the specific kpp operation for computing the shared secret
368  * for a given kpp algorithm.
369  *
370  * @req:	kpp key request
371  *
372  * Return: zero on success; error code in case of error
373  */
crypto_kpp_compute_shared_secret(struct kpp_request * req)374 static inline int crypto_kpp_compute_shared_secret(struct kpp_request *req)
375 {
376 	struct crypto_kpp *tfm = crypto_kpp_reqtfm(req);
377 	struct kpp_alg *alg = crypto_kpp_alg(tfm);
378 
379 	if (IS_ENABLED(CONFIG_CRYPTO_STATS))
380 		atomic64_inc(&kpp_get_stat(alg)->compute_shared_secret_cnt);
381 
382 	return crypto_kpp_errstat(alg, alg->compute_shared_secret(req));
383 }
384 
385 /**
386  * crypto_kpp_maxsize() - Get len for output buffer
387  *
388  * Function returns the output buffer size required for a given key.
389  * Function assumes that the key is already set in the transformation. If this
390  * function is called without a setkey or with a failed setkey, you will end up
391  * in a NULL dereference.
392  *
393  * @tfm:	KPP tfm handle allocated with crypto_alloc_kpp()
394  */
crypto_kpp_maxsize(struct crypto_kpp * tfm)395 static inline unsigned int crypto_kpp_maxsize(struct crypto_kpp *tfm)
396 {
397 	struct kpp_alg *alg = crypto_kpp_alg(tfm);
398 
399 	return alg->max_size(tfm);
400 }
401 
402 #endif
403