xref: /openbmc/linux/crypto/cryptd.c (revision 22246614)
1 /*
2  * Software async crypto daemon.
3  *
4  * Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
5  *
6  * This program is free software; you can redistribute it and/or modify it
7  * under the terms of the GNU General Public License as published by the Free
8  * Software Foundation; either version 2 of the License, or (at your option)
9  * any later version.
10  *
11  */
12 
13 #include <crypto/algapi.h>
14 #include <linux/err.h>
15 #include <linux/init.h>
16 #include <linux/kernel.h>
17 #include <linux/kthread.h>
18 #include <linux/list.h>
19 #include <linux/module.h>
20 #include <linux/mutex.h>
21 #include <linux/scatterlist.h>
22 #include <linux/sched.h>
23 #include <linux/slab.h>
24 #include <linux/spinlock.h>
25 
26 #define CRYPTD_MAX_QLEN 100
27 
28 struct cryptd_state {
29 	spinlock_t lock;
30 	struct mutex mutex;
31 	struct crypto_queue queue;
32 	struct task_struct *task;
33 };
34 
35 struct cryptd_instance_ctx {
36 	struct crypto_spawn spawn;
37 	struct cryptd_state *state;
38 };
39 
40 struct cryptd_blkcipher_ctx {
41 	struct crypto_blkcipher *child;
42 };
43 
44 struct cryptd_blkcipher_request_ctx {
45 	crypto_completion_t complete;
46 };
47 
48 
49 static inline struct cryptd_state *cryptd_get_state(struct crypto_tfm *tfm)
50 {
51 	struct crypto_instance *inst = crypto_tfm_alg_instance(tfm);
52 	struct cryptd_instance_ctx *ictx = crypto_instance_ctx(inst);
53 	return ictx->state;
54 }
55 
56 static int cryptd_blkcipher_setkey(struct crypto_ablkcipher *parent,
57 				   const u8 *key, unsigned int keylen)
58 {
59 	struct cryptd_blkcipher_ctx *ctx = crypto_ablkcipher_ctx(parent);
60 	struct crypto_blkcipher *child = ctx->child;
61 	int err;
62 
63 	crypto_blkcipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
64 	crypto_blkcipher_set_flags(child, crypto_ablkcipher_get_flags(parent) &
65 					  CRYPTO_TFM_REQ_MASK);
66 	err = crypto_blkcipher_setkey(child, key, keylen);
67 	crypto_ablkcipher_set_flags(parent, crypto_blkcipher_get_flags(child) &
68 					    CRYPTO_TFM_RES_MASK);
69 	return err;
70 }
71 
72 static void cryptd_blkcipher_crypt(struct ablkcipher_request *req,
73 				   struct crypto_blkcipher *child,
74 				   int err,
75 				   int (*crypt)(struct blkcipher_desc *desc,
76 						struct scatterlist *dst,
77 						struct scatterlist *src,
78 						unsigned int len))
79 {
80 	struct cryptd_blkcipher_request_ctx *rctx;
81 	struct blkcipher_desc desc;
82 
83 	rctx = ablkcipher_request_ctx(req);
84 
85 	if (unlikely(err == -EINPROGRESS)) {
86 		rctx->complete(&req->base, err);
87 		return;
88 	}
89 
90 	desc.tfm = child;
91 	desc.info = req->info;
92 	desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
93 
94 	err = crypt(&desc, req->dst, req->src, req->nbytes);
95 
96 	req->base.complete = rctx->complete;
97 
98 	local_bh_disable();
99 	req->base.complete(&req->base, err);
100 	local_bh_enable();
101 }
102 
103 static void cryptd_blkcipher_encrypt(struct crypto_async_request *req, int err)
104 {
105 	struct cryptd_blkcipher_ctx *ctx = crypto_tfm_ctx(req->tfm);
106 	struct crypto_blkcipher *child = ctx->child;
107 
108 	cryptd_blkcipher_crypt(ablkcipher_request_cast(req), child, err,
109 			       crypto_blkcipher_crt(child)->encrypt);
110 }
111 
112 static void cryptd_blkcipher_decrypt(struct crypto_async_request *req, int err)
113 {
114 	struct cryptd_blkcipher_ctx *ctx = crypto_tfm_ctx(req->tfm);
115 	struct crypto_blkcipher *child = ctx->child;
116 
117 	cryptd_blkcipher_crypt(ablkcipher_request_cast(req), child, err,
118 			       crypto_blkcipher_crt(child)->decrypt);
119 }
120 
121 static int cryptd_blkcipher_enqueue(struct ablkcipher_request *req,
122 				    crypto_completion_t complete)
123 {
124 	struct cryptd_blkcipher_request_ctx *rctx = ablkcipher_request_ctx(req);
125 	struct crypto_ablkcipher *tfm = crypto_ablkcipher_reqtfm(req);
126 	struct cryptd_state *state =
127 		cryptd_get_state(crypto_ablkcipher_tfm(tfm));
128 	int err;
129 
130 	rctx->complete = req->base.complete;
131 	req->base.complete = complete;
132 
133 	spin_lock_bh(&state->lock);
134 	err = ablkcipher_enqueue_request(&state->queue, req);
135 	spin_unlock_bh(&state->lock);
136 
137 	wake_up_process(state->task);
138 	return err;
139 }
140 
141 static int cryptd_blkcipher_encrypt_enqueue(struct ablkcipher_request *req)
142 {
143 	return cryptd_blkcipher_enqueue(req, cryptd_blkcipher_encrypt);
144 }
145 
146 static int cryptd_blkcipher_decrypt_enqueue(struct ablkcipher_request *req)
147 {
148 	return cryptd_blkcipher_enqueue(req, cryptd_blkcipher_decrypt);
149 }
150 
151 static int cryptd_blkcipher_init_tfm(struct crypto_tfm *tfm)
152 {
153 	struct crypto_instance *inst = crypto_tfm_alg_instance(tfm);
154 	struct cryptd_instance_ctx *ictx = crypto_instance_ctx(inst);
155 	struct crypto_spawn *spawn = &ictx->spawn;
156 	struct cryptd_blkcipher_ctx *ctx = crypto_tfm_ctx(tfm);
157 	struct crypto_blkcipher *cipher;
158 
159 	cipher = crypto_spawn_blkcipher(spawn);
160 	if (IS_ERR(cipher))
161 		return PTR_ERR(cipher);
162 
163 	ctx->child = cipher;
164 	tfm->crt_ablkcipher.reqsize =
165 		sizeof(struct cryptd_blkcipher_request_ctx);
166 	return 0;
167 }
168 
169 static void cryptd_blkcipher_exit_tfm(struct crypto_tfm *tfm)
170 {
171 	struct cryptd_blkcipher_ctx *ctx = crypto_tfm_ctx(tfm);
172 	struct cryptd_state *state = cryptd_get_state(tfm);
173 	int active;
174 
175 	mutex_lock(&state->mutex);
176 	active = ablkcipher_tfm_in_queue(&state->queue,
177 					 __crypto_ablkcipher_cast(tfm));
178 	mutex_unlock(&state->mutex);
179 
180 	BUG_ON(active);
181 
182 	crypto_free_blkcipher(ctx->child);
183 }
184 
185 static struct crypto_instance *cryptd_alloc_instance(struct crypto_alg *alg,
186 						     struct cryptd_state *state)
187 {
188 	struct crypto_instance *inst;
189 	struct cryptd_instance_ctx *ctx;
190 	int err;
191 
192 	inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
193 	if (!inst) {
194 		inst = ERR_PTR(-ENOMEM);
195 		goto out;
196 	}
197 
198 	err = -ENAMETOOLONG;
199 	if (snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME,
200 		     "cryptd(%s)", alg->cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
201 		goto out_free_inst;
202 
203 	ctx = crypto_instance_ctx(inst);
204 	err = crypto_init_spawn(&ctx->spawn, alg, inst,
205 				CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_ASYNC);
206 	if (err)
207 		goto out_free_inst;
208 
209 	ctx->state = state;
210 
211 	memcpy(inst->alg.cra_name, alg->cra_name, CRYPTO_MAX_ALG_NAME);
212 
213 	inst->alg.cra_priority = alg->cra_priority + 50;
214 	inst->alg.cra_blocksize = alg->cra_blocksize;
215 	inst->alg.cra_alignmask = alg->cra_alignmask;
216 
217 out:
218 	return inst;
219 
220 out_free_inst:
221 	kfree(inst);
222 	inst = ERR_PTR(err);
223 	goto out;
224 }
225 
226 static struct crypto_instance *cryptd_alloc_blkcipher(
227 	struct rtattr **tb, struct cryptd_state *state)
228 {
229 	struct crypto_instance *inst;
230 	struct crypto_alg *alg;
231 
232 	alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_BLKCIPHER,
233 				  CRYPTO_ALG_TYPE_MASK);
234 	if (IS_ERR(alg))
235 		return ERR_CAST(alg);
236 
237 	inst = cryptd_alloc_instance(alg, state);
238 	if (IS_ERR(inst))
239 		goto out_put_alg;
240 
241 	inst->alg.cra_flags = CRYPTO_ALG_TYPE_ABLKCIPHER | CRYPTO_ALG_ASYNC;
242 	inst->alg.cra_type = &crypto_ablkcipher_type;
243 
244 	inst->alg.cra_ablkcipher.ivsize = alg->cra_blkcipher.ivsize;
245 	inst->alg.cra_ablkcipher.min_keysize = alg->cra_blkcipher.min_keysize;
246 	inst->alg.cra_ablkcipher.max_keysize = alg->cra_blkcipher.max_keysize;
247 
248 	inst->alg.cra_ablkcipher.geniv = alg->cra_blkcipher.geniv;
249 
250 	inst->alg.cra_ctxsize = sizeof(struct cryptd_blkcipher_ctx);
251 
252 	inst->alg.cra_init = cryptd_blkcipher_init_tfm;
253 	inst->alg.cra_exit = cryptd_blkcipher_exit_tfm;
254 
255 	inst->alg.cra_ablkcipher.setkey = cryptd_blkcipher_setkey;
256 	inst->alg.cra_ablkcipher.encrypt = cryptd_blkcipher_encrypt_enqueue;
257 	inst->alg.cra_ablkcipher.decrypt = cryptd_blkcipher_decrypt_enqueue;
258 
259 out_put_alg:
260 	crypto_mod_put(alg);
261 	return inst;
262 }
263 
264 static struct cryptd_state state;
265 
266 static struct crypto_instance *cryptd_alloc(struct rtattr **tb)
267 {
268 	struct crypto_attr_type *algt;
269 
270 	algt = crypto_get_attr_type(tb);
271 	if (IS_ERR(algt))
272 		return ERR_CAST(algt);
273 
274 	switch (algt->type & algt->mask & CRYPTO_ALG_TYPE_MASK) {
275 	case CRYPTO_ALG_TYPE_BLKCIPHER:
276 		return cryptd_alloc_blkcipher(tb, &state);
277 	}
278 
279 	return ERR_PTR(-EINVAL);
280 }
281 
282 static void cryptd_free(struct crypto_instance *inst)
283 {
284 	struct cryptd_instance_ctx *ctx = crypto_instance_ctx(inst);
285 
286 	crypto_drop_spawn(&ctx->spawn);
287 	kfree(inst);
288 }
289 
290 static struct crypto_template cryptd_tmpl = {
291 	.name = "cryptd",
292 	.alloc = cryptd_alloc,
293 	.free = cryptd_free,
294 	.module = THIS_MODULE,
295 };
296 
297 static inline int cryptd_create_thread(struct cryptd_state *state,
298 				       int (*fn)(void *data), const char *name)
299 {
300 	spin_lock_init(&state->lock);
301 	mutex_init(&state->mutex);
302 	crypto_init_queue(&state->queue, CRYPTD_MAX_QLEN);
303 
304 	state->task = kthread_run(fn, state, name);
305 	if (IS_ERR(state->task))
306 		return PTR_ERR(state->task);
307 
308 	return 0;
309 }
310 
311 static inline void cryptd_stop_thread(struct cryptd_state *state)
312 {
313 	BUG_ON(state->queue.qlen);
314 	kthread_stop(state->task);
315 }
316 
317 static int cryptd_thread(void *data)
318 {
319 	struct cryptd_state *state = data;
320 	int stop;
321 
322 	current->flags |= PF_NOFREEZE;
323 
324 	do {
325 		struct crypto_async_request *req, *backlog;
326 
327 		mutex_lock(&state->mutex);
328 		__set_current_state(TASK_INTERRUPTIBLE);
329 
330 		spin_lock_bh(&state->lock);
331 		backlog = crypto_get_backlog(&state->queue);
332 		req = crypto_dequeue_request(&state->queue);
333 		spin_unlock_bh(&state->lock);
334 
335 		stop = kthread_should_stop();
336 
337 		if (stop || req) {
338 			__set_current_state(TASK_RUNNING);
339 			if (req) {
340 				if (backlog)
341 					backlog->complete(backlog,
342 							  -EINPROGRESS);
343 				req->complete(req, 0);
344 			}
345 		}
346 
347 		mutex_unlock(&state->mutex);
348 
349 		schedule();
350 	} while (!stop);
351 
352 	return 0;
353 }
354 
355 static int __init cryptd_init(void)
356 {
357 	int err;
358 
359 	err = cryptd_create_thread(&state, cryptd_thread, "cryptd");
360 	if (err)
361 		return err;
362 
363 	err = crypto_register_template(&cryptd_tmpl);
364 	if (err)
365 		kthread_stop(state.task);
366 
367 	return err;
368 }
369 
370 static void __exit cryptd_exit(void)
371 {
372 	cryptd_stop_thread(&state);
373 	crypto_unregister_template(&cryptd_tmpl);
374 }
375 
376 module_init(cryptd_init);
377 module_exit(cryptd_exit);
378 
379 MODULE_LICENSE("GPL");
380 MODULE_DESCRIPTION("Software async crypto daemon");
381