xref: /openbmc/linux/crypto/aead.c (revision 65ab0dba) 
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * AEAD: Authenticated Encryption with Associated Data
4  *
5  * This file provides API support for AEAD algorithms.
6  *
7  * Copyright (c) 2007-2015 Herbert Xu <herbert@gondor.apana.org.au>
8  */
9 
10 #include <crypto/internal/geniv.h>
11 #include <crypto/internal/rng.h>
12 #include <crypto/null.h>
13 #include <crypto/scatterwalk.h>
14 #include <linux/err.h>
15 #include <linux/init.h>
16 #include <linux/kernel.h>
17 #include <linux/module.h>
18 #include <linux/rtnetlink.h>
19 #include <linux/slab.h>
20 #include <linux/seq_file.h>
21 #include <linux/cryptouser.h>
22 #include <linux/compiler.h>
23 #include <net/netlink.h>
24 
25 #include "internal.h"
26 
27 static int setkey_unaligned(struct crypto_aead *tfm, const u8 *key,
28 			    unsigned int keylen)
29 {
30 	unsigned long alignmask = crypto_aead_alignmask(tfm);
31 	int ret;
32 	u8 *buffer, *alignbuffer;
33 	unsigned long absize;
34 
35 	absize = keylen + alignmask;
36 	buffer = kmalloc(absize, GFP_ATOMIC);
37 	if (!buffer)
38 		return -ENOMEM;
39 
40 	alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
41 	memcpy(alignbuffer, key, keylen);
42 	ret = crypto_aead_alg(tfm)->setkey(tfm, alignbuffer, keylen);
43 	memset(alignbuffer, 0, keylen);
44 	kfree(buffer);
45 	return ret;
46 }
47 
48 int crypto_aead_setkey(struct crypto_aead *tfm,
49 		       const u8 *key, unsigned int keylen)
50 {
51 	unsigned long alignmask = crypto_aead_alignmask(tfm);
52 	int err;
53 
54 	if ((unsigned long)key & alignmask)
55 		err = setkey_unaligned(tfm, key, keylen);
56 	else
57 		err = crypto_aead_alg(tfm)->setkey(tfm, key, keylen);
58 
59 	if (unlikely(err)) {
60 		crypto_aead_set_flags(tfm, CRYPTO_TFM_NEED_KEY);
61 		return err;
62 	}
63 
64 	crypto_aead_clear_flags(tfm, CRYPTO_TFM_NEED_KEY);
65 	return 0;
66 }
67 EXPORT_SYMBOL_GPL(crypto_aead_setkey);
68 
69 int crypto_aead_setauthsize(struct crypto_aead *tfm, unsigned int authsize)
70 {
71 	int err;
72 
73 	if (authsize > crypto_aead_maxauthsize(tfm))
74 		return -EINVAL;
75 
76 	if (crypto_aead_alg(tfm)->setauthsize) {
77 		err = crypto_aead_alg(tfm)->setauthsize(tfm, authsize);
78 		if (err)
79 			return err;
80 	}
81 
82 	tfm->authsize = authsize;
83 	return 0;
84 }
85 EXPORT_SYMBOL_GPL(crypto_aead_setauthsize);
86 
87 int crypto_aead_encrypt(struct aead_request *req)
88 {
89 	struct crypto_aead *aead = crypto_aead_reqtfm(req);
90 	struct crypto_alg *alg = aead->base.__crt_alg;
91 	unsigned int cryptlen = req->cryptlen;
92 	int ret;
93 
94 	crypto_stats_get(alg);
95 	if (crypto_aead_get_flags(aead) & CRYPTO_TFM_NEED_KEY)
96 		ret = -ENOKEY;
97 	else
98 		ret = crypto_aead_alg(aead)->encrypt(req);
99 	crypto_stats_aead_encrypt(cryptlen, alg, ret);
100 	return ret;
101 }
102 EXPORT_SYMBOL_GPL(crypto_aead_encrypt);
103 
104 int crypto_aead_decrypt(struct aead_request *req)
105 {
106 	struct crypto_aead *aead = crypto_aead_reqtfm(req);
107 	struct crypto_alg *alg = aead->base.__crt_alg;
108 	unsigned int cryptlen = req->cryptlen;
109 	int ret;
110 
111 	crypto_stats_get(alg);
112 	if (crypto_aead_get_flags(aead) & CRYPTO_TFM_NEED_KEY)
113 		ret = -ENOKEY;
114 	else if (req->cryptlen < crypto_aead_authsize(aead))
115 		ret = -EINVAL;
116 	else
117 		ret = crypto_aead_alg(aead)->decrypt(req);
118 	crypto_stats_aead_decrypt(cryptlen, alg, ret);
119 	return ret;
120 }
121 EXPORT_SYMBOL_GPL(crypto_aead_decrypt);
122 
123 static void crypto_aead_exit_tfm(struct crypto_tfm *tfm)
124 {
125 	struct crypto_aead *aead = __crypto_aead_cast(tfm);
126 	struct aead_alg *alg = crypto_aead_alg(aead);
127 
128 	alg->exit(aead);
129 }
130 
131 static int crypto_aead_init_tfm(struct crypto_tfm *tfm)
132 {
133 	struct crypto_aead *aead = __crypto_aead_cast(tfm);
134 	struct aead_alg *alg = crypto_aead_alg(aead);
135 
136 	crypto_aead_set_flags(aead, CRYPTO_TFM_NEED_KEY);
137 
138 	aead->authsize = alg->maxauthsize;
139 
140 	if (alg->exit)
141 		aead->base.exit = crypto_aead_exit_tfm;
142 
143 	if (alg->init)
144 		return alg->init(aead);
145 
146 	return 0;
147 }
148 
149 #ifdef CONFIG_NET
150 static int crypto_aead_report(struct sk_buff *skb, struct crypto_alg *alg)
151 {
152 	struct crypto_report_aead raead;
153 	struct aead_alg *aead = container_of(alg, struct aead_alg, base);
154 
155 	memset(&raead, 0, sizeof(raead));
156 
157 	strscpy(raead.type, "aead", sizeof(raead.type));
158 	strscpy(raead.geniv, "<none>", sizeof(raead.geniv));
159 
160 	raead.blocksize = alg->cra_blocksize;
161 	raead.maxauthsize = aead->maxauthsize;
162 	raead.ivsize = aead->ivsize;
163 
164 	return nla_put(skb, CRYPTOCFGA_REPORT_AEAD, sizeof(raead), &raead);
165 }
166 #else
167 static int crypto_aead_report(struct sk_buff *skb, struct crypto_alg *alg)
168 {
169 	return -ENOSYS;
170 }
171 #endif
172 
173 static void crypto_aead_show(struct seq_file *m, struct crypto_alg *alg)
174 	__maybe_unused;
175 static void crypto_aead_show(struct seq_file *m, struct crypto_alg *alg)
176 {
177 	struct aead_alg *aead = container_of(alg, struct aead_alg, base);
178 
179 	seq_printf(m, "type         : aead\n");
180 	seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
181 					     "yes" : "no");
182 	seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
183 	seq_printf(m, "ivsize       : %u\n", aead->ivsize);
184 	seq_printf(m, "maxauthsize  : %u\n", aead->maxauthsize);
185 	seq_printf(m, "geniv        : <none>\n");
186 }
187 
188 static void crypto_aead_free_instance(struct crypto_instance *inst)
189 {
190 	struct aead_instance *aead = aead_instance(inst);
191 
192 	if (!aead->free) {
193 		inst->tmpl->free(inst);
194 		return;
195 	}
196 
197 	aead->free(aead);
198 }
199 
200 static const struct crypto_type crypto_aead_type = {
201 	.extsize = crypto_alg_extsize,
202 	.init_tfm = crypto_aead_init_tfm,
203 	.free = crypto_aead_free_instance,
204 #ifdef CONFIG_PROC_FS
205 	.show = crypto_aead_show,
206 #endif
207 	.report = crypto_aead_report,
208 	.maskclear = ~CRYPTO_ALG_TYPE_MASK,
209 	.maskset = CRYPTO_ALG_TYPE_MASK,
210 	.type = CRYPTO_ALG_TYPE_AEAD,
211 	.tfmsize = offsetof(struct crypto_aead, base),
212 };
213 
214 static int aead_geniv_setkey(struct crypto_aead *tfm,
215 			     const u8 *key, unsigned int keylen)
216 {
217 	struct aead_geniv_ctx *ctx = crypto_aead_ctx(tfm);
218 
219 	return crypto_aead_setkey(ctx->child, key, keylen);
220 }
221 
222 static int aead_geniv_setauthsize(struct crypto_aead *tfm,
223 				  unsigned int authsize)
224 {
225 	struct aead_geniv_ctx *ctx = crypto_aead_ctx(tfm);
226 
227 	return crypto_aead_setauthsize(ctx->child, authsize);
228 }
229 
230 struct aead_instance *aead_geniv_alloc(struct crypto_template *tmpl,
231 				       struct rtattr **tb, u32 type, u32 mask)
232 {
233 	const char *name;
234 	struct crypto_aead_spawn *spawn;
235 	struct crypto_attr_type *algt;
236 	struct aead_instance *inst;
237 	struct aead_alg *alg;
238 	unsigned int ivsize;
239 	unsigned int maxauthsize;
240 	int err;
241 
242 	algt = crypto_get_attr_type(tb);
243 	if (IS_ERR(algt))
244 		return ERR_CAST(algt);
245 
246 	if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
247 		return ERR_PTR(-EINVAL);
248 
249 	name = crypto_attr_alg_name(tb[1]);
250 	if (IS_ERR(name))
251 		return ERR_CAST(name);
252 
253 	inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
254 	if (!inst)
255 		return ERR_PTR(-ENOMEM);
256 
257 	spawn = aead_instance_ctx(inst);
258 
259 	/* Ignore async algorithms if necessary. */
260 	mask |= crypto_requires_sync(algt->type, algt->mask);
261 
262 	crypto_set_aead_spawn(spawn, aead_crypto_instance(inst));
263 	err = crypto_grab_aead(spawn, name, type, mask);
264 	if (err)
265 		goto err_free_inst;
266 
267 	alg = crypto_spawn_aead_alg(spawn);
268 
269 	ivsize = crypto_aead_alg_ivsize(alg);
270 	maxauthsize = crypto_aead_alg_maxauthsize(alg);
271 
272 	err = -EINVAL;
273 	if (ivsize < sizeof(u64))
274 		goto err_drop_alg;
275 
276 	err = -ENAMETOOLONG;
277 	if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
278 		     "%s(%s)", tmpl->name, alg->base.cra_name) >=
279 	    CRYPTO_MAX_ALG_NAME)
280 		goto err_drop_alg;
281 	if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
282 		     "%s(%s)", tmpl->name, alg->base.cra_driver_name) >=
283 	    CRYPTO_MAX_ALG_NAME)
284 		goto err_drop_alg;
285 
286 	inst->alg.base.cra_flags = alg->base.cra_flags & CRYPTO_ALG_ASYNC;
287 	inst->alg.base.cra_priority = alg->base.cra_priority;
288 	inst->alg.base.cra_blocksize = alg->base.cra_blocksize;
289 	inst->alg.base.cra_alignmask = alg->base.cra_alignmask;
290 	inst->alg.base.cra_ctxsize = sizeof(struct aead_geniv_ctx);
291 
292 	inst->alg.setkey = aead_geniv_setkey;
293 	inst->alg.setauthsize = aead_geniv_setauthsize;
294 
295 	inst->alg.ivsize = ivsize;
296 	inst->alg.maxauthsize = maxauthsize;
297 
298 out:
299 	return inst;
300 
301 err_drop_alg:
302 	crypto_drop_aead(spawn);
303 err_free_inst:
304 	kfree(inst);
305 	inst = ERR_PTR(err);
306 	goto out;
307 }
308 EXPORT_SYMBOL_GPL(aead_geniv_alloc);
309 
310 void aead_geniv_free(struct aead_instance *inst)
311 {
312 	crypto_drop_aead(aead_instance_ctx(inst));
313 	kfree(inst);
314 }
315 EXPORT_SYMBOL_GPL(aead_geniv_free);
316 
317 int aead_init_geniv(struct crypto_aead *aead)
318 {
319 	struct aead_geniv_ctx *ctx = crypto_aead_ctx(aead);
320 	struct aead_instance *inst = aead_alg_instance(aead);
321 	struct crypto_aead *child;
322 	int err;
323 
324 	spin_lock_init(&ctx->lock);
325 
326 	err = crypto_get_default_rng();
327 	if (err)
328 		goto out;
329 
330 	err = crypto_rng_get_bytes(crypto_default_rng, ctx->salt,
331 				   crypto_aead_ivsize(aead));
332 	crypto_put_default_rng();
333 	if (err)
334 		goto out;
335 
336 	ctx->sknull = crypto_get_default_null_skcipher();
337 	err = PTR_ERR(ctx->sknull);
338 	if (IS_ERR(ctx->sknull))
339 		goto out;
340 
341 	child = crypto_spawn_aead(aead_instance_ctx(inst));
342 	err = PTR_ERR(child);
343 	if (IS_ERR(child))
344 		goto drop_null;
345 
346 	ctx->child = child;
347 	crypto_aead_set_reqsize(aead, crypto_aead_reqsize(child) +
348 				      sizeof(struct aead_request));
349 
350 	err = 0;
351 
352 out:
353 	return err;
354 
355 drop_null:
356 	crypto_put_default_null_skcipher();
357 	goto out;
358 }
359 EXPORT_SYMBOL_GPL(aead_init_geniv);
360 
361 void aead_exit_geniv(struct crypto_aead *tfm)
362 {
363 	struct aead_geniv_ctx *ctx = crypto_aead_ctx(tfm);
364 
365 	crypto_free_aead(ctx->child);
366 	crypto_put_default_null_skcipher();
367 }
368 EXPORT_SYMBOL_GPL(aead_exit_geniv);
369 
370 int crypto_grab_aead(struct crypto_aead_spawn *spawn, const char *name,
371 		     u32 type, u32 mask)
372 {
373 	spawn->base.frontend = &crypto_aead_type;
374 	return crypto_grab_spawn(&spawn->base, name, type, mask);
375 }
376 EXPORT_SYMBOL_GPL(crypto_grab_aead);
377 
378 struct crypto_aead *crypto_alloc_aead(const char *alg_name, u32 type, u32 mask)
379 {
380 	return crypto_alloc_tfm(alg_name, &crypto_aead_type, type, mask);
381 }
382 EXPORT_SYMBOL_GPL(crypto_alloc_aead);
383 
384 static int aead_prepare_alg(struct aead_alg *alg)
385 {
386 	struct crypto_alg *base = &alg->base;
387 
388 	if (max3(alg->maxauthsize, alg->ivsize, alg->chunksize) >
389 	    PAGE_SIZE / 8)
390 		return -EINVAL;
391 
392 	if (!alg->chunksize)
393 		alg->chunksize = base->cra_blocksize;
394 
395 	base->cra_type = &crypto_aead_type;
396 	base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
397 	base->cra_flags |= CRYPTO_ALG_TYPE_AEAD;
398 
399 	return 0;
400 }
401 
402 int crypto_register_aead(struct aead_alg *alg)
403 {
404 	struct crypto_alg *base = &alg->base;
405 	int err;
406 
407 	err = aead_prepare_alg(alg);
408 	if (err)
409 		return err;
410 
411 	return crypto_register_alg(base);
412 }
413 EXPORT_SYMBOL_GPL(crypto_register_aead);
414 
415 void crypto_unregister_aead(struct aead_alg *alg)
416 {
417 	crypto_unregister_alg(&alg->base);
418 }
419 EXPORT_SYMBOL_GPL(crypto_unregister_aead);
420 
421 int crypto_register_aeads(struct aead_alg *algs, int count)
422 {
423 	int i, ret;
424 
425 	for (i = 0; i < count; i++) {
426 		ret = crypto_register_aead(&algs[i]);
427 		if (ret)
428 			goto err;
429 	}
430 
431 	return 0;
432 
433 err:
434 	for (--i; i >= 0; --i)
435 		crypto_unregister_aead(&algs[i]);
436 
437 	return ret;
438 }
439 EXPORT_SYMBOL_GPL(crypto_register_aeads);
440 
441 void crypto_unregister_aeads(struct aead_alg *algs, int count)
442 {
443 	int i;
444 
445 	for (i = count - 1; i >= 0; --i)
446 		crypto_unregister_aead(&algs[i]);
447 }
448 EXPORT_SYMBOL_GPL(crypto_unregister_aeads);
449 
450 int aead_register_instance(struct crypto_template *tmpl,
451 			   struct aead_instance *inst)
452 {
453 	int err;
454 
455 	err = aead_prepare_alg(&inst->alg);
456 	if (err)
457 		return err;
458 
459 	return crypto_register_instance(tmpl, aead_crypto_instance(inst));
460 }
461 EXPORT_SYMBOL_GPL(aead_register_instance);
462 
463 MODULE_LICENSE("GPL");
464 MODULE_DESCRIPTION("Authenticated Encryption with Associated Data (AEAD)");
465