xref: /openbmc/linux/crypto/aead.c (revision 26ba4e57) 
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 	    authsize > crypto_aead_maxauthsize(tfm))
75 		return -EINVAL;
76 
77 	if (crypto_aead_alg(tfm)->setauthsize) {
78 		err = crypto_aead_alg(tfm)->setauthsize(tfm, authsize);
79 		if (err)
80 			return err;
81 	}
82 
83 	tfm->authsize = authsize;
84 	return 0;
85 }
86 EXPORT_SYMBOL_GPL(crypto_aead_setauthsize);
87 
88 int crypto_aead_encrypt(struct aead_request *req)
89 {
90 	struct crypto_aead *aead = crypto_aead_reqtfm(req);
91 	struct crypto_alg *alg = aead->base.__crt_alg;
92 	unsigned int cryptlen = req->cryptlen;
93 	int ret;
94 
95 	crypto_stats_get(alg);
96 	if (crypto_aead_get_flags(aead) & CRYPTO_TFM_NEED_KEY)
97 		ret = -ENOKEY;
98 	else
99 		ret = crypto_aead_alg(aead)->encrypt(req);
100 	crypto_stats_aead_encrypt(cryptlen, alg, ret);
101 	return ret;
102 }
103 EXPORT_SYMBOL_GPL(crypto_aead_encrypt);
104 
105 int crypto_aead_decrypt(struct aead_request *req)
106 {
107 	struct crypto_aead *aead = crypto_aead_reqtfm(req);
108 	struct crypto_alg *alg = aead->base.__crt_alg;
109 	unsigned int cryptlen = req->cryptlen;
110 	int ret;
111 
112 	crypto_stats_get(alg);
113 	if (crypto_aead_get_flags(aead) & CRYPTO_TFM_NEED_KEY)
114 		ret = -ENOKEY;
115 	else if (req->cryptlen < crypto_aead_authsize(aead))
116 		ret = -EINVAL;
117 	else
118 		ret = crypto_aead_alg(aead)->decrypt(req);
119 	crypto_stats_aead_decrypt(cryptlen, alg, ret);
120 	return ret;
121 }
122 EXPORT_SYMBOL_GPL(crypto_aead_decrypt);
123 
124 static void crypto_aead_exit_tfm(struct crypto_tfm *tfm)
125 {
126 	struct crypto_aead *aead = __crypto_aead_cast(tfm);
127 	struct aead_alg *alg = crypto_aead_alg(aead);
128 
129 	alg->exit(aead);
130 }
131 
132 static int crypto_aead_init_tfm(struct crypto_tfm *tfm)
133 {
134 	struct crypto_aead *aead = __crypto_aead_cast(tfm);
135 	struct aead_alg *alg = crypto_aead_alg(aead);
136 
137 	crypto_aead_set_flags(aead, CRYPTO_TFM_NEED_KEY);
138 
139 	aead->authsize = alg->maxauthsize;
140 
141 	if (alg->exit)
142 		aead->base.exit = crypto_aead_exit_tfm;
143 
144 	if (alg->init)
145 		return alg->init(aead);
146 
147 	return 0;
148 }
149 
150 #ifdef CONFIG_NET
151 static int crypto_aead_report(struct sk_buff *skb, struct crypto_alg *alg)
152 {
153 	struct crypto_report_aead raead;
154 	struct aead_alg *aead = container_of(alg, struct aead_alg, base);
155 
156 	memset(&raead, 0, sizeof(raead));
157 
158 	strscpy(raead.type, "aead", sizeof(raead.type));
159 	strscpy(raead.geniv, "<none>", sizeof(raead.geniv));
160 
161 	raead.blocksize = alg->cra_blocksize;
162 	raead.maxauthsize = aead->maxauthsize;
163 	raead.ivsize = aead->ivsize;
164 
165 	return nla_put(skb, CRYPTOCFGA_REPORT_AEAD, sizeof(raead), &raead);
166 }
167 #else
168 static int crypto_aead_report(struct sk_buff *skb, struct crypto_alg *alg)
169 {
170 	return -ENOSYS;
171 }
172 #endif
173 
174 static void crypto_aead_show(struct seq_file *m, struct crypto_alg *alg)
175 	__maybe_unused;
176 static void crypto_aead_show(struct seq_file *m, struct crypto_alg *alg)
177 {
178 	struct aead_alg *aead = container_of(alg, struct aead_alg, base);
179 
180 	seq_printf(m, "type         : aead\n");
181 	seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
182 					     "yes" : "no");
183 	seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
184 	seq_printf(m, "ivsize       : %u\n", aead->ivsize);
185 	seq_printf(m, "maxauthsize  : %u\n", aead->maxauthsize);
186 	seq_printf(m, "geniv        : <none>\n");
187 }
188 
189 static void crypto_aead_free_instance(struct crypto_instance *inst)
190 {
191 	struct aead_instance *aead = aead_instance(inst);
192 
193 	if (!aead->free) {
194 		inst->tmpl->free(inst);
195 		return;
196 	}
197 
198 	aead->free(aead);
199 }
200 
201 static const struct crypto_type crypto_aead_type = {
202 	.extsize = crypto_alg_extsize,
203 	.init_tfm = crypto_aead_init_tfm,
204 	.free = crypto_aead_free_instance,
205 #ifdef CONFIG_PROC_FS
206 	.show = crypto_aead_show,
207 #endif
208 	.report = crypto_aead_report,
209 	.maskclear = ~CRYPTO_ALG_TYPE_MASK,
210 	.maskset = CRYPTO_ALG_TYPE_MASK,
211 	.type = CRYPTO_ALG_TYPE_AEAD,
212 	.tfmsize = offsetof(struct crypto_aead, base),
213 };
214 
215 static int aead_geniv_setkey(struct crypto_aead *tfm,
216 			     const u8 *key, unsigned int keylen)
217 {
218 	struct aead_geniv_ctx *ctx = crypto_aead_ctx(tfm);
219 
220 	return crypto_aead_setkey(ctx->child, key, keylen);
221 }
222 
223 static int aead_geniv_setauthsize(struct crypto_aead *tfm,
224 				  unsigned int authsize)
225 {
226 	struct aead_geniv_ctx *ctx = crypto_aead_ctx(tfm);
227 
228 	return crypto_aead_setauthsize(ctx->child, authsize);
229 }
230 
231 struct aead_instance *aead_geniv_alloc(struct crypto_template *tmpl,
232 				       struct rtattr **tb, u32 type, u32 mask)
233 {
234 	const char *name;
235 	struct crypto_aead_spawn *spawn;
236 	struct crypto_attr_type *algt;
237 	struct aead_instance *inst;
238 	struct aead_alg *alg;
239 	unsigned int ivsize;
240 	unsigned int maxauthsize;
241 	int err;
242 
243 	algt = crypto_get_attr_type(tb);
244 	if (IS_ERR(algt))
245 		return ERR_CAST(algt);
246 
247 	if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
248 		return ERR_PTR(-EINVAL);
249 
250 	name = crypto_attr_alg_name(tb[1]);
251 	if (IS_ERR(name))
252 		return ERR_CAST(name);
253 
254 	inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
255 	if (!inst)
256 		return ERR_PTR(-ENOMEM);
257 
258 	spawn = aead_instance_ctx(inst);
259 
260 	/* Ignore async algorithms if necessary. */
261 	mask |= crypto_requires_sync(algt->type, algt->mask);
262 
263 	crypto_set_aead_spawn(spawn, aead_crypto_instance(inst));
264 	err = crypto_grab_aead(spawn, name, type, mask);
265 	if (err)
266 		goto err_free_inst;
267 
268 	alg = crypto_spawn_aead_alg(spawn);
269 
270 	ivsize = crypto_aead_alg_ivsize(alg);
271 	maxauthsize = crypto_aead_alg_maxauthsize(alg);
272 
273 	err = -EINVAL;
274 	if (ivsize < sizeof(u64))
275 		goto err_drop_alg;
276 
277 	err = -ENAMETOOLONG;
278 	if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
279 		     "%s(%s)", tmpl->name, alg->base.cra_name) >=
280 	    CRYPTO_MAX_ALG_NAME)
281 		goto err_drop_alg;
282 	if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
283 		     "%s(%s)", tmpl->name, alg->base.cra_driver_name) >=
284 	    CRYPTO_MAX_ALG_NAME)
285 		goto err_drop_alg;
286 
287 	inst->alg.base.cra_flags = alg->base.cra_flags & CRYPTO_ALG_ASYNC;
288 	inst->alg.base.cra_priority = alg->base.cra_priority;
289 	inst->alg.base.cra_blocksize = alg->base.cra_blocksize;
290 	inst->alg.base.cra_alignmask = alg->base.cra_alignmask;
291 	inst->alg.base.cra_ctxsize = sizeof(struct aead_geniv_ctx);
292 
293 	inst->alg.setkey = aead_geniv_setkey;
294 	inst->alg.setauthsize = aead_geniv_setauthsize;
295 
296 	inst->alg.ivsize = ivsize;
297 	inst->alg.maxauthsize = maxauthsize;
298 
299 out:
300 	return inst;
301 
302 err_drop_alg:
303 	crypto_drop_aead(spawn);
304 err_free_inst:
305 	kfree(inst);
306 	inst = ERR_PTR(err);
307 	goto out;
308 }
309 EXPORT_SYMBOL_GPL(aead_geniv_alloc);
310 
311 void aead_geniv_free(struct aead_instance *inst)
312 {
313 	crypto_drop_aead(aead_instance_ctx(inst));
314 	kfree(inst);
315 }
316 EXPORT_SYMBOL_GPL(aead_geniv_free);
317 
318 int aead_init_geniv(struct crypto_aead *aead)
319 {
320 	struct aead_geniv_ctx *ctx = crypto_aead_ctx(aead);
321 	struct aead_instance *inst = aead_alg_instance(aead);
322 	struct crypto_aead *child;
323 	int err;
324 
325 	spin_lock_init(&ctx->lock);
326 
327 	err = crypto_get_default_rng();
328 	if (err)
329 		goto out;
330 
331 	err = crypto_rng_get_bytes(crypto_default_rng, ctx->salt,
332 				   crypto_aead_ivsize(aead));
333 	crypto_put_default_rng();
334 	if (err)
335 		goto out;
336 
337 	ctx->sknull = crypto_get_default_null_skcipher();
338 	err = PTR_ERR(ctx->sknull);
339 	if (IS_ERR(ctx->sknull))
340 		goto out;
341 
342 	child = crypto_spawn_aead(aead_instance_ctx(inst));
343 	err = PTR_ERR(child);
344 	if (IS_ERR(child))
345 		goto drop_null;
346 
347 	ctx->child = child;
348 	crypto_aead_set_reqsize(aead, crypto_aead_reqsize(child) +
349 				      sizeof(struct aead_request));
350 
351 	err = 0;
352 
353 out:
354 	return err;
355 
356 drop_null:
357 	crypto_put_default_null_skcipher();
358 	goto out;
359 }
360 EXPORT_SYMBOL_GPL(aead_init_geniv);
361 
362 void aead_exit_geniv(struct crypto_aead *tfm)
363 {
364 	struct aead_geniv_ctx *ctx = crypto_aead_ctx(tfm);
365 
366 	crypto_free_aead(ctx->child);
367 	crypto_put_default_null_skcipher();
368 }
369 EXPORT_SYMBOL_GPL(aead_exit_geniv);
370 
371 int crypto_grab_aead(struct crypto_aead_spawn *spawn, const char *name,
372 		     u32 type, u32 mask)
373 {
374 	spawn->base.frontend = &crypto_aead_type;
375 	return crypto_grab_spawn(&spawn->base, name, type, mask);
376 }
377 EXPORT_SYMBOL_GPL(crypto_grab_aead);
378 
379 struct crypto_aead *crypto_alloc_aead(const char *alg_name, u32 type, u32 mask)
380 {
381 	return crypto_alloc_tfm(alg_name, &crypto_aead_type, type, mask);
382 }
383 EXPORT_SYMBOL_GPL(crypto_alloc_aead);
384 
385 static int aead_prepare_alg(struct aead_alg *alg)
386 {
387 	struct crypto_alg *base = &alg->base;
388 
389 	if (max3(alg->maxauthsize, alg->ivsize, alg->chunksize) >
390 	    PAGE_SIZE / 8)
391 		return -EINVAL;
392 
393 	if (!alg->chunksize)
394 		alg->chunksize = base->cra_blocksize;
395 
396 	base->cra_type = &crypto_aead_type;
397 	base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
398 	base->cra_flags |= CRYPTO_ALG_TYPE_AEAD;
399 
400 	return 0;
401 }
402 
403 int crypto_register_aead(struct aead_alg *alg)
404 {
405 	struct crypto_alg *base = &alg->base;
406 	int err;
407 
408 	err = aead_prepare_alg(alg);
409 	if (err)
410 		return err;
411 
412 	return crypto_register_alg(base);
413 }
414 EXPORT_SYMBOL_GPL(crypto_register_aead);
415 
416 void crypto_unregister_aead(struct aead_alg *alg)
417 {
418 	crypto_unregister_alg(&alg->base);
419 }
420 EXPORT_SYMBOL_GPL(crypto_unregister_aead);
421 
422 int crypto_register_aeads(struct aead_alg *algs, int count)
423 {
424 	int i, ret;
425 
426 	for (i = 0; i < count; i++) {
427 		ret = crypto_register_aead(&algs[i]);
428 		if (ret)
429 			goto err;
430 	}
431 
432 	return 0;
433 
434 err:
435 	for (--i; i >= 0; --i)
436 		crypto_unregister_aead(&algs[i]);
437 
438 	return ret;
439 }
440 EXPORT_SYMBOL_GPL(crypto_register_aeads);
441 
442 void crypto_unregister_aeads(struct aead_alg *algs, int count)
443 {
444 	int i;
445 
446 	for (i = count - 1; i >= 0; --i)
447 		crypto_unregister_aead(&algs[i]);
448 }
449 EXPORT_SYMBOL_GPL(crypto_unregister_aeads);
450 
451 int aead_register_instance(struct crypto_template *tmpl,
452 			   struct aead_instance *inst)
453 {
454 	int err;
455 
456 	err = aead_prepare_alg(&inst->alg);
457 	if (err)
458 		return err;
459 
460 	return crypto_register_instance(tmpl, aead_crypto_instance(inst));
461 }
462 EXPORT_SYMBOL_GPL(aead_register_instance);
463 
464 MODULE_LICENSE("GPL");
465 MODULE_DESCRIPTION("Authenticated Encryption with Associated Data (AEAD)");
466