akcipher.c

  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * Public Key Encryption
  4 *
  5 * Copyright (c) 2015, Intel Corporation
  6 * Authors: Tadeusz Struk <tadeusz.struk@intel.com>
  7 */
  8#include <crypto/internal/akcipher.h>
  9#include <linux/cryptouser.h>
 10#include <linux/errno.h>
 11#include <linux/kernel.h>
 12#include <linux/module.h>
 13#include <linux/scatterlist.h>
 14#include <linux/seq_file.h>
 15#include <linux/slab.h>
 16#include <linux/string.h>
 17#include <net/netlink.h>
 18
 19#include "internal.h"
 20
 21#define CRYPTO_ALG_TYPE_AHASH_MASK	0x0000000e
 22
 23struct crypto_akcipher_sync_data {
 24	struct crypto_akcipher *tfm;
 25	const void *src;
 26	void *dst;
 27	unsigned int slen;
 28	unsigned int dlen;
 29
 30	struct akcipher_request *req;
 31	struct crypto_wait cwait;
 32	struct scatterlist sg;
 33	u8 *buf;
 34};
 35
 36static int __maybe_unused crypto_akcipher_report(
 37	struct sk_buff *skb, struct crypto_alg *alg)
 38{
 39	struct crypto_report_akcipher rakcipher;
 40
 41	memset(&rakcipher, 0, sizeof(rakcipher));
 42
 43	strscpy(rakcipher.type, "akcipher", sizeof(rakcipher.type));
 44
 45	return nla_put(skb, CRYPTOCFGA_REPORT_AKCIPHER,
 46		       sizeof(rakcipher), &rakcipher);
 47}
 48
 49static void crypto_akcipher_show(struct seq_file *m, struct crypto_alg *alg)
 50	__maybe_unused;
 51
 52static void crypto_akcipher_show(struct seq_file *m, struct crypto_alg *alg)
 53{
 54	seq_puts(m, "type         : akcipher\n");
 55}
 56
 57static void crypto_akcipher_exit_tfm(struct crypto_tfm *tfm)
 58{
 59	struct crypto_akcipher *akcipher = __crypto_akcipher_tfm(tfm);
 60	struct akcipher_alg *alg = crypto_akcipher_alg(akcipher);
 61
 62	alg->exit(akcipher);
 63}
 64
 65static int crypto_akcipher_init_tfm(struct crypto_tfm *tfm)
 66{
 67	struct crypto_akcipher *akcipher = __crypto_akcipher_tfm(tfm);
 68	struct akcipher_alg *alg = crypto_akcipher_alg(akcipher);
 69
 70	if (alg->exit)
 71		akcipher->base.exit = crypto_akcipher_exit_tfm;
 72
 73	if (alg->init)
 74		return alg->init(akcipher);
 75
 76	return 0;
 77}
 78
 79static void crypto_akcipher_free_instance(struct crypto_instance *inst)
 80{
 81	struct akcipher_instance *akcipher = akcipher_instance(inst);
 82
 83	akcipher->free(akcipher);
 84}
 85
 86static const struct crypto_type crypto_akcipher_type = {
 87	.extsize = crypto_alg_extsize,
 88	.init_tfm = crypto_akcipher_init_tfm,
 89	.free = crypto_akcipher_free_instance,
 90#ifdef CONFIG_PROC_FS
 91	.show = crypto_akcipher_show,
 92#endif
 93#if IS_ENABLED(CONFIG_CRYPTO_USER)
 94	.report = crypto_akcipher_report,
 95#endif
 96	.maskclear = ~CRYPTO_ALG_TYPE_MASK,
 97	.maskset = CRYPTO_ALG_TYPE_AHASH_MASK,
 98	.type = CRYPTO_ALG_TYPE_AKCIPHER,
 99	.tfmsize = offsetof(struct crypto_akcipher, base),
100	.algsize = offsetof(struct akcipher_alg, base),
101};
102
103int crypto_grab_akcipher(struct crypto_akcipher_spawn *spawn,
104			 struct crypto_instance *inst,
105			 const char *name, u32 type, u32 mask)
106{
107	spawn->base.frontend = &crypto_akcipher_type;
108	return crypto_grab_spawn(&spawn->base, inst, name, type, mask);
109}
110EXPORT_SYMBOL_GPL(crypto_grab_akcipher);
111
112struct crypto_akcipher *crypto_alloc_akcipher(const char *alg_name, u32 type,
113					      u32 mask)
114{
115	return crypto_alloc_tfm(alg_name, &crypto_akcipher_type, type, mask);
116}
117EXPORT_SYMBOL_GPL(crypto_alloc_akcipher);
118
119static void akcipher_prepare_alg(struct akcipher_alg *alg)
120{
121	struct crypto_alg *base = &alg->base;
122
123	base->cra_type = &crypto_akcipher_type;
124	base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
125	base->cra_flags |= CRYPTO_ALG_TYPE_AKCIPHER;
126}
127
128static int akcipher_default_op(struct akcipher_request *req)
129{
130	return -ENOSYS;
131}
132
133static int akcipher_default_set_key(struct crypto_akcipher *tfm,
134				     const void *key, unsigned int keylen)
135{
136	return -ENOSYS;
137}
138
139int crypto_register_akcipher(struct akcipher_alg *alg)
140{
141	struct crypto_alg *base = &alg->base;
142
143	if (!alg->encrypt)
144		alg->encrypt = akcipher_default_op;
145	if (!alg->decrypt)
146		alg->decrypt = akcipher_default_op;
147	if (!alg->set_priv_key)
148		alg->set_priv_key = akcipher_default_set_key;
149
150	akcipher_prepare_alg(alg);
151	return crypto_register_alg(base);
152}
153EXPORT_SYMBOL_GPL(crypto_register_akcipher);
154
155void crypto_unregister_akcipher(struct akcipher_alg *alg)
156{
157	crypto_unregister_alg(&alg->base);
158}
159EXPORT_SYMBOL_GPL(crypto_unregister_akcipher);
160
161int akcipher_register_instance(struct crypto_template *tmpl,
162			       struct akcipher_instance *inst)
163{
164	if (WARN_ON(!inst->free))
165		return -EINVAL;
166	akcipher_prepare_alg(&inst->alg);
167	return crypto_register_instance(tmpl, akcipher_crypto_instance(inst));
168}
169EXPORT_SYMBOL_GPL(akcipher_register_instance);
170
171static int crypto_akcipher_sync_prep(struct crypto_akcipher_sync_data *data)
172{
173	unsigned int reqsize = crypto_akcipher_reqsize(data->tfm);
174	struct akcipher_request *req;
175	struct scatterlist *sg;
176	unsigned int mlen;
177	unsigned int len;
178	u8 *buf;
179
180	mlen = max(data->slen, data->dlen);
181
182	len = sizeof(*req) + reqsize + mlen;
183	if (len < mlen)
184		return -EOVERFLOW;
185
186	req = kzalloc(len, GFP_KERNEL);
187	if (!req)
188		return -ENOMEM;
189
190	data->req = req;
191	akcipher_request_set_tfm(req, data->tfm);
192
193	buf = (u8 *)(req + 1) + reqsize;
194	data->buf = buf;
195	memcpy(buf, data->src, data->slen);
196
197	sg = &data->sg;
198	sg_init_one(sg, buf, mlen);
199	akcipher_request_set_crypt(req, sg, sg, data->slen, data->dlen);
200
201	crypto_init_wait(&data->cwait);
202	akcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP,
203				      crypto_req_done, &data->cwait);
204
205	return 0;
206}
207
208static int crypto_akcipher_sync_post(struct crypto_akcipher_sync_data *data,
209				     int err)
210{
211	err = crypto_wait_req(err, &data->cwait);
212	memcpy(data->dst, data->buf, data->dlen);
213	data->dlen = data->req->dst_len;
214	kfree_sensitive(data->req);
215	return err;
216}
217
218int crypto_akcipher_sync_encrypt(struct crypto_akcipher *tfm,
219				 const void *src, unsigned int slen,
220				 void *dst, unsigned int dlen)
221{
222	struct crypto_akcipher_sync_data data = {
223		.tfm = tfm,
224		.src = src,
225		.dst = dst,
226		.slen = slen,
227		.dlen = dlen,
228	};
229
230	return crypto_akcipher_sync_prep(&data) ?:
231	       crypto_akcipher_sync_post(&data,
232					 crypto_akcipher_encrypt(data.req));
233}
234EXPORT_SYMBOL_GPL(crypto_akcipher_sync_encrypt);
235
236int crypto_akcipher_sync_decrypt(struct crypto_akcipher *tfm,
237				 const void *src, unsigned int slen,
238				 void *dst, unsigned int dlen)
239{
240	struct crypto_akcipher_sync_data data = {
241		.tfm = tfm,
242		.src = src,
243		.dst = dst,
244		.slen = slen,
245		.dlen = dlen,
246	};
247
248	return crypto_akcipher_sync_prep(&data) ?:
249	       crypto_akcipher_sync_post(&data,
250					 crypto_akcipher_decrypt(data.req)) ?:
251	       data.dlen;
252}
253EXPORT_SYMBOL_GPL(crypto_akcipher_sync_decrypt);
254
255MODULE_LICENSE("GPL");
256MODULE_DESCRIPTION("Generic public key cipher type");