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1// SPDX-License-Identifier: GPL-2.0-or-later
2/* RSA asymmetric public-key algorithm [RFC3447]
3 *
4 * Copyright (c) 2015, Intel Corporation
5 * Authors: Tadeusz Struk <tadeusz.struk@intel.com>
6 */
7
8#include <linux/module.h>
9#include <linux/mpi.h>
10#include <crypto/internal/rsa.h>
11#include <crypto/internal/akcipher.h>
12#include <crypto/akcipher.h>
13#include <crypto/algapi.h>
14
15struct rsa_mpi_key {
16 MPI n;
17 MPI e;
18 MPI d;
19};
20
21/*
22 * RSAEP function [RFC3447 sec 5.1.1]
23 * c = m^e mod n;
24 */
25static int _rsa_enc(const struct rsa_mpi_key *key, MPI c, MPI m)
26{
27 /* (1) Validate 0 <= m < n */
28 if (mpi_cmp_ui(m, 0) < 0 || mpi_cmp(m, key->n) >= 0)
29 return -EINVAL;
30
31 /* (2) c = m^e mod n */
32 return mpi_powm(c, m, key->e, key->n);
33}
34
35/*
36 * RSADP function [RFC3447 sec 5.1.2]
37 * m = c^d mod n;
38 */
39static int _rsa_dec(const struct rsa_mpi_key *key, MPI m, MPI c)
40{
41 /* (1) Validate 0 <= c < n */
42 if (mpi_cmp_ui(c, 0) < 0 || mpi_cmp(c, key->n) >= 0)
43 return -EINVAL;
44
45 /* (2) m = c^d mod n */
46 return mpi_powm(m, c, key->d, key->n);
47}
48
49static inline struct rsa_mpi_key *rsa_get_key(struct crypto_akcipher *tfm)
50{
51 return akcipher_tfm_ctx(tfm);
52}
53
54static int rsa_enc(struct akcipher_request *req)
55{
56 struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
57 const struct rsa_mpi_key *pkey = rsa_get_key(tfm);
58 MPI m, c = mpi_alloc(0);
59 int ret = 0;
60 int sign;
61
62 if (!c)
63 return -ENOMEM;
64
65 if (unlikely(!pkey->n || !pkey->e)) {
66 ret = -EINVAL;
67 goto err_free_c;
68 }
69
70 ret = -ENOMEM;
71 m = mpi_read_raw_from_sgl(req->src, req->src_len);
72 if (!m)
73 goto err_free_c;
74
75 ret = _rsa_enc(pkey, c, m);
76 if (ret)
77 goto err_free_m;
78
79 ret = mpi_write_to_sgl(c, req->dst, req->dst_len, &sign);
80 if (ret)
81 goto err_free_m;
82
83 if (sign < 0)
84 ret = -EBADMSG;
85
86err_free_m:
87 mpi_free(m);
88err_free_c:
89 mpi_free(c);
90 return ret;
91}
92
93static int rsa_dec(struct akcipher_request *req)
94{
95 struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
96 const struct rsa_mpi_key *pkey = rsa_get_key(tfm);
97 MPI c, m = mpi_alloc(0);
98 int ret = 0;
99 int sign;
100
101 if (!m)
102 return -ENOMEM;
103
104 if (unlikely(!pkey->n || !pkey->d)) {
105 ret = -EINVAL;
106 goto err_free_m;
107 }
108
109 ret = -ENOMEM;
110 c = mpi_read_raw_from_sgl(req->src, req->src_len);
111 if (!c)
112 goto err_free_m;
113
114 ret = _rsa_dec(pkey, m, c);
115 if (ret)
116 goto err_free_c;
117
118 ret = mpi_write_to_sgl(m, req->dst, req->dst_len, &sign);
119 if (ret)
120 goto err_free_c;
121
122 if (sign < 0)
123 ret = -EBADMSG;
124err_free_c:
125 mpi_free(c);
126err_free_m:
127 mpi_free(m);
128 return ret;
129}
130
131static void rsa_free_mpi_key(struct rsa_mpi_key *key)
132{
133 mpi_free(key->d);
134 mpi_free(key->e);
135 mpi_free(key->n);
136 key->d = NULL;
137 key->e = NULL;
138 key->n = NULL;
139}
140
141static int rsa_check_key_length(unsigned int len)
142{
143 switch (len) {
144 case 512:
145 case 1024:
146 case 1536:
147 case 2048:
148 case 3072:
149 case 4096:
150 return 0;
151 }
152
153 return -EINVAL;
154}
155
156static int rsa_set_pub_key(struct crypto_akcipher *tfm, const void *key,
157 unsigned int keylen)
158{
159 struct rsa_mpi_key *mpi_key = akcipher_tfm_ctx(tfm);
160 struct rsa_key raw_key = {0};
161 int ret;
162
163 /* Free the old MPI key if any */
164 rsa_free_mpi_key(mpi_key);
165
166 ret = rsa_parse_pub_key(&raw_key, key, keylen);
167 if (ret)
168 return ret;
169
170 mpi_key->e = mpi_read_raw_data(raw_key.e, raw_key.e_sz);
171 if (!mpi_key->e)
172 goto err;
173
174 mpi_key->n = mpi_read_raw_data(raw_key.n, raw_key.n_sz);
175 if (!mpi_key->n)
176 goto err;
177
178 if (rsa_check_key_length(mpi_get_size(mpi_key->n) << 3)) {
179 rsa_free_mpi_key(mpi_key);
180 return -EINVAL;
181 }
182
183 return 0;
184
185err:
186 rsa_free_mpi_key(mpi_key);
187 return -ENOMEM;
188}
189
190static int rsa_set_priv_key(struct crypto_akcipher *tfm, const void *key,
191 unsigned int keylen)
192{
193 struct rsa_mpi_key *mpi_key = akcipher_tfm_ctx(tfm);
194 struct rsa_key raw_key = {0};
195 int ret;
196
197 /* Free the old MPI key if any */
198 rsa_free_mpi_key(mpi_key);
199
200 ret = rsa_parse_priv_key(&raw_key, key, keylen);
201 if (ret)
202 return ret;
203
204 mpi_key->d = mpi_read_raw_data(raw_key.d, raw_key.d_sz);
205 if (!mpi_key->d)
206 goto err;
207
208 mpi_key->e = mpi_read_raw_data(raw_key.e, raw_key.e_sz);
209 if (!mpi_key->e)
210 goto err;
211
212 mpi_key->n = mpi_read_raw_data(raw_key.n, raw_key.n_sz);
213 if (!mpi_key->n)
214 goto err;
215
216 if (rsa_check_key_length(mpi_get_size(mpi_key->n) << 3)) {
217 rsa_free_mpi_key(mpi_key);
218 return -EINVAL;
219 }
220
221 return 0;
222
223err:
224 rsa_free_mpi_key(mpi_key);
225 return -ENOMEM;
226}
227
228static unsigned int rsa_max_size(struct crypto_akcipher *tfm)
229{
230 struct rsa_mpi_key *pkey = akcipher_tfm_ctx(tfm);
231
232 return mpi_get_size(pkey->n);
233}
234
235static void rsa_exit_tfm(struct crypto_akcipher *tfm)
236{
237 struct rsa_mpi_key *pkey = akcipher_tfm_ctx(tfm);
238
239 rsa_free_mpi_key(pkey);
240}
241
242static struct akcipher_alg rsa = {
243 .encrypt = rsa_enc,
244 .decrypt = rsa_dec,
245 .set_priv_key = rsa_set_priv_key,
246 .set_pub_key = rsa_set_pub_key,
247 .max_size = rsa_max_size,
248 .exit = rsa_exit_tfm,
249 .base = {
250 .cra_name = "rsa",
251 .cra_driver_name = "rsa-generic",
252 .cra_priority = 100,
253 .cra_module = THIS_MODULE,
254 .cra_ctxsize = sizeof(struct rsa_mpi_key),
255 },
256};
257
258static int rsa_init(void)
259{
260 int err;
261
262 err = crypto_register_akcipher(&rsa);
263 if (err)
264 return err;
265
266 err = crypto_register_template(&rsa_pkcs1pad_tmpl);
267 if (err) {
268 crypto_unregister_akcipher(&rsa);
269 return err;
270 }
271
272 return 0;
273}
274
275static void rsa_exit(void)
276{
277 crypto_unregister_template(&rsa_pkcs1pad_tmpl);
278 crypto_unregister_akcipher(&rsa);
279}
280
281subsys_initcall(rsa_init);
282module_exit(rsa_exit);
283MODULE_ALIAS_CRYPTO("rsa");
284MODULE_LICENSE("GPL");
285MODULE_DESCRIPTION("RSA generic algorithm");
1/* RSA asymmetric public-key algorithm [RFC3447]
2 *
3 * Copyright (c) 2015, Intel Corporation
4 * Authors: Tadeusz Struk <tadeusz.struk@intel.com>
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public Licence
8 * as published by the Free Software Foundation; either version
9 * 2 of the Licence, or (at your option) any later version.
10 */
11
12#include <linux/module.h>
13#include <crypto/internal/rsa.h>
14#include <crypto/internal/akcipher.h>
15#include <crypto/akcipher.h>
16#include <crypto/algapi.h>
17
18/*
19 * RSAEP function [RFC3447 sec 5.1.1]
20 * c = m^e mod n;
21 */
22static int _rsa_enc(const struct rsa_key *key, MPI c, MPI m)
23{
24 /* (1) Validate 0 <= m < n */
25 if (mpi_cmp_ui(m, 0) < 0 || mpi_cmp(m, key->n) >= 0)
26 return -EINVAL;
27
28 /* (2) c = m^e mod n */
29 return mpi_powm(c, m, key->e, key->n);
30}
31
32/*
33 * RSADP function [RFC3447 sec 5.1.2]
34 * m = c^d mod n;
35 */
36static int _rsa_dec(const struct rsa_key *key, MPI m, MPI c)
37{
38 /* (1) Validate 0 <= c < n */
39 if (mpi_cmp_ui(c, 0) < 0 || mpi_cmp(c, key->n) >= 0)
40 return -EINVAL;
41
42 /* (2) m = c^d mod n */
43 return mpi_powm(m, c, key->d, key->n);
44}
45
46/*
47 * RSASP1 function [RFC3447 sec 5.2.1]
48 * s = m^d mod n
49 */
50static int _rsa_sign(const struct rsa_key *key, MPI s, MPI m)
51{
52 /* (1) Validate 0 <= m < n */
53 if (mpi_cmp_ui(m, 0) < 0 || mpi_cmp(m, key->n) >= 0)
54 return -EINVAL;
55
56 /* (2) s = m^d mod n */
57 return mpi_powm(s, m, key->d, key->n);
58}
59
60/*
61 * RSAVP1 function [RFC3447 sec 5.2.2]
62 * m = s^e mod n;
63 */
64static int _rsa_verify(const struct rsa_key *key, MPI m, MPI s)
65{
66 /* (1) Validate 0 <= s < n */
67 if (mpi_cmp_ui(s, 0) < 0 || mpi_cmp(s, key->n) >= 0)
68 return -EINVAL;
69
70 /* (2) m = s^e mod n */
71 return mpi_powm(m, s, key->e, key->n);
72}
73
74static inline struct rsa_key *rsa_get_key(struct crypto_akcipher *tfm)
75{
76 return akcipher_tfm_ctx(tfm);
77}
78
79static int rsa_enc(struct akcipher_request *req)
80{
81 struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
82 const struct rsa_key *pkey = rsa_get_key(tfm);
83 MPI m, c = mpi_alloc(0);
84 int ret = 0;
85 int sign;
86
87 if (!c)
88 return -ENOMEM;
89
90 if (unlikely(!pkey->n || !pkey->e)) {
91 ret = -EINVAL;
92 goto err_free_c;
93 }
94
95 ret = -ENOMEM;
96 m = mpi_read_raw_from_sgl(req->src, req->src_len);
97 if (!m)
98 goto err_free_c;
99
100 ret = _rsa_enc(pkey, c, m);
101 if (ret)
102 goto err_free_m;
103
104 ret = mpi_write_to_sgl(c, req->dst, &req->dst_len, &sign);
105 if (ret)
106 goto err_free_m;
107
108 if (sign < 0)
109 ret = -EBADMSG;
110
111err_free_m:
112 mpi_free(m);
113err_free_c:
114 mpi_free(c);
115 return ret;
116}
117
118static int rsa_dec(struct akcipher_request *req)
119{
120 struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
121 const struct rsa_key *pkey = rsa_get_key(tfm);
122 MPI c, m = mpi_alloc(0);
123 int ret = 0;
124 int sign;
125
126 if (!m)
127 return -ENOMEM;
128
129 if (unlikely(!pkey->n || !pkey->d)) {
130 ret = -EINVAL;
131 goto err_free_m;
132 }
133
134 ret = -ENOMEM;
135 c = mpi_read_raw_from_sgl(req->src, req->src_len);
136 if (!c)
137 goto err_free_m;
138
139 ret = _rsa_dec(pkey, m, c);
140 if (ret)
141 goto err_free_c;
142
143 ret = mpi_write_to_sgl(m, req->dst, &req->dst_len, &sign);
144 if (ret)
145 goto err_free_c;
146
147 if (sign < 0)
148 ret = -EBADMSG;
149err_free_c:
150 mpi_free(c);
151err_free_m:
152 mpi_free(m);
153 return ret;
154}
155
156static int rsa_sign(struct akcipher_request *req)
157{
158 struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
159 const struct rsa_key *pkey = rsa_get_key(tfm);
160 MPI m, s = mpi_alloc(0);
161 int ret = 0;
162 int sign;
163
164 if (!s)
165 return -ENOMEM;
166
167 if (unlikely(!pkey->n || !pkey->d)) {
168 ret = -EINVAL;
169 goto err_free_s;
170 }
171
172 ret = -ENOMEM;
173 m = mpi_read_raw_from_sgl(req->src, req->src_len);
174 if (!m)
175 goto err_free_s;
176
177 ret = _rsa_sign(pkey, s, m);
178 if (ret)
179 goto err_free_m;
180
181 ret = mpi_write_to_sgl(s, req->dst, &req->dst_len, &sign);
182 if (ret)
183 goto err_free_m;
184
185 if (sign < 0)
186 ret = -EBADMSG;
187
188err_free_m:
189 mpi_free(m);
190err_free_s:
191 mpi_free(s);
192 return ret;
193}
194
195static int rsa_verify(struct akcipher_request *req)
196{
197 struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
198 const struct rsa_key *pkey = rsa_get_key(tfm);
199 MPI s, m = mpi_alloc(0);
200 int ret = 0;
201 int sign;
202
203 if (!m)
204 return -ENOMEM;
205
206 if (unlikely(!pkey->n || !pkey->e)) {
207 ret = -EINVAL;
208 goto err_free_m;
209 }
210
211 ret = -ENOMEM;
212 s = mpi_read_raw_from_sgl(req->src, req->src_len);
213 if (!s) {
214 ret = -ENOMEM;
215 goto err_free_m;
216 }
217
218 ret = _rsa_verify(pkey, m, s);
219 if (ret)
220 goto err_free_s;
221
222 ret = mpi_write_to_sgl(m, req->dst, &req->dst_len, &sign);
223 if (ret)
224 goto err_free_s;
225
226 if (sign < 0)
227 ret = -EBADMSG;
228
229err_free_s:
230 mpi_free(s);
231err_free_m:
232 mpi_free(m);
233 return ret;
234}
235
236static int rsa_check_key_length(unsigned int len)
237{
238 switch (len) {
239 case 512:
240 case 1024:
241 case 1536:
242 case 2048:
243 case 3072:
244 case 4096:
245 return 0;
246 }
247
248 return -EINVAL;
249}
250
251static int rsa_set_pub_key(struct crypto_akcipher *tfm, const void *key,
252 unsigned int keylen)
253{
254 struct rsa_key *pkey = akcipher_tfm_ctx(tfm);
255 int ret;
256
257 ret = rsa_parse_pub_key(pkey, key, keylen);
258 if (ret)
259 return ret;
260
261 if (rsa_check_key_length(mpi_get_size(pkey->n) << 3)) {
262 rsa_free_key(pkey);
263 ret = -EINVAL;
264 }
265 return ret;
266}
267
268static int rsa_set_priv_key(struct crypto_akcipher *tfm, const void *key,
269 unsigned int keylen)
270{
271 struct rsa_key *pkey = akcipher_tfm_ctx(tfm);
272 int ret;
273
274 ret = rsa_parse_priv_key(pkey, key, keylen);
275 if (ret)
276 return ret;
277
278 if (rsa_check_key_length(mpi_get_size(pkey->n) << 3)) {
279 rsa_free_key(pkey);
280 ret = -EINVAL;
281 }
282 return ret;
283}
284
285static int rsa_max_size(struct crypto_akcipher *tfm)
286{
287 struct rsa_key *pkey = akcipher_tfm_ctx(tfm);
288
289 return pkey->n ? mpi_get_size(pkey->n) : -EINVAL;
290}
291
292static void rsa_exit_tfm(struct crypto_akcipher *tfm)
293{
294 struct rsa_key *pkey = akcipher_tfm_ctx(tfm);
295
296 rsa_free_key(pkey);
297}
298
299static struct akcipher_alg rsa = {
300 .encrypt = rsa_enc,
301 .decrypt = rsa_dec,
302 .sign = rsa_sign,
303 .verify = rsa_verify,
304 .set_priv_key = rsa_set_priv_key,
305 .set_pub_key = rsa_set_pub_key,
306 .max_size = rsa_max_size,
307 .exit = rsa_exit_tfm,
308 .base = {
309 .cra_name = "rsa",
310 .cra_driver_name = "rsa-generic",
311 .cra_priority = 100,
312 .cra_module = THIS_MODULE,
313 .cra_ctxsize = sizeof(struct rsa_key),
314 },
315};
316
317static int rsa_init(void)
318{
319 int err;
320
321 err = crypto_register_akcipher(&rsa);
322 if (err)
323 return err;
324
325 err = crypto_register_template(&rsa_pkcs1pad_tmpl);
326 if (err) {
327 crypto_unregister_akcipher(&rsa);
328 return err;
329 }
330
331 return 0;
332}
333
334static void rsa_exit(void)
335{
336 crypto_unregister_template(&rsa_pkcs1pad_tmpl);
337 crypto_unregister_akcipher(&rsa);
338}
339
340module_init(rsa_init);
341module_exit(rsa_exit);
342MODULE_ALIAS_CRYPTO("rsa");
343MODULE_LICENSE("GPL");
344MODULE_DESCRIPTION("RSA generic algorithm");