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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");
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/fips.h>
9#include <linux/module.h>
10#include <linux/mpi.h>
11#include <crypto/internal/rsa.h>
12#include <crypto/internal/akcipher.h>
13#include <crypto/akcipher.h>
14#include <crypto/algapi.h>
15
16struct rsa_mpi_key {
17 MPI n;
18 MPI e;
19 MPI d;
20 MPI p;
21 MPI q;
22 MPI dp;
23 MPI dq;
24 MPI qinv;
25};
26
27static int rsa_check_payload(MPI x, MPI n)
28{
29 MPI n1;
30
31 if (mpi_cmp_ui(x, 1) <= 0)
32 return -EINVAL;
33
34 n1 = mpi_alloc(0);
35 if (!n1)
36 return -ENOMEM;
37
38 if (mpi_sub_ui(n1, n, 1) || mpi_cmp(x, n1) >= 0) {
39 mpi_free(n1);
40 return -EINVAL;
41 }
42
43 mpi_free(n1);
44 return 0;
45}
46
47/*
48 * RSAEP function [RFC3447 sec 5.1.1]
49 * c = m^e mod n;
50 */
51static int _rsa_enc(const struct rsa_mpi_key *key, MPI c, MPI m)
52{
53 /*
54 * Even though (1) in RFC3447 only requires 0 <= m <= n - 1, we are
55 * slightly more conservative and require 1 < m < n - 1. This is in line
56 * with SP 800-56Br2, Section 7.1.1.
57 */
58 if (rsa_check_payload(m, key->n))
59 return -EINVAL;
60
61 /* (2) c = m^e mod n */
62 return mpi_powm(c, m, key->e, key->n);
63}
64
65/*
66 * RSADP function [RFC3447 sec 5.1.2]
67 * m_1 = c^dP mod p;
68 * m_2 = c^dQ mod q;
69 * h = (m_1 - m_2) * qInv mod p;
70 * m = m_2 + q * h;
71 */
72static int _rsa_dec_crt(const struct rsa_mpi_key *key, MPI m_or_m1_or_h, MPI c)
73{
74 MPI m2, m12_or_qh;
75 int ret = -ENOMEM;
76
77 /*
78 * Even though (1) in RFC3447 only requires 0 <= c <= n - 1, we are
79 * slightly more conservative and require 1 < c < n - 1. This is in line
80 * with SP 800-56Br2, Section 7.1.2.
81 */
82 if (rsa_check_payload(c, key->n))
83 return -EINVAL;
84
85 m2 = mpi_alloc(0);
86 m12_or_qh = mpi_alloc(0);
87 if (!m2 || !m12_or_qh)
88 goto err_free_mpi;
89
90 /* (2i) m_1 = c^dP mod p */
91 ret = mpi_powm(m_or_m1_or_h, c, key->dp, key->p);
92 if (ret)
93 goto err_free_mpi;
94
95 /* (2i) m_2 = c^dQ mod q */
96 ret = mpi_powm(m2, c, key->dq, key->q);
97 if (ret)
98 goto err_free_mpi;
99
100 /* (2iii) h = (m_1 - m_2) * qInv mod p */
101 mpi_sub(m12_or_qh, m_or_m1_or_h, m2);
102 mpi_mulm(m_or_m1_or_h, m12_or_qh, key->qinv, key->p);
103
104 /* (2iv) m = m_2 + q * h */
105 mpi_mul(m12_or_qh, key->q, m_or_m1_or_h);
106 mpi_addm(m_or_m1_or_h, m2, m12_or_qh, key->n);
107
108 ret = 0;
109
110err_free_mpi:
111 mpi_free(m12_or_qh);
112 mpi_free(m2);
113 return ret;
114}
115
116static inline struct rsa_mpi_key *rsa_get_key(struct crypto_akcipher *tfm)
117{
118 return akcipher_tfm_ctx(tfm);
119}
120
121static int rsa_enc(struct akcipher_request *req)
122{
123 struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
124 const struct rsa_mpi_key *pkey = rsa_get_key(tfm);
125 MPI m, c = mpi_alloc(0);
126 int ret = 0;
127 int sign;
128
129 if (!c)
130 return -ENOMEM;
131
132 if (unlikely(!pkey->n || !pkey->e)) {
133 ret = -EINVAL;
134 goto err_free_c;
135 }
136
137 ret = -ENOMEM;
138 m = mpi_read_raw_from_sgl(req->src, req->src_len);
139 if (!m)
140 goto err_free_c;
141
142 ret = _rsa_enc(pkey, c, m);
143 if (ret)
144 goto err_free_m;
145
146 ret = mpi_write_to_sgl(c, req->dst, req->dst_len, &sign);
147 if (ret)
148 goto err_free_m;
149
150 if (sign < 0)
151 ret = -EBADMSG;
152
153err_free_m:
154 mpi_free(m);
155err_free_c:
156 mpi_free(c);
157 return ret;
158}
159
160static int rsa_dec(struct akcipher_request *req)
161{
162 struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
163 const struct rsa_mpi_key *pkey = rsa_get_key(tfm);
164 MPI c, m = mpi_alloc(0);
165 int ret = 0;
166 int sign;
167
168 if (!m)
169 return -ENOMEM;
170
171 if (unlikely(!pkey->n || !pkey->d)) {
172 ret = -EINVAL;
173 goto err_free_m;
174 }
175
176 ret = -ENOMEM;
177 c = mpi_read_raw_from_sgl(req->src, req->src_len);
178 if (!c)
179 goto err_free_m;
180
181 ret = _rsa_dec_crt(pkey, m, c);
182 if (ret)
183 goto err_free_c;
184
185 ret = mpi_write_to_sgl(m, req->dst, req->dst_len, &sign);
186 if (ret)
187 goto err_free_c;
188
189 if (sign < 0)
190 ret = -EBADMSG;
191err_free_c:
192 mpi_free(c);
193err_free_m:
194 mpi_free(m);
195 return ret;
196}
197
198static void rsa_free_mpi_key(struct rsa_mpi_key *key)
199{
200 mpi_free(key->d);
201 mpi_free(key->e);
202 mpi_free(key->n);
203 mpi_free(key->p);
204 mpi_free(key->q);
205 mpi_free(key->dp);
206 mpi_free(key->dq);
207 mpi_free(key->qinv);
208 key->d = NULL;
209 key->e = NULL;
210 key->n = NULL;
211 key->p = NULL;
212 key->q = NULL;
213 key->dp = NULL;
214 key->dq = NULL;
215 key->qinv = NULL;
216}
217
218static int rsa_check_key_length(unsigned int len)
219{
220 switch (len) {
221 case 512:
222 case 1024:
223 case 1536:
224 if (fips_enabled)
225 return -EINVAL;
226 fallthrough;
227 case 2048:
228 case 3072:
229 case 4096:
230 return 0;
231 }
232
233 return -EINVAL;
234}
235
236static int rsa_check_exponent_fips(MPI e)
237{
238 MPI e_max = NULL;
239
240 /* check if odd */
241 if (!mpi_test_bit(e, 0)) {
242 return -EINVAL;
243 }
244
245 /* check if 2^16 < e < 2^256. */
246 if (mpi_cmp_ui(e, 65536) <= 0) {
247 return -EINVAL;
248 }
249
250 e_max = mpi_alloc(0);
251 if (!e_max)
252 return -ENOMEM;
253 mpi_set_bit(e_max, 256);
254
255 if (mpi_cmp(e, e_max) >= 0) {
256 mpi_free(e_max);
257 return -EINVAL;
258 }
259
260 mpi_free(e_max);
261 return 0;
262}
263
264static int rsa_set_pub_key(struct crypto_akcipher *tfm, const void *key,
265 unsigned int keylen)
266{
267 struct rsa_mpi_key *mpi_key = akcipher_tfm_ctx(tfm);
268 struct rsa_key raw_key = {0};
269 int ret;
270
271 /* Free the old MPI key if any */
272 rsa_free_mpi_key(mpi_key);
273
274 ret = rsa_parse_pub_key(&raw_key, key, keylen);
275 if (ret)
276 return ret;
277
278 mpi_key->e = mpi_read_raw_data(raw_key.e, raw_key.e_sz);
279 if (!mpi_key->e)
280 goto err;
281
282 mpi_key->n = mpi_read_raw_data(raw_key.n, raw_key.n_sz);
283 if (!mpi_key->n)
284 goto err;
285
286 if (rsa_check_key_length(mpi_get_size(mpi_key->n) << 3)) {
287 rsa_free_mpi_key(mpi_key);
288 return -EINVAL;
289 }
290
291 if (fips_enabled && rsa_check_exponent_fips(mpi_key->e)) {
292 rsa_free_mpi_key(mpi_key);
293 return -EINVAL;
294 }
295
296 return 0;
297
298err:
299 rsa_free_mpi_key(mpi_key);
300 return -ENOMEM;
301}
302
303static int rsa_set_priv_key(struct crypto_akcipher *tfm, const void *key,
304 unsigned int keylen)
305{
306 struct rsa_mpi_key *mpi_key = akcipher_tfm_ctx(tfm);
307 struct rsa_key raw_key = {0};
308 int ret;
309
310 /* Free the old MPI key if any */
311 rsa_free_mpi_key(mpi_key);
312
313 ret = rsa_parse_priv_key(&raw_key, key, keylen);
314 if (ret)
315 return ret;
316
317 mpi_key->d = mpi_read_raw_data(raw_key.d, raw_key.d_sz);
318 if (!mpi_key->d)
319 goto err;
320
321 mpi_key->e = mpi_read_raw_data(raw_key.e, raw_key.e_sz);
322 if (!mpi_key->e)
323 goto err;
324
325 mpi_key->n = mpi_read_raw_data(raw_key.n, raw_key.n_sz);
326 if (!mpi_key->n)
327 goto err;
328
329 mpi_key->p = mpi_read_raw_data(raw_key.p, raw_key.p_sz);
330 if (!mpi_key->p)
331 goto err;
332
333 mpi_key->q = mpi_read_raw_data(raw_key.q, raw_key.q_sz);
334 if (!mpi_key->q)
335 goto err;
336
337 mpi_key->dp = mpi_read_raw_data(raw_key.dp, raw_key.dp_sz);
338 if (!mpi_key->dp)
339 goto err;
340
341 mpi_key->dq = mpi_read_raw_data(raw_key.dq, raw_key.dq_sz);
342 if (!mpi_key->dq)
343 goto err;
344
345 mpi_key->qinv = mpi_read_raw_data(raw_key.qinv, raw_key.qinv_sz);
346 if (!mpi_key->qinv)
347 goto err;
348
349 if (rsa_check_key_length(mpi_get_size(mpi_key->n) << 3)) {
350 rsa_free_mpi_key(mpi_key);
351 return -EINVAL;
352 }
353
354 if (fips_enabled && rsa_check_exponent_fips(mpi_key->e)) {
355 rsa_free_mpi_key(mpi_key);
356 return -EINVAL;
357 }
358
359 return 0;
360
361err:
362 rsa_free_mpi_key(mpi_key);
363 return -ENOMEM;
364}
365
366static unsigned int rsa_max_size(struct crypto_akcipher *tfm)
367{
368 struct rsa_mpi_key *pkey = akcipher_tfm_ctx(tfm);
369
370 return mpi_get_size(pkey->n);
371}
372
373static void rsa_exit_tfm(struct crypto_akcipher *tfm)
374{
375 struct rsa_mpi_key *pkey = akcipher_tfm_ctx(tfm);
376
377 rsa_free_mpi_key(pkey);
378}
379
380static struct akcipher_alg rsa = {
381 .encrypt = rsa_enc,
382 .decrypt = rsa_dec,
383 .set_priv_key = rsa_set_priv_key,
384 .set_pub_key = rsa_set_pub_key,
385 .max_size = rsa_max_size,
386 .exit = rsa_exit_tfm,
387 .base = {
388 .cra_name = "rsa",
389 .cra_driver_name = "rsa-generic",
390 .cra_priority = 100,
391 .cra_module = THIS_MODULE,
392 .cra_ctxsize = sizeof(struct rsa_mpi_key),
393 },
394};
395
396static int __init rsa_init(void)
397{
398 int err;
399
400 err = crypto_register_akcipher(&rsa);
401 if (err)
402 return err;
403
404 err = crypto_register_template(&rsa_pkcs1pad_tmpl);
405 if (err) {
406 crypto_unregister_akcipher(&rsa);
407 return err;
408 }
409
410 return 0;
411}
412
413static void __exit rsa_exit(void)
414{
415 crypto_unregister_template(&rsa_pkcs1pad_tmpl);
416 crypto_unregister_akcipher(&rsa);
417}
418
419subsys_initcall(rsa_init);
420module_exit(rsa_exit);
421MODULE_ALIAS_CRYPTO("rsa");
422MODULE_LICENSE("GPL");
423MODULE_DESCRIPTION("RSA generic algorithm");