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b4d0d230 | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
cfc2bb32 TS |
2 | /* RSA asymmetric public-key algorithm [RFC3447] |
3 | * | |
4 | * Copyright (c) 2015, Intel Corporation | |
5 | * Authors: Tadeusz Struk <[email protected]> | |
cfc2bb32 TS |
6 | */ |
7 | ||
1ce1bacc | 8 | #include <linux/fips.h> |
cfc2bb32 | 9 | #include <linux/module.h> |
5a7de973 | 10 | #include <linux/mpi.h> |
cfc2bb32 TS |
11 | #include <crypto/internal/rsa.h> |
12 | #include <crypto/internal/akcipher.h> | |
13 | #include <crypto/akcipher.h> | |
3d5b1ecd | 14 | #include <crypto/algapi.h> |
cfc2bb32 | 15 | |
5a7de973 TA |
16 | struct rsa_mpi_key { |
17 | MPI n; | |
18 | MPI e; | |
19 | MPI d; | |
f145d411 IK |
20 | MPI p; |
21 | MPI q; | |
22 | MPI dp; | |
23 | MPI dq; | |
24 | MPI qinv; | |
5a7de973 TA |
25 | }; |
26 | ||
cfc2bb32 TS |
27 | /* |
28 | * RSAEP function [RFC3447 sec 5.1.1] | |
29 | * c = m^e mod n; | |
30 | */ | |
5a7de973 | 31 | static int _rsa_enc(const struct rsa_mpi_key *key, MPI c, MPI m) |
cfc2bb32 TS |
32 | { |
33 | /* (1) Validate 0 <= m < n */ | |
34 | if (mpi_cmp_ui(m, 0) < 0 || mpi_cmp(m, key->n) >= 0) | |
35 | return -EINVAL; | |
36 | ||
37 | /* (2) c = m^e mod n */ | |
38 | return mpi_powm(c, m, key->e, key->n); | |
39 | } | |
40 | ||
41 | /* | |
42 | * RSADP function [RFC3447 sec 5.1.2] | |
f145d411 IK |
43 | * m_1 = c^dP mod p; |
44 | * m_2 = c^dQ mod q; | |
45 | * h = (m_1 - m_2) * qInv mod p; | |
46 | * m = m_2 + q * h; | |
cfc2bb32 | 47 | */ |
f145d411 | 48 | static int _rsa_dec_crt(const struct rsa_mpi_key *key, MPI m_or_m1_or_h, MPI c) |
cfc2bb32 | 49 | { |
f145d411 IK |
50 | MPI m2, m12_or_qh; |
51 | int ret = -ENOMEM; | |
52 | ||
cfc2bb32 TS |
53 | /* (1) Validate 0 <= c < n */ |
54 | if (mpi_cmp_ui(c, 0) < 0 || mpi_cmp(c, key->n) >= 0) | |
55 | return -EINVAL; | |
56 | ||
f145d411 IK |
57 | m2 = mpi_alloc(0); |
58 | m12_or_qh = mpi_alloc(0); | |
59 | if (!m2 || !m12_or_qh) | |
60 | goto err_free_mpi; | |
61 | ||
62 | /* (2i) m_1 = c^dP mod p */ | |
63 | ret = mpi_powm(m_or_m1_or_h, c, key->dp, key->p); | |
64 | if (ret) | |
65 | goto err_free_mpi; | |
66 | ||
67 | /* (2i) m_2 = c^dQ mod q */ | |
68 | ret = mpi_powm(m2, c, key->dq, key->q); | |
69 | if (ret) | |
70 | goto err_free_mpi; | |
71 | ||
72 | /* (2iii) h = (m_1 - m_2) * qInv mod p */ | |
73 | mpi_sub(m12_or_qh, m_or_m1_or_h, m2); | |
74 | mpi_mulm(m_or_m1_or_h, m12_or_qh, key->qinv, key->p); | |
75 | ||
76 | /* (2iv) m = m_2 + q * h */ | |
77 | mpi_mul(m12_or_qh, key->q, m_or_m1_or_h); | |
78 | mpi_addm(m_or_m1_or_h, m2, m12_or_qh, key->n); | |
79 | ||
80 | ret = 0; | |
81 | ||
82 | err_free_mpi: | |
83 | mpi_free(m12_or_qh); | |
84 | mpi_free(m2); | |
85 | return ret; | |
cfc2bb32 TS |
86 | } |
87 | ||
5a7de973 | 88 | static inline struct rsa_mpi_key *rsa_get_key(struct crypto_akcipher *tfm) |
cfc2bb32 TS |
89 | { |
90 | return akcipher_tfm_ctx(tfm); | |
91 | } | |
92 | ||
93 | static int rsa_enc(struct akcipher_request *req) | |
94 | { | |
95 | struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req); | |
5a7de973 | 96 | const struct rsa_mpi_key *pkey = rsa_get_key(tfm); |
cfc2bb32 TS |
97 | MPI m, c = mpi_alloc(0); |
98 | int ret = 0; | |
99 | int sign; | |
100 | ||
101 | if (!c) | |
102 | return -ENOMEM; | |
103 | ||
104 | if (unlikely(!pkey->n || !pkey->e)) { | |
105 | ret = -EINVAL; | |
106 | goto err_free_c; | |
107 | } | |
108 | ||
22287b0b TS |
109 | ret = -ENOMEM; |
110 | m = mpi_read_raw_from_sgl(req->src, req->src_len); | |
111 | if (!m) | |
cfc2bb32 | 112 | goto err_free_c; |
cfc2bb32 TS |
113 | |
114 | ret = _rsa_enc(pkey, c, m); | |
115 | if (ret) | |
116 | goto err_free_m; | |
117 | ||
9b45b7bb | 118 | ret = mpi_write_to_sgl(c, req->dst, req->dst_len, &sign); |
cfc2bb32 TS |
119 | if (ret) |
120 | goto err_free_m; | |
121 | ||
22287b0b | 122 | if (sign < 0) |
cfc2bb32 | 123 | ret = -EBADMSG; |
cfc2bb32 TS |
124 | |
125 | err_free_m: | |
126 | mpi_free(m); | |
127 | err_free_c: | |
128 | mpi_free(c); | |
129 | return ret; | |
130 | } | |
131 | ||
132 | static int rsa_dec(struct akcipher_request *req) | |
133 | { | |
134 | struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req); | |
5a7de973 | 135 | const struct rsa_mpi_key *pkey = rsa_get_key(tfm); |
cfc2bb32 TS |
136 | MPI c, m = mpi_alloc(0); |
137 | int ret = 0; | |
138 | int sign; | |
139 | ||
140 | if (!m) | |
141 | return -ENOMEM; | |
142 | ||
143 | if (unlikely(!pkey->n || !pkey->d)) { | |
144 | ret = -EINVAL; | |
145 | goto err_free_m; | |
146 | } | |
147 | ||
22287b0b TS |
148 | ret = -ENOMEM; |
149 | c = mpi_read_raw_from_sgl(req->src, req->src_len); | |
150 | if (!c) | |
cfc2bb32 | 151 | goto err_free_m; |
cfc2bb32 | 152 | |
f145d411 | 153 | ret = _rsa_dec_crt(pkey, m, c); |
cfc2bb32 TS |
154 | if (ret) |
155 | goto err_free_c; | |
156 | ||
9b45b7bb | 157 | ret = mpi_write_to_sgl(m, req->dst, req->dst_len, &sign); |
cfc2bb32 TS |
158 | if (ret) |
159 | goto err_free_c; | |
160 | ||
22287b0b | 161 | if (sign < 0) |
cfc2bb32 | 162 | ret = -EBADMSG; |
cfc2bb32 TS |
163 | err_free_c: |
164 | mpi_free(c); | |
165 | err_free_m: | |
166 | mpi_free(m); | |
167 | return ret; | |
168 | } | |
169 | ||
5a7de973 TA |
170 | static void rsa_free_mpi_key(struct rsa_mpi_key *key) |
171 | { | |
172 | mpi_free(key->d); | |
173 | mpi_free(key->e); | |
174 | mpi_free(key->n); | |
f145d411 IK |
175 | mpi_free(key->p); |
176 | mpi_free(key->q); | |
177 | mpi_free(key->dp); | |
178 | mpi_free(key->dq); | |
179 | mpi_free(key->qinv); | |
5a7de973 TA |
180 | key->d = NULL; |
181 | key->e = NULL; | |
182 | key->n = NULL; | |
f145d411 IK |
183 | key->p = NULL; |
184 | key->q = NULL; | |
185 | key->dp = NULL; | |
186 | key->dq = NULL; | |
187 | key->qinv = NULL; | |
5a7de973 TA |
188 | } |
189 | ||
6e8ec66c TS |
190 | static int rsa_check_key_length(unsigned int len) |
191 | { | |
192 | switch (len) { | |
193 | case 512: | |
194 | case 1024: | |
195 | case 1536: | |
1ce1bacc SM |
196 | if (fips_enabled) |
197 | return -EINVAL; | |
198 | fallthrough; | |
6e8ec66c TS |
199 | case 2048: |
200 | case 3072: | |
201 | case 4096: | |
202 | return 0; | |
203 | } | |
204 | ||
205 | return -EINVAL; | |
206 | } | |
207 | ||
6637e11e MA |
208 | static int rsa_check_exponent_fips(MPI e) |
209 | { | |
210 | MPI e_max = NULL; | |
211 | ||
212 | /* check if odd */ | |
213 | if (!mpi_test_bit(e, 0)) { | |
214 | return -EINVAL; | |
215 | } | |
216 | ||
217 | /* check if 2^16 < e < 2^256. */ | |
218 | if (mpi_cmp_ui(e, 65536) <= 0) { | |
219 | return -EINVAL; | |
220 | } | |
221 | ||
222 | e_max = mpi_alloc(0); | |
223 | mpi_set_bit(e_max, 256); | |
224 | ||
225 | if (mpi_cmp(e, e_max) >= 0) { | |
226 | mpi_free(e_max); | |
227 | return -EINVAL; | |
228 | } | |
229 | ||
230 | mpi_free(e_max); | |
231 | return 0; | |
232 | } | |
233 | ||
22287b0b TS |
234 | static int rsa_set_pub_key(struct crypto_akcipher *tfm, const void *key, |
235 | unsigned int keylen) | |
cfc2bb32 | 236 | { |
5a7de973 TA |
237 | struct rsa_mpi_key *mpi_key = akcipher_tfm_ctx(tfm); |
238 | struct rsa_key raw_key = {0}; | |
6e8ec66c | 239 | int ret; |
cfc2bb32 | 240 | |
5a7de973 TA |
241 | /* Free the old MPI key if any */ |
242 | rsa_free_mpi_key(mpi_key); | |
243 | ||
244 | ret = rsa_parse_pub_key(&raw_key, key, keylen); | |
6e8ec66c TS |
245 | if (ret) |
246 | return ret; | |
247 | ||
5a7de973 TA |
248 | mpi_key->e = mpi_read_raw_data(raw_key.e, raw_key.e_sz); |
249 | if (!mpi_key->e) | |
250 | goto err; | |
251 | ||
252 | mpi_key->n = mpi_read_raw_data(raw_key.n, raw_key.n_sz); | |
253 | if (!mpi_key->n) | |
254 | goto err; | |
255 | ||
256 | if (rsa_check_key_length(mpi_get_size(mpi_key->n) << 3)) { | |
257 | rsa_free_mpi_key(mpi_key); | |
258 | return -EINVAL; | |
6e8ec66c | 259 | } |
5a7de973 | 260 | |
6637e11e MA |
261 | if (fips_enabled && rsa_check_exponent_fips(mpi_key->e)) { |
262 | rsa_free_mpi_key(mpi_key); | |
263 | return -EINVAL; | |
264 | } | |
265 | ||
5a7de973 TA |
266 | return 0; |
267 | ||
268 | err: | |
269 | rsa_free_mpi_key(mpi_key); | |
270 | return -ENOMEM; | |
cfc2bb32 TS |
271 | } |
272 | ||
22287b0b TS |
273 | static int rsa_set_priv_key(struct crypto_akcipher *tfm, const void *key, |
274 | unsigned int keylen) | |
275 | { | |
5a7de973 TA |
276 | struct rsa_mpi_key *mpi_key = akcipher_tfm_ctx(tfm); |
277 | struct rsa_key raw_key = {0}; | |
22287b0b TS |
278 | int ret; |
279 | ||
5a7de973 TA |
280 | /* Free the old MPI key if any */ |
281 | rsa_free_mpi_key(mpi_key); | |
282 | ||
283 | ret = rsa_parse_priv_key(&raw_key, key, keylen); | |
22287b0b TS |
284 | if (ret) |
285 | return ret; | |
286 | ||
5a7de973 TA |
287 | mpi_key->d = mpi_read_raw_data(raw_key.d, raw_key.d_sz); |
288 | if (!mpi_key->d) | |
289 | goto err; | |
290 | ||
291 | mpi_key->e = mpi_read_raw_data(raw_key.e, raw_key.e_sz); | |
292 | if (!mpi_key->e) | |
293 | goto err; | |
294 | ||
295 | mpi_key->n = mpi_read_raw_data(raw_key.n, raw_key.n_sz); | |
296 | if (!mpi_key->n) | |
297 | goto err; | |
298 | ||
f145d411 IK |
299 | mpi_key->p = mpi_read_raw_data(raw_key.p, raw_key.p_sz); |
300 | if (!mpi_key->p) | |
301 | goto err; | |
302 | ||
303 | mpi_key->q = mpi_read_raw_data(raw_key.q, raw_key.q_sz); | |
304 | if (!mpi_key->q) | |
305 | goto err; | |
306 | ||
307 | mpi_key->dp = mpi_read_raw_data(raw_key.dp, raw_key.dp_sz); | |
308 | if (!mpi_key->dp) | |
309 | goto err; | |
310 | ||
311 | mpi_key->dq = mpi_read_raw_data(raw_key.dq, raw_key.dq_sz); | |
312 | if (!mpi_key->dq) | |
313 | goto err; | |
314 | ||
315 | mpi_key->qinv = mpi_read_raw_data(raw_key.qinv, raw_key.qinv_sz); | |
316 | if (!mpi_key->qinv) | |
317 | goto err; | |
318 | ||
5a7de973 TA |
319 | if (rsa_check_key_length(mpi_get_size(mpi_key->n) << 3)) { |
320 | rsa_free_mpi_key(mpi_key); | |
321 | return -EINVAL; | |
22287b0b | 322 | } |
5a7de973 | 323 | |
6637e11e MA |
324 | if (fips_enabled && rsa_check_exponent_fips(mpi_key->e)) { |
325 | rsa_free_mpi_key(mpi_key); | |
326 | return -EINVAL; | |
327 | } | |
328 | ||
5a7de973 TA |
329 | return 0; |
330 | ||
331 | err: | |
332 | rsa_free_mpi_key(mpi_key); | |
333 | return -ENOMEM; | |
22287b0b TS |
334 | } |
335 | ||
1c23b466 | 336 | static unsigned int rsa_max_size(struct crypto_akcipher *tfm) |
22287b0b | 337 | { |
5a7de973 | 338 | struct rsa_mpi_key *pkey = akcipher_tfm_ctx(tfm); |
22287b0b | 339 | |
1c23b466 | 340 | return mpi_get_size(pkey->n); |
22287b0b TS |
341 | } |
342 | ||
cfc2bb32 TS |
343 | static void rsa_exit_tfm(struct crypto_akcipher *tfm) |
344 | { | |
5a7de973 | 345 | struct rsa_mpi_key *pkey = akcipher_tfm_ctx(tfm); |
cfc2bb32 | 346 | |
5a7de973 | 347 | rsa_free_mpi_key(pkey); |
cfc2bb32 TS |
348 | } |
349 | ||
350 | static struct akcipher_alg rsa = { | |
351 | .encrypt = rsa_enc, | |
352 | .decrypt = rsa_dec, | |
22287b0b TS |
353 | .set_priv_key = rsa_set_priv_key, |
354 | .set_pub_key = rsa_set_pub_key, | |
355 | .max_size = rsa_max_size, | |
cfc2bb32 TS |
356 | .exit = rsa_exit_tfm, |
357 | .base = { | |
358 | .cra_name = "rsa", | |
359 | .cra_driver_name = "rsa-generic", | |
360 | .cra_priority = 100, | |
361 | .cra_module = THIS_MODULE, | |
5a7de973 | 362 | .cra_ctxsize = sizeof(struct rsa_mpi_key), |
cfc2bb32 TS |
363 | }, |
364 | }; | |
365 | ||
33837be3 | 366 | static int __init rsa_init(void) |
cfc2bb32 | 367 | { |
3d5b1ecd AZ |
368 | int err; |
369 | ||
370 | err = crypto_register_akcipher(&rsa); | |
371 | if (err) | |
372 | return err; | |
373 | ||
374 | err = crypto_register_template(&rsa_pkcs1pad_tmpl); | |
375 | if (err) { | |
376 | crypto_unregister_akcipher(&rsa); | |
377 | return err; | |
378 | } | |
379 | ||
380 | return 0; | |
cfc2bb32 TS |
381 | } |
382 | ||
33837be3 | 383 | static void __exit rsa_exit(void) |
cfc2bb32 | 384 | { |
3d5b1ecd | 385 | crypto_unregister_template(&rsa_pkcs1pad_tmpl); |
cfc2bb32 TS |
386 | crypto_unregister_akcipher(&rsa); |
387 | } | |
388 | ||
c4741b23 | 389 | subsys_initcall(rsa_init); |
cfc2bb32 TS |
390 | module_exit(rsa_exit); |
391 | MODULE_ALIAS_CRYPTO("rsa"); | |
392 | MODULE_LICENSE("GPL"); | |
393 | MODULE_DESCRIPTION("RSA generic algorithm"); |