]>
git.ipfire.org Git - thirdparty/kernel/stable.git/blob - crypto/rsa.c
1 /* RSA asymmetric public-key algorithm [RFC3447]
3 * Copyright (c) 2015, Intel Corporation
4 * Authors: Tadeusz Struk <tadeusz.struk@intel.com>
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.
12 #include <linux/module.h>
13 #include <linux/mpi.h>
14 #include <crypto/internal/rsa.h>
15 #include <crypto/internal/akcipher.h>
16 #include <crypto/akcipher.h>
17 #include <crypto/algapi.h>
26 * RSAEP function [RFC3447 sec 5.1.1]
29 static int _rsa_enc(const struct rsa_mpi_key
*key
, MPI c
, MPI m
)
31 /* (1) Validate 0 <= m < n */
32 if (mpi_cmp_ui(m
, 0) < 0 || mpi_cmp(m
, key
->n
) >= 0)
35 /* (2) c = m^e mod n */
36 return mpi_powm(c
, m
, key
->e
, key
->n
);
40 * RSADP function [RFC3447 sec 5.1.2]
43 static int _rsa_dec(const struct rsa_mpi_key
*key
, MPI m
, MPI c
)
45 /* (1) Validate 0 <= c < n */
46 if (mpi_cmp_ui(c
, 0) < 0 || mpi_cmp(c
, key
->n
) >= 0)
49 /* (2) m = c^d mod n */
50 return mpi_powm(m
, c
, key
->d
, key
->n
);
53 static inline struct rsa_mpi_key
*rsa_get_key(struct crypto_akcipher
*tfm
)
55 return akcipher_tfm_ctx(tfm
);
58 static int rsa_enc(struct akcipher_request
*req
)
60 struct crypto_akcipher
*tfm
= crypto_akcipher_reqtfm(req
);
61 const struct rsa_mpi_key
*pkey
= rsa_get_key(tfm
);
62 MPI m
, c
= mpi_alloc(0);
69 if (unlikely(!pkey
->n
|| !pkey
->e
)) {
75 m
= mpi_read_raw_from_sgl(req
->src
, req
->src_len
);
79 ret
= _rsa_enc(pkey
, c
, m
);
83 ret
= mpi_write_to_sgl(c
, req
->dst
, req
->dst_len
, &sign
);
97 static int rsa_dec(struct akcipher_request
*req
)
99 struct crypto_akcipher
*tfm
= crypto_akcipher_reqtfm(req
);
100 const struct rsa_mpi_key
*pkey
= rsa_get_key(tfm
);
101 MPI c
, m
= mpi_alloc(0);
108 if (unlikely(!pkey
->n
|| !pkey
->d
)) {
114 c
= mpi_read_raw_from_sgl(req
->src
, req
->src_len
);
118 ret
= _rsa_dec(pkey
, m
, c
);
122 ret
= mpi_write_to_sgl(m
, req
->dst
, req
->dst_len
, &sign
);
135 static void rsa_free_mpi_key(struct rsa_mpi_key
*key
)
145 static int rsa_check_key_length(unsigned int len
)
160 static int rsa_set_pub_key(struct crypto_akcipher
*tfm
, const void *key
,
163 struct rsa_mpi_key
*mpi_key
= akcipher_tfm_ctx(tfm
);
164 struct rsa_key raw_key
= {0};
167 /* Free the old MPI key if any */
168 rsa_free_mpi_key(mpi_key
);
170 ret
= rsa_parse_pub_key(&raw_key
, key
, keylen
);
174 mpi_key
->e
= mpi_read_raw_data(raw_key
.e
, raw_key
.e_sz
);
178 mpi_key
->n
= mpi_read_raw_data(raw_key
.n
, raw_key
.n_sz
);
182 if (rsa_check_key_length(mpi_get_size(mpi_key
->n
) << 3)) {
183 rsa_free_mpi_key(mpi_key
);
190 rsa_free_mpi_key(mpi_key
);
194 static int rsa_set_priv_key(struct crypto_akcipher
*tfm
, const void *key
,
197 struct rsa_mpi_key
*mpi_key
= akcipher_tfm_ctx(tfm
);
198 struct rsa_key raw_key
= {0};
201 /* Free the old MPI key if any */
202 rsa_free_mpi_key(mpi_key
);
204 ret
= rsa_parse_priv_key(&raw_key
, key
, keylen
);
208 mpi_key
->d
= mpi_read_raw_data(raw_key
.d
, raw_key
.d_sz
);
212 mpi_key
->e
= mpi_read_raw_data(raw_key
.e
, raw_key
.e_sz
);
216 mpi_key
->n
= mpi_read_raw_data(raw_key
.n
, raw_key
.n_sz
);
220 if (rsa_check_key_length(mpi_get_size(mpi_key
->n
) << 3)) {
221 rsa_free_mpi_key(mpi_key
);
228 rsa_free_mpi_key(mpi_key
);
232 static unsigned int rsa_max_size(struct crypto_akcipher
*tfm
)
234 struct rsa_mpi_key
*pkey
= akcipher_tfm_ctx(tfm
);
236 return mpi_get_size(pkey
->n
);
239 static void rsa_exit_tfm(struct crypto_akcipher
*tfm
)
241 struct rsa_mpi_key
*pkey
= akcipher_tfm_ctx(tfm
);
243 rsa_free_mpi_key(pkey
);
246 static struct akcipher_alg rsa
= {
249 .set_priv_key
= rsa_set_priv_key
,
250 .set_pub_key
= rsa_set_pub_key
,
251 .max_size
= rsa_max_size
,
252 .exit
= rsa_exit_tfm
,
255 .cra_driver_name
= "rsa-generic",
257 .cra_module
= THIS_MODULE
,
258 .cra_ctxsize
= sizeof(struct rsa_mpi_key
),
262 static int rsa_init(void)
266 err
= crypto_register_akcipher(&rsa
);
270 err
= crypto_register_template(&rsa_pkcs1pad_tmpl
);
272 crypto_unregister_akcipher(&rsa
);
279 static void rsa_exit(void)
281 crypto_unregister_template(&rsa_pkcs1pad_tmpl
);
282 crypto_unregister_akcipher(&rsa
);
285 subsys_initcall(rsa_init
);
286 module_exit(rsa_exit
);
287 MODULE_ALIAS_CRYPTO("rsa");
288 MODULE_LICENSE("GPL");
289 MODULE_DESCRIPTION("RSA generic algorithm");