1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
|
/*
* Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License").
* You may not use this file except in compliance with the License.
* A copy of the License is located at
*
* http://aws.amazon.com/apache2.0
*
* or in the "license" file accompanying this file. This file is distributed
* on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
* express or implied. See the License for the specific language governing
* permissions and limitations under the License.
*/
#include "crypto/s2n_rsa.h"
#include <openssl/evp.h>
#include <openssl/rsa.h>
#include <stdint.h>
#include "crypto/s2n_drbg.h"
#include "crypto/s2n_evp_signing.h"
#include "crypto/s2n_hash.h"
#include "crypto/s2n_pkey.h"
#include "crypto/s2n_rsa_signing.h"
#include "error/s2n_errno.h"
#include "stuffer/s2n_stuffer.h"
#include "utils/s2n_blob.h"
#include "utils/s2n_compiler.h"
#include "utils/s2n_random.h"
#include "utils/s2n_result.h"
#include "utils/s2n_safety.h"
RSA *s2n_unsafe_rsa_get_non_const(const struct s2n_rsa_key *rsa_key)
{
PTR_ENSURE_REF(rsa_key);
#ifdef S2N_DIAGNOSTICS_PUSH_SUPPORTED
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wcast-qual"
#endif
RSA *out_rsa_key = (RSA *) rsa_key->rsa;
#ifdef S2N_DIAGNOSTICS_POP_SUPPORTED
#pragma GCC diagnostic pop
#endif
return out_rsa_key;
}
static S2N_RESULT s2n_rsa_modulus_check(const RSA *rsa)
{
/* RSA was made opaque starting in Openssl 1.1.0 */
#if S2N_OPENSSL_VERSION_AT_LEAST(1, 1, 0)
const BIGNUM *n = NULL;
/* RSA still owns the memory for n */
RSA_get0_key(rsa, &n, NULL, NULL);
RESULT_ENSURE_REF(n);
#else
RESULT_ENSURE_REF(rsa->n);
#endif
return S2N_RESULT_OK;
}
static S2N_RESULT s2n_rsa_encrypted_size(const struct s2n_pkey *pkey, uint32_t *size_out)
{
RESULT_ENSURE_REF(pkey);
RESULT_ENSURE_REF(size_out);
const struct s2n_rsa_key *rsa_key = &pkey->key.rsa_key;
RESULT_ENSURE_REF(rsa_key->rsa);
RESULT_GUARD(s2n_rsa_modulus_check(rsa_key->rsa));
const int size = RSA_size(rsa_key->rsa);
RESULT_GUARD_POSIX(size);
*size_out = size;
return S2N_RESULT_OK;
}
static int s2n_rsa_sign(const struct s2n_pkey *priv, s2n_signature_algorithm sig_alg, struct s2n_hash_state *digest,
struct s2n_blob *signature)
{
switch (sig_alg) {
case S2N_SIGNATURE_RSA:
return s2n_rsa_pkcs1v15_sign(priv, digest, signature);
case S2N_SIGNATURE_RSA_PSS_RSAE:
return s2n_rsa_pss_sign(priv, digest, signature);
default:
POSIX_BAIL(S2N_ERR_INVALID_SIGNATURE_ALGORITHM);
}
return S2N_SUCCESS;
}
static int s2n_rsa_verify(const struct s2n_pkey *pub, s2n_signature_algorithm sig_alg, struct s2n_hash_state *digest,
struct s2n_blob *signature)
{
switch (sig_alg) {
case S2N_SIGNATURE_RSA:
return s2n_rsa_pkcs1v15_verify(pub, digest, signature);
case S2N_SIGNATURE_RSA_PSS_RSAE:
return s2n_rsa_pss_verify(pub, digest, signature);
default:
POSIX_BAIL(S2N_ERR_INVALID_SIGNATURE_ALGORITHM);
}
return S2N_SUCCESS;
}
static int s2n_rsa_encrypt(const struct s2n_pkey *pub, struct s2n_blob *in, struct s2n_blob *out)
{
uint32_t size = 0;
POSIX_GUARD_RESULT(s2n_rsa_encrypted_size(pub, &size));
S2N_ERROR_IF(out->size < size, S2N_ERR_NOMEM);
const s2n_rsa_public_key *pub_key = &pub->key.rsa_key;
/* Safety: RSA_public_encrypt does not mutate the key */
int r = RSA_public_encrypt(in->size, (unsigned char *) in->data, (unsigned char *) out->data,
s2n_unsafe_rsa_get_non_const(pub_key), RSA_PKCS1_PADDING);
POSIX_ENSURE((int64_t) r == (int64_t) out->size, S2N_ERR_SIZE_MISMATCH);
return 0;
}
static int s2n_rsa_decrypt(const struct s2n_pkey *priv, struct s2n_blob *in, struct s2n_blob *out)
{
unsigned char intermediate[4096];
uint32_t expected_size = 0;
POSIX_GUARD_RESULT(s2n_rsa_encrypted_size(priv, &expected_size));
S2N_ERROR_IF(expected_size > sizeof(intermediate), S2N_ERR_NOMEM);
S2N_ERROR_IF(out->size > sizeof(intermediate), S2N_ERR_NOMEM);
POSIX_GUARD_RESULT(s2n_get_public_random_data(out));
const s2n_rsa_private_key *priv_key = &priv->key.rsa_key;
/* Safety: RSA_private_decrypt does not mutate the key */
int r = RSA_private_decrypt(in->size, (unsigned char *) in->data, intermediate,
s2n_unsafe_rsa_get_non_const(priv_key), RSA_NO_PADDING);
POSIX_ENSURE((int64_t) r == (int64_t) expected_size, S2N_ERR_SIZE_MISMATCH);
s2n_constant_time_pkcs1_unpad_or_dont(out->data, intermediate, r, out->size);
return 0;
}
static int s2n_rsa_keys_match(const struct s2n_pkey *pub, const struct s2n_pkey *priv)
{
uint8_t plain_inpad[36] = { 1 }, plain_outpad[36] = { 0 }, encpad[8192];
struct s2n_blob plain_in = { 0 }, plain_out = { 0 }, enc = { 0 };
plain_in.data = plain_inpad;
plain_in.size = sizeof(plain_inpad);
enc.data = encpad;
POSIX_GUARD_RESULT(s2n_rsa_encrypted_size(pub, &enc.size));
POSIX_ENSURE_LTE(enc.size, sizeof(encpad));
POSIX_GUARD(s2n_rsa_encrypt(pub, &plain_in, &enc));
plain_out.data = plain_outpad;
plain_out.size = sizeof(plain_outpad);
POSIX_GUARD(s2n_rsa_decrypt(priv, &enc, &plain_out));
S2N_ERROR_IF(memcmp(plain_in.data, plain_out.data, plain_in.size), S2N_ERR_KEY_MISMATCH);
return 0;
}
static int s2n_rsa_key_free(struct s2n_pkey *pkey)
{
POSIX_ENSURE_REF(pkey);
struct s2n_rsa_key *rsa_key = &pkey->key.rsa_key;
if (rsa_key->rsa == NULL) {
return S2N_SUCCESS;
}
/* Safety: freeing the key owned by this object */
RSA_free(s2n_unsafe_rsa_get_non_const(rsa_key));
rsa_key->rsa = NULL;
return S2N_SUCCESS;
}
static int s2n_rsa_check_key_exists(const struct s2n_pkey *pkey)
{
const struct s2n_rsa_key *rsa_key = &pkey->key.rsa_key;
POSIX_ENSURE_REF(rsa_key->rsa);
return 0;
}
int s2n_evp_pkey_to_rsa_public_key(s2n_rsa_public_key *rsa_key, EVP_PKEY *evp_public_key)
{
const RSA *rsa = EVP_PKEY_get1_RSA(evp_public_key);
S2N_ERROR_IF(rsa == NULL, S2N_ERR_DECODE_CERTIFICATE);
rsa_key->rsa = rsa;
return 0;
}
int s2n_evp_pkey_to_rsa_private_key(s2n_rsa_private_key *rsa_key, EVP_PKEY *evp_private_key)
{
const RSA *rsa = EVP_PKEY_get1_RSA(evp_private_key);
S2N_ERROR_IF(rsa == NULL, S2N_ERR_DECODE_PRIVATE_KEY);
rsa_key->rsa = rsa;
return 0;
}
int s2n_rsa_pkey_init(struct s2n_pkey *pkey)
{
pkey->size = &s2n_rsa_encrypted_size;
pkey->sign = &s2n_rsa_sign;
pkey->verify = &s2n_rsa_verify;
pkey->encrypt = &s2n_rsa_encrypt;
pkey->decrypt = &s2n_rsa_decrypt;
pkey->match = &s2n_rsa_keys_match;
pkey->free = &s2n_rsa_key_free;
pkey->check_key = &s2n_rsa_check_key_exists;
POSIX_GUARD_RESULT(s2n_evp_signing_set_pkey_overrides(pkey));
return 0;
}
|
