xref: /openssl/crypto/ec/ecx_key.c (revision da1c088f)
1 /*
2  * Copyright 2020-2023 The OpenSSL Project Authors. All Rights Reserved.
3  *
4  * Licensed under the Apache License 2.0 (the "License").  You may not use
5  * this file except in compliance with the License.  You can obtain a copy
6  * in the file LICENSE in the source distribution or at
7  * https://www.openssl.org/source/license.html
8  */
9 
10 #include <string.h>
11 #include <openssl/err.h>
12 #include <openssl/proverr.h>
13 #include "crypto/ecx.h"
14 #include "internal/common.h" /* for ossl_assert() */
15 
16 #ifdef S390X_EC_ASM
17 # include "s390x_arch.h"
18 #endif
19 
ossl_ecx_key_new(OSSL_LIB_CTX * libctx,ECX_KEY_TYPE type,int haspubkey,const char * propq)20 ECX_KEY *ossl_ecx_key_new(OSSL_LIB_CTX *libctx, ECX_KEY_TYPE type, int haspubkey,
21                           const char *propq)
22 {
23     ECX_KEY *ret = OPENSSL_zalloc(sizeof(*ret));
24 
25     if (ret == NULL)
26         return NULL;
27 
28     ret->libctx = libctx;
29     ret->haspubkey = haspubkey;
30     switch (type) {
31     case ECX_KEY_TYPE_X25519:
32         ret->keylen = X25519_KEYLEN;
33         break;
34     case ECX_KEY_TYPE_X448:
35         ret->keylen = X448_KEYLEN;
36         break;
37     case ECX_KEY_TYPE_ED25519:
38         ret->keylen = ED25519_KEYLEN;
39         break;
40     case ECX_KEY_TYPE_ED448:
41         ret->keylen = ED448_KEYLEN;
42         break;
43     }
44     ret->type = type;
45 
46     if (!CRYPTO_NEW_REF(&ret->references, 1))
47         goto err;
48 
49     if (propq != NULL) {
50         ret->propq = OPENSSL_strdup(propq);
51         if (ret->propq == NULL)
52             goto err;
53     }
54     return ret;
55 err:
56     if (ret != NULL) {
57         OPENSSL_free(ret->propq);
58         CRYPTO_FREE_REF(&ret->references);
59     }
60     OPENSSL_free(ret);
61     return NULL;
62 }
63 
ossl_ecx_key_free(ECX_KEY * key)64 void ossl_ecx_key_free(ECX_KEY *key)
65 {
66     int i;
67 
68     if (key == NULL)
69         return;
70 
71     CRYPTO_DOWN_REF(&key->references, &i);
72     REF_PRINT_COUNT("ECX_KEY", key);
73     if (i > 0)
74         return;
75     REF_ASSERT_ISNT(i < 0);
76 
77     OPENSSL_free(key->propq);
78     OPENSSL_secure_clear_free(key->privkey, key->keylen);
79     CRYPTO_FREE_REF(&key->references);
80     OPENSSL_free(key);
81 }
82 
ossl_ecx_key_set0_libctx(ECX_KEY * key,OSSL_LIB_CTX * libctx)83 void ossl_ecx_key_set0_libctx(ECX_KEY *key, OSSL_LIB_CTX *libctx)
84 {
85     key->libctx = libctx;
86 }
87 
ossl_ecx_key_up_ref(ECX_KEY * key)88 int ossl_ecx_key_up_ref(ECX_KEY *key)
89 {
90     int i;
91 
92     if (CRYPTO_UP_REF(&key->references, &i) <= 0)
93         return 0;
94 
95     REF_PRINT_COUNT("ECX_KEY", key);
96     REF_ASSERT_ISNT(i < 2);
97     return ((i > 1) ? 1 : 0);
98 }
99 
ossl_ecx_key_allocate_privkey(ECX_KEY * key)100 unsigned char *ossl_ecx_key_allocate_privkey(ECX_KEY *key)
101 {
102     key->privkey = OPENSSL_secure_zalloc(key->keylen);
103 
104     return key->privkey;
105 }
106 
ossl_ecx_compute_key(ECX_KEY * peer,ECX_KEY * priv,size_t keylen,unsigned char * secret,size_t * secretlen,size_t outlen)107 int ossl_ecx_compute_key(ECX_KEY *peer, ECX_KEY *priv, size_t keylen,
108                          unsigned char *secret, size_t *secretlen, size_t outlen)
109 {
110     if (priv == NULL
111             || priv->privkey == NULL
112             || peer == NULL) {
113         ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_KEY);
114         return 0;
115     }
116 
117     if (!ossl_assert(keylen == X25519_KEYLEN
118             || keylen == X448_KEYLEN)) {
119         ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_KEY_LENGTH);
120         return 0;
121     }
122 
123     if (secret == NULL) {
124         *secretlen = keylen;
125         return 1;
126     }
127     if (outlen < keylen) {
128         ERR_raise(ERR_LIB_PROV, PROV_R_OUTPUT_BUFFER_TOO_SMALL);
129         return 0;
130     }
131 
132     if (keylen == X25519_KEYLEN) {
133 #ifdef S390X_EC_ASM
134         if (OPENSSL_s390xcap_P.pcc[1]
135                 & S390X_CAPBIT(S390X_SCALAR_MULTIPLY_X25519)) {
136             if (s390x_x25519_mul(secret, peer->pubkey, priv->privkey) == 0) {
137                 ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_DURING_DERIVATION);
138                 return 0;
139             }
140         } else
141 #endif
142         if (ossl_x25519(secret, priv->privkey, peer->pubkey) == 0) {
143             ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_DURING_DERIVATION);
144             return 0;
145         }
146     } else {
147 #ifdef S390X_EC_ASM
148         if (OPENSSL_s390xcap_P.pcc[1]
149                 & S390X_CAPBIT(S390X_SCALAR_MULTIPLY_X448)) {
150             if (s390x_x448_mul(secret, peer->pubkey, priv->privkey) == 0) {
151                 ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_DURING_DERIVATION);
152                 return 0;
153             }
154         } else
155 #endif
156         if (ossl_x448(secret, priv->privkey, peer->pubkey) == 0) {
157             ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_DURING_DERIVATION);
158             return 0;
159         }
160     }
161     *secretlen = keylen;
162     return 1;
163 }
164