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
|
/* copyright (c) 2022 - 2023 grunfink / MIT license */
#ifndef _XS_OPENSSL_H
#define _XS_OPENSSL_H
xs_str *_xs_digest(const xs_val *input, int size, const char *digest, int as_hex);
#define xs_md5_hex(input, size) _xs_digest(input, size, "md5", 1)
#define xs_sha1_hex(input, size) _xs_digest(input, size, "sha1", 1)
#define xs_sha256_hex(input, size) _xs_digest(input, size, "sha256", 1)
#define xs_sha256_base64(input, size) _xs_digest(input, size, "sha256", 0)
xs_dict *xs_evp_genkey(int bits);
xs_str *xs_evp_sign(const char *secret, const char *mem, int size);
int xs_evp_verify(const char *pubkey, const char *mem, int size, const char *b64sig);
#ifdef XS_IMPLEMENTATION
#include "openssl/rsa.h"
#include "openssl/pem.h"
#include "openssl/evp.h"
xs_str *_xs_digest(const xs_val *input, int size, const char *digest, int as_hex)
/* generic function for generating and encoding digests */
{
const EVP_MD *md;
if ((md = EVP_get_digestbyname(digest)) == NULL)
return NULL;
unsigned char output[1024];
unsigned int out_size;
EVP_MD_CTX *mdctx;
mdctx = EVP_MD_CTX_new();
EVP_DigestInit_ex(mdctx, md, NULL);
EVP_DigestUpdate(mdctx, input, size);
EVP_DigestFinal_ex(mdctx, output, &out_size);
EVP_MD_CTX_free(mdctx);
return as_hex ? xs_hex_enc ((char *)output, out_size) :
xs_base64_enc((char *)output, out_size);
}
xs_dict *xs_evp_genkey(int bits)
/* generates an RSA keypair using the EVP interface */
{
xs_dict *keypair = NULL;
EVP_PKEY_CTX *ctx;
EVP_PKEY *pkey = NULL;
if ((ctx = EVP_PKEY_CTX_new_id(EVP_PKEY_RSA, NULL)) == NULL)
goto end;
if (EVP_PKEY_keygen_init(ctx) <= 0 ||
EVP_PKEY_CTX_set_rsa_keygen_bits(ctx, bits) <= 0 ||
EVP_PKEY_keygen(ctx, &pkey) <= 0)
goto end;
BIO *bs = BIO_new(BIO_s_mem());
BIO *bp = BIO_new(BIO_s_mem());
BUF_MEM *sptr;
BUF_MEM *pptr;
PEM_write_bio_PrivateKey(bs, pkey, NULL, NULL, 0, 0, NULL);
BIO_get_mem_ptr(bs, &sptr);
PEM_write_bio_PUBKEY(bp, pkey);
BIO_get_mem_ptr(bp, &pptr);
keypair = xs_dict_new();
keypair = xs_dict_append(keypair, "secret", sptr->data);
keypair = xs_dict_append(keypair, "public", pptr->data);
BIO_free(bs);
BIO_free(bp);
end:
return keypair;
}
xs_str *xs_evp_sign(const char *secret, const char *mem, int size)
/* signs a memory block (secret is in PEM format) */
{
xs_str *signature = NULL;
BIO *b;
unsigned char *sig;
unsigned int sig_len;
EVP_PKEY *pkey;
EVP_MD_CTX *mdctx;
const EVP_MD *md;
/* un-PEM the key */
b = BIO_new_mem_buf(secret, strlen(secret));
pkey = PEM_read_bio_PrivateKey(b, NULL, NULL, NULL);
/* I've learnt all these magical incantations by watching
the Python module code and the OpenSSL manual pages */
/* Well, "learnt" may be an overstatement */
md = EVP_get_digestbyname("sha256");
mdctx = EVP_MD_CTX_new();
sig_len = EVP_PKEY_size(pkey);
sig = xs_realloc(NULL, sig_len);
EVP_SignInit(mdctx, md);
EVP_SignUpdate(mdctx, mem, size);
if (EVP_SignFinal(mdctx, sig, &sig_len, pkey) == 1)
signature = xs_base64_enc((char *)sig, sig_len);
EVP_MD_CTX_free(mdctx);
EVP_PKEY_free(pkey);
BIO_free(b);
xs_free(sig);
return signature;
}
int xs_evp_verify(const char *pubkey, const char *mem, int size, const char *b64sig)
/* verifies a base64 block, returns non-zero on ok */
{
int r = 0;
BIO *b;
EVP_PKEY *pkey;
EVP_MD_CTX *mdctx;
const EVP_MD *md;
/* un-PEM the key */
b = BIO_new_mem_buf(pubkey, strlen(pubkey));
pkey = PEM_read_bio_PUBKEY(b, NULL, NULL, NULL);
md = EVP_get_digestbyname("sha256");
mdctx = EVP_MD_CTX_new();
if (pkey != NULL) {
xs *sig = NULL;
int s_size;
/* de-base64 */
sig = xs_base64_dec(b64sig, &s_size);
if (sig != NULL) {
EVP_VerifyInit(mdctx, md);
EVP_VerifyUpdate(mdctx, mem, size);
r = EVP_VerifyFinal(mdctx, (unsigned char *)sig, s_size, pkey);
}
}
EVP_MD_CTX_free(mdctx);
EVP_PKEY_free(pkey);
BIO_free(b);
return r;
}
#endif /* XS_IMPLEMENTATION */
#endif /* _XS_OPENSSL_H */
|
