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
|
/* Simple S/MIME verification example */
#include <openssl/pem.h>
#include <openssl/pkcs7.h>
#include <openssl/err.h>
int main(int argc, char **argv)
{
BIO *in = NULL, *out = NULL, *tbio = NULL, *cont = NULL;
X509_STORE *st = NULL;
X509 *cacert = NULL;
PKCS7 *p7 = NULL;
int ret = 1;
OpenSSL_add_all_algorithms();
ERR_load_crypto_strings();
/* Set up trusted CA certificate store */
st = X509_STORE_new();
/* Read in signer certificate and private key */
tbio = BIO_new_file("cacert.pem", "r");
if (!tbio)
goto err;
cacert = PEM_read_bio_X509(tbio, NULL, 0, NULL);
if (!cacert)
goto err;
if (!X509_STORE_add_cert(st, cacert))
goto err;
/* Open content being signed */
in = BIO_new_file("smout.txt", "r");
if (!in)
goto err;
/* Sign content */
p7 = SMIME_read_PKCS7(in, &cont);
if (!p7)
goto err;
/* File to output verified content to */
out = BIO_new_file("smver.txt", "w");
if (!out)
goto err;
if (!PKCS7_verify(p7, NULL, st, cont, out, 0))
{
fprintf(stderr, "Verification Failure\n");
goto err;
}
fprintf(stderr, "Verification Successful\n");
ret = 0;
err:
if (ret)
{
fprintf(stderr, "Error Verifying Data\n");
ERR_print_errors_fp(stderr);
}
if (p7)
PKCS7_free(p7);
if (cacert)
X509_free(cacert);
if (in)
BIO_free(in);
if (out)
BIO_free(out);
if (tbio)
BIO_free(tbio);
return ret;
}
|
