Problem - Kevin Tafuro

if (!fgets(answer, sizeof(answer), stdin)) continue;
if (answer[0] = = 'r' || answer[0] = = 'R') return 0;
if (answer[0] = = 'o' || answer[0] = = 'O') return 1;
if (answer[0] = = 'a' || answer[0] = = 'A') break;
}
ssl_ptr = (SSL *)X509_STORE_CTX_get_app_data(store);
ctx = SSL_get_SSL_CTX(ssl_ptr);
spc_store = (spc_x509store_t *)SSL_CTX_get_app_data(ctx);
if (!spc_store->capath || !spc_remember_cert(spc_store->capath, cert))
printf("Error remembering certificate! It will be accepted this one time "
"only.\n");
return 1;
}
For keys, we will store the base64-encoded key in a flat file, much as OpenSSH does.
We will also associate the IP address of the server that presented the key so that we
can determine when the server’s key has changed and warn the user. When we
receive a key that we’d like to check to see whether we already know about it, we can
call spc_lookup_key( ) with the filename of the key store, the IP number we received
the key from, and the key we’ve just received. If we do not know anything about the
key or if some kind of error occurs, 0 is returned. If we know about the key, and
everything matches—that is, the IP numbers and the keys are the same—1 is
returned. If we have a key stored for the IP number and it does not match the key we
have just received, –1 is returned.
If you have multiple servers running on the same system, you need to
make sure that they each keep separate caches so that the keys and IP
numbers do not collide.
#include
#include
#include
#include
#include
#include
#include
static int get_keydata(EVP_PKEY *key, char **keydata) {
BIO *b64 = 0, *bio = 0;
int keytype, length;
char *dummy;
*keydata = 0;
keytype = EVP_PKEY_type(key->type);
if (!(length = i2d_PublicKey(key, 0))) goto error_exit;
if (!(dummy = *keydata = (char *)malloc(length))) goto error_exit;
i2d_PublicKey(key, (unsigned char **)&dummy);
Minimizing the Window of Vulnerability When Authenticating Without a PKI | 441
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