I am having a problem about verifying a certificate against the CRL that was created by the same CA that created the certificate.
I have created my own certificate authority (CA) and an intermediate CA. By using this intermediate CA, I created several certificates and revoked some of them. I updated the certificate revocation list (CRL) after I revoked them. Then, I appended the CRL to the chain certificate (concatenation of root CA's and intermediate CA's certificates). I wanted to use this file to check if a certificate is revoked or not. The C code I am running returns as expected for revoked certificates while it displays an unexpected message for valid certificates: unable to get certificate CRL. In addition, it returns expected results when I removed CRL checks. What can be the reason for this?
The code that I am running is given below.
#include <openssl/bio.h>
#include <openssl/err.h>
#include <openssl/pem.h>
#include <openssl/x509.h>
#include <openssl/x509_vfy.h>
int main() {
const char ca_bundlestr[] = "./ca-chain.crl.pem";//"./ca-chain.cert.pem";//"./ca-chain.crl.pem";
const char cert_filestr[] = "./RasPi3B-10.1.1.10.crt.pem";//"./ToBeRevoked3.crt.pem";
BIO *certbio = NULL;
BIO *outbio = NULL;
X509 *error_cert = NULL;
X509 *cert = NULL;
X509_NAME *certsubject = NULL;
X509_STORE *store = NULL;
X509_STORE_CTX *vrfy_ctx = NULL;
int ret;
/* ---------------------------------------------------------- *
* These function calls initialize openssl for correct work. *
* ---------------------------------------------------------- */
OpenSSL_add_all_algorithms();
ERR_load_BIO_strings();
ERR_load_crypto_strings();
X509_VERIFY_PARAM *param = X509_VERIFY_PARAM_new();
/* ---------------------------------------------------------- *
* Create the Input/Output BIO's. *
* ---------------------------------------------------------- */
certbio = BIO_new(BIO_s_file());
outbio = BIO_new_fp(stdout, BIO_NOCLOSE);
/* ---------------------------------------------------------- *
* Initialize the global certificate validation store object. *
* ---------------------------------------------------------- */
if (!(store=X509_STORE_new()))
BIO_printf(outbio, "Error creating X509_STORE_CTX object\n");
/* ---------------------------------------------------------- *
* Create the context structure for the validation operation. *
* ---------------------------------------------------------- */
vrfy_ctx = X509_STORE_CTX_new();
/* ---------------------------------------------------------- *
* Load the certificate and cacert chain from file (PEM). *
* ---------------------------------------------------------- */
ret = BIO_read_filename(certbio, cert_filestr);
if (! (cert = PEM_read_bio_X509(certbio, NULL, 0, NULL))) {
BIO_printf(outbio, "Error loading cert into memory\n");
exit(-1);
}
ret = X509_STORE_load_locations(store, ca_bundlestr, NULL);
if (ret != 1)
BIO_printf(outbio, "Error loading CA cert or chain file\n");
X509_STORE_set_flags(store, X509_V_FLAG_CRL_CHECK|X509_V_FLAG_CRL_CHECK_ALL);
//X509_VERIFY_PARAM_set_depth(param, 1);
//X509_STORE_CTX_set0_param(vrfy_ctx, param);
/* ---------------------------------------------------------- *
* Initialize the ctx structure for a verification operation: *
* Set the trusted cert store, the unvalidated cert, and any *
* potential certs that could be needed (here we set it NULL) *
* ---------------------------------------------------------- */
X509_STORE_CTX_init(vrfy_ctx, store, cert, NULL);
/* ---------------------------------------------------------- *
* Check the complete cert chain can be build and validated. *
* Returns 1 on success, 0 on verification failures, and -1 *
* for trouble with the ctx object (i.e. missing certificate) *
* ---------------------------------------------------------- */
ret = X509_verify_cert(vrfy_ctx);
BIO_printf(outbio, "Verification return code: %d\n", ret);
if(ret == 0 || ret == 1)
BIO_printf(outbio, "Verification result text: %s\n",
X509_verify_cert_error_string(vrfy_ctx->error));
/* ---------------------------------------------------------- *
* The error handling below shows how to get failure details *
* from the offending certificate. *
* ---------------------------------------------------------- */
if(ret == 0) {
/* get the offending certificate causing the failure */
error_cert = X509_STORE_CTX_get_current_cert(vrfy_ctx);
certsubject = X509_NAME_new();
certsubject = X509_get_subject_name(error_cert);
BIO_printf(outbio, "Verification failed cert:\n");
X509_NAME_print_ex(outbio, certsubject, 0, XN_FLAG_MULTILINE);
BIO_printf(outbio, "\n");
}
/* ---------------------------------------------------------- *
* Free up all structures *
* ---------------------------------------------------------- */
X509_STORE_CTX_free(vrfy_ctx);
X509_STORE_free(store);
X509_free(cert);
BIO_free_all(certbio);
BIO_free_all(outbio);
exit(0);
}
