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/* parse_certificate_files.c -- Parses PEM or PKCS12 formatted cert. files
*
* GPLv2 only - Copyright (C) 2008, 2009
* David Sommerseth <dazo@users.sourceforge.net>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; version 2
* of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
*/
/**
* @file parse_certificate_files.c
* @author David Sommerseth <dazo@users.sourceforge.net>
* @date 2008-12-21
*
* @brief Parses PEM/DER or PKCS#12 certificate files to retrieve information
* needed by eurephia. This feature requires OpenSSL to be available.
*
*/
#ifdef HAVE_OPENSSL
#include <stdio.h>
#include <string.h>
#include <assert.h>
#include <openssl/ssl.h>
#include <openssl/pkcs12.h>
#include <openssl/evp.h>
#include <openssl/err.h>
#include <eurephia_nullsafe.h>
#include <certinfo.h>
#include "get_console_input.h"
#define _PARSE_CERTFICIATE_FILES_C
#include "parse_certificate_files.h"
/**
* Extracts a specific X.509 field from an X509 struct pointer.
*
* @param module String containing a module name, only used in error situations
* @param cert Pointer to an X509 struct with the certificate information
* @param fieldname X.509 field name to extract
*
* @return Returns a string (char *) to the field value if found, otherwise NULL.
*/
char *ExtractCertInfo(const char *module, X509 *cert, const char *fieldname) {
unsigned char *buf = (unsigned char *)1; // Needs to be 1 to avoid OpenSSL 0.9.6b bug
char resbuf[2050];
X509_NAME *name = NULL;
X509_NAME_ENTRY *namentry = NULL;
ASN1_STRING *asn1 = NULL;
int nid, tmp = -1, pos = -1;
//
// Extract subject information
//
memset(resbuf, 0, 2050);
nid = OBJ_txt2nid(fieldname);
name = X509_get_subject_name(cert);
do {
pos = tmp;
tmp = X509_NAME_get_index_by_NID(name, nid, pos);
} while ( tmp > -1 );
if( pos == -1 ) {
fprintf(stderr, "%s: Field '%s' not found\n", module, fieldname);
return 0;
}
if( !(namentry = X509_NAME_get_entry(name, pos)) ) {
fprintf(stderr, "%s: Failed to extract name entry from field '%s'\n", module, fieldname);
return 0;
}
if( !(asn1 = X509_NAME_ENTRY_get_data(namentry)) ) {
fprintf(stderr, "%s: Failed to extract data from name entry field '%s'\n", module, fieldname);
return 0;
}
if( ASN1_STRING_to_UTF8(&buf, asn1) <= 0 ) {
fprintf(stderr, "%s: Failed to convert ASN1 string to UTF-8 for '%s'\n", module, fieldname);
return 0;
}
snprintf(resbuf, 2048, "%s%c", buf, '\0');
OPENSSL_free(buf);
return strdup_nullsafe(resbuf);
}
/**
* Internal function, usually called via the Cert_ParseFile(...) macro. Parses a certificate
* file of a given format.
*
* @param module String containing a module name, only used in error situations
* @param certfile File name of the input file
* @param certfile_format Certificate format of the file
*
* @return Returns a certinfo struct pointer with the parsed result on success, otherwise NULL.
*/
certinfo *_Cert_ParseFile(const char *module, const char *certfile, int certfile_format) {
BIO *bio_err = NULL;
PKCS12 *p12 = NULL;
EVP_PKEY *pkey = NULL;
X509 *cert = NULL;
FILE *fp;
certinfo *ret = NULL;
/* Needed to convert X509 digest into hex string */
unsigned char md_sha1[EVP_MAX_MD_SIZE];
unsigned int mdlen;
if( !bio_err ) {
SSL_library_init();
SSL_load_error_strings();
bio_err = BIO_new_fp(stderr, BIO_NOCLOSE);
}
// Open file - according to defined format
switch( certfile_format ) {
case CERTFILE_PEM: // PEM/DER format
fp = fopen(certfile, "r");
if( !(cert = PEM_read_X509(fp, NULL, NULL, NULL)) ) {
fprintf(stderr, "%s: Failed to open certificate file\n", module);
return NULL;
}
fclose(fp);
break;
case CERTFILE_PKCS12: // PKCS#12 format
fp = fopen(certfile, "r");
p12 = d2i_PKCS12_fp(fp, NULL);
fclose(fp);
if( p12 == NULL ) {
fprintf(stderr, "%s: Could not open PKCS#12 file\n", module);
return NULL;
}
OpenSSL_add_all_ciphers();
// First, try without password
if( !PKCS12_parse(p12, "", &pkey, &cert, NULL) ) {
char pwd[130];
// If empty password failed, get password and try again
memset(&pwd, 0, 130);
if( get_console_input(pwd, 128, "PKCS12 password:", 1) < 0 ) {
fprintf(stderr, "Could not retrieve password\n");
}
if( !PKCS12_parse(p12, pwd, &pkey, &cert, NULL) ) {
PKCS12_free(p12); p12 = NULL;
fprintf(stderr,
"%s: Could not open PKCS#12 file - wrong password\n", module);
fprintf(stderr,
"%s: %s\n", module, ERR_error_string(ERR_get_error(), NULL));
BIO_free(bio_err);
return NULL;
}
}
EVP_PKEY_free(pkey); pkey = NULL;
PKCS12_free(p12); p12 = NULL;
break;
default: // Unknown
fprintf(stderr, "%s: Unknown certificate file format\n", module);
return NULL;
}
ret = (certinfo *) malloc_nullsafe(NULL, sizeof(certinfo)+2);
assert( ret != NULL );
ret->digest = (char *) malloc_nullsafe(NULL, 66);
assert(ret != NULL);
// extract SHA1 digest from certificate
if (X509_digest(cert, EVP_sha1(), md_sha1, &mdlen) && mdlen > 0) {
static const char hexcodes[] = "0123456789ABCDEF";
int j;
for (j = 0; j < (int) mdlen; j++) {
ret->digest[j * 3] = hexcodes[(md_sha1[j] & 0xf0) >> 4U];
ret->digest[(j * 3) + 1] = hexcodes[(md_sha1[j] & 0x0f)];
if (j + 1 != (int) mdlen) {
ret->digest[(j * 3) + 2] = ':';
} else {
ret->digest[(j * 3) + 2] = '\0';
}
}
}
// Extract the subject information we want
ret->common_name = ExtractCertInfo(module, cert, "CN");
ret->org = ExtractCertInfo(module, cert, "O");
ret->email = ExtractCertInfo(module, cert, "emailAddress");
X509_free(cert);
BIO_free(bio_err);
return ret;
}
#endif
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