/*
** Copyright (c) 2009 D. Richard Hipp
**
** This program is free software; you can redistribute it and/or
** modify it under the terms of the GNU General Public
** License version 2 as published by the Free Software Foundation.
**
** 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 library; if not, write to the
** Free Software Foundation, Inc., 59 Temple Place - Suite 330,
** Boston, MA 02111-1307, USA.
**
** Author contact information:
** drh@hwaci.com
** http://www.hwaci.com/drh/
**
*******************************************************************************
**
** This file manages low-level SSL communications.
**
** This file implements a singleton. A single SSL connection may be active
** at a time. State information is stored in static variables. The identity
** of the server is held in global variables that are set by url_parse().
**
** SSL support is abstracted out into this module because Fossil can
** be compiled without SSL support (which requires OpenSSL library)
*/
#include "config.h"
#ifdef FOSSIL_ENABLE_SSL
#include <openssl/bio.h>
#include <openssl/ssl.h>
#include <openssl/err.h>
#include "http_ssl.h"
#include <assert.h>
#include <sys/types.h>
/*
** There can only be a single OpenSSL IO connection open at a time.
** State information about that IO is stored in the following
** local variables:
*/
static int sslIsInit = 0; /* True after global initialization */
static BIO *iBio; /* OpenSSL I/O abstraction */
static char *sslErrMsg = 0; /* Text of most recent OpenSSL error */
static SSL_CTX *sslCtx; /* SSL context */
static SSL *ssl;
/*
** Clear the SSL error message
*/
static void ssl_clear_errmsg(void){
free(sslErrMsg);
sslErrMsg = 0;
}
/*
** Set the SSL error message.
*/
void ssl_set_errmsg(char *zFormat, ...){
va_list ap;
ssl_clear_errmsg();
va_start(ap, zFormat);
sslErrMsg = vmprintf(zFormat, ap);
va_end(ap);
}
/*
** Return the current SSL error message
*/
const char *ssl_errmsg(void){
return sslErrMsg;
}
/*
** Call this routine once before any other use of the SSL interface.
** This routine does initial configuration of the SSL module.
*/
void ssl_global_init(void){
if( sslIsInit==0 ){
SSL_library_init();
SSL_load_error_strings();
ERR_load_BIO_strings();
OpenSSL_add_all_algorithms();
sslCtx = SSL_CTX_new(SSLv23_client_method());
sslIsInit = 1;
}
}
/*
** Call this routine to shutdown the SSL module prior to program exit.
*/
void ssl_global_shutdown(void){
if( sslIsInit ){
SSL_CTX_free(sslCtx);
ssl_clear_errmsg();
sslIsInit = 0;
}
}
/*
** Close the currently open SSL connection. If no connection is open,
** this routine is a no-op.
*/
void ssl_close(void){
if( iBio!=NULL ){
BIO_reset(iBio);
BIO_free_all(iBio);
}
}
/*
** Open an SSL connection. The identify of the server is determined
** by global varibles that are set using url_parse():
**
** g.urlName Name of the server. Ex: www.fossil-scm.org
** g.urlPort TCP/IP port to use. Ex: 80
**
** Return the number of errors.
*/
int ssl_open(void){
X509 *cert;
int hasSavedCertificate = 0;
ssl_global_init();
/* Get certificate for current server from global config and
* (if we have it in config) add it to certificate store.
*/
cert = ssl_get_certificate();
if ( cert != NULL ){
X509_STORE_add_cert(SSL_CTX_get_cert_store(sslCtx), cert);
X509_free(cert);
hasSavedCertificate = 1;
}
iBio = BIO_new_ssl_connect(sslCtx);
BIO_get_ssl(iBio, &ssl);
SSL_set_mode(ssl, SSL_MODE_AUTO_RETRY);
if( iBio==NULL ) {
ssl_set_errmsg("SSL: cannot open SSL (%s)",
ERR_reason_error_string(ERR_get_error()));
return 1;
}
char *connStr = mprintf("%s:%d", g.urlName, g.urlPort);
BIO_set_conn_hostname(iBio, connStr);
free(connStr);
if( BIO_do_connect(iBio)<=0 ){
ssl_set_errmsg("SSL: cannot connect to host %s:%d (%s)",
g.urlName, g.urlPort, ERR_reason_error_string(ERR_get_error()));
ssl_close();
return 1;
}
if( BIO_do_handshake(iBio)<=0 ) {
ssl_set_errmsg("Error establishing SSL connection %s:%d (%s)",
g.urlName, g.urlPort, ERR_reason_error_string(ERR_get_error()));
ssl_close();
return 1;
}
/* Check if certificate is valid */
cert = SSL_get_peer_certificate(ssl);
if ( cert == NULL ){
ssl_set_errmsg("No SSL certificate was presented by the peer");
ssl_close();
return 1;
}
if( SSL_get_verify_result(ssl) != X509_V_OK ){
char *desc, *prompt;
BIO *mem;
mem = BIO_new(BIO_s_mem());
X509_NAME_print_ex(mem, X509_get_subject_name(cert), 2, XN_FLAG_MULTILINE);
BIO_puts(mem, "\n\nIssued By:\n\n");
X509_NAME_print_ex(mem, X509_get_issuer_name(cert), 2, XN_FLAG_MULTILINE);
BIO_write(mem, "", 1); // null-terminate mem buffer
BIO_get_mem_data(mem, &desc);
char *warning = "";
if( hasSavedCertificate ){
warning = "WARNING: Certificate doesn't match the "
"saved certificate for this host!";
}
prompt = mprintf("\nUnknown SSL certificate:\n\n%s\n\n%s\n"
"Accept certificate [a=always/y/N]? ", desc, warning);
BIO_free(mem);
Blob ans;
blob_zero(&ans);
prompt_user(prompt, &ans);
free( prompt );
if( blob_str(&ans)[0]!='y' && blob_str(&ans)[0]!='a' ) {
X509_free(cert);
ssl_set_errmsg("SSL certificate declined");
ssl_close();
return 1;
}
if( blob_str(&ans)[0]=='a' ) {
ssl_save_certificate(cert);
}
}
X509_free(cert);
return 0;
}
/*
** Save certificate to global config.
*/
void ssl_save_certificate(X509 *cert)
{
BIO *mem;
char *zCert, *zHost;
mem = BIO_new(BIO_s_mem());
PEM_write_bio_X509(mem, cert);
BIO_write(mem, "", 1); // null-terminate mem buffer
BIO_get_mem_data(mem, &zCert);
zHost = mprintf("cert:%s", g.urlName);
db_set(zHost, zCert, 1);
free(zHost);
BIO_free(mem);
}
/*
** Get certificate for g.urlName from global config.
** Return NULL if no certificate found.
*/
X509 *ssl_get_certificate()
{
char *zHost, *zCert;
BIO *mem;
X509 *cert;
zHost = mprintf("cert:%s", g.urlName);
zCert = db_get(zHost, NULL);
free(zHost);
if ( zCert==NULL )
return NULL;
mem = BIO_new(BIO_s_mem());
BIO_puts(mem, zCert);
cert = PEM_read_bio_X509(mem, NULL, 0, NULL);
free(zCert);
BIO_free(mem);
return cert;
}
/*
** Send content out over the SSL connection.
*/
size_t ssl_send(void *NotUsed, void *pContent, size_t N){
size_t sent;
size_t total = 0;
while( N>0 ){
sent = BIO_write(iBio, pContent, N);
if( sent<=0 ) break;
total += sent;
N -= sent;
pContent = (void*)&((char*)pContent)[sent];
}
return total;
}
/*
** Receive content back from the SSL connection.
*/
size_t ssl_receive(void *NotUsed, void *pContent, size_t N){
size_t got;
size_t total = 0;
while( N>0 ){
got = BIO_read(iBio, pContent, N);
if( got<=0 ) break;
total += got;
N -= got;
pContent = (void*)&((char*)pContent)[got];
}
return total;
}
#endif /* FOSSIL_ENABLE_SSL */