source: lib/ssl_nss.c @ af5764e

  /********************************************************************\
  * BitlBee -- An IRC to other IM-networks gateway                     *
  *                                                                    *
  * Copyright 2002-2005 Wilmer van der Gaast and others                *
  \********************************************************************/

/* SSL module - NSS version                                             */

/* Copyright 2005 Jelmer Vernooij                                       */

/*
  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; either version 2 of the License, or
  (at your option) any later version.

  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 with
  the Debian GNU/Linux distribution in /usr/share/common-licenses/GPL;
  if not, write to the Free Software Foundation, Inc., 59 Temple Place,
  Suite 330, Boston, MA  02111-1307  USA
*/

#include "bitlbee.h"
#include "proxy.h"
#include "ssl_client.h"
#include "sock.h"
#include <nspr.h>
#include <prio.h>
#include <sslproto.h>
#include <nss.h>
#include <pk11pub.h>
#include <private/pprio.h>
#include <ssl.h>
#include <seccomon.h>
#include <secerr.h>
#include <sslerr.h>

int ssl_errno = 0;

static gboolean initialized = FALSE;

struct scd
{
        ssl_input_function func;
        gpointer data;
        int fd;
        PRFileDesc *prfd;
        gboolean established;
        gboolean verify;
};

static gboolean ssl_connected( gpointer data, gint source, b_input_condition cond );
static gboolean ssl_starttls_real( gpointer data, gint source, b_input_condition cond );


static SECStatus nss_auth_cert (void *arg, PRFileDesc *socket, PRBool checksig, PRBool isserver)
{
        return SECSuccess;
}

static SECStatus nss_bad_cert (void *arg, PRFileDesc *socket) 
{
        PRErrorCode err;

        if(!arg) return SECFailure;

        *(PRErrorCode *)arg = err = PORT_GetError();

        switch(err) {
        case SEC_ERROR_INVALID_AVA:
        case SEC_ERROR_INVALID_TIME:
        case SEC_ERROR_BAD_SIGNATURE:
        case SEC_ERROR_EXPIRED_CERTIFICATE:
        case SEC_ERROR_UNKNOWN_ISSUER:
        case SEC_ERROR_UNTRUSTED_CERT:
        case SEC_ERROR_CERT_VALID:
        case SEC_ERROR_EXPIRED_ISSUER_CERTIFICATE:
        case SEC_ERROR_CRL_EXPIRED:
        case SEC_ERROR_CRL_BAD_SIGNATURE:
        case SEC_ERROR_EXTENSION_VALUE_INVALID:
        case SEC_ERROR_CA_CERT_INVALID:
        case SEC_ERROR_CERT_USAGES_INVALID:
        case SEC_ERROR_UNKNOWN_CRITICAL_EXTENSION:
                return SECSuccess;

        default:
                return SECFailure;
        }
}


void ssl_init( void )
{
        PR_Init( PR_SYSTEM_THREAD, PR_PRIORITY_NORMAL, 1);
        NSS_NoDB_Init(NULL);
        NSS_SetDomesticPolicy();
        initialized = TRUE;
}

void *ssl_connect( char *host, int port, ssl_input_function func, gpointer data )
{
        struct scd *conn = g_new0( struct scd, 1 );
        
        conn->fd = proxy_connect( host, port, ssl_connected, conn );
        conn->func = func;
        conn->data = data;
        
        if( conn->fd < 0 )
        {
                g_free( conn );
                return( NULL );
        }
        
        if( !initialized )
        {
                ssl_init();
        }

        
        return( conn );
}

static gboolean ssl_starttls_real( gpointer data, gint source, b_input_condition cond )
{
        struct scd *conn = data;

        return ssl_connected( conn, conn->fd, B_EV_IO_WRITE );
}

void *ssl_starttls( int fd, char *hostname, gboolean verify, ssl_input_function func, gpointer data )
{
        struct scd *conn = g_new0( struct scd, 1 );

        conn->fd = fd;
        conn->func = func;
        conn->data = data;
        conn->verify = verify;

        /* This function should be called via a (short) timeout instead of
           directly from here, because these SSL calls are *supposed* to be
           *completely* asynchronous and not ready yet when this function
           (or *_connect, for examle) returns. Also, errors are reported via
           the callback function, not via this function's return value.

           In short, doing things like this makes the rest of the code a lot
           simpler. */

        b_timeout_add( 1, ssl_starttls_real, conn );

        return conn;
}

static gboolean ssl_connected( gpointer data, gint source, b_input_condition cond )
{
        struct scd *conn = data;
        
        /* Right now we don't have any verification functionality for nss so we 
           fail in case verification has been requested by the user. */

        if( conn->verify )
        {
                conn->func( conn->data, NSS_VERIFY_ERROR, NULL, cond );
                if( source >= 0 ) closesocket( source );
                g_free( conn );

                return FALSE;
        }
        
        if( source == -1 )
                goto ssl_connected_failure;
        
        /* Until we find out how to handle non-blocking I/O with NSS... */
        sock_make_blocking( conn->fd );
        
        conn->prfd = SSL_ImportFD(NULL, PR_ImportTCPSocket(source));
        SSL_OptionSet(conn->prfd, SSL_SECURITY, PR_TRUE);
        SSL_OptionSet(conn->prfd, SSL_HANDSHAKE_AS_CLIENT, PR_TRUE);
        SSL_BadCertHook(conn->prfd, (SSLBadCertHandler)nss_bad_cert, NULL);
        SSL_AuthCertificateHook(conn->prfd, (SSLAuthCertificate)nss_auth_cert, (void *)CERT_GetDefaultCertDB());
        SSL_ResetHandshake(conn->prfd, PR_FALSE);

        if (SSL_ForceHandshake(conn->prfd)) {
                goto ssl_connected_failure;
        }
        
        
        conn->established = TRUE;
        conn->func( conn->data, 0, conn, cond );
        return FALSE;
        
        ssl_connected_failure:
        
        conn->func( conn->data, 0, NULL, cond );
        
        PR_Close( conn -> prfd );
        if( source >= 0 ) closesocket( source );
        g_free( conn );
        
        return FALSE;
}

int ssl_read( void *conn, char *buf, int len )
{
        if( !((struct scd*)conn)->established )
                return( 0 );
        
        return( PR_Read( ((struct scd*)conn)->prfd, buf, len ) );
}

int ssl_write( void *conn, const char *buf, int len )
{
        if( !((struct scd*)conn)->established )
                return( 0 );
        
        return( PR_Write ( ((struct scd*)conn)->prfd, buf, len ) );
}

int ssl_pending( void *conn )
{
        struct scd *c = (struct scd *) conn;

        if( c == NULL ) {
                return 0;
        }

        return ( c->established && SSL_DataPending( c->prfd ) > 0 );
}

void ssl_disconnect( void *conn_ )
{
        struct scd *conn = conn_;
        
        PR_Close( conn->prfd );
        closesocket( conn->fd );
        
        g_free( conn );
}

int ssl_getfd( void *conn )
{
        return( ((struct scd*)conn)->fd );
}

b_input_condition ssl_getdirection( void *conn )
{
        /* Just in case someone calls us, let's return the most likely case: */
        return B_EV_IO_READ;
}

char *ssl_verify_strerror( int code )
{
        return g_strdup( "SSL certificate verification not supported by BitlBee NSS code." );
}