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|
/* nsd_gtls.c
*
* An implementation of the nsd interface for GnuTLS.
*
* Copyright (C) 2007, 2008 Rainer Gerhards and Adiscon GmbH.
*
* This file is part of the rsyslog runtime library.
*
* The rsyslog runtime library is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* The rsyslog runtime library 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 Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with the rsyslog runtime library. If not, see <http://www.gnu.org/licenses/>.
*
* A copy of the GPL can be found in the file "COPYING" in this distribution.
* A copy of the LGPL can be found in the file "COPYING.LESSER" in this distribution.
*/
#include "config.h"
#include <stdlib.h>
#include <assert.h>
#include <gnutls/gnutls.h>
#include "rsyslog.h"
#include "syslogd-types.h"
#include "module-template.h"
#include "cfsysline.h"
#include "obj.h"
#include "errmsg.h"
#include "nsd_ptcp.h"
#include "nsdsel_gtls.h"
#include "nsd_gtls.h"
/* things to move to some better place/functionality - TODO */
#define DH_BITS 1024
#define CRLFILE "crl.pem"
MODULE_TYPE_LIB
/* static data */
DEFobjStaticHelpers
DEFobjCurrIf(errmsg)
DEFobjCurrIf(glbl)
DEFobjCurrIf(nsd_ptcp)
static int bGlblSrvrInitDone = 0; /**< 0 - server global init not yet done, 1 - already done */
/* a macro to check GnuTLS calls against unexpected errors */
#define CHKgnutls(x) \
if((gnuRet = (x)) != 0) { \
uchar *pErr = gtlsStrerror(gnuRet); \
dbgprintf("unexpected GnuTLS error %d in %s:%d: %s\n", gnuRet, __FILE__, __LINE__, pErr); \
free(pErr); \
ABORT_FINALIZE(RS_RET_GNUTLS_ERR); \
}
/* ------------------------------ GnuTLS specifics ------------------------------ */
static gnutls_certificate_credentials xcred;
static gnutls_dh_params dh_params;
/* a thread-safe variant of gnutls_strerror - TODO: implement it!
* The caller must free the returned string.
* rgerhards, 2008-04-30
*/
uchar *gtlsStrerror(int error)
{
uchar *pErr;
// TODO: guard by mutex!
pErr = (uchar*) strdup(gnutls_strerror(error));
return pErr;
}
/* globally initialize GnuTLS */
static rsRetVal
gtlsGlblInit(void)
{
int gnuRet;
uchar *cafile;
DEFiRet;
CHKgnutls(gnutls_global_init());
/* X509 stuff */
CHKgnutls(gnutls_certificate_allocate_credentials(&xcred));
/* sets the trusted cas file */
cafile = glbl.GetDfltNetstrmDrvrCAF();
dbgprintf("GTLS CA file: '%s'\n", cafile);
gnuRet = gnutls_certificate_set_x509_trust_file(xcred, (char*)cafile, GNUTLS_X509_FMT_PEM);
if(gnuRet < 0) {
/* TODO; a more generic error-tracking function (this one based on CHKgnutls()) */
uchar *pErr = gtlsStrerror(gnuRet);
dbgprintf("unexpected GnuTLS error %d in %s:%d: %s\n", gnuRet, __FILE__, __LINE__, pErr);
free(pErr);
ABORT_FINALIZE(RS_RET_GNUTLS_ERR);
}
finalize_it:
RETiRet;
}
static rsRetVal
gtlsInitSession(nsd_gtls_t *pThis)
{
DEFiRet;
int gnuRet;
gnutls_session session;
gnutls_init(&session, GNUTLS_SERVER);
pThis->bHaveSess = 1;
pThis->bIsInitiator = 0;
/* avoid calling all the priority functions, since the defaults are adequate. */
CHKgnutls(gnutls_set_default_priority(session));
CHKgnutls(gnutls_credentials_set(session, GNUTLS_CRD_CERTIFICATE, xcred));
/* request client certificate if any. */
gnutls_certificate_server_set_request( session, GNUTLS_CERT_REQUEST);
gnutls_dh_set_prime_bits(session, DH_BITS);
pThis->sess = session;
finalize_it:
RETiRet;
}
static rsRetVal
generate_dh_params(void)
{
int gnuRet;
DEFiRet;
/* Generate Diffie Hellman parameters - for use with DHE
* kx algorithms. These should be discarded and regenerated
* once a day, once a week or once a month. Depending on the
* security requirements.
*/
CHKgnutls(gnutls_dh_params_init( &dh_params));
CHKgnutls(gnutls_dh_params_generate2( dh_params, DH_BITS));
finalize_it:
RETiRet;
}
/* set up all global things that are needed for server operations
* rgerhards, 2008-04-30
*/
static rsRetVal
gtlsGlblInitLstn(void)
{
int gnuRet;
uchar *keyFile;
uchar *certFile;
DEFiRet;
if(bGlblSrvrInitDone == 0) {
/* we do not use CRLs right now, and I doubt we'll ever do. This functionality is
* considered legacy. -- rgerhards, 2008-05-05
*/
/*CHKgnutls(gnutls_certificate_set_x509_crl_file(xcred, CRLFILE, GNUTLS_X509_FMT_PEM));*/
certFile = glbl.GetDfltNetstrmDrvrCertFile();
keyFile = glbl.GetDfltNetstrmDrvrKeyFile();
dbgprintf("GTLS certificate file: '%s'\n", certFile);
dbgprintf("GTLS key file: '%s'\n", keyFile);
CHKgnutls(gnutls_certificate_set_x509_key_file(xcred, (char*)certFile, (char*)keyFile, GNUTLS_X509_FMT_PEM));
CHKiRet(generate_dh_params());
gnutls_certificate_set_dh_params(xcred, dh_params); /* this is void */
bGlblSrvrInitDone = 1; /* we are all set now */
}
finalize_it:
RETiRet;
}
/* globally de-initialize GnuTLS */
static rsRetVal
gtlsGlblExit(void)
{
DEFiRet;
/* X509 stuff */
gnutls_certificate_free_credentials(xcred);
gnutls_global_deinit(); /* we are done... */
RETiRet;
}
/* end a GnuTLS session
* The function checks if we have a session and ends it only if so. So it can
* always be called, even if there currently is no session.
*/
static rsRetVal
gtlsEndSess(nsd_gtls_t *pThis)
{
int gnuRet;
DEFiRet;
if(pThis->bHaveSess) {
if(pThis->bIsInitiator) {
gnuRet = gnutls_bye(pThis->sess, GNUTLS_SHUT_RDWR);
while(gnuRet == GNUTLS_E_INTERRUPTED || gnuRet == GNUTLS_E_AGAIN) {
gnuRet = gnutls_bye(pThis->sess, GNUTLS_SHUT_RDWR);
}
}
gnutls_deinit(pThis->sess);
}
RETiRet;
}
/* ---------------------------- end GnuTLS specifics ---------------------------- */
/* Standard-Constructor */
BEGINobjConstruct(nsd_gtls) /* be sure to specify the object type also in END macro! */
iRet = nsd_ptcp.Construct(&pThis->pTcp);
ENDobjConstruct(nsd_gtls)
/* destructor for the nsd_gtls object */
BEGINobjDestruct(nsd_gtls) /* be sure to specify the object type also in END and CODESTART macros! */
CODESTARTobjDestruct(nsd_gtls)
if(pThis->iMode == 1) {
gtlsEndSess(pThis);
}
if(pThis->pTcp != NULL) {
nsd_ptcp.Destruct(&pThis->pTcp);
}
ENDobjDestruct(nsd_gtls)
/* Set the driver mode. For us, this has the following meaning:
* 0 - work in plain tcp mode, without tls (e.g. before a STARTTLS)
* 1 - work in TLS mode
* rgerhards, 2008-04-28
*/
static rsRetVal
SetMode(nsd_t *pNsd, int mode)
{
DEFiRet;
nsd_gtls_t *pThis = (nsd_gtls_t*) pNsd;
dbgprintf("SetMOde tries to set mode %d\n", mode);
ISOBJ_TYPE_assert((pThis), nsd_gtls);
if(mode != 0 && mode != 1)
ABORT_FINALIZE(RS_RET_INVAID_DRVR_MODE);
pThis->iMode = mode;
finalize_it:
RETiRet;
}
/* Provide access to the underlying OS socket. This is primarily
* useful for other drivers (like nsd_gtls) who utilize ourselfs
* for some of their functionality. -- rgerhards, 2008-04-18
*/
static rsRetVal
SetSock(nsd_t *pNsd, int sock)
{
DEFiRet;
nsd_gtls_t *pThis = (nsd_gtls_t*) pNsd;
ISOBJ_TYPE_assert((pThis), nsd_gtls);
assert(sock >= 0);
nsd_ptcp.SetSock(pThis->pTcp, sock);
RETiRet;
}
/* abort a connection. This is meant to be called immediately
* before the Destruct call. -- rgerhards, 2008-03-24
*/
static rsRetVal
Abort(nsd_t *pNsd)
{
nsd_gtls_t *pThis = (nsd_gtls_t*) pNsd;
DEFiRet;
ISOBJ_TYPE_assert((pThis), nsd_gtls);
if(pThis->iMode == 0) {
nsd_ptcp.Abort(pThis->pTcp);
}
RETiRet;
}
/* initialize the tcp socket for a listner
* Here, we use the ptcp driver - because there is nothing special
* at this point with GnuTLS. Things become special once we accept
* a session, but not during listener setup.
* gerhards, 2008-04-25
*/
static rsRetVal
LstnInit(netstrms_t *pNS, void *pUsr, rsRetVal(*fAddLstn)(void*,netstrm_t*),
uchar *pLstnPort, uchar *pLstnIP, int iSessMax)
{
DEFiRet;
CHKiRet(gtlsGlblInitLstn());
iRet = nsd_ptcp.LstnInit(pNS, pUsr, fAddLstn, pLstnPort, pLstnIP, iSessMax);
finalize_it:
RETiRet;
}
/* get the remote hostname. The returned hostname must be freed by the caller.
* rgerhards, 2008-04-25
*/
static rsRetVal
GetRemoteHName(nsd_t *pNsd, uchar **ppszHName)
{
DEFiRet;
nsd_gtls_t *pThis = (nsd_gtls_t*) pNsd;
ISOBJ_TYPE_assert(pThis, nsd_gtls);
iRet = nsd_ptcp.GetRemoteHName(pThis->pTcp, ppszHName);
RETiRet;
}
/* get the remote host's IP address. The returned string must be freed by the
* caller.
* rgerhards, 2008-04-25
*/
static rsRetVal
GetRemoteIP(nsd_t *pNsd, uchar **ppszIP)
{
DEFiRet;
nsd_gtls_t *pThis = (nsd_gtls_t*) pNsd;
ISOBJ_TYPE_assert(pThis, nsd_gtls);
iRet = nsd_ptcp.GetRemoteIP(pThis->pTcp, ppszIP);
RETiRet;
}
/* accept an incoming connection request - here, we do the usual accept
* handling. TLS specific handling is done thereafter (and if we run in TLS
* mode at this time).
* rgerhards, 2008-04-25
*/
static rsRetVal
AcceptConnReq(nsd_t *pNsd, nsd_t **ppNew)
{
DEFiRet;
int gnuRet;
nsd_gtls_t *pNew = NULL;
nsd_gtls_t *pThis = (nsd_gtls_t*) pNsd;
ISOBJ_TYPE_assert((pThis), nsd_gtls);
CHKiRet(nsd_gtlsConstruct(&pNew));
CHKiRet(nsd_ptcp.Destruct(&pNew->pTcp));
CHKiRet(nsd_ptcp.AcceptConnReq(pThis->pTcp, &pNew->pTcp));
if(pThis->iMode == 0) {
/* we are in non-TLS mode, so we are done */
*ppNew = (nsd_t*) pNew;
FINALIZE;
}
/* if we reach this point, we are in TLS mode */
CHKiRet(gtlsInitSession(pNew));
gnutls_transport_set_ptr(pNew->sess, (gnutls_transport_ptr_t)((nsd_ptcp_t*) (pNew->pTcp))->sock);
/* we now do the handshake. This is a bit complicated, because we are
* on non-blocking sockets. Usually, the handshake will not complete
* immediately, so that we need to retry it some time later.
*/
gnuRet = gnutls_handshake(pNew->sess);
if(gnuRet == GNUTLS_E_AGAIN || gnuRet == GNUTLS_E_INTERRUPTED) {
pNew->rtryCall = gtlsRtry_handshake;
dbgprintf("GnuTLS handshake does not complete immediately - setting to retry (this is OK and normal)\n");
} else if(gnuRet != 0) {
ABORT_FINALIZE(RS_RET_TLS_HANDSHAKE_ERR);
}
pNew->iMode = 1; /* this session is now in TLS mode! */
*ppNew = (nsd_t*) pNew;
finalize_it:
if(iRet != RS_RET_OK) {
if(pNew != NULL)
nsd_gtlsDestruct(&pNew);
}
RETiRet;
}
/* receive data from a tcp socket
* The lenBuf parameter must contain the max buffer size on entry and contains
* the number of octets read (or -1 in case of error) on exit. This function
* never blocks, not even when called on a blocking socket. That is important
* for client sockets, which are set to block during send, but should not
* block when trying to read data. If *pLenBuf is -1, an error occured and
* errno holds the exact error cause.
* rgerhards, 2008-03-17
*/
static rsRetVal
Rcv(nsd_t *pNsd, uchar *pBuf, ssize_t *pLenBuf)
{
DEFiRet;
ssize_t lenRcvd;
nsd_gtls_t *pThis = (nsd_gtls_t*) pNsd;
ISOBJ_TYPE_assert(pThis, nsd_gtls);
if(pThis->iMode == 0) {
CHKiRet(nsd_ptcp.Rcv(pThis->pTcp, pBuf, pLenBuf));
FINALIZE;
}
/* in TLS mode now */
lenRcvd = gnutls_record_recv(pThis->sess, pBuf, *pLenBuf);
*pLenBuf = lenRcvd;
finalize_it:
RETiRet;
}
/* send a buffer. On entry, pLenBuf contains the number of octets to
* write. On exit, it contains the number of octets actually written.
* If this number is lower than on entry, only a partial buffer has
* been written.
* rgerhards, 2008-03-19
*/
static rsRetVal
Send(nsd_t *pNsd, uchar *pBuf, ssize_t *pLenBuf)
{
int iSent;
nsd_gtls_t *pThis = (nsd_gtls_t*) pNsd;
DEFiRet;
ISOBJ_TYPE_assert(pThis, nsd_gtls);
if(pThis->iMode == 0) {
CHKiRet(nsd_ptcp.Send(pThis->pTcp, pBuf, pLenBuf));
FINALIZE;
}
/* in TLS mode now */
while(1) { /* loop broken inside */
iSent = gnutls_record_send(pThis->sess, pBuf, *pLenBuf);
if(iSent >= 0) {
*pLenBuf = iSent;
break;
}
if(iSent != GNUTLS_E_INTERRUPTED && iSent != GNUTLS_E_AGAIN) {
dbgprintf("unexpected GnuTLS error %d in %s:%d\n", iSent, __FILE__, __LINE__);
gnutls_perror(iSent); /* TODO: can we do better? */
ABORT_FINALIZE(RS_RET_GNUTLS_ERR);
}
}
finalize_it:
RETiRet;
}
/* open a connection to a remote host (server). With GnuTLS, we always
* open a plain tcp socket and then, if in TLS mode, do a handshake on it.
* rgerhards, 2008-03-19
*/
static rsRetVal
Connect(nsd_t *pNsd, int family, uchar *port, uchar *host)
{
nsd_gtls_t *pThis = (nsd_gtls_t*) pNsd;
int sock;
int gnuRet;
static const int cert_type_priority[3] = { GNUTLS_CRT_X509, GNUTLS_CRT_OPENPGP, 0 };
DEFiRet;
ISOBJ_TYPE_assert(pThis, nsd_gtls);
assert(port != NULL);
assert(host != NULL);
CHKiRet(nsd_ptcp.Connect(pThis->pTcp, family, port, host));
if(pThis->iMode == 0)
FINALIZE;
/* we reach this point if in TLS mode */
CHKgnutls(gnutls_init(&pThis->sess, GNUTLS_CLIENT));
pThis->bHaveSess = 1;
pThis->bIsInitiator = 1;
/* Use default priorities */
CHKgnutls(gnutls_set_default_priority(pThis->sess));
CHKgnutls(gnutls_certificate_type_set_priority(pThis->sess, cert_type_priority));
/* put the x509 credentials to the current session */
CHKgnutls(gnutls_credentials_set(pThis->sess, GNUTLS_CRD_CERTIFICATE, xcred));
/* assign the socket to GnuTls */
CHKiRet(nsd_ptcp.GetSock(pThis->pTcp, &sock));
gnutls_transport_set_ptr(pThis->sess, (gnutls_transport_ptr_t)sock);
/* and perform the handshake */
CHKgnutls(gnutls_handshake(pThis->sess));
dbgprintf("GnuTLS handshake succeeded\n");
finalize_it:
if(iRet != RS_RET_OK) {
if(pThis->bHaveSess) {
gnutls_deinit(pThis->sess);
pThis->bHaveSess = 0;
}
}
RETiRet;
}
/* queryInterface function */
BEGINobjQueryInterface(nsd_gtls)
CODESTARTobjQueryInterface(nsd_gtls)
if(pIf->ifVersion != nsdCURR_IF_VERSION) {/* check for current version, increment on each change */
ABORT_FINALIZE(RS_RET_INTERFACE_NOT_SUPPORTED);
}
/* ok, we have the right interface, so let's fill it
* Please note that we may also do some backwards-compatibility
* work here (if we can support an older interface version - that,
* of course, also affects the "if" above).
*/
pIf->Construct = (rsRetVal(*)(nsd_t**)) nsd_gtlsConstruct;
pIf->Destruct = (rsRetVal(*)(nsd_t**)) nsd_gtlsDestruct;
pIf->Abort = Abort;
pIf->LstnInit = LstnInit;
pIf->AcceptConnReq = AcceptConnReq;
pIf->Rcv = Rcv;
pIf->Send = Send;
pIf->Connect = Connect;
pIf->SetSock = SetSock;
pIf->SetMode = SetMode;
pIf->GetRemoteHName = GetRemoteHName;
pIf->GetRemoteIP = GetRemoteIP;
finalize_it:
ENDobjQueryInterface(nsd_gtls)
/* exit our class
*/
BEGINObjClassExit(nsd_gtls, OBJ_IS_LOADABLE_MODULE) /* CHANGE class also in END MACRO! */
CODESTARTObjClassExit(nsd_gtls)
gtlsGlblExit(); /* shut down GnuTLS */
/* release objects we no longer need */
objRelease(nsd_ptcp, LM_NSD_PTCP_FILENAME);
objRelease(glbl, CORE_COMPONENT);
objRelease(errmsg, CORE_COMPONENT);
ENDObjClassExit(nsd_gtls)
/* Initialize the nsd_gtls class. Must be called as the very first method
* before anything else is called inside this class.
* rgerhards, 2008-02-19
*/
BEGINObjClassInit(nsd_gtls, 1, OBJ_IS_LOADABLE_MODULE) /* class, version */
/* request objects we use */
CHKiRet(objUse(errmsg, CORE_COMPONENT));
CHKiRet(objUse(glbl, CORE_COMPONENT));
CHKiRet(objUse(nsd_ptcp, LM_NSD_PTCP_FILENAME));
/* now do global TLS init stuff */
CHKiRet(gtlsGlblInit());
ENDObjClassInit(nsd_gtls)
/* --------------- here now comes the plumbing that makes as a library module --------------- */
BEGINmodExit
CODESTARTmodExit
nsdsel_gtlsClassExit();
nsd_gtlsClassExit();
ENDmodExit
BEGINqueryEtryPt
CODESTARTqueryEtryPt
CODEqueryEtryPt_STD_LIB_QUERIES
ENDqueryEtryPt
BEGINmodInit()
CODESTARTmodInit
*ipIFVersProvided = CURR_MOD_IF_VERSION; /* we only support the current interface specification */
/* Initialize all classes that are in our module - this includes ourselfs */
CHKiRet(nsd_gtlsClassInit(pModInfo)); /* must be done after tcps_sess, as we use it */
CHKiRet(nsdsel_gtlsClassInit(pModInfo)); /* must be done after tcps_sess, as we use it */
ENDmodInit
/* vi:set ai:
*/
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