summaryrefslogtreecommitdiffstats
path: root/runtime/nsd_gtls.c
blob: fd709fe39a84dcd4196d4b1df6c4812d4b08cb7f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
/* 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 <string.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:
 */