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source: trunk/src/sh_audit.c@ 526

Last change on this file since 526 was 516, checked in by katerina, 8 years ago
Fix for ticket #409 and #410 (unprivileged suidcheck and gcc 6.2 compiler warnings).
File size: 15.2 KB

Rev	Line
[294]	1	/* SAMHAIN file system integrity testing */
	2	/* Copyright (C) 2010 Rainer Wichmann */
	3	/* */
	4	/* This program is free software; you can redistribute it */
	5	/* and/or modify */
	6	/* it under the terms of the GNU General Public License as */
	7	/* published by */
	8	/* the Free Software Foundation; either version 2 of the License, or */
	9	/* (at your option) any later version. */
	10	/* */
	11	/* This program is distributed in the hope that it will be useful, */
	12	/* but WITHOUT ANY WARRANTY; without even the implied warranty of */
	13	/* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the */
	14	/* GNU General Public License for more details. */
	15	/* */
	16	/* You should have received a copy of the GNU General Public License */
	17	/* along with this program; if not, write to the Free Software */
	18	/* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
	19
	20	#include "config_xor.h"
	21
	22	#if defined(SH_WITH_CLIENT) \|\| defined(SH_STANDALONE)
	23
	24
	25	#include <stdio.h>
	26	#include <stdlib.h>
	27	#include <string.h>
	28	#include <errno.h>
	29	#include <unistd.h>
[488]	30	#include <fcntl.h>
	31	#include <sys/stat.h>
[294]	32
[488]	33	#include "samhain.h"
	34	#include "sh_error.h"
	35
[489]	36	#undef FIL__
	37	#define FIL__ _("sh_audit.c")
	38
[294]	39	#if !defined(SH_COMPILE_STATIC) && defined(__linux__) && defined(HAVE_AUPARSE_H) && defined(HAVE_AUPARSE_LIB)
	40	#include <auparse.h>
	41
	42	#include "sh_extern.h"
	43	#include "sh_utils.h"
	44
	45
	46	#define REC_SIZE_SYSCALL 32
	47	#define REC_SIZE_EXE 64
	48	#define REC_SIZE_SUCCESS 32
	49
	50	struct recordState {
	51	char syscall[REC_SIZE_SYSCALL];
	52	char exe[REC_SIZE_EXE];
	53	char success[REC_SIZE_SUCCESS];
	54	unsigned int auid;
	55	unsigned int uid;
	56	unsigned int gid;
	57	unsigned int euid;
	58	unsigned int egid;
	59	unsigned int fsuid;
	60	unsigned int fsgid;
	61	time_t time;
	62	unsigned int milli;
	63	};
	64
	65	static int listRecords (auparse_state_t * au, struct recordState * state)
	66	{
	67	if (auparse_first_record(au) != 1)
	68	return -1;
	69
	70	state->time = auparse_get_time(au);
	71	state->milli = auparse_get_milli(au);
	72
	73	if (auparse_find_field(au, _("syscall")))
	74	sl_strlcpy(state->syscall, auparse_interpret_field(au), REC_SIZE_SYSCALL);
	75
	76	if (auparse_find_field(au, _("success")))
	77	strncpy(state->success, auparse_interpret_field(au), REC_SIZE_SUCCESS);
	78
	79	if (auparse_find_field(au, "uid"))
	80	state->uid = auparse_get_field_int(au);
	81	if (auparse_find_field(au, "gid"))
	82	state->gid = auparse_get_field_int(au);
	83
	84	if (auparse_find_field(au, _("euid")))
	85	state->euid = auparse_get_field_int(au);
	86	if (auparse_find_field(au, _("fsuid")))
	87	state->fsuid = auparse_get_field_int(au);
	88
	89	auparse_first_field(au);
	90
	91	if (auparse_find_field(au, _("auid")))
	92	state->auid = auparse_get_field_int(au);
	93
	94	auparse_first_field(au);
	95
	96	if (auparse_find_field(au, _("egid")))
	97	state->egid = auparse_get_field_int(au);
	98	if (auparse_find_field(au, _("fsgid")))
	99	state->fsgid = auparse_get_field_int(au);
	100
	101	auparse_first_field(au);
	102
	103	if (auparse_find_field(au, "exe"))
	104	sl_strlcpy(state->exe, auparse_interpret_field(au), REC_SIZE_EXE);
	105
	106	return 0;
	107	}
	108
[488]	109	static char * doAuparse (const char * file, time_t time, int tol, char * result, size_t rsize, int redo_flag)
[294]	110	{
	111	struct recordState state;
	112	struct recordState stateFetched;
[488]	113	unsigned int found_flag = 0;
	114
[294]	115	auparse_state_t * au = auparse_init(AUSOURCE_LOGS, NULL);
	116
	117	if (!au)
	118	{
	119	char ebuf[SH_ERRBUF_SIZE];
	120	int errnum = errno;
	121
	122	sl_snprintf(ebuf, sizeof(ebuf), _("Error in auparse_init() - %s\n"),
	123	strerror(errnum));
	124	sh_error_handle (SH_ERR_ERR, FIL__, __LINE__, errnum, MSG_E_SUBGEN,
	125	ebuf,
	126	_("doAuparse") );
	127	return NULL;
	128	}
	129
	130	if (ausearch_add_interpreted_item(au, _("name"), "=", file,
	131	AUSEARCH_RULE_CLEAR) != 0)
	132	{
	133	goto err;
	134	}
	135
	136	if (time != 0)
	137	{
[488]	138	ausearch_add_timestamp_item(au, ">=", time-tol, 0, AUSEARCH_RULE_AND);
	139	ausearch_add_timestamp_item(au, "<=", time+tol, 0, AUSEARCH_RULE_AND);
[294]	140	}
	141
	142	if (ausearch_set_stop(au, AUSEARCH_STOP_RECORD) != 0)
	143	{
	144	sh_error_handle (SH_ERR_ERR, FIL__, __LINE__, 0, MSG_E_SUBGEN,
	145	_("Error in ausearch_set_stop\n"),
	146	_("doAuparse") );
	147	goto err;
	148	}
	149
	150	memset(&state, '\0', sizeof(state));
	151
	152	while (ausearch_next_event(au) == 1)
	153	{
	154	memset(&stateFetched, '\0', sizeof(state));
	155	listRecords(au, &stateFetched);
	156	if (0 == strcmp(stateFetched.success, "yes"))
	157	{
	158	memcpy(&state, &stateFetched, sizeof(state));
[488]	159	++found_flag;
[294]	160	}
	161	auparse_next_event(au);
	162	}
	163
[488]	164	if (found_flag == 0 && redo_flag == S_FALSE)
	165	{
	166	size_t len = strlen(file);
	167	char * path = SH_ALLOC(len + 2);
	168	char * altres;
	169
	170	sl_strlcpy(path, file, len+2);
	171	path[len] = '/'; path[len+1] = '\0';
	172	auparse_destroy(au);
	173
	174	altres = doAuparse(path, time, tol, result, rsize, S_TRUE);
	175
	176	SH_FREE(path);
	177	return altres;
	178	}
	179
[294]	180	if (0 == strcmp(state.success, "yes"))
	181	{
[514]	182	char time_str[81];
[294]	183	char * tmp_exe = sh_util_safe_name(state.exe);
[514]	184
	185	(void) sh_unix_gmttime (state.time, time_str, sizeof(time_str));
[294]	186	sl_snprintf(result, rsize,
[514]	187	_("time=%lu.%u, timestamp=%s, syscall=%s, auid=%u, uid=%u, gid=%u, euid=%u, egid=%u, fsuid=%u, fsgid=%u, exe=%s"),
	188	(unsigned long) state.time, state.milli, time_str,
[294]	189	state.syscall,
	190	state.auid, state.uid, state.gid, state.euid, state.egid,
	191	state.fsuid, state.fsgid, tmp_exe);
	192	SH_FREE(tmp_exe);
	193	auparse_destroy(au);
	194	return result;
	195	}
	196
	197	err:
	198	auparse_destroy(au);
	199	return NULL;
	200	}
	201
[514]	202	#define SH_AUDIT_DEF "wa"
	203	static char sh_audit_flags[32] = SH_AUDIT_DEF;
	204
	205	int sh_audit_set_flags(const char * str)
	206	{
	207	if (!str \|\| strlen(str) >= sizeof(sh_audit_flags))
	208	return -1;
	209	sl_strlcpy(sh_audit_flags, str, sizeof(sh_audit_flags));
	210	return 0;
	211	}
	212	static void reset_audit_flags()
	213	{
	214	sl_strlcpy(sh_audit_flags, SH_AUDIT_DEF, sizeof(sh_audit_flags));
	215	return;
	216	}
	217
	218
[294]	219	static int sh_audit_checkdaemon();
	220	static int actl_pnum = -1;
	221	static char * actl_paths[4] =
	222	{
	223	N_("/sbin/auditctl"),
	224	N_("/usr/sbin/auditctl"),
	225	N_("/bin/auditctl"),
	226	N_("/usr/bin/auditctl")
	227	};
	228
[514]	229	static char * getflags (char * file);
[294]	230
	231	/* Public function to fetch an audit record for path 'file', time 'time'
	232	* The 'result' array should be sized ~256 char.
	233	*/
[514]	234	char * sh_audit_fetch (char * file, time_t mtime, time_t ctime, time_t atime, char * result, size_t rsize)
[294]	235	{
[514]	236	char * res = NULL;
	237	char * flags = getflags(file);
[294]	238
	239	if (sh_audit_checkdaemon() >= 0)
	240	{
[488]	241	time_t new;
[294]	242
[514]	243	if (flags && (strchr(flags, 'r') \|\| strchr(flags, 'x')) && atime >= ctime && atime >= mtime) { new = atime; }
	244	else if (mtime >= ctime) { new = mtime; }
	245	else { new = ctime; }
	246
[488]	247	res = doAuparse (file, new, 1, result, rsize, S_FALSE);
	248
[294]	249	if (!res)
	250	{
[488]	251	res = doAuparse (file, new, 3, result, rsize, S_FALSE);
[294]	252	}
[488]	253
[294]	254	}
	255	return res;
	256	}
	257
	258	void sh_audit_delete_all ()
	259	{
	260	int p = sh_audit_checkdaemon();
	261
	262	if (p >= 0)
	263	{
[415]	264	char ctl[64];
[294]	265
[415]	266	sl_snprintf(ctl, sizeof(ctl), _("%s -D -k samhain"),
[294]	267	_(actl_paths[p]));
	268	sh_error_handle (SH_ERR_ALL, FIL__, __LINE__,
	269	0, MSG_E_SUBGEN,
	270	_("Deleting audit daemon rules with key samhain"),
	271	_("sh_audit_delete_all") );
[415]	272
	273	sl_strlcpy(ctl, _(actl_paths[p]), sizeof(ctl));
	274	sh_ext_system(ctl, ctl, "-D", "-k", _("samhain"), NULL);
[294]	275	}
[514]	276	reset_audit_flags();
[294]	277	return;
	278	}
	279
[488]	280	static int sh_audit_isdir(const char * file)
	281	{
	282	struct stat buf;
	283
	284	if ( (0 == lstat (file, &buf)) && S_ISDIR(buf.st_mode))
	285	return S_TRUE;
	286	return S_FALSE;
	287	}
	288
[514]	289	static void sh_audit_mark_int (const char * file, const char * flags)
[294]	290	{
	291	static int flushRules = 0;
	292
	293	int p = sh_audit_checkdaemon();
	294
	295	/* Flush all rules at startup.
	296	*/
	297	if (flushRules == 0)
	298	{
	299	sh_audit_delete_all ();
	300	flushRules = 1;
	301	}
	302
	303	if (p >= 0)
	304	{
	305	size_t len = strlen(file) + 64;
	306	char * command = SH_ALLOC(len);
	307	char * safe;
[415]	308	char ctl[64];
[488]	309	char a1[32];
	310	char a2[32];
	311	char a3[32];
[514]	312	char a4[32];
[294]	313
[514]	314	sl_snprintf(command, len, _("%s -w %s -p %s -k samhain"),
	315	_(actl_paths[p]), file, flags);
[294]	316
	317	safe = sh_util_safe_name_keepspace(command);
	318	sh_error_handle (SH_ERR_ALL, FIL__, __LINE__,
	319	0, MSG_E_SUBGEN,
	320	safe,
	321	_("sh_audit_mark") );
[488]	322
[294]	323	SH_FREE(safe);
	324
[415]	325	sl_strlcpy(ctl, _(actl_paths[p]), sizeof(ctl));
	326	sl_strlcpy(command, file, len);
	327
[488]	328	sl_strlcpy(a3, _("samhain"), sizeof(a3));
[514]	329	sl_strlcpy(a4, flags, sizeof(a4));
	330	sh_ext_system(ctl, ctl, "-w", command, "-p", a4, "-k", a3, NULL);
[415]	331
[488]	332	/* Placing a watch on a directory will not place a watch on the
	333	* directory inode, so we do this explicitely.
	334	*/
	335	if (S_TRUE == sh_audit_isdir(file))
	336	{
	337	safe = sh_util_safe_name(file);
	338	sh_error_handle (SH_ERR_ALL, FIL__, __LINE__,
	339	0, MSG_E_SUBGPATH,
	340	_("Add path watch for directory"),
	341	_("sh_audit_mark_int"), safe );
	342	SH_FREE(safe);
	343	sl_strlcpy(command, _("path="), len);
	344	sl_strlcat(command, file, len);
	345	sl_strlcpy(a1, _("always,exit"), sizeof(a1));
[514]	346	sl_strlcpy(a2, _("perm="), sizeof(a2));
	347	sl_strlcat(a2, flags, sizeof(a2));
[488]	348	sh_ext_system(ctl, ctl, "-a", a1, "-F", command, "-F", a2, "-k", a3, NULL);
	349	}
[415]	350	SH_FREE(command);
[294]	351	}
	352	return;
	353	}
	354
[514]	355	#define SH_AU_FLAGS_SIZ 32
[415]	356	struct aud_list {
	357	char * file;
[514]	358	char flags[SH_AU_FLAGS_SIZ];
[415]	359	struct aud_list * next;
	360	};
[294]	361
[415]	362	struct aud_list * mark_these = NULL;
[514]	363	static int marked_committed = 0;
[415]	364
[514]	365	static void delete_listofmarked()
	366	{
	367	struct aud_list * tmp;
	368	struct aud_list * this = mark_these;
	369
	370	mark_these = NULL;
	371
	372	while (this)
	373	{
	374	tmp = this;
	375	this = this->next;
	376
	377	SH_FREE(tmp->file);
	378	SH_FREE(tmp);
	379	}
	380	marked_committed = 0;
	381	}
	382
	383	static char * getflags (char * file)
	384	{
	385	struct aud_list * this = mark_these;
	386
	387	while (this)
	388	{
	389	if (0 == strcmp(file, this->file))
	390	return this->flags;
	391	this = this->next;
	392	}
	393	/* no explicit rule for this file */
	394	return NULL;
	395	}
	396
[415]	397	static void add_this (char * file)
	398	{
	399	struct aud_list * this = SH_ALLOC(sizeof(struct aud_list));
[488]	400	size_t len = strlen(file);
	401
[419]	402	this->file = sh_util_strdup(file);
[514]	403
	404	/* strip trailing '/' */
[488]	405	if ((len > 1) && (file[len-1] == '/'))
	406	this->file[len-1] = '\0';
[514]	407
	408	sl_strlcpy(this->flags, sh_audit_flags, SH_AU_FLAGS_SIZ);
[488]	409
[415]	410	this->next = mark_these;
[434]	411	mark_these = this;
[415]	412	return;
	413	}
	414
[488]	415	/* Check whether it is already covered by a higher directory
	416	*/
[516]	417	static int test_exchange (struct aud_list * this, const char * file)
[415]	418	{
	419	size_t len0 = sl_strlen(this->file);
	420	size_t len1 = sl_strlen(file);
	421	int ret = -1;
	422
[516]	423	if (!file \|\| !this \|\| !this->file)
	424	return 0;
	425
[415]	426	if (len0 == len1)
	427	{
	428	return strcmp(this->file, file);
	429	}
	430	else
	431	{
[514]	432	if (0 == strcmp(this->flags, sh_audit_flags))
	433	{
	434	char * s0 = SH_ALLOC(len0 + 2);
	435	char * s1 = SH_ALLOC(len1 + 2);
	436
	437	sl_strlcpy(s0, this->file, len0 + 2);
	438	sl_strlcpy(s1, file, len1 + 2);
	439
	440	if (s0 < s1)
	441	{
	442	sl_strlcat(s0, "/", len0 + 2);
	443	ret = strncmp(s0, s1, len0 + 1);
	444	}
	445	else
	446	{
	447	sl_strlcat(s1, "/", len1 + 2);
	448	if (0 == strncmp(s0, s1, len1 + 1))
	449	{
	450	size_t len = strlen(file);
	451	SH_FREE(this->file);
	452	this->file = sh_util_strdup(file);
	453	if ((len > 1) && (file[len-1] == '/'))
	454	this->file[len-1] = '\0';
	455	ret = 0;
	456	}
	457	}
	458	SH_FREE(s0);
	459	SH_FREE(s1);
	460	}
[415]	461	}
	462
	463	return ret;
	464	}
	465
[488]	466	/* Place a path on the list of of paths to be watched
	467	*/
[415]	468	void sh_audit_mark (char * file)
	469	{
[514]	470	struct aud_list * this;
[415]	471
[514]	472	if (marked_committed != 0)
	473	delete_listofmarked();
	474
[415]	475	if (!mark_these) {
	476	add_this (file);
	477	return;
	478	}
	479
[514]	480	this = mark_these;
	481
[415]	482	while (this)
	483	{
[488]	484	/* Check whether it is already covered by a higher
	485	* directory
	486	*/
[415]	487	if (0 == test_exchange(this, file))
	488	return;
[514]	489
[415]	490	this = this->next;
	491	}
	492
	493	add_this (file);
	494	return;
	495	}
	496
	497	void sh_audit_commit ()
	498	{
	499	struct aud_list * this = mark_these;
	500
	501	while (this)
	502	{
[514]	503	sh_audit_mark_int (this->file, this->flags);
	504	this = this->next;
[415]	505	}
[514]	506	marked_committed = 1;
[415]	507	}
	508
[294]	509	static int sh_audit_checkdaemon()
	510	{
	511	int i;
	512	static int flag = 0;
	513	char command[64];
	514	char * p;
	515
	516	if (flag != 0)
	517	return -1;
	518
	519	if (actl_pnum >= 0)
	520	return actl_pnum;
	521
	522	for (i = 0; i < 4; ++i)
	523	{
[295]	524	if (0 == access(_(actl_paths[i]), F_OK))/* flawfinder: ignore */
[294]	525	{
[295]	526	if (0 == access(_(actl_paths[i]), X_OK))/* flawfinder: ignore */
[294]	527	{
	528	actl_pnum = i;
	529	break;
	530	}
	531	else
	532	{
	533	char ebuf[SH_ERRBUF_SIZE];
	534	int errnum = errno;
	535
	536	sl_snprintf(ebuf, sizeof(ebuf),
	537	_("Cannot execute auditctl - %s\n"),
	538	strerror(errnum));
	539	sh_error_handle (SH_ERR_ERR, FIL__, __LINE__,
	540	errnum, MSG_E_SUBGEN,
	541	ebuf,
	542	_("sh_audit_checkdaemon") );
	543	flag = 1;
	544	actl_pnum = -1;
	545	return -1;
	546	}
	547	}
	548	}
	549
	550	if (actl_pnum == -1 && flag == 0)
	551	{
	552	char ebuf[SH_ERRBUF_SIZE];
	553	int errnum = errno;
	554
	555	sl_snprintf(ebuf, sizeof(ebuf),
	556	_("Cannot find auditctl - %s\n"),
	557	strerror(errnum));
	558	sh_error_handle (SH_ERR_ERR, FIL__, __LINE__,
	559	errnum, MSG_E_SUBGEN,
	560	ebuf,
	561	_("sh_audit_checkdaemon") );
	562	flag = 1;
	563	actl_pnum = -1;
	564	return -1;
	565	}
	566
	567	/* We found an executable auditctl */
	568
	569	sl_snprintf(command, sizeof(command), _("%s -s"), _(actl_paths[actl_pnum]));
	570	sh_error_handle (SH_ERR_ALL, FIL__, __LINE__,
	571	0, MSG_E_SUBGEN,
	572	command,
	573	_("sh_audit_checkdaemon") );
	574	p = sh_ext_popen_str (command);
	575
	576	if (p)
	577	{
	578	int retval = -1;
	579	if (strstr(p, _(" pid=0 ")))
	580	{
	581	sh_error_handle (SH_ERR_ERR, FIL__, __LINE__,
	582	0, MSG_E_SUBGEN,
	583	_("Audit daemon for Linux kernel audit system is not running"),
	584	_("sh_audit_checkdaemon") );
	585	flag = 1;
	586	actl_pnum = -1;
	587	}
	588	else
	589	{
	590	retval = actl_pnum;
	591	sh_error_handle (SH_ERR_ALL, FIL__, __LINE__,
	592	retval, MSG_E_SUBGEN,
	593	_("Audit daemon is running"),
	594	_("sh_audit_checkdaemon") );
	595	}
	596	SH_FREE(p);
	597	return retval;
	598	}
	599
	600	sh_error_handle (SH_ERR_ERR, FIL__, __LINE__,
	601	errno, MSG_E_SUBGEN,
	602	_("No output from auditctl -s"),
	603	_("sh_audit_checkdaemon") );
	604	flag = 1;
	605	actl_pnum = -1;
	606	return -1;
	607	}
	608
	609	/* HAVE_AUPARSE_H */
	610	#else
[514]	611	char * sh_audit_fetch (char * file, time_t mtime, time_t ctime, time_t atime, char * result, size_t rsize)
[294]	612	{
	613	(void) file;
[488]	614	(void) mtime;
	615	(void) ctime;
[514]	616	(void) atime;
[294]	617	(void) result;
	618	(void) rsize;
	619
	620	return 0;
	621	}
[373]	622	void sh_audit_mark (const char * file)
[294]	623	{
	624	(void) file;
[488]	625	sh_error_handle(SH_ERR_WARN, FIL__, __LINE__, 0, MSG_E_SUBGEN,
	626	_("Setting audit watch not supported"),
	627	_("sh_audit_mark"));
[294]	628	return;
	629	}
	630	void sh_audit_delete_all ()
	631	{
	632	return;
	633	}
[415]	634	void sh_audit_commit ()
	635	{
	636	return;
	637	}
[514]	638	int sh_audit_set_flags(const char * str)
	639	{
	640	(void) str;
	641	return -1;
	642	}
[294]	643	#endif
	644
	645	/* client \|\| standalone */
	646	#endif
	647

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