Fine-tune blocking rules one notch down.

Before, most rules would block on the 3rd rule hit, with this,
it's 4, which means 1 extra failure before a 1hr block is started
and this is a bit more sympathetic towards `typo` failures.

.gitignore

@@ -11,6 +11,8 @@ install-sh
 missing
 tallow
 tallow-*.tar.gz
-tallow-1/
+tallow-*/
 tallow.o
 tallow.service
+*~
+DEADJOE

.travis.yml

@@ -0,0 +1,21 @@
+sudo: required
+dist: trusty
+language: c
+compiler: gcc
+os: linux
+
+before_script:
+    - ./autogen.sh
+
+addons:
+    apt:
+        sources:
+            - ubuntu-toolchain-r-test
+        packages:
+            - libsystemd-journal-dev
+            - valgrind
+            - autoconf
+            - automake
+
+script:
+    - ./configure && make && make distcheck

Makefile.am

@@ -1,17 +1,26 @@
 
-AM_CFLAGS = -g $(LIBSYSTEMD_CFLAGS) -Wall -Wno-uninitialized
+AM_CFLAGS = -g $(PCRE_CFLAGS) $(LIBSYSTEMD_CFLAGS) -Wall -Wno-uninitialized -W -D_FORTIFY_SOURCE=2
 
 systemdsystemunitdir = @SYSTEMD_SYSTEMUNITDIR@
 systemdsystemunit_DATA = tallow.service
 
 sbin_PROGRAMS = tallow
 tallow_SOURCES = tallow.c
-tallow_LDADD = $(LIBSYSTEMD_LIBS)
+tallow_LDADD = $(PCRE_LIBS) $(LIBSYSTEMD_LIBS)
 
-EXTRA_DIST = AUTHORS COPYING INSTALL tallow.service.in
+EXTRA_DIST = AUTHORS COPYING INSTALL README.md tallow.service.in tallow.conf.5.md tallow.1.md
+
+dist_man_MANS = tallow.1 tallow.conf.5
 
 dist_doc_DATA = tallow.conf
-dist_man_MANS = tallow.1 tallow.conf.5
 
 DISTCHECK_CONFIGURE_FLAGS = \
 	--with-systemdsystemunitdir=$(DESTDIR)$(SYSTEMDSYSTEMUNITDIR)
+
+docs: tallow.1 tallow.conf.5
+tallow.conf.5: tallow.conf.5.md
+	ronn -r tallow.conf.5.md --pipe > tallow.conf.5
+
+tallow.1: tallow.1.md
+	ronn -r tallow.1.md --pipe > tallow.1
+

configure.ac

@@ -2,17 +2,20 @@
 # Process this file with autoconf to produce a configure script.
 
 AC_PREREQ([2.64])
-AC_INIT([tallow], [1], [auke-jan.h.kok@intel.com])
-AM_INIT_AUTOMAKE([])
+AC_INIT([tallow], [9], [auke-jan.h.kok@intel.com])
+AM_INIT_AUTOMAKE([foreign])
 AC_CONFIG_FILES([Makefile])
 
 # Checks for programs.
 AC_PROG_CC
 AC_PROG_INSTALL
 
-PKG_CHECK_MODULES([LIBSYSTEMD], [libsystemd])
+PKG_CHECK_MODULES(PCRE, libpcre)
+PKG_CHECK_MODULES(LIBSYSTEMD, libsystemd,, [PKG_CHECK_MODULES(LIBSYSTEMD, libsystemd-journal)])
 AC_SUBST(LIBSYSTEMD_CFLAGS)
 AC_SUBST(LIBSYSTEMD_LIBS)
+AC_SUBST(LIBSYSTEMD_JOURNAL_CFLAGS)
+AC_SUBST(LIBSYSTEMD_JOURNAL_LIBS)
 
 AC_ARG_WITH([systemdsystemunitdir], AC_HELP_STRING([--with-systemdsystemunitdir=DIR],
 	[path to systemd system service directory]), [path_systemdsystemunit=${withval}],

tallow.1

@@ -1,41 +1,40 @@
-.TH tallow 1 "31 October 2012" ".1" "Tallow"
-.SH NAME
-Tallow \- Reduce log clutter due to ssh login attempts.
-.SH SYNOPSIS
-/usr/sbin/tallow
-.SH DESCRIPTION
-\fBtallow\fR is a daemon that watches the systemd journal for
-messages from the \fBsshd\fR service. It parses the messages
-and looks for attempted random logins such as failed logins to the
-root account and failed logins to invalid user accounts.
-.PP
-If such logins were detected, the offending IP address is stored
-in a list. Items from this list are regularly purged, but if
-the amount of times that a specific IP address is seen exceeds
-a threshold (default 3), an iptables(1) rule is inserted in the
-\fBTALLOW\fR chain in the \fBfilter\fR netfilter table. The
-rule will match all packets from the IP address and \fBDROP\dR
-them.
-.PP
-The system administrator needs to assure that all incoming packets
-are routed through the \fBTALLOW\fR chain by inserting a rule
-appropriately, e.g. \`iptables -I INPUT -j TALLOW\`. The \fBTALLOW\fR
-chain may have to be created manually first with e.g. \`iptables -N
-TALLOW\`.
-.PP
-Care should be taken to assure that legitimate users are not
-blocked inadvertently. You may wish to list any valid IP address
-with the whitelist option in tallow.conf(5). Multiple addresses
-can be whitelisted.
-
-.SH OPTIONS
-The \fBtallow\fR daemon itself has no runtime configuration. All
-configuration is done through the tallow.conf(5) config file.
-.SH SEE ALSO
-systemd-journald(1), iptables(1), tallow.conf(5)
-.SH BUGS
-\fBtallow\fR is \fBNOT A SECURITY SOLUTION\fR, nor does it protect
-against random password logins. A attacker may still be able to
-logon to your systems if you allow password logins.
-.SH AUTHOR
-Auke Kok <auke-jan.h.kok@intel.com>
+.\" generated with Ronn/v0.7.3
+.\" http://github.com/rtomayko/ronn/tree/0.7.3
+.
+.TH "TALLOW" "1" "January 2018" "" ""
+.
+.SH "NAME"
+\fBtallow\fR
+.
+.SH "tallow"
+Reduce log clutter due to ssh login attempts\.
+.
+.SH "SYNOPSIS"
+\fB/usr/sbin/tallow\fR
+.
+.SH "DESCRIPTION"
+\fBtallow\fR is a daemon that watches the systemd journal for messages from the \fBsshd\fR service\. It parses the messages and looks for attempted random logins such as failed logins to the root account and failed logins to invalid user accounts, and various other obviously malicious login attempts that try things as forcing old protocols, or weak key systems\.
+.
+.P
+If such logins were detected, the offending IP address is stored in a list\. Items from this list are regularly purged, but if the amount of times that a specific IP address is seen exceeds a threshold, an ipset(1) entry is inserted in the \fBtallow\fR or \fBtallow6\fR ipset, and further packets from that ip address will be blocked by an \fBiptables(1)\fR or \fBip6tables(1)\fR rule that tallow creates at startup\. Additionally, certain types of login failure will trigger a short term ban of further packets from the offending IP address immediately\.
+.
+.P
+The system administrator needs to assure that the tallow and tallow6 ipsets are left alone and that the inserted iptables rules are properly matching on packets\.
+.
+.P
+Care should be taken to assure that legitimate users are not blocked inadvertently\. You may wish to list any valid IP address with the whitelist option in tallow\.conf(5)\. Multiple addresses can be whitelisted\.
+.
+.SH "OPTIONS"
+The \fBtallow\fR daemon itself has no runtime configuration\. All configuration is done through the tallow\.conf(5) config file\.
+.
+.SH "SIGNALS"
+The \fBUSR1\fR signal causes \fBtallow\fR to print out it\'s internal tracking table of IP addresses\.
+.
+.SH "SEE ALSO"
+systemd\-journald(1), iptables(1), ipset(1), tallow\.conf(5)
+.
+.SH "BUGS"
+\fBtallow\fR is \fBNOT A SECURITY SOLUTION\fR, nor does it protect against random password logins\. A attacker may still be able to logon to your systems if you allow password logins\.
+.
+.SH "AUTHOR"
+Auke Kok \fIauke\-jan\.h\.kok@intel\.com\fR

tallow.1.md

@@ -0,0 +1,60 @@
+
+## tallow 
+
+Reduce log clutter due to ssh login attempts.
+
+## SYNOPSIS
+
+`/usr/sbin/tallow`
+
+## DESCRIPTION
+
+`tallow` is a daemon that watches the systemd journal for messages
+from the `sshd` service. It parses the messages and looks for
+attempted random logins such as failed logins to the root account and
+failed logins to invalid user accounts, and various other obviously
+malicious login attempts that try things as forcing old protocols,
+or weak key systems.
+
+If such logins were detected, the offending IP address is stored in
+a list. Items from this list are regularly purged, but if the amount
+of times that a specific IP address is seen exceeds a threshold,
+an ipset(1) entry is inserted in the `tallow` or `tallow6`
+ipset, and further packets from that ip address will be blocked
+by an `iptables(1)` or `ip6tables(1)` rule that tallow creates at
+startup. Additionally, certain types of login failure will trigger
+a short term ban of further packets from the offending IP address
+immediately.
+
+The system administrator needs to assure that the tallow and tallow6
+ipsets are left alone and that the inserted iptables rules are properly
+matching on packets.
+
+Care should be taken to assure that legitimate users are not
+blocked inadvertently. You may wish to list any valid IP address
+with the whitelist option in tallow.conf(5). Multiple addresses can
+be whitelisted.
+
+## OPTIONS
+
+The `tallow` daemon itself has no runtime configuration. All
+configuration is done through the tallow.conf(5) config file.
+
+## SIGNALS
+
+The `USR1` signal causes `tallow` to print out it's internal tracking
+table of IP addresses.
+
+## SEE ALSO
+
+systemd-journald(1), iptables(1), ipset(1), tallow.conf(5)
+
+## BUGS
+
+`tallow` is `NOT A SECURITY SOLUTION`, nor does it protect against
+random password logins. A attacker may still be able to logon to your
+systems if you allow password logins.
+
+## AUTHOR
+
+Auke Kok <auke-jan.h.kok@intel.com>

tallow.c

@@ -15,31 +15,67 @@
 #include <stdio.h>
 #include <string.h>
 #include <stdarg.h>
+#include <stdbool.h>
 #include <signal.h>
 #include <unistd.h>
 #include <limits.h>
 #include <sys/time.h>
+#include <pcre.h>
 
 #include <systemd/sd-journal.h>
 
+#ifdef DEBUG
+#define dbg(args...) fprintf(stderr, ##args)
+#else
+#define dbg(args...) do {} while (0)
+#endif
+
 struct tallow_struct {
 	char *ip;
-	int count;
+	float score;
 	struct timeval time;
 	struct tallow_struct *next;
+	bool blocked;
 };
 
 static struct tallow_struct *head;
 
-static struct tallow_struct *whitelist;
+struct whitelist_struct {
+	char *ip;
+	size_t len;
+	struct whitelist_struct *next;
+};
+
+static struct whitelist_struct *whitelist;
 
 #define FILTER_STRING "SYSLOG_IDENTIFIER=sshd"
+struct pattern_struct {
+	int instant_block;
+	float weight;
+	char *pattern;
+	pcre *re;
+};
 
-static char iptables_path[PATH_MAX] = "/usr/sbin";
-static char chain[PATH_MAX] = "TALLOW";
-static int threshold = 3;
+#define PATTERN_COUNT 10
+static struct pattern_struct patterns[PATTERN_COUNT] = {
+	{ 0, 0.3, "MESSAGE=Failed .* for .* from ([0-9a-z:.]+) port \\d+ ssh2", NULL},
+	{ 0, 0.3, "MESSAGE=error: PAM: Authentication failure for .* from ([0-9a-z:.]+)", NULL},
+	{15, 0.3, "MESSAGE=Invalid user .* from ([0-9a-z:.]+) port \\d+", NULL},
+	{15, 0.3, "MESSAGE=Did not receive identification string from ([0-9a-z:.]+) port \\d+", NULL},
+	{15, 0.4, "MESSAGE=Bad protocol version identification .* from ([0-9a-z:.]+)", NULL},
+	{15, 0.4, "MESSAGE=Connection closed by authenticating user .* ([0-9a-z:.]+) port \\d+", NULL},
+	{15, 0.4, "MESSAGE=Received disconnect from ([0-9a-z:.]+) port .*\\[preauth\\]", NULL},
+	{15, 0.4, "MESSAGE=Connection closed by ([0-9a-z:.]+) port .*\\[preauth\\]", NULL},
+	{30, 0.5, "MESSAGE=Failed .* for root from ([0-9a-z:.]+) port \\d+ ssh2", NULL},
+	{60, 0.6, "MESSAGE=Unable to negotiate with ([0-9a-z:.]+) port \\d+: no matching key exchange method found.", NULL}
+};
+
+#define MAX_OFFSETS 30
+
+static char ipt_path[PATH_MAX];
 static int expires = 3600;
 static int has_ipv6 = 0;
+static bool nocreate = false;
 static sd_journal *j;
 
 static int ext(char *fmt, ...)
@@ -67,55 +103,98 @@ static void ext_ignore(char *fmt, ...)
 	vsnprintf(cmd, sizeof(cmd), fmt, args);
 	va_end(args);
 
-	(void) system(cmd);
+	__attribute__((unused)) int ret = system(cmd);
 }
 
-static void block(struct tallow_struct *s)
+static void setup(void)
 {
-	if (s->count != threshold)
+	static bool done = false;
+	if (done)
+		return;
+	done = true;
+
+	if (nocreate)
 		return;
 
-	if (strchr(s->ip, ':')) {
-		if (has_ipv6)
-			(void) ext("%s/ip6tables -t filter -A %s -s %s -j DROP", iptables_path, chain, s->ip);
-	} else {
-		(void) ext("%s/iptables -t filter -A %s -s %s -j DROP", iptables_path, chain, s->ip);
+	/* init ipset and iptables */
+	/* delete iptables ref to set before the ipset! */
+	ext_ignore("%s/iptables -t filter -D INPUT -m set --match-set tallow src -j DROP 2> /dev/null", ipt_path);
+	ext_ignore("%s/ipset destroy tallow 2> /dev/null", ipt_path);
+	if (ext("%s/ipset create tallow hash:ip family inet timeout %d", ipt_path, expires)) {
+		fprintf(stderr, "Unable to create ipv4 ipset.\n");
+		exit(EXIT_FAILURE);
+	}
+	if (ext("%s/iptables -t filter -A INPUT -m set --match-set tallow src -j DROP", ipt_path)) {
+		fprintf(stderr, "Unable to create iptables rule.\n");
+		exit(EXIT_FAILURE);
 	}
 
-	fprintf(stderr, "Blocked %s\n", s->ip);
+	if (has_ipv6) {
+		ext_ignore("%s/ip6tables -t filter -D INPUT -m set --match-set tallow6 src -j DROP 2> /dev/null", ipt_path);
+		ext_ignore("%s/ipset destroy tallow6 2> /dev/null", ipt_path);
+		if (ext("%s/ipset create tallow6 hash:ip family inet6 timeout %d", ipt_path, expires)) {
+			fprintf(stderr, "Unable to create ipv6 ipset.\n");
+			exit(EXIT_FAILURE);
+		}
+		if (ext("%s/ip6tables -t filter -A INPUT -m set --match-set tallow6 src -j DROP", ipt_path)) {
+			fprintf(stderr, "Unable to create ipt6ables rule.\n");
+			exit(EXIT_FAILURE);
+		}
+	}
 }
 
-static void unblock(struct tallow_struct *s)
+static void block(struct tallow_struct *s, int instant_block)
 {
-	if (s->count < threshold)
-		return;
+	setup();
+
 
 	if (strchr(s->ip, ':')) {
-		if (has_ipv6)
-			(void) ext("%s/ip6tables -t filter -D %s -s %s -j DROP", iptables_path, chain, s->ip);
+		if (has_ipv6) {
+			if (instant_block > 0) {
+				(void) ext("%s/ipset -! add tallow6 %s timeout %d",
+					   ipt_path, s->ip, instant_block);
+			} else {
+				(void) ext("%s/ipset -! add tallow6 %s", ipt_path, s->ip);
+				s->blocked = true;
+			}
+		}
 	} else {
-		(void) ext("%s/iptables -t filter -D %s -s %s -j DROP", iptables_path, chain, s->ip);
+		if (instant_block > 0) {
+			(void) ext("%s/ipset -! add tallow %s timeout %d",
+				   ipt_path, s->ip, instant_block);
+		} else {
+			(void) ext("%s/ipset -! add tallow %s", ipt_path, s->ip);
+			s->blocked = true;
+		}
 	}
 
-	fprintf(stderr, "Unblocked %s\n", s->ip);
+	if (s->blocked) {
+		fprintf(stderr, "Blocked %s\n", s->ip);
+	} else {
+		dbg("Throttled %s\n", s->ip);
+	}
 }
 
 static void whitelist_add(char *ip)
 {
-	struct tallow_struct *w = whitelist;
-	struct tallow_struct *n;
+	struct whitelist_struct *w = whitelist;
+	struct whitelist_struct *n;
 
 	while (w && w->next)
 		w = w->next;
 
-	n = malloc(sizeof(struct tallow_struct));
+	n = calloc(1, sizeof(struct whitelist_struct));
 	if (!n) {
 		fprintf(stderr, "Out of memory.\n");
-		exit(1);
+		exit(EXIT_FAILURE);
 	}
-	memset(n, 0, sizeof(struct tallow_struct));
+
 	n->ip = strdup(ip);
-	n->next = NULL;
+	size_t l = strlen(ip);
+	if ((ip[l-1] == '.') || (ip[l-1] == ':'))
+		n->len = l;
+	else
+		n->len = -1;
 
 	if (!whitelist)
 		whitelist = n;
@@ -123,11 +202,14 @@ static void whitelist_add(char *ip)
 		w->next = n;
 }
 
-static void find(char *ip)
+static void find(const char *ip, float weight, int instant_block)
 {
 	struct tallow_struct *s = head;
 	struct tallow_struct *n;
-	struct tallow_struct *w = whitelist;
+	struct whitelist_struct *w = whitelist;
+
+	if (!ip)
+		return;
 
 	/*
 	 * not validating the IP address format here, just
@@ -139,18 +221,33 @@ static void find(char *ip)
 
 	/* whitelist */
 	while (w) {
-		if (!strcmp(w->ip, ip))
-			return;
+		if (w->len > 0) {
+			if (!strncmp(w->ip, ip, w->len))
+				return;
+		} else {
+			if (!strcmp(w->ip, ip))
+				return;
+		}
 		w = w->next;
 	}
 
 	/* walk and update entry */
 	while (s) {
 		if (!strcmp(s->ip, ip)) {
-			s->count++;
+			s->score += weight;
+			dbg("%s: %1.3f\n", s->ip, s->score);
 			(void) gettimeofday(&s->time, NULL);
 
-			block(s);
+			if (s->blocked) {
+				return;
+			}
+
+			if (s->score >= 1.0) {
+				block(s, 0);
+			} else if (instant_block > 0) {
+				block(s, instant_block);
+			}
+
 			return;
 		}
 
@@ -161,12 +258,11 @@ static void find(char *ip)
 	}
 
 	/* append */
-	n = malloc(sizeof(struct tallow_struct));
+	n = calloc(1, sizeof(struct tallow_struct));
 	if (!n) {
 		fprintf(stderr, "Out of memory.\n");
-		exit(1);
+		exit(EXIT_FAILURE);
 	}
-	memset(n, 0, sizeof(struct tallow_struct));
 
 	if (!head)
 		head = n;
@@ -174,43 +270,44 @@ static void find(char *ip)
 		s->next = n;
 
 	n->ip = strdup(ip);
-	n->count = 1;
+	n->score = weight;
 	n->next = NULL;
+	n->blocked = false;
 	(void) gettimeofday(&n->time, NULL);
+	dbg("%s: %1.3f\n", n->ip, n->score);
 
-	block(n);
+	if (weight >= 1.0) {
+		block(n, 0);
+	} else if (instant_block > 0) {
+		block(n, instant_block);
+	}
 	return;
 }
 
-static void dump(void)
+static void sig(int u __attribute__ ((unused)))
 {
-	struct tallow_struct *s = head;
-	fprintf(stderr, "Received SIGUSR1 - dumping address table: address: count, time\n");
+	fprintf(stderr, "Exiting on request.\n");
+	sd_journal_close(j);
 
+	struct tallow_struct *s = head;
 	while (s) {
-		fprintf(stderr, "%s: %d, %lu.%lu\n", s->ip, s->count, s->time.tv_sec, s->time.tv_usec);
+		struct tallow_struct *n = NULL;
+
+		free(s->ip);
+		n = s;
 		s = s->next;
+		free(n);
 	}
+	exit(EXIT_SUCCESS);
 }
 
-static void sig(int s)
+static void sigusr1(int u __attribute__ ((unused)))
 {
-	if (s == SIGUSR1) {
-		dump();
-	} else {
-		fprintf(stderr, "Exiting on request.\n");
-		sd_journal_close(j);
-
-		struct tallow_struct *s = head;
-		while (s) {
-			struct tallow_struct *n = NULL;
-
-			free(s->ip);
-			n = s;
-			s = s->next;
-			free(n);
-		}
-		exit(0);
+	fprintf(stderr, "Dumping score list on request:\n");
+	struct tallow_struct *s = head;
+	while (s) {
+		fprintf(stderr, "%ld %s %1.3f\n", s->time.tv_sec, s->ip, s->score);
+		s = s->next;
 	}
 }
 
@@ -224,16 +321,22 @@ static void prune(void)
 	p = NULL;
 
 	while (s) {
-		if ((tv.tv_sec - s->time.tv_sec) > expires) {
+		/*
+		 * Expire all records, but if they are blocked, make sure to
+		 * expire them *before* the ipset rule expires, otherwise
+		 * you might get an IP to bypass checks.
+		 */
+		time_t age = tv.tv_sec - s->time.tv_sec;
+		if ((age > expires) ||
+		    ((s->blocked) && (age > expires / 2))) {
+			dbg("Expired record for %s\n", s->ip);
 			if (p) {
-				unblock(s);
 				p->next = s->next;
 				free(s->ip);
 				free(s);
 				s = p->next;
 				continue;
 			} else {
-				unblock(s);
 				head = s->next;
 				free(s->ip);
 				free(s);
@@ -247,20 +350,25 @@ static void prune(void)
 	}
 }
 
-int main(int argc, char *argv[])
+int main(void)
 {
 	int r;
 	FILE *f;
 	struct sigaction s;
 	int timeout = 60;
 
+	strcpy(ipt_path, "/usr/sbin");
+
 	memset(&s, 0, sizeof(struct sigaction));
 	s.sa_handler = sig;
-	sigaction(SIGUSR1, &s, NULL);
 	sigaction(SIGHUP, &s, NULL);
 	sigaction(SIGTERM, &s, NULL);
 	sigaction(SIGINT, &s, NULL);
 
+	memset(&s, 0, sizeof(struct sigaction));
+	s.sa_handler = sigusr1;
+	sigaction(SIGUSR1, &s, NULL);
+
 	if (access("/proc/sys/net/ipv6", R_OK | X_OK) == 0)
 		has_ipv6 = 1;
 
@@ -287,19 +395,16 @@ int main(int argc, char *argv[])
 				continue;
 
 			// todo: filter leading/trailing whitespace
-
-			if (!strcmp(key, "iptables_path"))
-				strncpy(iptables_path, val, PATH_MAX - 1);
-			if (!strcmp(key, "chain"))
-				strncpy(chain, val, PATH_MAX - 1);
-			if (!strcmp(key, "threshold"))
-				threshold = atoi(val);
+			if (!strcmp(key, "ipt_path"))
+				strncpy(ipt_path, val, PATH_MAX - 1);
 			if (!strcmp(key, "expires"))
 				expires = atoi(val);
 			if (!strcmp(key, "whitelist"))
 				whitelist_add(val);
 			if (!strcmp(key, "ipv6"))
 				has_ipv6 = atoi(val);
+			if (!strcmp(key, "nocreate"))
+				nocreate = (atoi(val) == 1);
 		}
 		fclose(f);
 	}
@@ -313,35 +418,32 @@ int main(int argc, char *argv[])
 	r = sd_journal_open(&j, SD_JOURNAL_LOCAL_ONLY);
 	if (r < 0) {
 		fprintf(stderr, "Failed to open journal: %s\n", strerror(-r));
-		exit(1);
+		exit(EXIT_FAILURE);
 	}
 
-	/* init ip(6)tables chains */
-	ext_ignore("%s/iptables -t filter -N %s > /dev/null 2>&1", iptables_path, chain);
-	if (ext("%s/iptables -t filter -F %s", iptables_path, chain)) {
-		fprintf(stderr, "Unable to create/flush iptables chain \"%s\".\n", chain);
-		exit(1);
-	}
-
-	if (has_ipv6) {
-		ext_ignore("%s/ip6tables -t filter -N %s > /dev/null 2>&1", iptables_path, chain);
-		if (ext("%s/ip6tables -t filter -F %s", iptables_path, chain)) {
-			fprintf(stderr, "Unable to create/flush ip6tables chain \"%s\".\n", chain);
-			exit(1);
-		}
-	}
 
 	/* ffwd journal */
 	sd_journal_add_match(j, FILTER_STRING, 0);
 	r = sd_journal_seek_tail(j);
 	sd_journal_wait(j, (uint64_t) 0);
-	fprintf(stderr, "sd_journal_seek_tail() returned %d\n", r);
+	dbg("sd_journal_seek_tail() returned %d\n", r);
 	while (sd_journal_next(j) != 0)
 		r++;
-	fprintf(stderr, "Forwarded through %d items in the journal to reach the end\n", r);
+	dbg("Forwarded through %d items in the journal to reach the end\n", r);
 
 	fprintf(stderr, "Started\n");
 
+	for (int i = 0; i < PATTERN_COUNT; i++) {
+		int err;
+		const char *pcre_err;
+		patterns[i].re = pcre_compile(patterns[i].pattern, 0, &pcre_err, &err, NULL);
+		if (!patterns[i].re) {
+			fprintf(stderr, "PCRE compilation failed. Pattern %d, offset %d: %s\n",
+				i, err, pcre_err);
+			exit(EXIT_FAILURE);
+		}
+	}
+
 	for (;;) {
 		const void *d;
 		size_t l;
@@ -353,9 +455,7 @@ int main(int argc, char *argv[])
 		}
 
 		while (sd_journal_next(j) != 0) {
-			char *t;
 			char *m;
-			int i;
 
 			if (sd_journal_get_data(j, "MESSAGE", &d, &l) < 0) {
 				fprintf(stderr, "Failed to read message field: %s\n", strerror(-r));
@@ -365,21 +465,22 @@ int main(int argc, char *argv[])
 			m = strndup(d, l+1);
 			m[l] = '\0';
 
-			if (strstr(m, "MESSAGE=Failed password for invalid user ")) {
-				t = strtok(m, " ");
-				for (i = 0; i < 7; i++)
-					t = strtok(NULL, " ");
-				find(t);
-			}
-
-			if (strstr(m, "MESSAGE=Failed password for root ")) {
-				t = strtok(m, " ");
-				for (i = 0; i < 5; i++)
-					t = strtok(NULL, " ");
-				find(t);
+			for (int i = 0; i < PATTERN_COUNT; i++) {
+				int off[MAX_OFFSETS];
+				int ret = pcre_exec(patterns[i].re, NULL, m, l, 0, 0, off, MAX_OFFSETS);
+				if (ret == 2) {
+					const char *s;
+					ret = pcre_get_substring(m, off, 2, 1, &s);
+					if (ret > 0) {
+						dbg("%s == %s\n", s, patterns[i].pattern);
+						find(s, patterns[i].weight, patterns[i].instant_block);
+						pcre_free_substring(s);
+					}
+				}
 			}
 
 			free(m);
+
 		}
 
 		prune();
@@ -387,5 +488,5 @@ int main(int argc, char *argv[])
 
 	sd_journal_close(j);
 
-	exit(0);
+	exit(EXIT_SUCCESS);
 }

tallow.conf

@@ -1,8 +1,7 @@
 
 # tallow.conf - see `man tallow.conf` for more information
 
-#path_iptables=/usr/sbin
-#threshold=3
+#ipt_path=/usr/sbin
 #expires=3600
 #whitelist=127.0.0.1
 #ipv6=0

tallow.conf.5

@@ -1,47 +1,57 @@
-.TH tallow.conf 5 "31 October 2012" ".5" "The tallow configuration file"
-.SH NAME
-tallow.conf \- Tallow daemon configuration file
-.SH SYNOPSIS
-/etc/tallow.conf
-.SH DESCRIPTION
-This file is read on startup by the tallow(1) daemon, and can
-be used to provide options to the tallow daemon. If not present,
-tallow will operate with built-in defaults.
-.SH OPTIONS
-.TP
-\fBiptables_path\fR=\<string\>
-Specifies the location of the iptables(1) or ip6tables(1)  program.
-By default, tallow will look in "/usr/sbin" for them.
-.TP
-\fBchain\fR=\<string\>
-Specifies the iptables(1) chain name to use for maintaining the
-block list. By default, tallow maintains its iptables(1) rules
-in the \fBTALLOW\fR chain.
-.TP
-\fBexpires\fR=\<int\>
-The number of seconds that IP addresses are blocked for. Note that
-due to the implementation, IP addresses may be blocked for much
-longer than this period. If IP addresses are seen, but not
-blocked within this period, they are also removed from the
-watch list. Defaults to 3600s.
-.TP
-\fBthreshold\fR=\<int\>
-Specifies the number of times an IP address may appear before it
-is blocked. Defaults to 3.
-.TP
-\fBwhitelist\fR=\<ipv4 address\>
-Specify an IP address that should never be blocked. Multiple IP
-addresses can be included by repeating the \fBwhitelist\fR
-option several times. By default, only 127.0.0.1 is whitelisted.
-.TP
-\fBipv6\fR=\<0|1\>
-Enable of disable ipv6 (ip6tables) support. Ipv6 is disabled
-automatically on systems that do not appear to have ipv6 support
-and enabled when ipv6 is present. Use this option to explicitly
-disable ipv6 support if your system does not have ipv6 or is
-missing ip6tables. Even with ipv6 disabled, tallow will track
-and log ipv6 addresses.
-.SH SEE ALSO
-tallow(1), iptables(1)
-.SH AUTHOR
-Auke Kok <auke-jan.h.kok@intel.com>
+.\" generated with Ronn/v0.7.3
+.\" http://github.com/rtomayko/ronn/tree/0.7.3
+.
+.TH "TALLOW" "5" "January 2018" "" ""
+.
+.SH "NAME"
+\fBtallow\fR
+.
+.SH "tallow\.conf"
+The tallow configuration file
+.
+.SH "NAME"
+tallow\.conf \- Tallow daemon configuration file
+.
+.SH "SYNOPSIS"
+\fB/etc/tallow\.conf\fR
+.
+.SH "DESCRIPTION"
+This file is read on startup by the tallow(1) daemon, and can be used to provide options to the tallow daemon\. If not present, tallow will operate with built\-in defaults\.
+.
+.SH "OPTIONS"
+\fBipt_path\fR=\fB<string>\fR Specifies the location of the ipset(1), iptables(1) or ip6tables(1) program\. By default, tallow will look in "/usr/sbin" for them\.
+.
+.P
+\fBexpires\fR=\fB<int>\fR The number of seconds that IP addresses are blocked for\. Note that due to the implementation, IP addresses may be blocked for much longer than this period\. If IP addresses are seen, but not blocked within this period, they are also removed from the watch list\. Defaults to 3600s\.
+.
+.P
+\fBwhitelist\fR=\fB<ip address|pattern>\fR Specify an IP address or \fBpattern\fR that should never be blocked\. Multiple IP addresses can be included by repeating the \fBwhitelist\fR option several times\. By default, only 127\.0\.0\.1 is whitelisted\.
+.
+.P
+If the last character of the listed ip adress is a \fB\.\fR or a \fB:\fR, then the matching is only performed on the leftmost characters of an IP address against the whitelist entry\. For instance, if you whitelist \fB10\.\fR then all IP addresses in the \fB10/8\fR subnet mask will match this whitelist entry and never be blocked\.
+.
+.P
+\fBipv6\fR=\fB<0|1>\fR Enable of disable ipv6 (ip6tables) support\. Ipv6 is disabled automatically on systems that do not appear to have ipv6 support and enabled when ipv6 is present\. Use this option to explicitly disable ipv6 support if your system does not have ipv6 or is missing ip6tables\. Even with ipv6 disabled, tallow will track and log ipv6 addresses\.
+.
+.P
+\fBnocreate\fR=\fB<0|1>\fR Disable the creation of iptables rules and ipset sets\. By default, tallow will create new iptables(1) and ip6tables(1) rules when needed automatically\. If set to \fB1\fR, \fBtallow(1)\fR will not create any new iptables rules or ipset sets to work\. You should create them manually before tallow starts up and remove them afterwards\. To create them manually, you can use the following commands:
+.
+.IP "" 4
+.
+.nf
+
+  iptables \-t filter \-I INPUT \-m set \-\-match\-set tallow src \-j DROP
+  ipset create tallow hash:ip family inet timeout 3600
+
+  ip6tables \-t filter \-I INPUT \-m set \-\-match\-set tallow6 src \-j DROP
+  ipset create tallow6 hash:ip family inet6 timeout 3600
+.
+.fi
+.
+.IP "" 0
+.
+.SH "SEE ALSO"
+tallow(1)
+.
+.SH "AUTHOR"
+Auke Kok \fIauke\-jan\.h\.kok@intel\.com\fR

tallow.conf.5.md

@@ -0,0 +1,76 @@
+
+## tallow.conf
+
+The tallow configuration file
+
+## NAME
+
+tallow.conf - Tallow daemon configuration file
+
+## SYNOPSIS
+
+`/etc/tallow.conf`
+
+## DESCRIPTION
+
+This file is read on startup by the tallow(1) daemon, and can
+be used to provide options to the tallow daemon. If not present,
+tallow will operate with built-in defaults.
+
+## OPTIONS
+
+`ipt_path`=`<string>`
+Specifies the location of the ipset(1), iptables(1) or ip6tables(1)
+program. By default, tallow will look in "/usr/sbin" for them.
+
+`expires`=`<int>`
+The number of seconds that IP addresses are blocked for. Note that
+due to the implementation, IP addresses may be blocked for much
+longer than this period. If IP addresses are seen, but not
+blocked within this period, they are also removed from the
+watch list. Defaults to 3600s.
+
+`whitelist`=`<ip address|pattern>`
+Specify an IP address or `pattern` that should never be
+blocked. Multiple IP addresses can be included by repeating the
+`whitelist` option several times. By default, only 127.0.0.1 is
+whitelisted.
+
+If the last character of the listed ip adress is a `.` or a `:`, then
+the matching is only performed on the leftmost characters of an IP
+address against the whitelist entry. For instance, if you whitelist
+`10.` then all IP addresses in the `10/8` subnet mask will match this
+whitelist entry and never be blocked.
+
+`ipv6`=`<0|1>`
+Enable of disable ipv6 (ip6tables) support. Ipv6 is disabled
+automatically on systems that do not appear to have ipv6 support
+and enabled when ipv6 is present. Use this option to explicitly
+disable ipv6 support if your system does not have ipv6 or is
+missing ip6tables. Even with ipv6 disabled, tallow will track
+and log ipv6 addresses.
+
+`nocreate`=`<0|1>`
+Disable the creation of iptables rules and ipset sets. By default,
+tallow will create new iptables(1) and ip6tables(1) rules when needed
+automatically. If set to `1`, `tallow(1)` will not create any new
+iptables rules or ipset sets to work. You should create them manually
+before tallow starts up and remove them afterwards. To create them
+manually, you can use the following commands:
+
+  ```
+  iptables -t filter -I INPUT -m set --match-set tallow src -j DROP
+  ipset create tallow hash:ip family inet timeout 3600
+
+  ip6tables -t filter -I INPUT -m set --match-set tallow6 src -j DROP
+  ipset create tallow6 hash:ip family inet6 timeout 3600
+  ```
+
+## SEE ALSO
+
+tallow(1)
+
+## AUTHOR
+
+Auke Kok <auke-jan.h.kok@intel.com>
+