Git init

1 files changed, 155 insertions, 0 deletions

diff --git a/extensions/libxt_osf.c b/extensions/libxt_osf.c
new file mode 100644
index 0000000..07b86e4
--- /dev/null
+++ b/extensions/libxt_osf.c
@@ -0,0 +1,155 @@
+/*
+ * Copyright (c) 2003+ Evgeniy Polyakov <zbr@ioremap.net>
+ *
+ *
+ * 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
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+/*
+ * xtables interface for OS fingerprint matching module.
+ */
+
+#include <stdio.h>
+#include <netdb.h>
+#include <string.h>
+#include <stdlib.h>
+#include <getopt.h>
+#include <ctype.h>
+
+#include <linux/types.h>
+
+#include <xtables.h>
+
+#include <netinet/ip.h>
+#include <netinet/tcp.h>
+
+#include <linux/netfilter/xt_osf.h>
+
+static void osf_help(void)
+{
+	printf("OS fingerprint match options:\n"
+		"[!] --genre string     Match a OS genre by passive fingerprinting.\n"
+		"--ttl level            Use some TTL check extensions to determine OS:\n"
+		"       0                       true ip and fingerprint TTL comparison. Works for LAN.\n"
+		"       1                       check if ip TTL is less than fingerprint one. Works for global addresses.\n"
+		"       2                       do not compare TTL at all. Allows to detect NMAP, but can produce false results.\n"
+		"--log level            Log determined genres into dmesg even if they do not match desired one:\n"
+		"       0                       log all matched or unknown signatures.\n"
+		"       1                       log only first one.\n"
+		"       2                       log all known matched signatures.\n"
+		);
+}
+
+
+static const struct option osf_opts[] = {
+	{ .name = "genre",	.has_arg = true, .val = '1' },
+	{ .name = "ttl",	.has_arg = true, .val = '2' },
+	{ .name = "log",	.has_arg = true, .val = '3' },
+	{ .name = NULL }
+};
+
+
+static void osf_parse_string(const char *s, struct xt_osf_info *info)
+{
+	if (strlen(s) < MAXGENRELEN)
+		strcpy(info->genre, s);
+	else
+		xtables_error(PARAMETER_PROBLEM,
+			      "Genre string too long `%s' [%zd], max=%d",
+			      s, strlen(s), MAXGENRELEN);
+}
+
+static int osf_parse(int c, char **argv, int invert, unsigned int *flags,
+      			const void *entry,
+      			struct xt_entry_match **match)
+{
+	struct xt_osf_info *info = (struct xt_osf_info *)(*match)->data;
+
+	switch(c) {
+		case '1': /* --genre */
+			if (*flags & XT_OSF_GENRE)
+				xtables_error(PARAMETER_PROBLEM,
+					      "Can't specify multiple genre parameter");
+			xtables_check_inverse(optarg, &invert, &optind, 0, argv);
+			osf_parse_string(argv[optind-1], info);
+			if (invert)
+				info->flags |= XT_OSF_INVERT;
+			info->len=strlen(info->genre);
+			*flags |= XT_OSF_GENRE;
+			break;
+		case '2': /* --ttl */
+			if (*flags & XT_OSF_TTL)
+				xtables_error(PARAMETER_PROBLEM,
+					      "Can't specify multiple ttl parameter");
+			*flags |= XT_OSF_TTL;
+			info->flags |= XT_OSF_TTL;
+			if (!xtables_strtoui(argv[optind-1], NULL, &info->ttl, 0, 2))
+				xtables_error(PARAMETER_PROBLEM, "TTL parameter is too big");
+			break;
+		case '3': /* --log */
+			if (*flags & XT_OSF_LOG)
+				xtables_error(PARAMETER_PROBLEM,
+					      "Can't specify multiple log parameter");
+			*flags |= XT_OSF_LOG;
+			if (!xtables_strtoui(argv[optind-1], NULL, &info->loglevel, 0, 2))
+				xtables_error(PARAMETER_PROBLEM, "Log level parameter is too big");
+			info->flags |= XT_OSF_LOG;
+			break;
+		default:
+			return 0;
+	}
+
+	return 1;
+}
+
+static void osf_final_check(unsigned int flags)
+{
+	if (!flags)
+		xtables_error(PARAMETER_PROBLEM,
+			      "OS fingerprint match: You must specify `--genre'");
+}
+
+static void osf_print(const void *ip, const struct xt_entry_match *match, int numeric)
+{
+	const struct xt_osf_info *info = (const struct xt_osf_info*) match->data;
+
+	printf("OS fingerprint match %s%s ", (info->flags & XT_OSF_INVERT) ? "! " : "", info->genre);
+}
+
+static void osf_save(const void *ip, const struct xt_entry_match *match)
+{
+	const struct xt_osf_info *info = (const struct xt_osf_info*) match->data;
+
+	printf("--genre %s%s ", (info->flags & XT_OSF_INVERT) ? "! ": "", info->genre);
+}
+
+static struct xtables_match osf_match = {
+	.name		= "osf",
+	.version	= XTABLES_VERSION,
+	.size		= XT_ALIGN(sizeof(struct xt_osf_info)),
+	.userspacesize	= XT_ALIGN(sizeof(struct xt_osf_info)),
+	.help		= osf_help,
+	.parse		= osf_parse,
+	.print		= osf_print,
+	.final_check	= osf_final_check,
+	.save		= osf_save,
+	.extra_opts	= osf_opts,
+	.family		= NFPROTO_IPV4
+};
+
+void _init(void)
+{
+	xtables_register_match(&osf_match);
+}