add support for rpc match

2 files changed, 381 insertions, 5 deletions

diff --git a/extensions/Makefile b/extensions/Makefile
index 63980397..5d0d844e 100644
--- a/extensions/Makefile
+++ b/extensions/Makefile
@@ -1,10 +1,12 @@
 #! /usr/bin/make
 
-PF_EXT_SLIB:=ah conntrack dscp ecn esp helper icmp length limit mac mark multiport owner pkttype standard state tcp tcpmss tos ttl udp unclean DNAT DSCP ECN LOG MARK MASQUERADE MIRROR REDIRECT REJECT SAME SNAT TARPIT TCPMSS TOS ULOG
-PF6_EXT_SLIB:=eui64 icmpv6 length limit mac mark multiport owner standard tcp udp LOG MARK
-
-# The following may not be present, but compile them anyway.
-PF_EXT_SLIB+=TTL iplimit
+# WARNING:
+# only add extensions here that are either present in the kernel, or whose
+# header files are present in the include/linux directory of this iptables
+# package (HW)
+#
+PF_EXT_SLIB:=ah conntrack dscp ecn esp helper icmp iplimit length limit mac mark multiport owner pkttype rpc standard state tcp tcpmss tos ttl udp unclean DNAT DSCP ECN LOG MARK MASQUERADE MIRROR REDIRECT REJECT SAME SNAT TARPIT TCPMSS TOS TTL ULOG
+PF6_EXT_SLIB:=eui64 hl icmpv6 length limit mac mark multiport owner standard tcp udp HL LOG MARK
 
 # Optionals
 PF_EXT_SLIB_OPTS:=$(foreach T,$(wildcard extensions/.*-test),$(shell KERNEL_DIR=$(KERNEL_DIR) $(T)))
diff --git a/extensions/libipt_rpc.c b/extensions/libipt_rpc.c
new file mode 100644
index 00000000..e3400a87
--- /dev/null
+++ b/extensions/libipt_rpc.c
@@ -0,0 +1,374 @@
+/* RPC extension for IP connection matching, Version 2.2
+ * (C) 2000 by Marcelo Barbosa Lima <marcelo.lima@dcc.unicamp.br>
+ *	- original rpc tracking module
+ *	- "recent" connection handling for kernel 2.3+ netfilter
+ *
+ * (C) 2001 by Rusty Russell <rusty@rustcorp.com.au>
+ *	- upgraded conntrack modules to oldnat api - kernel 2.4.0+
+ *
+ * (C) 2002,2003 by Ian (Larry) Latter <Ian.Latter@mq.edu.au>
+ *	- upgraded conntrack modules to newnat api - kernel 2.4.20+
+ *	- extended matching to support filtering on procedures
+ *
+ * libipt_rpc.c,v 2.2 2003/01/12 18:30:00
+ *
+ *	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.
+ **
+ *	Userspace library syntax:
+ *	--rpc [--rpcs procedure1,procedure2,...procedure128] [--static]
+ *
+ *	Procedures can be supplied in either numeric or named formats.
+ *	Without --rpcs, this module will behave as the old record-rpc.
+ **
+ *	Note to all:
+ *
+ *	RPCs should not be exposed to the internet - ask the Pentagon;
+ *
+ *	  "The unidentified crackers pleaded guilty in July to charges
+ *	   of juvenile delinquency stemming from a string of Pentagon
+ *	   network intrusions in February.
+ *
+ *	   The youths, going by the names TooShort and Makaveli, used
+ *	   a common server security hole to break in, according to
+ *	   Dane Jasper, owner of the California Internet service
+ *	   provider, Sonic. They used the hole, known as the 'statd'
+ *	   exploit, to attempt more than 800 break-ins, Jasper said."
+ *
+ *	From: Wired News; "Pentagon Kids Kicked Off Grid" - Nov 6, 1998
+ *	URL:  http://www.wired.com/news/politics/0,1283,16098,00.html
+ **
+ */
+
+#include <stdio.h>
+#include <netdb.h>
+#include <string.h>
+#include <stdlib.h>
+#include <getopt.h>
+#include "/usr/include/rpc/rpc.h"
+
+#include <iptables.h>
+#include <linux/netfilter_ipv4/ipt_rpc.h>
+#include <time.h>
+
+
+const int IPT_RPC_RPCS = 1;
+const int IPT_RPC_STRC = 2;
+
+const int IPT_RPC_INT_LBL = 1;
+const int IPT_RPC_INT_NUM = 2;
+const int IPT_RPC_INT_BTH = 3;
+
+const int IPT_RPC_CHAR_LEN = 11;
+const int IPT_RPC_MAX_ENTS = 128;
+
+const char preerr[11] = "RPC match:";
+
+
+static int k_itoa(char *string, int number)
+{
+	int maxoctet = IPT_RPC_CHAR_LEN - 1;
+	int store[IPT_RPC_CHAR_LEN];
+	int counter;
+
+
+        for (counter=0 ; maxoctet != 0 && number != 0; counter++, maxoctet--) {
+		store[counter] = number / 10;
+		store[counter] = number - ( store[counter] * 10 );
+		number = number / 10;
+        }
+
+        for ( ; counter != 0; counter--, string++)
+		*string = store[counter - 1] + 48;
+
+	*string = 0;
+
+	return(0);
+}
+
+
+static int k_atoi(char *string)
+{
+	unsigned int result = 0;
+	int maxoctet = IPT_RPC_CHAR_LEN;
+
+
+        for ( ; *string != 0 && maxoctet != 0; maxoctet--, string++) {
+                if (*string < 0)
+                        return(0);
+                if (*string == 0)
+                        break;
+                if (*string < 48 || *string > 57) {
+                        return(0);
+                }
+                result = result * 10 + ( *string - 48 );
+        }
+
+	return(result);
+}
+
+
+static void print_rpcs(char *c_procs, int i_procs, int labels)
+{
+	int   proc_ctr;
+	char *proc_ptr;
+	unsigned int proc_num;
+	struct rpcent *rpcent;
+
+
+	for (proc_ctr=0; proc_ctr <= i_procs; proc_ctr++) {
+
+		if ( proc_ctr != 0 )
+			printf(",");
+
+		proc_ptr = c_procs;
+		proc_ptr += proc_ctr * IPT_RPC_CHAR_LEN;
+		proc_num = k_atoi(proc_ptr);
+
+		/* labels(1) == no labels, only numbers
+		 * labels(2) == no numbers, only labels
+		 * labels(3) == both labels and numbers
+		 */
+
+		if (labels == IPT_RPC_INT_LBL || labels == IPT_RPC_INT_BTH ) {
+			if ( (rpcent = getrpcbynumber(proc_num)) == NULL )
+				printf("unknown");
+			else
+				printf("%s", rpcent->r_name);
+		}
+
+		if (labels == IPT_RPC_INT_BTH )
+			printf("(");
+
+		if (labels == IPT_RPC_INT_NUM || labels == IPT_RPC_INT_BTH )
+			printf("%i", proc_num);
+
+		if (labels == IPT_RPC_INT_BTH )
+			printf(")");
+
+	}
+
+}
+
+
+static void help(void) 
+{
+	printf(
+		"RPC v%s options:\n"
+		"  --rpcs list,of,procedures"
+		"\ta list of rpc program numbers to apply\n"
+		"\t\t\t\tie. 100003,mountd,rquotad (numeric or\n"
+		"\t\t\t\tname form; see /etc/rpc).\n"
+		"  --strict"
+		"\t\t\ta flag to force the drop of packets\n"
+		"\t\t\t\tnot containing \"get\" portmapper requests.\n",
+		IPTABLES_VERSION);
+}
+
+
+static struct option opts[] = {
+	{ "rpcs", 1, 0, '1'},
+	{ "strict", 0, 0, '2'},
+	{0}
+};
+
+
+static void init(struct ipt_entry_match *match, unsigned int *nfcache)
+{
+	struct ipt_rpc_info *rpcinfo = ((struct ipt_rpc_info *)match->data);
+
+
+	/* caching not yet implemented */
+        *nfcache |= NFC_UNKNOWN;
+
+	/* initialise those funky user vars */
+	rpcinfo->i_procs = -1;
+	rpcinfo->strict  =  0;
+	memset((char *)rpcinfo->c_procs, 0, sizeof(rpcinfo->c_procs));
+}
+
+
+static void parse_rpcs_string(char *string, struct ipt_entry_match **match)
+{
+	char err1[64] = "%s invalid --rpcs option-set: `%s' (at character %i)";
+	char err2[64] = "%s unable to resolve rpc name entry: `%s'";
+	char err3[64] = "%s maximum number of --rpc options (%i) exceeded";
+	char buf[256];
+	char *dup = buf;
+	int idup = 0;
+	int term = 0;
+	char *src, *dst;
+	char *c_procs;
+	struct rpcent *rpcent_ptr;
+	struct ipt_rpc_info *rpcinfo = (struct ipt_rpc_info *)(*match)->data;
+
+
+	memset(buf, 0, sizeof(buf));
+
+	for (src=string, dst=buf; term != 1 ; src++, dst++) {
+
+		if ( *src != ',' && *src != '\0' ) {
+			if ( ( *src >= 65 && *src <= 90 ) || ( *src >= 97 && *src <= 122) ) {
+				*dst = *src;
+				idup = 1;
+
+			} else if ( *src >= 48 && *src <= 57 ) {
+				*dst = *src;
+
+			} else {
+				exit_error(PARAMETER_PROBLEM, err1, preerr,
+					   string, src - string + 1);
+
+			}
+
+		} else {
+			*dst = '\0';
+			if ( idup == 1 ) {
+				if ( (rpcent_ptr = getrpcbyname(dup)) == NULL )
+					exit_error(PARAMETER_PROBLEM, err2,
+						   preerr, dup);
+				idup = rpcent_ptr->r_number;
+			} else {
+				idup = k_atoi(dup);
+			}
+
+			rpcinfo->i_procs++;
+			if ( rpcinfo->i_procs > IPT_RPC_MAX_ENTS )
+				exit_error(PARAMETER_PROBLEM, err3, preerr,
+					   IPT_RPC_MAX_ENTS);
+				
+			c_procs  = (char *)rpcinfo->c_procs;
+			c_procs += rpcinfo->i_procs * IPT_RPC_CHAR_LEN;
+			
+			memset(buf, 0, sizeof(buf));
+			k_itoa((char *)dup, idup);
+
+			strcpy(c_procs, dup);
+	
+			if ( *src == '\0')
+				term = 1;
+
+			idup = 0;
+			memset(buf, 0, sizeof(buf));
+			dst = (char *)buf - 1;
+		}
+	}
+
+	return;
+}
+
+
+static int parse(int c, char **argv, int invert, unsigned int *flags,
+		const struct ipt_entry *entry,
+		unsigned int *nfcache,
+		struct ipt_entry_match **match)
+{
+	struct ipt_rpc_info *rpcinfo = (struct ipt_rpc_info *)(*match)->data;
+
+
+	switch (c)
+	{
+	case '1':
+		if (invert)
+			exit_error(PARAMETER_PROBLEM,
+                                   "%s unexpected '!' with --rpcs\n", preerr);
+		if (*flags & IPT_RPC_RPCS)
+                        exit_error(PARAMETER_PROBLEM,
+                                   "%s repeated use of --rpcs\n", preerr);
+		parse_rpcs_string(optarg, match);
+
+		*flags |= IPT_RPC_RPCS;
+		break;
+
+	case '2':
+		if (invert)
+			exit_error(PARAMETER_PROBLEM,
+                                   "%s unexpected '!' with --strict\n", preerr);
+		if (*flags & IPT_RPC_STRC)
+                        exit_error(PARAMETER_PROBLEM,
+                                   "%s repeated use of --strict\n", preerr);
+		rpcinfo->strict = 1;
+		*flags |= IPT_RPC_STRC;
+		break;
+
+	default:
+		return 0;
+	}
+
+	return 1;
+
+}
+
+
+static void final_check(unsigned int flags)
+{
+	if (flags != (flags | IPT_RPC_RPCS)) {
+		printf("%s option \"--rpcs\" was not used ... reverting ", preerr);
+		printf("to old \"record-rpc\" functionality ..\n");
+	}
+}
+
+
+static void print(const struct ipt_ip *ip,
+		const struct ipt_entry_match *match,
+		int numeric)
+{
+	struct ipt_rpc_info *rpcinfo = ((struct ipt_rpc_info *)match->data);
+
+
+	printf("RPCs");
+	if(rpcinfo->strict == 1)
+		printf("[strict]");
+
+	printf(": ");
+
+	if(rpcinfo->i_procs == -1) {
+		printf("any(*)");
+
+	} else {
+		print_rpcs((char *)&rpcinfo->c_procs, rpcinfo->i_procs, IPT_RPC_INT_BTH);
+	}
+	printf(" ");
+
+}
+
+
+static void save(const struct ipt_ip *ip, const struct ipt_entry_match *match)
+{
+	struct ipt_rpc_info *rpcinfo = ((struct ipt_rpc_info *)match->data);
+
+
+	if(rpcinfo->i_procs > -1) {
+		printf("--rpcs ");
+		print_rpcs((char *)&rpcinfo->c_procs, rpcinfo->i_procs, IPT_RPC_INT_NUM);
+		printf(" ");
+	}
+
+	if(rpcinfo->strict == 1)
+		printf("--strict ");
+
+}
+
+
+static struct iptables_match rpcstruct = { NULL,
+    "rpc",
+    IPTABLES_VERSION,
+    IPT_ALIGN(sizeof(struct ipt_rpc_info)),
+    IPT_ALIGN(sizeof(struct ipt_rpc_info)),
+    &help,
+    &init,
+    &parse,
+    &final_check,
+    &print,
+    &save,
+    opts
+};
+
+
+void _init(void)
+{
+	register_match(&rpcstruct);
+}
+