From 3488eecf1a5d9baa1808eaea7670a7aa2931e1ad Mon Sep 17 00:00:00 2001
From: Jo-Philipp Wich <jow@openwrt.org>
Date: Thu, 2 May 2013 16:44:50 +0200
Subject: [PATCH] Check whether ipset exists before referencing it in rules or
 redirects

---
 ipsets.c    | 37 +++++++++++++++++++++++++++++++++++++
 ipsets.h    |  5 +++++
 redirects.c |  8 ++++++++
 rules.c     |  8 ++++++++
 4 files changed, 58 insertions(+)

diff --git a/ipsets.c b/ipsets.c
index 713b343..9f43523 100644
--- a/ipsets.c
+++ b/ipsets.c
@@ -358,3 +358,40 @@ fw3_lookup_ipset(struct fw3_state *state, const char *name)
 
 	return NULL;
 }
+
+bool
+fw3_check_ipset(struct fw3_ipset *set)
+{
+	bool rv = false;
+
+	socklen_t sz;
+	int s = socket(AF_INET, SOCK_RAW, IPPROTO_RAW);
+	struct ip_set_req_version req_ver;
+	struct ip_set_req_get_set req_name;
+
+	if (s < 0 || fcntl(s, F_SETFD, FD_CLOEXEC))
+		goto out;
+
+	sz = sizeof(req_ver);
+	req_ver.op = IP_SET_OP_VERSION;
+
+	if (getsockopt(s, SOL_IP, SO_IP_SET, &req_ver, &sz))
+		goto out;
+
+	sz = sizeof(req_name);
+	req_name.op = IP_SET_OP_GET_BYNAME;
+	req_name.version = req_ver.version;
+	snprintf(req_name.set.name, IPSET_MAXNAMELEN - 1, "%s",
+	         (set->external && *set->external) ? set->external : set->name);
+
+	if (getsockopt(s, SOL_IP, SO_IP_SET, &req_name, &sz))
+		goto out;
+
+	rv = ((sz == sizeof(req_name)) && (req_name.set.index != IPSET_INVALID_ID));
+
+out:
+	if (s >= 0)
+		close(s);
+
+	return rv;
+}
diff --git a/ipsets.h b/ipsets.h
index 929f311..9704177 100644
--- a/ipsets.h
+++ b/ipsets.h
@@ -19,9 +19,12 @@
 #ifndef __FW3_IPSETS_H
 #define __FW3_IPSETS_H
 
+#include <linux/netfilter/ipset/ip_set.h>
+
 #include "options.h"
 #include "utils.h"
 
+
 extern const struct fw3_option fw3_ipset_opts[];
 
 struct fw3_ipset * fw3_alloc_ipset(void);
@@ -31,6 +34,8 @@ void fw3_destroy_ipsets(struct fw3_state *state);
 
 struct fw3_ipset * fw3_lookup_ipset(struct fw3_state *state, const char *name);
 
+bool fw3_check_ipset(struct fw3_ipset *set);
+
 #define fw3_free_ipset(ipset) \
 	fw3_free_object(ipset, fw3_ipset_opts)
 
diff --git a/redirects.c b/redirects.c
index 6ea91b8..24d1356 100644
--- a/redirects.c
+++ b/redirects.c
@@ -372,6 +372,14 @@ print_redirect(struct fw3_state *state, enum fw3_family family,
 			return;
 		}
 
+		if (!fw3_check_ipset(redir->_ipset))
+		{
+			info("     ! Skipping due to missing ipset '%s'",
+			     (redir->_ipset->external && *redir->_ipset->external) ?
+					redir->_ipset->external : redir->_ipset->name);
+			return;
+		}
+
 		set(redir->_ipset->flags, family, family);
 	}
 
diff --git a/rules.c b/rules.c
index 5a6ea00..785621f 100644
--- a/rules.c
+++ b/rules.c
@@ -365,6 +365,14 @@ expand_rule(struct fw3_state *state, enum fw3_family family,
 			return;
 		}
 
+		if (!fw3_check_ipset(rule->_ipset))
+		{
+			info("     ! Skipping due to missing ipset '%s'",
+			     (rule->_ipset->external && *rule->_ipset->external) ?
+					rule->_ipset->external : rule->_ipset->name);
+			return;
+		}
+
 		set(rule->_ipset->flags, family, family);
 	}
 
-- 
2.25.1