Alignment problem between 64bit kernel 32bit userspace

Sven-Haegar Koch reported the issue:

sims:~# iptables -A OUTPUT -m set --match-set testset src -j ACCEPT
iptables: Invalid argument. Run `dmesg' for more information.

In syslog:
x_tables: ip_tables: set.3 match: invalid size 48 (kernel) != (user) 32

which was introduced by the counter extension in ipset.

The patch fixes the alignment issue with introducing a new set match
revision with the fixed underlying 'struct ip_set_counter_match'
structure.

2 files changed, 18 insertions, 3 deletions

diff --git a/kernel/include/uapi/linux/netfilter/ipset/ip_set.h b/kernel/include/uapi/linux/netfilter/ipset/ip_set.h
index ae4127d..337ecd5 100644
--- a/kernel/include/uapi/linux/netfilter/ipset/ip_set.h
+++ b/kernel/include/uapi/linux/netfilter/ipset/ip_set.h
@@ -257,11 +257,17 @@ enum {
 	IPSET_COUNTER_GT,
 };
 
-struct ip_set_counter_match {
+/* Backward compatibility for set match v3 */
+struct ip_set_counter_match0 {
 	__u8 op;
 	__u64 value;
 };
 
+struct ip_set_counter_match {
+	__aligned_u64 value;
+	__u8 op;
+};
+
 /* Interface to iptables/ip6tables */
 
 #define SO_IP_SET		83
diff --git a/kernel/include/uapi/linux/netfilter/xt_set.h b/kernel/include/uapi/linux/netfilter/xt_set.h
index d6a1df1..d4e0234 100644
--- a/kernel/include/uapi/linux/netfilter/xt_set.h
+++ b/kernel/include/uapi/linux/netfilter/xt_set.h
@@ -66,8 +66,8 @@ struct xt_set_info_target_v2 {
 
 struct xt_set_info_match_v3 {
 	struct xt_set_info match_set;
-	struct ip_set_counter_match packets;
-	struct ip_set_counter_match bytes;
+	struct ip_set_counter_match0 packets;
+	struct ip_set_counter_match0 bytes;
 	__u32 flags;
 };
 
@@ -81,4 +81,13 @@ struct xt_set_info_target_v3 {
 	__u32 timeout;
 };
 
+/* Revision 4 match */
+
+struct xt_set_info_match_v4 {
+	struct xt_set_info match_set;
+	struct ip_set_counter_match packets;
+	struct ip_set_counter_match bytes;
+	__u32 flags;
+};
+
 #endif /*_XT_SET_H*/