netfilter: xt_CT: fix assignation of the generic protocol tracker

`iptables -p all' uses 0 to match all protocols, while the conntrack
subsystem uses 255. We still need `-p all' to attach the custom
timeout policies for the generic protocol tracker.

Moreover, we may use `iptables -p sctp' while the SCTP tracker is
not loaded. In that case, we have to default on the generic protocol
tracker.

Another possibility is `iptables -p ip' that should be supported
as well. This patch makes sure we validate all possible scenarios.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 8 insertions, 1 deletions

diff --git a/net/netfilter/xt_CT.c b/net/netfilter/xt_CT.c
index 33a02b41abb4..0c8e43810ce3 100644
--- a/net/netfilter/xt_CT.c
+++ b/net/netfilter/xt_CT.c
@@ -14,6 +14,7 @@
 #include <linux/netfilter/x_tables.h>
 #include <linux/netfilter/xt_CT.h>
 #include <net/netfilter/nf_conntrack.h>
+#include <net/netfilter/nf_conntrack_l4proto.h>
 #include <net/netfilter/nf_conntrack_helper.h>
 #include <net/netfilter/nf_conntrack_ecache.h>
 #include <net/netfilter/nf_conntrack_l4proto.h>
@@ -224,6 +225,7 @@ static int xt_ct_tg_check_v1(const struct xt_tgchk_param *par)
 
                 if (timeout_find_get) {
                         const struct ipt_entry *e = par->entryinfo;
+                        struct nf_conntrack_l4proto *l4proto;
 
                         if (e->ip.invflags & IPT_INV_PROTO) {
                                 ret = -EINVAL;
@@ -245,7 +247,12 @@ static int xt_ct_tg_check_v1(const struct xt_tgchk_param *par)
                                         info->timeout, timeout->l3num);
                                 goto err4;
                         }
-                        if (timeout->l4proto->l4proto != e->ip.proto) {
+                        /* Make sure the timeout policy matches any existing
+                         * protocol tracker, otherwise default to generic.
+                         */
+                        l4proto = __nf_ct_l4proto_find(par->family,
+                                                       e->ip.proto);
+                        if (timeout->l4proto->l4proto != l4proto->l4proto) {
                                 ret = -EINVAL;
                                 pr_info("Timeout policy `%s' can only be "
                                         "used by L4 protocol number %d\n",