[NETFILTER]: PPTP conntrack: fix another GRE keymap leak

When the master PPTP connection times out while still having unfullfilled
expectations (and a GRE keymap entry) associated with it, the keymap entry
is not destroyed.

Add a destroy callback to struct ip_conntrack_helper and use it to destroy
PPTP siblings when the master is destroyed.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 9 insertions, 10 deletions

diff --git a/include/linux/netfilter_ipv4/ip_conntrack_helper.h b/include/linux/netfilter_ipv4/ip_conntrack_helper.h
index 8d69279ccfe4..77fe868d36ff 100644
--- a/include/linux/netfilter_ipv4/ip_conntrack_helper.h
+++ b/include/linux/netfilter_ipv4/ip_conntrack_helper.h
@@ -25,6 +25,8 @@ struct ip_conntrack_helper
                     struct ip_conntrack *ct,
                     enum ip_conntrack_info conntrackinfo);
 
+        void (*destroy)(struct ip_conntrack *ct);
+
         int (*to_nfattr)(struct sk_buff *skb, const struct ip_conntrack *ct);
 };
 
diff --git a/net/ipv4/netfilter/ip_conntrack_core.c b/net/ipv4/netfilter/ip_conntrack_core.c
index 2b6f24fc727e..c432b3163609 100644
--- a/net/ipv4/netfilter/ip_conntrack_core.c
+++ b/net/ipv4/netfilter/ip_conntrack_core.c
@@ -307,6 +307,7 @@ destroy_conntrack(struct nf_conntrack *nfct)
 {
         struct ip_conntrack *ct = (struct ip_conntrack *)nfct;
         struct ip_conntrack_protocol *proto;
+        struct ip_conntrack_helper *helper;
 
         DEBUGP("destroy_conntrack(%p)\n", ct);
         IP_NF_ASSERT(atomic_read(&nfct->use) == 0);
@@ -315,6 +316,10 @@ destroy_conntrack(struct nf_conntrack *nfct)
         ip_conntrack_event(IPCT_DESTROY, ct);
         set_bit(IPS_DYING_BIT, &ct->status);
 
+        helper = ct->helper;
+        if (helper && helper->destroy)
+                helper->destroy(ct);
+
         /* To make sure we don't get any weird locking issues here:
          * destroy_conntrack() MUST NOT be called with a write lock
          * to ip_conntrack_lock!!! -HW */
diff --git a/net/ipv4/netfilter/ip_conntrack_helper_pptp.c b/net/ipv4/netfilter/ip_conntrack_helper_pptp.c
index 98267b0d2a47..fb0aee691721 100644
--- a/net/ipv4/netfilter/ip_conntrack_helper_pptp.c
+++ b/net/ipv4/netfilter/ip_conntrack_helper_pptp.c
@@ -553,15 +553,6 @@ conntrack_pptp_help(struct sk_buff **pskb,
         nexthdr_off += tcph->doff * 4;
         datalen = tcplen - tcph->doff * 4;
 
-        if (tcph->fin || tcph->rst) {
-                DEBUGP("RST/FIN received, timeouting GRE\n");
-                /* can't do this after real newnat */
-                info->cstate = PPTP_CALL_NONE;
-
-                /* untrack this call id, unexpect GRE packets */
-                pptp_destroy_siblings(ct);
-        }
-
         pptph = skb_header_pointer(*pskb, nexthdr_off, sizeof(_pptph), &_pptph);
         if (!pptph) {
                 DEBUGP("no full PPTP header, can't track\n");
@@ -640,7 +631,8 @@ static struct ip_conntrack_helper pptp = {
                            .protonum = 0xff
                          }
                 },
-        .help = conntrack_pptp_help
+        .help = conntrack_pptp_help,
+        .destroy = pptp_destroy_siblings,
 };
 
 extern void ip_ct_proto_gre_fini(void);