From: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
Add egress hook for AF_PACKET sockets that have the PACKET_QDISC_BYPASS
socket option set to on, which allows packets to escape without being
filtered in the egress path.
This patch only updates the AF_PACKET path, it does not update
dev_direct_xmit() so the XDP infrastructure has a chance to bypass
Netfilter.
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
[lukas: acquire rcu_read_lock, fix typos, rebase]
Signed-off-by: Lukas Wunner <lukas@xxxxxxxxx>
---
net/packet/af_packet.c | 35 +++++++++++++++++++++++++++++++++++
1 file changed, 35 insertions(+)
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 2a2bc64f75cf..46943a18a10d 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -91,6 +91,7 @@
#endif
#include <linux/bpf.h>
#include <net/compat.h>
+#include <linux/netfilter_netdev.h>
#include "internal.h"
@@ -241,8 +242,42 @@ struct packet_skb_cb {
static void __fanout_unlink(struct sock *sk, struct packet_sock *po);
static void __fanout_link(struct sock *sk, struct packet_sock *po);
+#ifdef CONFIG_NETFILTER_EGRESS
+static noinline struct sk_buff *nf_hook_direct_egress(struct sk_buff *skb)
+{
+ struct sk_buff *next, *head = NULL, *tail;
+ int rc;
+
+ rcu_read_lock();
+ for (; skb != NULL; skb = next) {
+ next = skb->next;
+ skb_mark_not_on_list(skb);
+
+ if (!nf_hook_egress(skb, &rc, skb->dev))
+ continue;
+
+ if (!head)
+ head = skb;
+ else
+ tail->next = skb;
+
+ tail = skb;
+ }
+ rcu_read_unlock();
+
+ return head;
+}
+#endif
+
static int packet_direct_xmit(struct sk_buff *skb)
{
+#ifdef CONFIG_NETFILTER_EGRESS
+ if (nf_hook_egress_active()) {
+ skb = nf_hook_direct_egress(skb);
+ if (!skb)
+ return NET_XMIT_DROP;
+ }
+#endif
return dev_direct_xmit(skb, packet_pick_tx_queue(skb));
}
--
2.31.1
