linux-kernel - [PATCH net] ipvlan: Ignore PACKET_LOOPBACK in handle_mode

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <20251202103906.4087675-1-skorodumov.dmitry@huawei.com>
Date: Tue, 2 Dec 2025 13:39:03 +0300
From: Dmitry Skorodumov <skorodumov.dmitry@...wei.com>
To: <netdev@...r.kernel.org>, Jakub Kicinski <kuba@...nel.org>, Dmitry
 Skorodumov <skorodumov.dmitry@...wei.com>, Julian Vetter
	<julian@...er-limits.org>, Guillaume Nault <gnault@...hat.com>, Eric Dumazet
	<edumazet@...gle.com>, Mahesh Bandewar <maheshb@...gle.com>, "David S.
 Miller" <davem@...emloft.net>, <linux-kernel@...r.kernel.org>
CC: Andrew Lunn <andrew+netdev@...n.ch>, Paolo Abeni <pabeni@...hat.com>
Subject: [PATCH net] ipvlan: Ignore PACKET_LOOPBACK in handle_mode_l2()

Packets with pkt_type == PACKET_LOOPBACK are captured by
handle_frame() function, but they don't have L2 header.
We should not process them in handle_mode_l2().

This doesn't affect old L2 functionality, since handling
was anyway incorrect.

Handle them the same way as in br_handle_frame():
just pass the skb.

To observe invalid behaviour, just start "ping -b" on bcast address
of port-interface.

Fixes: 2ad7bf363841 ("ipvlan: Initial check-in of the IPVLAN driver.")
Signed-off-by: Dmitry Skorodumov <skorodumov.dmitry@...wei.com>
---
 drivers/net/ipvlan/ipvlan_core.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/net/ipvlan/ipvlan_core.c b/drivers/net/ipvlan/ipvlan_core.c
index dea411e132db..2efa3ba148aa 100644
--- a/drivers/net/ipvlan/ipvlan_core.c
+++ b/drivers/net/ipvlan/ipvlan_core.c
@@ -737,6 +737,9 @@ static rx_handler_result_t ipvlan_handle_mode_l2(struct sk_buff **pskb,
 	struct ethhdr *eth = eth_hdr(skb);
 	rx_handler_result_t ret = RX_HANDLER_PASS;
 
+	if (unlikely(skb->pkt_type == PACKET_LOOPBACK))
+		return RX_HANDLER_PASS;
+
 	if (is_multicast_ether_addr(eth->h_dest)) {
 		if (ipvlan_external_frame(skb, port)) {
 			struct sk_buff *nskb = skb_clone(skb, GFP_ATOMIC);
-- 
2.25.1