From 59630e2ccd728703cc826e3a3515d70f8c7a766c Mon Sep 17 00:00:00 2001 From: Jianbo Liu Date: Wed, 29 Oct 2025 11:50:25 +0200 Subject: [PATCH] xfrm: Prevent locally generated packets from direct output in tunnel mode Add a check to ensure locally generated packets (skb->sk != NULL) do not use direct output in tunnel mode, as these packets require proper L2 header setup that is handled by the normal XFRM processing path. Fixes: 5eddd76ec2fd ("xfrm: fix tunnel mode TX datapath in packet offload mode") Signed-off-by: Jianbo Liu Reviewed-by: Leon Romanovsky Signed-off-by: Steffen Klassert --- net/xfrm/xfrm_output.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/net/xfrm/xfrm_output.c b/net/xfrm/xfrm_output.c index a98b5bf55ac31..54222fcbd7fd8 100644 --- a/net/xfrm/xfrm_output.c +++ b/net/xfrm/xfrm_output.c @@ -772,8 +772,12 @@ int xfrm_output(struct sock *sk, struct sk_buff *skb) /* Exclusive direct xmit for tunnel mode, as * some filtering or matching rules may apply * in transport mode. + * Locally generated packets also require + * the normal XFRM path for L2 header setup, + * as the hardware needs the L2 header to match + * for encryption, so skip direct output as well. */ - if (x->props.mode == XFRM_MODE_TUNNEL) + if (x->props.mode == XFRM_MODE_TUNNEL && !skb->sk) return xfrm_dev_direct_output(sk, x, skb); return xfrm_output_resume(sk, skb, 0); -- 2.47.3