From 96f01b53c2d05e003b040892256de54a586e8529 Mon Sep 17 00:00:00 2001 From: Wyatt Feng Date: Sat, 29 Aug 2026 23:44:32 +0800 Subject: [PATCH] net: xfrm: reject unrepresentable espintcp transport headers ESP-in-TCP can hand xfrm packets whose transport header offset no longer fits after the stream parser trims the TCP envelope. The plain transport header reset truncates that offset and triggers the skb warning path. Use the careful transport-header helper and drop the skb through the existing XFRM error path when the offset cannot be represented. Fixes: e27cca96cd68 ("xfrm: add espintcp (RFC 8229)") Cc: stable@vger.kernel.org Reported-by: Vega Assisted-by: Codex:GPT-5.4 Signed-off-by: Wyatt Feng Signed-off-by: Ren Wei Signed-off-by: Steffen Klassert --- net/xfrm/espintcp.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/net/xfrm/espintcp.c b/net/xfrm/espintcp.c index 674aedc5af5a..3e72b9f067b9 100644 --- a/net/xfrm/espintcp.c +++ b/net/xfrm/espintcp.c @@ -30,7 +30,11 @@ static void handle_esp(struct sk_buff *skb, struct sock *sk) { struct tcp_skb_cb *tcp_cb = (struct tcp_skb_cb *)skb->cb; - skb_reset_transport_header(skb); + if (!skb_reset_transport_header_careful(skb)) { + XFRM_INC_STATS(sock_net(sk), LINUX_MIB_XFRMINERROR); + kfree_skb(skb); + return; + } /* restore IP CB, we need at least IP6CB->nhoff */ memmove(skb->cb, &tcp_cb->header, sizeof(tcp_cb->header));