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authorZhiling Zou <roxy520tt@gmail.com>2026-07-18 15:12:50 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2026-09-02 14:29:20 +0200
commit2dd1609cadff46c4b20ce53b91ab9cce1380456a (patch)
treedd606f8889388340b084525ba8bc33160ce1f7bb
parentff8dd7a932f34409a56e1b91a1219340f17457e9 (diff)
downloadlinux-2dd1609cadff46c4b20ce53b91ab9cce1380456a.tar.gz
linux-2dd1609cadff46c4b20ce53b91ab9cce1380456a.zip
xfrm: drop ESP-in-TCP packets with no ingress device
commit e1d7c5ac1c246ce5775f604515de0a59fbf2116e upstream. ESP-in-TCP receives records through the TCP strparser. handle_esp() restores skb->dev from the saved skb_iif before passing the packet into the XFRM input path. Queued TCP data can be processed after the original ingress device has been removed, for example during veth or net namespace teardown. In that case dev_get_by_index_rcu() returns NULL. The XFRM IPv4 and IPv6 input paths both expect skb->dev to be valid while building the route lookup, so queued ESP-in-TCP data can dereference a NULL device. Drop the packet if the saved ingress device can no longer be resolved. Such a packet can no longer be routed through the normal XFRM receive path, and this preserves the existing behaviour for packets whose ingress device still exists. Fixes: e27cca96cd68 ("xfrm: add espintcp (RFC 8229)") Cc: stable@vger.kernel.org Reported-by: Vega <vega@nebusec.ai> Signed-off-by: Zhiling Zou <roxy520tt@gmail.com> Assisted-by: Codex:gpt-5.4 Reviewed-by: Ren Wei <enjou1224z@gmail.com> Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--net/xfrm/espintcp.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/net/xfrm/espintcp.c b/net/xfrm/espintcp.c
index 8c971b75e118..a066301658f2 100644
--- a/net/xfrm/espintcp.c
+++ b/net/xfrm/espintcp.c
@@ -39,6 +39,11 @@ static void handle_esp(struct sk_buff *skb, struct sock *sk)
rcu_read_lock();
skb->dev = dev_get_by_index_rcu(sock_net(sk), skb->skb_iif);
+ if (!skb->dev) {
+ XFRM_INC_STATS(sock_net(sk), LINUX_MIB_XFRMINERROR);
+ kfree_skb(skb);
+ goto out;
+ }
local_bh_disable();
#if IS_ENABLED(CONFIG_IPV6)
if (sk->sk_family == AF_INET6)
@@ -47,6 +52,7 @@ static void handle_esp(struct sk_buff *skb, struct sock *sk)
#endif
xfrm4_rcv_encap(skb, IPPROTO_ESP, 0, TCP_ENCAP_ESPINTCP);
local_bh_enable();
+out:
rcu_read_unlock();
}