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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 14:28:35 +0200
commit6af5cdb03819a5ce6e945992635c6c5e91045367 (patch)
tree7b654a19d3bd4d92b5e44afbff3bcea69dc7fd77
parent4bc0dfa28dca6fc0084203732695968049c44072 (diff)
downloadlinux-stable-6af5cdb03819a5ce6e945992635c6c5e91045367.tar.gz
linux-stable-6af5cdb03819a5ce6e945992635c6c5e91045367.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 e618f7626482..6e3a62660a93 100644
--- a/net/xfrm/espintcp.c
+++ b/net/xfrm/espintcp.c
@@ -38,6 +38,11 @@ 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)
@@ -46,6 +51,7 @@ 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();
}