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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 14:26:44 +0200
commit239d0f71af09dc2029fd4d730cb24b8c83aaa43a (patch)
treed4565b0d8ba518a90e472131e35814b523ae957c
parent29121c5e6591da527e8e36ddac7120dc527f574d (diff)
downloadlinux-stable-239d0f71af09dc2029fd4d730cb24b8c83aaa43a.tar.gz
linux-stable-239d0f71af09dc2029fd4d730cb24b8c83aaa43a.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 eca1b4838a10..c929bef82368 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();
}