openvswitch: fix lockup on tx to unregistering netdev with c…(CVE-2025-21681)

概要

openvswitch: fix lockup on tx to unregistering netdev with carrier

原文の説明

取得元が公開している説明をそのまま載せています (多くは英語)。

In the Linux kernel, the following vulnerability has been resolved:

openvswitch: fix lockup on tx to unregistering netdev with carrier

Commit in a fixes tag attempted to fix the issue in the following
sequence of calls:

do_output
-> ovs_vport_send
   -> dev_queue_xmit
      -> __dev_queue_xmit
         -> netdev_core_pick_tx
            -> skb_tx_hash

When device is unregistering, the 'dev->real_num_tx_queues' goes to
zero and the 'while (unlikely(hash >= qcount))' loop inside the
'skb_tx_hash' becomes infinite, locking up the core forever.

But unfortunately, checking just the carrier status is not enough to
fix the issue, because some devices may still be in unregistering
state while reporting carrier status OK.

One example of such device is a net/dummy. It sets carrier ON
on start, but it doesn't implement .ndo_stop to set the carrier off.
And it makes sense, because dummy doesn't really have a carrier.
Therefore, while this device is unregistering, it's still easy to hit
the infinite loop in the skb_tx_hash() from the OVS datapath. There
might be other drivers that do the same, but dummy by itself is
important for the OVS ecosystem, because it is frequently used as a
packet sink for tcpdump while debugging OVS deployments. And when the
issue is hit, the only way to recover is to reboot.

Fix that by also checking if the device is running. The running
state is handled by the net core during unregistering, so it covers
unregistering case bet…

出典: OSV.dev (Open Source Vulnerabilities) NVD OSV

影響パッケージ

Linux Kernel

[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.1.127"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.74"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.3.0"},{"fixed":"6.12.11"}]}]

ディストリビューション別の修正状況

各ディストリビューションが公開している、この CVE の修正パッケージ

BellSoft Alpaquita BELL-CVE-2025-21681 linux-lts 修正版: 6.1.127-r0
Debian DEBIAN-CVE-2025-21681 linux 修正版: 6.1.128-1
Ubuntu UBUNTU-CVE-2025-21681 linux-hwe-edge

概要

原文の説明

影響パッケージ

ディストリビューション別の修正状況

参照URL