Author: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: Fri Nov 6 13:15:59 2026 -0500
Linux 6.6.162
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Author: Juergen Gross <jgross@suse.com>
Date: Thu Nov 5 08:27:38 2026 +0100
xen-blkback: Avoid UAF when reading I/O statistics
commit a02926f7c89bfc798ee9514e09694ff4279928a1 upstream.
Reading I/O statistics via sysfs concurrently with tearing down a
frontend device might result in UAF or a NULL dereference, as the
reading of the statistics data is not synchronized with freeing the
data.
Use a rwlock for synchronizing.
This is XSA-528 / CVE-2026-100082
Reported-by: Yehyeong Lee <yhlee@isslab.korea.ac.kr>
Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Roger Pau Monné <roger@xenproject.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Author: Jan Beulich <jbeulich@suse.com>
Date: Fri Nov 6 17:07:01 2026 +0100
xen-netback: defer xenvif_mcast_addr_list_free()
commit bfddc420afe827d9f06458cdf8087cd602f8c9cb upstream.
In order for the function to legitimately avoid locking/RCU, it needs to
run after all TX/RX processing has finished/stopped: Lookups happen from
xenvif_start_xmit(), while adds/removes happen from xenvif_tx_action()
(called out of xenvif_poll()).
Move the call out of xenvif_disconnect_data() (the call to the function
from connect()'s error path doesn't require any cleaning up there), and
put it past the synchronization point in backend_disconnect().
This is XSA-527 / CVE-2026-100081.
Fixes: b17075d5c198 ("xen-netback: fix race condition on XenBus disconnect")
Reported-by: kerhunt <kerhunt@proton.me>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Author: Juergen Gross <jgross@suse.com>
Date: Fri Nov 6 13:07:52 2026 +0100
xen-netback: Fix UAF when reading statistics data
commit 5fb756f1bbec7a3862dda5d79028bf656271804c upstream.
The network statistic data in the driver is protected by RCU.
Unfortunately when tearing down the queues after an error during
connecting to the frontend (e.g. due to illegal Xenstore data filled
in by the guest), the statistic data is being freed without
synchronizing the RCU state. In case the data is being read via sysfs
in this phase, access to already freed memory or memory being in new
use is possible.
Fix that by calling synchronize_net() before freeing the queue data.
This is XSA-526 / CVE-2026-100080
Reported-by: Yehyeong Lee <yhlee@isslab.korea.ac.kr>
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>