CVE-2022-49687

/// Technical description

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

virtio_net: fix xdp_rxq_info bug after suspend/resume

The following sequence currently causes a driver bug warning

when using virtio_net:

# ip link set eth0 up

# echo mem > /sys/power/state (or e.g. # rtcwake -s 10 -m mem)

<resume>

# ip link set eth0 down

Missing register, driver bug

WARNING: CPU: 0 PID: 375 at net/core/xdp.c:138 xdp_rxq_info_unreg+0x58/0x60

Call trace:

xdp_rxq_info_unreg+0x58/0x60

virtnet_close+0x58/0xac

__dev_close_many+0xac/0x140

__dev_change_flags+0xd8/0x210

dev_change_flags+0x24/0x64

do_setlink+0x230/0xdd0

...

This happens because virtnet_freeze() frees the receive_queue

completely (including struct xdp_rxq_info) but does not call

xdp_rxq_info_unreg(). Similarly, virtnet_restore() sets up the

receive_queue again but does not call xdp_rxq_info_reg().

Actually, parts of virtnet_freeze_down() and virtnet_restore_up()

are almost identical to virtnet_close() and

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References