CVE-2022-49687

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)

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 virtnet_open(): only the calls to xdp_rxq_info_(un)reg() are missing. This means that we can fix this easily and avoid such problems in the future by just calling virtnet_close()/open() from the freeze/restore handlers.

Aside from adding the missing xdp_rxq_info calls the only difference is that the refill work is only cancelled if netif_running(). However, this should not make any functional difference since the refill work should only be active if the network interface is actually up.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.