** Description changed: NOTE TO SRU REVIEWER: the upload for stonking is ready, but I'm not uploading now to avoid disrupting the beta freeze. [ Impact ] * dnsmasq enters an infinite loop when handling a second PXE boot request when the dhcp-range option contains a set: directive. * This impacts users of LTSP, for example. * This is a regression introduced in the recent backport of 2.91 to Jammy and Noble. * In special, Ubuntu Resolute (which ships dnsmasq 2.92), is affected by another similar bug, also related to PXE. This is also fixed by this SRU. [ Test Plan ] * Create the following files in the current working directory: % cat 60-eth1.yaml network: version: 2 ethernets: eth1: dhcp4: true % cat dnsmasq.conf port=0 log-dhcp enable-tftp tftp-root=/srv/tftp interface=eth1 bind-interfaces dhcp-range=set:proxy,10.10.10.0,proxy,255.255.255.0 pxe-service=x86PC,"ltsp",ltsp/ltsp.ipxe % cat ltsp.ipxe #!ipxe echo BIOS boot shell * Create an isolated LXD network. lxc network create pxe ipv4.address=10.10.10.1/24 ipv4.dhcp=true ipv6.address=none sudo ip tuntap add dev tap-pxe mode tap sudo ip link set tap-pxe master pxe sudo ip link set dev tap-pxe up - * Deploy a dnsmasq container + * Deploy a dnsmasq container. Replace jammy with the release you're + testing lxc launch ubuntu:jammy dnsmasq-jammy lxc network attach pxe dnsmasq-jammy eth1 lxc file push 60-eth1.yaml dnsmasq-jammy/etc/netplan/ lxc exec dnsmasq-jammy -- netplan apply * Configure dnsmasq. If testing version from -proposed, enable it here and install dnsmasq from -proposed. lxc exec dnsmasq-jammy -- apt update lxc exec dnsmasq-jammy -- apt install -y dnsmasq lxc exec dnsmasq-jammy -- mkdir -p /srv/tftp/ltsp lxc file push ltsp.ipxe dnsmasq-jammy/srv/tftp/ltsp/ lxc file push dnsmasq.conf dnsmasq-jammy/etc/ lxc exec dnsmasq-jammy -- systemctl restart dnsmasq * Boot a VM that connects to the dnsmasq container. qemu-system-x86_64 -m 512 -nographic -netdev tap,id=n1,ifname=tap- pxe,script=no,downscript=no -device virtio-net,netdev=n1 * If the VM can boot twice with no errors, the bug is fixed. [ Where problems could occur ] * The patch modifies PXE packet parsing logic. If the patch is flawed, it could break other PXE usage. * The patch is not yet present upstream, and was not reviewed by the upstream maintainer. [ Other Info ] * This bug has not been fixed upstream, and is present in every release since 2.91. [ Original Report ] Hello, Security update dnsmasq 2.91-0ubuntu0.24.04.1 broke ProxyDHCP mode. LTSP (netbooted) clients can not boot anymore. Downgrading to 2.90-2ubuntu0.4 resolves the issue. This security update is now phased 40%, please stop shipping it so the rest 60% is unaffected. Thank you. @Affected users, you can restore the previous version of dnsmasq with: sudo apt install dnsmasq=2.90-2ubuntu0.4 dnsmasq-base=2.90-2ubuntu0.4 sudo apt-mark hold dnsmasq dnsmasq-base reboot
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2166430 Title: dnsmasq 2.91-0ubuntu0.24.04.1 update broke ProxyDHCP mode To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/dnsmasq/+bug/2166430/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
