Package: dhcpcd-base Version: 9.4.1-22 Severity: critical Tags: security Justification: breaks unrelated software X-Debbugs-Cc: Debian Security Team <t...@security.debian.org>
When the dhcpcd DHCPv4 client receives a zero-length UDP packet on port 68, the "network proxy" dhcpcd process exits with status 0. dhcpcd then stops all network activity: It does not renew leases and eventually expires the current lease (unless it has infinite duration) and removes the IP address, leaving the system without networking. This bug can be triggered remotely over the internet from any UDP port and is critical on an internet-facing system that needs DHCP to get an IP address, such as a gateway, a dedicated server or a VM. This affects version 9.4.1-22 (stable) and 1:9.4.1-24~deb12u2 (stable proposed update) but not 1:10.0.2-4 (testing/unstable) as upstream fixed it in 10.0.2: Upstream Bug report: https://github.com/NetworkConfiguration/dhcpcd/issues/179 Upstream Fix: https://github.com/NetworkConfiguration/dhcpcd/commit/8b29c0ddf026c1c5647c3b8c6cfe21699c4056ae This patch does not apply cleanly to 9.4.1 because the privsep structure changed in 10.0.2. It's likely that only the src/privsep.c hunks about len == 0 and eloop_exit() needs to be backported, the other changes are just here to avoid compiler warnings about unused parameters. -- System Information: Debian Release: 12.1 APT prefers stable-updates APT policy: (500, 'stable-updates'), (500, 'stable-security'), (500, 'stable') Architecture: amd64 (x86_64) Kernel: Linux 6.1.0-11-amd64 (SMP w/8 CPU threads; PREEMPT) Kernel taint flags: TAINT_WARN Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE not set Shell: /bin/sh linked to /usr/bin/dash Init: systemd (via /run/systemd/system) LSM: AppArmor: enabled Versions of packages dhcpcd-base depends on: ii adduser 3.134 ii libc6 2.36-9+deb12u1 ii libudev1 252.12-1~deb12u1 Versions of packages dhcpcd-base recommends: pn wpasupplicant <none> Versions of packages dhcpcd-base suggests: ii openresolv [resolvconf] 3.12.0-3 -- Configuration Files: /etc/dhcpcd.conf changed [not included] -- no debconf information
