📖 ~4 min read • Source: FreeBSD VuXML
VuXML topic: FreeBSD — EAP-pwd message reassembly issue with unexpected fragment
Related CVEs: CVE-2015-4141 CVE-2015-4142 CVE-2015-4143 CVE-2015-4144 CVE-2015-4145 CVE-2015-4146 CVE-2015-5310 CVE-2015-5315 +12 more
Upstream summary: Problem Description: EAP-pwd implementation in hostapd (EAP server) and wpa_supplicant (EAP peer) does not to validate fragmentation reassembly state properly for a case where an unexpected fragment could be received. This could result in process termination due to NULL pointer dereference. See https://w1.fi/security/2019-5/eap-pwd-message-reassembly-issue-with-unexpected-fragment.txt for a detailed description of the bug. Impact: All wpa_supplicant and hostapd versions with
Table of contents
Symptom & Impact
hostapd runs as a long-lived process on FreeBSD 13, started at boot and holding open sockets (visible in ss -lntp), so a flaw in it stays reachable for as long as the service is up. Exploitation usually means code execution in the daemon’s own security context, memory disclosure from a process holding credentials and cached client data, or a crash that takes the listener down. Workers started before the upgrade keep running the old binary until the service is restarted. hostapd is a genuine long-running service, so restart steps do apply — but confirm the service name first with service -e | grep hostapd, since it often differs from the package name (bind ships named).
Environment & Reproduction
Reproduction targets FreeBSD 13. Confirm release, installed package, and capture baseline state:
freebsd-version -kru
uname -a
pkg info hostapd
pkg query "%n-%v" hostapd
pkg audit -F
service -e
Exercise the workload that uses hostapd while collecting:
tail -200 /var/log/messages
dmesg -a | tail -200
tail -200 /var/log/pkg.log
Root Cause Analysis
Root cause is tracked at FreeBSD VuXML. The FreeBSD ports security team shipped a corrective hostapd port revision; hosts on an outdated build remain exposed. Correlate package logs with system logs and kernel state to isolate the change that triggered the failure mode:
tail -500 /var/log/pkg.log
tail -500 /var/log/messages
sysctl kern.lastpid
sysctl kern.osreldate # numeric __FreeBSD_version, e.g. 1400097
Quick Triage
Run these checks on FreeBSD 13 to confirm the failure mode and current state of hostapd:
pkg version -v hostapd # installed vs available version
pkg audit hostapd # advisory match for this package
tail -100 /var/log/messages
dmesg -a | tail -100
kldstat # kernel module state (for kernel/driver pkgs)
pfctl -sr 2>/dev/null || ipfw list # only if pf/ipfw is enabled
# hostapd runs as the "hostapd" service - restart it once the upgrade is in place:
# e.g. bind918→named, php83→php-fpm), check it:
service -e | grep -i hostapd && service hostapd status
Step-by-Step Diagnosis
-
List enabled services (only relevant if the package provides one).
service -e -
Follow live logs.
tail -F /var/log/messages dmesg -
Validate firewall rules (skip if neither pf nor ipfw is enabled).
pfctl -sr -v 2>/dev/null || ipfw show -
Check package integrity for
hostapd.pkg check -B hostapd pkg check -d hostapd # verify shared-library deps -
Reinstall
hostapdif integrity check fails.pkg install -fy hostapd -
Correlate findings with
/var/log/pkg.logand FreeBSD VuXML to pin the commit that introduced the regression.
Solution – Primary Fix
Install the corrective hostapd port revision referenced by FreeBSD VuXML:
sudo pkg update
sudo pkg upgrade hostapd # or: sudo pkg upgrade -y for the whole system
# hostapd runs as the "hostapd" service - restart it once the upgrade is in place:
sudo service hostapd restart
pkg audit hostapd # confirm no remaining advisory for this package
For ports-tree builders (FreeBSD 13.x and earlier used portsnap; on FreeBSD 14+ the ports tree is fetched with Git):
# FreeBSD 14+ (portsnap was removed):
sudo pkg install -y git-lite
sudo git clone --depth 1 https://git.FreeBSD.org/ports.git /usr/ports
# FreeBSD 13.x and earlier:
# sudo portsnap fetch update
cd /usr/ports/<category>/hostapd
sudo make deinstall reinstall clean
Reboot only if the package ships a kernel module or replaces a shared library used by long-running daemons.
Need help rolling this patch across a FreeBSD fleet? Our IT Solutions & Services team manages FreeBSD jail/bhyve patch windows. Get in touch for a free consultation.
Solution – Alternative Approaches
If the primary fix is not viable, choose from these alternatives:
-
Lock the package until the fix is vetted:
sudo pkg lock hostapd -
Downgrade to a known-good revision.
pkg install pkgname-VERSIONis not a real downgrade syntax — fetch a specific build instead:# 1. Discover available versions across configured repos: pkg search -e hostapd pkg rquery -r FreeBSD-quarterly '%n-%v' hostapd # 2. Install from a specific saved .pkg file: sudo pkg add -f /path/to/hostapd-<older-version>.pkg # 3. Or switch the host repo to the quarterly branch (see snippet below) and: sudo pkg upgrade -fr FreeBSD-quarterly hostapd -
Switch the pkg repository between
quarterlyandlatestby editing/usr/local/etc/pkg/repos/FreeBSD.conf:FreeBSD: { url: "pkg+https://pkg.FreeBSD.org/${ABI}/quarterly", mirror_type: "srv", signature_type: "fingerprints", fingerprints: "/usr/share/keys/pkg", enabled: yes } -
Isolate the affected service in a jail with stricter firewall rules:
iocage create -n hostapd-jail -r 13.4-RELEASE iocage set allow_raw_sockets=0 hostapd-jail # or with Bastille: bastille create hostapd-jail 13.4-RELEASE 10.0.0.10 -
Replace the service with a vendored static build for the period between exposure detection and full rollout.
Verification & Acceptance Criteria
All of these should pass after the fix:
pkg info hostapd # shows the expected fixed version
pkg audit hostapd # no advisory for this package (exit code 0)
tail -50 /var/log/messages # no new errors after upgrade
# If hostapd ships a service, confirm it is running under its rc.d name:
# service hostapd status
The conditions described in the advisory must no longer be reported for hostapd across two consecutive runs.
Rollback Plan
Capture state before any change (only ZFS root has boot environments — UFS hosts skip bectl):
pkg query "%n-%v" > /root/pkg-pre.txt
# ZFS-on-root only:
sudo bectl create pre-hostapd-patch
To revert if the upgrade is bad, reinstall the previously saved .pkg file:
sudo pkg add -f /var/cache/pkg/hostapd-<previous-version>.pkg
# Or activate the pre-patch boot environment and reboot (ZFS-on-root only):
sudo bectl activate pre-hostapd-patch
sudo shutdown -r now
For kernel/loader changes on a UFS host, boot the previous kernel from the loader prompt (press 3 at the menu, then boot kernel.old).
Prevention & Hardening
Prevent recurrence on FreeBSD 13 hosts running hostapd:
-
Enable the daily security pkg audit in
/etc/periodic.conf:daily_status_security_pkgaudit_enable="YES" -
Subscribe to
freebsd-security-notificationsat lists.freebsd.org. -
Mirror through a local pkg repository managed by
poudriere:poudriere jail -c -j 13amd64 -v 13.4-RELEASE poudriere ports -c -p default poudriere bulk -j 13amd64 -p default <category>/hostapd -
Version-pin sensitive packages:
sudo pkg lock hostapd -
Take an automatic ZFS boot-environment snapshot before every upgrade (ZFS root only):
sudo bectl create pre-upgrade-$(date +%Y%m%d) -
Monitor file integrity (create a baseline, verify against it later):
# Create a baseline (use -c; target /usr/local/etc, /etc, /boot — NOT /): sudo mtree -c -K sha256digest -p /usr/local/etc > /var/db/usr-local-etc.mtree sudo mtree -c -K sha256digest -p /etc > /var/db/etc.mtree # Verify later: sudo mtree -p /usr/local/etc < /var/db/usr-local-etc.mtree # Or with AIDE for a richer ruleset: sudo pkg install -y aide && sudo aide --init && sudo aide --check -
Harden jails with
allow.*tunables in/etc/jail.conf:hostapd_jail { allow.raw_sockets = 0; allow.sysvipc = 0; allow.mount = 0; allow.chflags = 0; }
Related Errors & Cross-Refs
Issues that commonly surface alongside a hostapd update: pkg lock contention, mismatched ABI after kernel/userland skew, pf rule drift, and stale shared-library references after upgrade. Triage with:
freebsd-version -kru
uname -K
pkg check -d
pfctl -sr
View all freebsd-13 tutorials on the Tutorials Hub →
Browse all common problems & solutions on the Tutorials Hub.
References & Further Reading
Primary reference: FreeBSD VuXML. Useful manual pages on FreeBSD 13:
man pkg
man freebsd-update
man pfctl
man ipfw
man bectl
man periodic.conf
Other resources: the FreeBSD Handbook, the FreeBSD Security Advisories at security.freebsd.org, and the /usr/ports/UPDATING file for port-specific notes implicated in this advisory.