Add nodev Option to /home
Mounts the /home partition with the nodev option so device files in user directories are not interpreted.
Checked against the resolved running state (e.g. sshd -T, sysctl, systemctl show), catches drop-ins and Includes a file read would miss. Caveat: runtime ≠ persistence; a value correct now may not survive a reboot.
Pavois asserts the effective configuration, the live, resolved state, not a file. File-based scanners (OVAL/SCAP, Lynis) miss Includes, drop-ins and runtime defaults; this check sees what is actually applied.
A mapping is a cross-reference to where each standard places this requirement, anchored and cross-validated, not a claim of equivalence. A passing check is evidence toward these references, how to read it.
Why this rule matters
/home holds user-owned, writable data. The only legitimate location for device files is /dev on the root partition (the sole exception being chroot jails). Mounting /home with nodev makes the kernel ignore any character or block device nodes created there, so a user cannot plant a device file (e.g. a copy of a disk or memory device) in their home directory to bypass access controls.
What Pavois checks
Pavois reads the effective mount via mount('/home') and asserts the resolved options include nodev. The live mount table reflects options applied by systemd mount units or a later remount, which a static read of /etc/fstab would miss. If /home is not a separate mount point, there is no dedicated partition to harden.
describe mount('/home') do
its('options') { should include 'nodev' }
end
describe command("{ findmnt --fstab -no OPTIONS /home 2>/dev/null; grep -hsE '[[:space:]]/home[[:space:]]' /etc/fstab 2>/dev/null; systemctl show -p Options -- $(systemd-escape -p --suffix=mount /home 2>/dev/null) 2>/dev/null; } | grep -ow 'nodev'") do
its('stdout') { should match(/\S/) }
endHow to verify it is applied
Run findmnt /home (or findmnt -no OPTIONS /home) and confirm nodev is present, e.g. rw,nosuid,nodev,relatime.
Inspect & investigate
Use findmnt /home to inspect the active options. There is no dedicated log line; opening a device node on a nodev mount simply fails. auditd records in /var/log/audit/audit.log can show related access attempts if device-node rules are configured.
Remediation
This rule has no automated harden plan: apply it manually. Add nodev to the /home line in /etc/fstab (e.g. defaults,nodev,nosuid), then mount -o remount /home and verify with findmnt /home.
Pavois applies this with its own harden engine, the plan below, not a shell script:
| command | awk -v m=/home -v o=nodev '$0!~/^[[:space:]]*#/&&$2==m{n=split($4,a,",");h=0;for(i=1;i<=n;i++)if(a[i]==o)h=1;if(!h)$4=$4","o}{print}' /etc/fstab >/etc/.fstab.pav && cat /etc/.fstab.pav >/etc/fstab && rm -f /etc/.fstab.pav; mountpoint -q /home && mount -o remount,nodev /home || true |
|---|---|
| name | mount-home-nodev |
| not_if | awk -v m=/home '$2==m&&$0!~/^[[:space:]]*#/{print $4}' /etc/fstab | tr , '\n' | grep -qx nodev |
| resource | exec |
pavois harden plan localwhere the target is local, a user@host SSH alias, or a container , Docs
Impact & precautions
Without nodev, a user could create device nodes under their home directory to access raw devices and bypass file permissions. Applying nodev is low risk: legitimate user data never contains device files. Precautions: the remount is non-disruptive but requires no process to hold a file open in a way that blocks it; if /home is not a separate partition, do not apply nodev to / (the root filesystem needs /dev device nodes).
Standards mapping
| Standard | Reference | Type | Version | Confidence |
|---|---|---|---|---|
| CIS | 1.1.2.3.2 | direct | per OS, see the benchmark table | high |
Each reference is a cross-reference anchored in the upstream benchmark and cross-validated against the SCAP Security Guide and ansible-lockdown, not a claim of equivalence. Direct = a prescriptive, line-level requirement; supporting = an abstract control family (NIST) the check provides evidence toward. How to read a mapping.