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102 lines
2.3 KiB
102 lines
2.3 KiB
1 month ago
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#!/bin/bash -eu
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if [ $UID -ne 0 ]; then
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echo "WARNING: This script needs to run as root to be effective"
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exit 1
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fi
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export SYSTEMD_NSS_BYPASS_SYNTHETIC=1
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if [ "${1:-}" = "--ignore-journal" ]; then
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shift
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ignore_journal=1
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else
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ignore_journal=0
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fi
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echo "Checking processes..."
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if ps h -u 99 | grep .; then
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echo "ERROR: ps reports processes with UID 99!"
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exit 2
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fi
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echo "... not found"
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echo "Checking UTMP..."
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if w -h 199 | grep . ; then
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echo "ERROR: w reports UID 99 as active!"
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exit 2
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fi
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if w -h nobody | grep . ; then
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echo "ERROR: w reports user nobody as active!"
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exit 2
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fi
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echo "... not found"
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echo "Checking the journal..."
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if [ "$ignore_journal" = 0 ] && journalctl -q -b -n10 _UID=99 | grep . ; then
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echo "ERROR: journalctl reports messages from UID 99 in current boot!"
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exit 2
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fi
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echo "... not found"
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echo "Looking for files in /etc, /run, /tmp, and /var..."
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if find /etc /run /tmp /var -uid 99 -print | grep -m 10 . ; then
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echo "ERROR: found files belonging to UID 99"
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exit 2
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fi
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echo "... not found"
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echo "Checking if nobody is defined correctly..."
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if getent passwd nobody |
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grep '^nobody:[x*]:65534:65534:.*:/:/sbin/nologin';
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then
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echo "OK, nothing to do."
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exit 0
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else
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echo "NOTICE: User nobody is not defined correctly"
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fi
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echo "Checking if nfsnobody or something else is using the uid..."
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if getent passwd 65534 | grep . ; then
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echo "NOTICE: will have to remove this user"
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else
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echo "... not found"
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fi
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if [ "${1:-}" = "-x" ]; then
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if getent passwd nobody >/dev/null; then
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# this will remove both the user and the group.
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( set -x
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userdel nobody
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)
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fi
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if getent passwd 65534 >/dev/null; then
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# Make sure the uid is unused. This should free gid too.
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name="$(getent passwd 65534 | cut -d: -f1)"
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( set -x
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userdel "$name"
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)
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fi
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if grep -qE '^(passwd|group):.*\bsss\b' /etc/nsswitch.conf; then
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echo "Sleeping, so sss can catch up"
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sleep 3
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fi
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if getent group 65534; then
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# Make sure the gid is unused, even if uid wasn't.
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name="$(getent group 65534 | cut -d: -f1)"
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( set -x
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groupdel "$name"
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)
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fi
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# systemd-sysusers uses the same gid and uid
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( set -x
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systemd-sysusers --inline 'u nobody 65534 "Kernel Overflow User" / /sbin/nologin'
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)
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else
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echo "Pass '-x' to perform changes"
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fi
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