ima-evm-utils/ima-setup.sh
Bruno Meneguele 5ff49ee731
ima-setup: check for required argument
The IMA policy file is required for the setup but it was not being checked
if the user passed it before checking if the policy file existed, thus an
empty argument would fail with a weird "  doesn't exist" message.

This commit adds the check for the argument presence at the beginning of the
script, guaranteeing it cannot be empty, and remove the policy file
existence from the middle of runtime, leaving the check already in place at
the argument parsing logic.

At the same time, reword parts of the usage message to make things clearer.

Signed-off-by: Bruno Meneguele <bmeneg@redhat.com>
2026-07-06 08:35:48 -03:00

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#!/bin/bash
#
# This script helps set up IMA.
#
IMA_SYSTEMD_POLICY=/etc/ima/ima-policy
IMA_POLICY_SYSFS=/sys/kernel/security/ima/policy
usage() {
echo "Set up IMA."
cat <<EOF
usage: $0 --policy=IMA_POLICY_PATH [--reinstall_threshold=NUM]
--policy
The path of IMA policy to be loaded. Sample polices are inside
/usr/share/ima/policies or you can use your own IMA policy
--reinstall_threshold
By default, IMA sigatures will be obtained from the RPM DB. However the
RPM DB may not have the signatures. Dectect this case by checking if
there are >reinstall_threshold package missing IMA signatures and
reinstall them.
EOF
exit 1
}
for _opt in "$@"; do
case "$_opt" in
--policy=*)
ima_policy_path=${_opt#*=}
if [[ ! -r $ima_policy_path ]]; then
echo "$ima_policy_path doesn't exist"
exit 1
fi
;;
--reinstall_threshold=*)
reinstall_threshold=${_opt#*=}
;;
*)
usage
;;
esac
done
if [[ $# -eq 0 ]]; then
usage
fi
# Check for required argument
if [[ "$ima_policy_path" == "" ]]; then
echo "No policy file was given"
echo
usage
exit 1
fi
if ! rpm --quiet -q rpm-plugin-ima; then
echo "Installing prerequisite package rpm-plugin-ima"
if ! dnf install rpm-plugin-ima -yq; then
echo "Failed to install rpm-plugin-ima, abort"
exit 1
fi
fi
# Add IMA signatures
if test -f /run/ostree-booted; then
echo "You are using OSTree, please enable IMA signatures as part of the OSTree creation process."
else
echo "Adding IMA signatures to installed package files"
if ! ima-add-sigs --reinstall_threshold="$reinstall_threshold"; then
echo "Failed to add IMA signatures, abort"
exit 1
fi
fi
load_ima_keys() {
local _key_loaded
if line=$(keyctl describe %keyring:.ima); then
_ima_id=${line%%:*}
else
echo "Failed to get ID of the .ima keyring"
exit 1
fi
for i in /etc/keys/ima/*; do
if [ ! -f "${i}" ]; then
echo "No IMA key exist"
exit 1
fi
if ! evmctl import "${i}" "${_ima_id}" &>/dev/null; then
echo "Failed to load IMA key ${i}"
else
_key_loaded=yes
fi
done
if [[ $_key_loaded != yes ]]; then
echo "No IMA key loaded"
exit 1
fi
}
load_ima_policy() {
local ima_policy_path
ima_policy_path=$1
if ! echo "$ima_policy_path" >"$IMA_POLICY_SYSFS"; then
echo "$ima_policy_path can't be loaded"
return 1
fi
# Let systemd load the IMA policy which will load LSM rules first so IMA
# policy containing rules like "appraise obj_type=ifconfig_exec_t" can be
# loaded
[[ -e /etc/ima ]] || mkdir -p /etc/ima/
if ! cp --preserve=xattr "$ima_policy_path" "$IMA_SYSTEMD_POLICY"; then
echo "Failed to copy $ima_policy_path to $IMA_SYSTEMD_POLICY"
return 1
fi
}
echo "Loading IMA keys"
load_ima_keys
# Include the dracut integrity module to load the IMA keys and policy
# automatically when there is a system reboot
if ! lsinitrd --mod | grep -q integrity; then
cp --preserve=xattr /usr/share/ima/dracut-98-integrity.conf /etc/dracut.conf.d/98-integrity.conf
echo "Regenerating all initramfs images to include the dracut integrity module"
if ! dracut -f --regenerate-all; then
echo "Failed to Regenerate all initramfs images"
exit 1
fi
[[ $(uname -m) == s390x ]] && zipl &> /dev/null
fi
if ! load_ima_policy "$ima_policy_path"; then
echo "Failed to load IMA policy $ima_policy_path!"
exit 1
fi