| #!/bin/sh |
| # |
| # Loads IMA policy into the kernel. |
| |
| force_ima=@@FORCE_IMA@@ |
| |
| ima_enabled() { |
| if [ "$force_ima" = "true" ]; then |
| return 0 |
| elif [ "$bootparam_no_ima" = "true" ]; then |
| return 1 |
| else |
| return 0 |
| fi |
| } |
| |
| ima_run() { |
| info "Initializing IMA (can be skipped with no_ima boot parameter)." |
| if ! grep -w securityfs /proc/mounts >/dev/null; then |
| if ! mount -t securityfs securityfs /sys/kernel/security; then |
| fatal "Could not mount securityfs." |
| fi |
| fi |
| if [ ! -d /sys/kernel/security/ima ]; then |
| fatal "No /sys/kernel/security/ima. Cannot proceed without IMA enabled in the kernel." |
| fi |
| |
| # Instead of depending on the kernel to load the IMA X.509 certificate, |
| # use keyctl. This avoids a bug in certain kernels (https://lkml.org/lkml/2015/9/10/492) |
| # where the loaded key was not checked sufficiently. We use keyctl here because it is |
| # slightly smaller than evmctl and is needed anyway. |
| # (see http://sourceforge.net/p/linux-ima/ima-evm-utils/ci/v0.9/tree/README#l349). |
| for kind in ima evm; do |
| key=/etc/keys/x509_$kind.der |
| if [ -s $key ]; then |
| id=$(grep -w -e "\.$kind" /proc/keys | cut -d ' ' -f1 | head -n 1) |
| if [ "$id" ]; then |
| id=$(printf "%d" 0x$id) |
| fi |
| if [ -z "$id" ]; then |
| id=`keyctl search @u keyring _$kind 2>/dev/null` |
| if [ -z "$id" ]; then |
| id=`keyctl newring _$kind @u` |
| fi |
| fi |
| info "Loading $key into $kind keyring $id" |
| keyctl padd asymmetric "" $id <$key |
| fi |
| done |
| |
| # In theory, a simple "cat" should be enough. In practice, loading sometimes fails randomly |
| # ("[Linux-ima-user] IMA policy loading via cat") and we get better error reporting when |
| # checking the write of each line. To minimize the risk of policy loading going wrong we |
| # also remove comments and blank lines ourselves. |
| if ! (set -e; while read i; do if echo "$i" | grep -q -e '^#' -e '^ *$'; then debug "Skipping IMA policy: $i"; else debug "Writing IMA policy: $i"; if echo $i; then sleep ${bootparam_ima_delay:-0}; else fatal "Invalid line in IMA policy: $i"; exit 1; fi; fi; done) </etc/ima/ima-policy >/sys/kernel/security/ima/policy; then |
| fatal "Could not load IMA policy." |
| fi |
| } |