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Date: Fri, 22 Mar 2019 04:34:38 -0400
From: djacobs7@...ghamton.edu
To: linux-integrity@...r.kernel.org, linux-kernel@...r.kernel.org
Cc: zohar@...ux.ibm.com, pvorel@...e.cz, vt@...linux.org,
David Jacobson <djacobs7@...ghamton.edu>
Subject: [PATCH v2 5/8] evmtest: validate boot record
From: David Jacobson <djacobs7@...ghamton.edu>
The first record in the IMA runtime measurement list is the boot
aggregate - a hash of PCRs 0-7. This test calculates the boot aggregate
based off the PCRs and compares it to IMA's boot aggregate.
Dependencies: a TPM, IBMTSS2.
Signed-off-by: David Jacobson <djacobs7@...ghamton.edu>
Changelog:
* Added boot_aggregate to test list
* shellcheck compliant
* minor fixes
* move from functions to tests
* redid tss parsing
* checkbashisms complaint
* remove begin
* removed long opts
* restructured to use functions
* added changes from Mimi to work with new TSS
* removed searching for TSS locations
---
evmtest/README | 1 +
evmtest/evmtest | 1 +
evmtest/tests/boot_aggregate.sh | 140 ++++++++++++++++++++++++++++++++
3 files changed, 142 insertions(+)
create mode 100755 evmtest/tests/boot_aggregate.sh
diff --git a/evmtest/README b/evmtest/README
index 91c8cda..b2d37e2 100644
--- a/evmtest/README
+++ b/evmtest/README
@@ -36,6 +36,7 @@ OPTIONS
TEST NAMES
----------
+ boot_aggregate - verify the IMA boot-aggregate
env_validate - verify kernel build
example_test - example test
policy_sig - verify loading IMA policies
diff --git a/evmtest/evmtest b/evmtest/evmtest
index cd5e238..3c967f9 100755
--- a/evmtest/evmtest
+++ b/evmtest/evmtest
@@ -26,6 +26,7 @@ usage (){
# Any test should be added here manually
# The reason this is manual is to prevent the accidental / malicious
# placement of a script in tests/
+ echo "[R] boot_aggregate"
echo "[R] env_validate"
echo "[ ] examples_test"
echo "[R] kexec_sig"
diff --git a/evmtest/tests/boot_aggregate.sh b/evmtest/tests/boot_aggregate.sh
new file mode 100755
index 0000000..adecfeb
--- /dev/null
+++ b/evmtest/tests/boot_aggregate.sh
@@ -0,0 +1,140 @@
+#!/bin/bash
+# Author: David Jacobson <davidj@...ux.ibm.com>
+TEST="boot_aggregate"
+
+ROOT="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null && pwd )/.."
+source "$ROOT"/files/common.sh
+
+VERBOSE=0
+TPM_VERSION="2.0"
+# This test validates the eventlog against the hardware PCRs in the TPM, and
+# the boot aggregate against IMA.
+
+usage (){
+ echo "boot_aggregate [-hv]"
+ echo ""
+ echo " This test must be run as root"
+ echo ""
+ echo " This test validates PCRs 0-7 in the TPM"
+ echo " It also validates the boot_aggregate based those PCRs"
+ echo " against what IMA has recorded"
+ echo ""
+ echo " -h Display this help message"
+ echo " -v Verbose logging"
+}
+
+parse_args () {
+ TEMP=$(getopt -o 'hv' -n 'boot_aggregate' -- "$@")
+ eval set -- "$TEMP"
+
+ while true ; do
+ case "$1" in
+ -h) usage; exit; shift;;
+ -v) VERBOSE=1; shift;;
+ --) shift; break;;
+ *) echo "[*] Unrecognized option $1"; exit 1 ;;
+ esac
+ done
+}
+
+check_requirements () {
+ v_out "Checking if securityfs is mounted..."
+ if [ -z "$EVMTEST_SECFS_EXISTS" ]; then
+ fail "securityfs not found..."
+ fi
+
+ v_out "Verifying TPM is present..."
+ if [ ! -d "$EVMTEST_SECFS/tpm0" ]; then
+ fail "Could not locate TPM in $EVMTEST_SECFS"
+ fi
+
+ v_out "TPM found..."
+
+ v_out "Checking if system supports reading event log..."
+
+ if [ ! -f "$EVMTEST_SECFS"/tpm0/binary_bios_measurements ]; then
+ fail "Kernel does not support reading BIOS measurements,
+ please update to at least 4.16.0"
+ fi
+
+ v_out "Verifying TPM Version"
+ if [ -e /sys/class/tpm/tpm0/device/caps ]; then
+ TPM_VERSION="1.2"
+ fi
+}
+
+check_pcrs () {
+ v_out "Grabbing PCR values..."
+ local pcrs=() # array to store the Hardware PCR values
+ local sim_pcrs=() # What PCRs should be according to the event log
+ local eventextend=tsseventextend
+ local pcrread="tsspcrread -halg sha1"
+ local eventlog=/sys/kernel/security/tpm0/binary_bios_measurements
+
+ if [ "$TPM_VERSION" == "1.2" ]; then
+ eventextend=tss1eventextend
+ pcrread=tss1pcrread
+ fi
+
+ for ((i=0; i<=7; i++)); do
+ pcrs[i]=$(TPM_INTERFACE_TYPE=dev $pcrread -ha "$i" -ns)
+ done
+
+ local output=$(mktemp -u)
+ "$eventextend" -if "$eventlog" -sim -ns > "$output"
+
+ # Some PTT's are using TPM 1.2 event log format. Retry on failure.
+ if [ $? -ne 0 ]; then
+ eventextend=tss1eventextend
+ "$eventextend" -if "$eventlog" -sim -ns > "$output"
+ fi
+
+ IFS=$'\n' read -d '' -r -a lines < "$output"
+ rm "$output"
+
+ for line in "${lines[@]}"
+ do
+ :
+ sim_pcrs+=( "$(echo "$line" | cut -d ':' -f2 | \
+ tr -d '[:space:]')" )
+ if printf '%s' "$line" | grep -E -q "boot aggregate"; then
+ tss_agg=$(echo "$line" | cut -d ':' -f2 | \
+ tr -d '[:space:]')
+ fi
+ done
+
+ v_out "Validating PCRs.."
+ for ((i=0; i<=7; i++)); do
+ v_out "SIM PCR [$i]: ${sim_pcrs[$i]}"
+ v_out "TPM PCR [$i]: ${pcrs[$i]}"
+ if [ "${pcrs[$i]}" != "${sim_pcrs[$i]}" ]; then
+ v_out "PCRs are incorrect..."
+ fail "Mismatch at PCR $i "
+ else
+ v_out "PCR $i validated..."
+ fi
+ done
+}
+
+check_boot_aggregate () {
+ v_out "Validating Boot Aggregate..."
+ ima_agg=$(grep boot_aggregate \
+ "$EVMTEST_SECFS"/ima/ascii_runtime_measurements| head -1 | cut \
+ -d ":" -f2|cut -d " " -f1)
+ v_out "TSS BOOT AGG: $tss_agg"
+ v_out "IMA BOOT AGG: $ima_agg"
+
+ if [ "$tss_agg" != "$ima_agg" ]; then
+ fail "Boot Aggregate is inconsistent"
+ else
+ v_out "Boot Aggregate validated"
+ fi
+}
+
+EVMTEST_require_root
+echo "[*] Starting test: $TEST"
+parse_args "$@"
+check_requirements
+check_pcrs
+check_boot_aggregate
+passed
--
2.20.1
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