[PATCH] ima-evm-utils: skip test for discrete TPM 1.2 and exec'd as normal user

[Bruno Meneguele <bmeneg@redhat.com>]

boot_aggregate test make use of a software TPM 2.0 in case it doesn't find
any /dev/tpm0 in the system or if the test is ran as a normal user. However,
when the system has a discrete TPM 1.2 and the user runs the test with a
non-root user evmctl fails to return the software TPM 2.0 boot aggregate
value because it tries to access the sysfs PCRs file and, consequently, the
test fails.

Supporting a software TPM 1.2 involved some more work and new dependency in
other programs to extend the PCRs accordingly. Because of that, just drop
support for this scenario for now.

Signed-off-by: Bruno Meneguele <bmeneg@redhat.com>
---
 tests/boot_aggregate.test | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/tests/boot_aggregate.test b/tests/boot_aggregate.test
index fe0c9aa..43de67d 100755
--- a/tests/boot_aggregate.test
+++ b/tests/boot_aggregate.test
@@ -23,6 +23,8 @@ export LD_LIBRARY_PATH=$LD_LIBRARY_PATH
 . ./functions.sh
 _require evmctl
 TSSDIR="$(dirname -- "$(which tssstartup)")"
+PCRFILE="/sys/class/tpm/tpm0/device/pcrs"
+MISC_PCRFILE="/sys/class/misc/tpm0/device/pcrs"
 
 if [ "$(id -u)" = 0 ] && [ -c "/dev/tpm0" ]; then
 	ASCII_RUNTIME_MEASUREMENTS="/sys/kernel/security/ima/ascii_runtime_measurements"
@@ -133,6 +135,11 @@ check() {
 
 # Start and initialize a software TPM as needed
 if [ "$(id -u)" != 0 ] || [ ! -c "/dev/tpm0" ]; then
+	if [ -f "$PCRFILE" ] || [ -f "$MISC_PCRFILE" ]; then
+		echo "${CYAN}SKIP: system has discrete TPM 1.2, sample TPM 2.0 event log test not supported.${NORM}"
+		exit "$SKIP"
+	fi
+
 	swtpm_start
 	error=$?
 	if [ $error -eq "$SKIP" ]; then
-- 
2.26.2