[PATCH v2] ima-evm-utils: skip test for discrete TPM 1.2 and exec'd as normal user

[PATCH v2] ima-evm-utils: skip test for discrete TPM 1.2 and exec'd as normal user

[Bruno Meneguele]

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 TPM 1.2 the sysfs PCRs file and,
consequently, the test fails. Thus TPM 2.0 log test is not supported on
systems with a discrete TPM 1.2

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

Re: [PATCH v2] ima-evm-utils: skip test for discrete TPM 1.2 and exec'd as normal user

[Bruno Meneguele]

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On Wed, Jun 24, 2020 at 07:38:29PM -0300, Bruno Meneguele wrote:
> 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 TPM 1.2 the sysfs PCRs file and,
> consequently, the test fails. Thus TPM 2.0 log test is not supported on
> systems with a discrete TPM 1.2
> 
> Signed-off-by: Bruno Meneguele <bmeneg@redhat.com>
> ---

Should've added the changelog note, but considering it doesn't make git
history, for those reviewing the patch:

v1->v2:
  - fixed a statement in commit log only.


>  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
> 

-- 
bmeneg 
PGP Key: http://bmeneg.com/pubkey.txt

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