| Message ID | 20200624212420.3300-1-bmeneg@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | ima-evm-utils: skip test for discrete TPM 1.2 and exec'd as normal user | expand |
Hi Bruno, On Wed, 2020-06-24 at 18:24 -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 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. The problem is that the TPM 1.2 PCRs are visible to userspace. Insteaad of reading the software TPM PCRs, it's reading the discrete TPM 1.2 PCRs. I would drop this paragraph and simply say the sample TPM 2.0 log test is not supported on systems with a discrete TPM 1.2. The patch itself is fine. thanks, Mimi
On Wed, Jun 24, 2020 at 06:14:08PM -0400, Mimi Zohar wrote: > Hi Bruno, > > On Wed, 2020-06-24 at 18:24 -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 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. > > The problem is that the TPM 1.2 PCRs are visible to userspace. > Insteaad of reading the software TPM PCRs, it's reading the discrete > TPM 1.2 PCRs. I would drop this paragraph and simply say the sample > TPM 2.0 log test is not supported on systems with a discrete TPM 1.2. > Ack. Will send a v2 dropping it. > The patch itself is fine. > > thanks, > > Mimi >
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
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(+)