On Mon, 2020-12-14 at 23:19 +0100, Petr Vorel wrote: > for TPM 2.0 and support more evmctl versions. > > Because exporting PCR registers for TPM 2.0 has not been upstreamed [1], > we use user space code, which requires evmctl >= 1.3.1 and tsspcrread. Yes, really annoying. > Using evmctl allows to test for TPM devices which does not export event > log (/sys/kernel/security/tpm0/binary_bios_measurements). Interesting way of phrasing the lack of a TPM 2.0 event log parser in ima-evm-utils. Until someone contributes a TPM 2.0 event log parser, we're dependent on users verifying the event log against the TPM 2.0 PCR banks some other way (e.g. "tsseventextend -sim -if /sys/kernel/security/tpm0/binary_bios_measurements -ns"). > > For TPM 1.2 read tpm0 device's pcrs file from sysfs. (tss1pcrread could > be also used, but it's not yet packaged by distros.) > > For old kernels which use SHA1/MD5, any evmctl version is required (evmctl > ima_measurement was introduced in very old v0.7), but > * newer sysctl path /sys/class/tpm/tpm0/device/pcrs requires evmctl 1.1 > * using ima_policy=tcb requires 1.3.1 due --ignore-violations > > We now support output format of ima_measurement command for various > evmctl versions: > * 1.3: "sha256: TPM PCR-10:" (or other algorithm, e.g. "sha1:") > * 1.1-1.2.1: "HW PCR-10:" (the only previously supported format) > * 0.7-1.0: "PCR-10:" > > NOTE: we ignore evmctl failure for evmctl < 1.3.1 (missing --ignore-violations, > also evmctl < 1.1 fails with "PCRAgg does not match PCR-10") > > As for previous commit fix testing with TPM 2.0 device which does not > export event log (/sys/kernel/security/tpm0/binary_bios_measurements): > not wrongly assuming TPM-bypass when kernel didn't export other TPM > 2.0 files we check in get_tpm_version() but bios boot aggregate is > correct (i.e. not 0x00s). In that case evmctl ima_boot_aggregate can get > boot aggregate even without TPM event log. > > [1] https://patchwork.kernel.org/patch/11759729/ > > Co-developed-by: Mimi Zohar <zohar@xxxxxxxxxxxxx> > Signed-off-by: Petr Vorel <pvorel@xxxxxxx> Thanks, Petr! Other than the typo below, it looks good. Mimi > +test2() > { > - tst_res TINFO "verify PCR (Process Control Register)" > + local hash pcr_aggregate out ret > > - local dev_pcrs="$1" > - local pcr hash aggregate_pcr > + tst_res TINFO "verify PCR values" > > - aggregate_pcr="$(evmctl -v ima_measurement $BINARY_MEASUREMENTS 2>&1 | \ > - grep 'HW PCR-10:' | awk '{print $3}')" > - if [ -z "$aggregate_pcr" ]; then > - tst_res TFAIL "failed to get PCR-10" > - return 1 > + if [ "$MAYBE_TPM2" = 1 ]; then > + tst_res TINFO "TMP version not detected ($ERRMSG_TPM), assume TPM 2" ^ TPM above and below > + TPM_VERSION=2 > fi > > - while read line; do > - pcr="$(echo $line | cut -d':' -f1)" > - if [ "$pcr" = "PCR-10" ]; then > - hash="$(echo $line | cut -d':' -f2 | awk '{ gsub (" ", "", $0); print tolower($0) }')" > - [ "$hash" = "$aggregate_pcr" ] > - return $? > - fi > - done < $dev_pcrs > - return 1 > -} > + if [ -z "$TPM_VERSION" ]; then > + tst_brk TCONF "TMP version not detected ($ERRMSG_TPM)" and here
