tpm: Don't create an EventLog if algorithms are misconfigured

We already check the active banks vs what U-Boot was compiled with when
trying to extend a PCR and we refuse to do so if the TPM active ones
don't match the ones U-Boot supports.

Do the same thing for the EventLog creation since extending will fail
anyway and print a message so the user can figure out the missing
algorithms.

Co-developed-by: Raymond Mao <raymond.mao@linaro.org>
Signed-off-by: Raymond Mao <raymond.mao@linaro.org>
Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
This commit is contained in:
Ilias Apalodimas
2024-12-24 08:01:08 -08:00
parent 27891e85f3
commit 8dc886ce31
3 changed files with 56 additions and 1 deletions

View File

@@ -770,4 +770,11 @@ bool tpm2_check_active_banks(struct udevice *dev);
*/ */
bool tpm2_is_active_bank(struct tpms_pcr_selection *selection); bool tpm2_is_active_bank(struct tpms_pcr_selection *selection);
/**
* tpm2_print_active_banks() - Print the active TPM PCRs
*
* @dev: TPM device
*/
void tpm2_print_active_banks(struct udevice *dev);
#endif /* __TPM_V2_H */ #endif /* __TPM_V2_H */

View File

@@ -926,3 +926,26 @@ bool tpm2_check_active_banks(struct udevice *dev)
return true; return true;
} }
void tpm2_print_active_banks(struct udevice *dev)
{
struct tpml_pcr_selection pcrs;
size_t i;
int rc;
rc = tpm2_get_pcr_info(dev, &pcrs);
if (rc) {
log_err("Can't retrieve active PCRs\n");
return;
}
for (i = 0; i < pcrs.count; i++) {
if (tpm2_is_active_bank(&pcrs.selection[i])) {
const char *str;
str = tpm2_algorithm_name(pcrs.selection[i].hash);
if (str)
log_info("%s\n", str);
}
}
}

View File

@@ -567,11 +567,36 @@ int tcg2_log_prepare_buffer(struct udevice *dev, struct tcg2_event_log *elog,
bool ignore_existing_log) bool ignore_existing_log)
{ {
struct tcg2_event_log log; struct tcg2_event_log log;
int rc; int rc, i;
elog->log_position = 0; elog->log_position = 0;
elog->found = false; elog->found = false;
/*
* Make sure U-Boot is compiled with all the active PCRs
* since we are about to create an EventLog and we won't
* measure anything if the PCR banks don't match
*/
if (!tpm2_check_active_banks(dev)) {
log_err("Cannot create EventLog\n");
log_err("Mismatch between U-Boot and TPM hash algos\n");
log_info("TPM:\n");
tpm2_print_active_banks(dev);
log_info("U-Boot:\n");
for (i = 0; i < ARRAY_SIZE(hash_algo_list); i++) {
const struct digest_info *algo = &hash_algo_list[i];
const char *str;
if (!algo->supported)
continue;
str = tpm2_algorithm_name(algo->hash_alg);
if (str)
log_info("%s\n", str);
}
return -EINVAL;
}
rc = tcg2_platform_get_log(dev, (void **)&log.log, &log.log_size); rc = tcg2_platform_get_log(dev, (void **)&log.log, &log.log_size);
if (!rc) { if (!rc) {
log.log_position = 0; log.log_position = 0;