From: Bartosz Szczepanek <[email protected]> Currently, the only way to get TPM 2.0 event log from firmware is to use device tree. Introduce efi_retrieve_tpm2_eventlog_2 function to enable retrieving it from EFI structures.
Include lib/tpm.c into EFI stub to calculate event sizes using helper function. Signed-off-by: Bartosz Szczepanek <[email protected]> --- drivers/firmware/efi/libstub/Makefile | 3 +- drivers/firmware/efi/libstub/tpm.c | 107 +++++++++++++++++++++++++++++++++- 2 files changed, 107 insertions(+), 3 deletions(-) diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile index d9845099635e..0d7d66ad916d 100644 --- a/drivers/firmware/efi/libstub/Makefile +++ b/drivers/firmware/efi/libstub/Makefile @@ -38,7 +38,8 @@ OBJECT_FILES_NON_STANDARD := y # Prevents link failures: __sanitizer_cov_trace_pc() is not linked in. KCOV_INSTRUMENT := n -lib-y := efi-stub-helper.o gop.o secureboot.o tpm.o +lib-y := efi-stub-helper.o gop.o secureboot.o tpm.o \ + lib-tpm.o # include the stub's generic dependencies from lib/ when building for ARM/arm64 arm-deps-y := fdt_rw.c fdt_ro.c fdt_wip.c fdt.c fdt_empty_tree.c fdt_sw.c diff --git a/drivers/firmware/efi/libstub/tpm.c b/drivers/firmware/efi/libstub/tpm.c index a90b0b8fc69a..c8c2531be413 100644 --- a/drivers/firmware/efi/libstub/tpm.c +++ b/drivers/firmware/efi/libstub/tpm.c @@ -129,8 +129,111 @@ static void efi_retrieve_tpm2_eventlog_1_2(efi_system_table_t *sys_table_arg) efi_call_early(free_pool, log_tbl); } +static efi_status_t +efi_calc_tpm2_eventlog_2_size(efi_system_table_t *sys_table_arg, + void *log, void *last_entry, ssize_t *log_size) +{ + struct tcg_pcr_event2 *event = last_entry; + struct tcg_efi_specid_event *efispecid; + struct tcg_pcr_event *log_header = log; + ssize_t last_entry_size; + + efispecid = (struct tcg_efi_specid_event *) log_header->event; + + if (last_entry == NULL || log_size == NULL) + return EFI_INVALID_PARAMETER; + + if (log == last_entry) { + /* + * Only one entry (header) in the log. + */ + *log_size = log_header->event_size + + sizeof(struct tcg_pcr_event); + return EFI_SUCCESS; + } + + if (event->count > efispecid->num_algs) { + efi_printk(sys_table_arg, + "TCG2 event uses more algorithms than defined\n"); + return EFI_INVALID_PARAMETER; + } + + last_entry_size = calc_tpm2_event_size(last_entry, efispecid); + if (last_entry_size < 0) { + efi_printk(sys_table_arg, + "TCG2 log has invalid last entry size\n"); + return EFI_INVALID_PARAMETER; + } + + *log_size = last_entry + last_entry_size - log; + return EFI_SUCCESS; +} + +static efi_status_t efi_retrieve_tpm2_eventlog_2(efi_system_table_t *sys_table_arg) +{ + efi_guid_t linux_eventlog_guid = LINUX_EFI_TPM_EVENT_LOG_GUID; + efi_physical_addr_t log_location = 0, log_last_entry = 0; + efi_guid_t tcg2_guid = EFI_TCG2_PROTOCOL_GUID; + efi_bool_t truncated; + efi_status_t status; + struct linux_efi_tpm_eventlog *log_tbl = NULL; + void *tcg2_protocol = NULL; + ssize_t log_size; + + status = efi_call_early(locate_protocol, &tcg2_guid, NULL, + &tcg2_protocol); + if (status != EFI_SUCCESS) + return status; + + status = efi_call_proto(efi_tcg2_protocol, get_event_log, tcg2_protocol, + EFI_TCG2_EVENT_LOG_FORMAT_TCG_2, + &log_location, &log_last_entry, &truncated); + if (status != EFI_SUCCESS) + return status; + + if (!log_location) + return EFI_NOT_FOUND; + + status = efi_calc_tpm2_eventlog_2_size(sys_table_arg, + (void *)log_location, + (void *) log_last_entry, + &log_size); + if (status != EFI_SUCCESS) + return status; + + /* Allocate space for the logs and copy them. */ + status = efi_call_early(allocate_pool, EFI_LOADER_DATA, + sizeof(*log_tbl) + log_size, + (void **) &log_tbl); + + if (status != EFI_SUCCESS) { + efi_printk(sys_table_arg, + "Unable to allocate memory for event log\n"); + return status; + } + + memset(log_tbl, 0, sizeof(*log_tbl) + log_size); + log_tbl->size = log_size; + log_tbl->version = EFI_TCG2_EVENT_LOG_FORMAT_TCG_2; + memcpy(log_tbl->log, (void *) log_location, log_size); + + status = efi_call_early(install_configuration_table, + &linux_eventlog_guid, log_tbl); + if (status != EFI_SUCCESS) + goto err_free; + + return EFI_SUCCESS; + +err_free: + efi_call_early(free_pool, log_tbl); + return status; +} + void efi_retrieve_tpm2_eventlog(efi_system_table_t *sys_table_arg) { - /* Only try to retrieve the logs in 1.2 format. */ - efi_retrieve_tpm2_eventlog_1_2(sys_table_arg); + efi_status_t status; + + status = efi_retrieve_tpm2_eventlog_2(sys_table_arg); + if (status != EFI_SUCCESS) + efi_retrieve_tpm2_eventlog_1_2(sys_table_arg); } -- 2.14.4
