From: Loïc Yhuel loic.yhuel@gmail.com
commit b4f1874c62168159fdb419ced4afc77c1b51c475 upstream.
This fixes the boot issues since 5.3 on several Dell models when the TPM is enabled. Depending on the exact grub binary, booting the kernel would freeze early, or just report an error parsing the final events log.
We get an event log in the SHA-1 format, which doesn't have a tcg_efi_specid_event_head in the first event, and there is a final events table which doesn't match the crypto agile format. __calc_tpm2_event_size reads bad "count" and "efispecid->num_algs", and either fails, or loops long enough for the machine to be appear frozen.
So we now only parse the final events table, which is per the spec always supposed to be in the crypto agile format, when we got a event log in this format.
Fixes: c46f3405692de ("tpm: Reserve the TPM final events table") Fixes: 166a2809d65b2 ("tpm: Don't duplicate events from the final event log in the TCG2 log") Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1779611 Signed-off-by: Loïc Yhuel loic.yhuel@gmail.com Link: https://lore.kernel.org/r/20200512040113.277768-1-loic.yhuel@gmail.com Reviewed-by: Javier Martinez Canillas javierm@redhat.com Reviewed-by: Jerry Snitselaar jsnitsel@redhat.com Reviewed-by: Matthew Garrett mjg59@google.com [ardb: warn when final events table is missing or in the wrong format] Signed-off-by: Ard Biesheuvel ardb@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/firmware/efi/libstub/tpm.c | 5 +++-- drivers/firmware/efi/tpm.c | 5 ++++- 2 files changed, 7 insertions(+), 3 deletions(-)
--- a/drivers/firmware/efi/libstub/tpm.c +++ b/drivers/firmware/efi/libstub/tpm.c @@ -54,7 +54,7 @@ void efi_retrieve_tpm2_eventlog(void) efi_status_t status; efi_physical_addr_t log_location = 0, log_last_entry = 0; struct linux_efi_tpm_eventlog *log_tbl = NULL; - struct efi_tcg2_final_events_table *final_events_table; + struct efi_tcg2_final_events_table *final_events_table = NULL; unsigned long first_entry_addr, last_entry_addr; size_t log_size, last_entry_size; efi_bool_t truncated; @@ -127,7 +127,8 @@ void efi_retrieve_tpm2_eventlog(void) * Figure out whether any events have already been logged to the * final events structure, and if so how much space they take up */ - final_events_table = get_efi_config_table(LINUX_EFI_TPM_FINAL_LOG_GUID); + if (version == EFI_TCG2_EVENT_LOG_FORMAT_TCG_2) + final_events_table = get_efi_config_table(LINUX_EFI_TPM_FINAL_LOG_GUID); if (final_events_table && final_events_table->nr_events) { struct tcg_pcr_event2_head *header; int offset; --- a/drivers/firmware/efi/tpm.c +++ b/drivers/firmware/efi/tpm.c @@ -62,8 +62,11 @@ int __init efi_tpm_eventlog_init(void) tbl_size = sizeof(*log_tbl) + log_tbl->size; memblock_reserve(efi.tpm_log, tbl_size);
- if (efi.tpm_final_log == EFI_INVALID_TABLE_ADDR) + if (efi.tpm_final_log == EFI_INVALID_TABLE_ADDR || + log_tbl->version != EFI_TCG2_EVENT_LOG_FORMAT_TCG_2) { + pr_warn(FW_BUG "TPM Final Events table missing or invalid\n"); goto out; + }
final_tbl = early_memremap(efi.tpm_final_log, sizeof(*final_tbl));