From 2052759a5e331376c037760a84d36280be0ef3e9 Mon Sep 17 00:00:00 2001 From: Ilias Apalodimas Date: Wed, 12 May 2021 00:03:41 +0300 Subject: [PATCH] efi_loader: Don't stop EFI subsystem init if installing TCG2 fails Up to now we are stopping the EFI subsystem if a TPMv2 exists but the protocol fails to install. Now that we've switched the config to 'default y' the sandbox TPM fails, since it doesn't support all the required capabilities of the protocol. Not installing the protocol is not catastrophic. If the protocol fails to install the PCRs will never be extended to the expected values, so some other entity later in the boot flow will eventually figure it out and take the necessary actions. While at it fix a corner case were the user can see an invalid error message when the protocol failed to install. We do have a tcg2_uninit() which we call when the protocol installation fails. There are cases though that this might be called before the configuration table is installed (e.g probing the TPM for capabilities failed). In that case the user will see "Failed to delete final events config table". So stop printing it since it's not an actual failure , simply because the config table was never installed in the first place. In order to stop printing it make efi_init_event_log() and create_final_event() cleanup themselves and only call tcg2_uninit() when the protocol installation fails. Signed-off-by: Ilias Apalodimas Reviewed-by: Heinrich Schuchardt --- lib/efi_loader/efi_tcg2.c | 33 ++++++++++++++++++++++++++++----- 1 file changed, 28 insertions(+), 5 deletions(-) diff --git a/lib/efi_loader/efi_tcg2.c b/lib/efi_loader/efi_tcg2.c index c8616bf31e..39ef250bf9 100644 --- a/lib/efi_loader/efi_tcg2.c +++ b/lib/efi_loader/efi_tcg2.c @@ -999,6 +999,11 @@ static efi_status_t create_final_event(void) event_log.final_pos = sizeof(*final_event); ret = efi_install_configuration_table(&efi_guid_final_events, final_event); + if (ret != EFI_SUCCESS) { + efi_free_pool(event_log.final_buffer); + event_log.final_buffer = NULL; + } + out: return ret; } @@ -1047,15 +1052,22 @@ static efi_status_t efi_init_event_log(void) ret = create_specid_event(dev, (void *)((uintptr_t)event_log.buffer + sizeof(*event_header)), &spec_event_size); if (ret != EFI_SUCCESS) - goto out; + goto free_pool; put_unaligned_le32(spec_event_size, &event_header->event_size); event_log.pos = spec_event_size + sizeof(*event_header); event_log.last_event_size = event_log.pos; ret = create_final_event(); + if (ret != EFI_SUCCESS) + goto free_pool; out: return ret; + +free_pool: + efi_free_pool(event_log.buffer); + event_log.buffer = NULL; + return ret; } /** @@ -1111,18 +1123,29 @@ efi_status_t efi_tcg2_register(void) goto fail; ret = efi_append_scrtm_version(dev); - if (ret != EFI_SUCCESS) + if (ret != EFI_SUCCESS) { + tcg2_uninit(); goto fail; + } ret = efi_add_protocol(efi_root, &efi_guid_tcg2_protocol, (void *)&efi_tcg2_protocol); if (ret != EFI_SUCCESS) { - log_err("Cannot install EFI_TCG2_PROTOCOL\n"); + tcg2_uninit(); goto fail; } return ret; fail: - tcg2_uninit(); - return ret; + log_err("Cannot install EFI_TCG2_PROTOCOL\n"); + /* + * Return EFI_SUCCESS and don't stop the EFI subsystem. + * That's done for 2 reasons + * - If the protocol is not installed the PCRs won't be extended. So + * someone later in the boot flow will notice that and take the + * necessary actions. + * - The TPM sandbox is limited and we won't be able to run any efi + * related tests with TCG2 enabled + */ + return EFI_SUCCESS; } -- 2.39.5