[PATCH] efi_loader: check tcg2 protocol installation outside the TCG protocol
Masahisa Kojima
masahisa.kojima at linaro.org
Thu Nov 25 12:34:14 CET 2021
Hi Ilias,
On Thu, 25 Nov 2021 at 17:25, Ilias Apalodimas
<ilias.apalodimas at linaro.org> wrote:
>
> Hello Kojima-san
>
> On Thu, 25 Nov 2021 at 08:04, Masahisa Kojima
> <masahisa.kojima at linaro.org> wrote:
> >
> > There are functions that calls tcg2_agile_log_append() outside
> > of the TCG protocol invocation (e.g tcg2_measure_pe_image).
> > These functions must to check that tcg2 protocol is installed.
> > If not, measurement shall be skipped.
> >
> > Together with above change, this commit also removes the
> > unnecessary tcg2_uninit() call in efi_tcg2_register(),
> > refactors efi_tcg2_register() not to include the process
> > that is not related to the tcg2 protocol registration.
> >
> > Signed-off-by: Masahisa Kojima <masahisa.kojima at linaro.org>
> > ---
> > include/efi_loader.h | 4 ++
> > lib/efi_loader/efi_setup.c | 3 ++
> > lib/efi_loader/efi_tcg2.c | 89 +++++++++++++++++++++++++++++++-------
> > 3 files changed, 81 insertions(+), 15 deletions(-)
> >
> > diff --git a/include/efi_loader.h b/include/efi_loader.h
> > index d52e399841..fe29c10906 100644
> > --- a/include/efi_loader.h
> > +++ b/include/efi_loader.h
> > @@ -525,6 +525,10 @@ efi_status_t efi_disk_register(void);
> > efi_status_t efi_rng_register(void);
> > /* Called by efi_init_obj_list() to install EFI_TCG2_PROTOCOL */
> > efi_status_t efi_tcg2_register(void);
> > +/* Called by efi_init_obj_list() to do the required setup for the measurement */
> > +efi_status_t efi_tcg2_setup_measurement(void);
> > +/* Called by efi_init_obj_list() to do initial measurement */
> > +efi_status_t efi_tcg2_do_initial_measurement(void);
> > /* measure the pe-coff image, extend PCR and add Event Log */
> > efi_status_t tcg2_measure_pe_image(void *efi, u64 efi_size,
> > struct efi_loaded_image_obj *handle,
> > diff --git a/lib/efi_loader/efi_setup.c b/lib/efi_loader/efi_setup.c
> > index a2338d74af..781d10590d 100644
> > --- a/lib/efi_loader/efi_setup.c
> > +++ b/lib/efi_loader/efi_setup.c
> > @@ -271,6 +271,9 @@ efi_status_t efi_init_obj_list(void)
> > ret = efi_tcg2_register();
> > if (ret != EFI_SUCCESS)
> > goto out;
> > +
> > + efi_tcg2_setup_measurement();
> > + efi_tcg2_do_initial_measurement();
> > }
> >
> > /* Secure boot */
> > diff --git a/lib/efi_loader/efi_tcg2.c b/lib/efi_loader/efi_tcg2.c
> > index 8c1f22e337..46300cae79 100644
> > --- a/lib/efi_loader/efi_tcg2.c
> > +++ b/lib/efi_loader/efi_tcg2.c
> > @@ -153,6 +153,20 @@ static u16 alg_to_len(u16 hash_alg)
> > return 0;
> > }
> >
> > +/**
> > + * is_tcg2_protocol_installed - chech whether tcg2 protocol is installed
> > + *
> > + * @Return: true if tcg2 protocol is installed, false if not
> > + */
> > +bool is_tcg2_protocol_installed(void)
> > +{
> > + struct efi_handler *handler;
> > + efi_status_t ret;
> > +
> > + ret = efi_search_protocol(efi_root, &efi_guid_tcg2_protocol, &handler);
> > + return ((ret == EFI_SUCCESS) ? true : false);
> > +}
> > +
> > static u32 tcg_event_final_size(struct tpml_digest_values *digest_list)
> > {
> > u32 len;
> > @@ -886,6 +900,9 @@ efi_status_t tcg2_measure_pe_image(void *efi, u64 efi_size,
> > IMAGE_NT_HEADERS32 *nt;
> > struct efi_handler *handler;
> >
> > + if (!is_tcg2_protocol_installed())
> > + return EFI_NOT_READY;
> > +
> > ret = platform_get_tpm2_device(&dev);
> > if (ret != EFI_SUCCESS)
> > return ret;
> > @@ -1759,6 +1776,9 @@ efi_status_t efi_tcg2_measure_efi_app_invocation(struct efi_loaded_image_obj *ha
> > u32 event = 0;
> > struct smbios_entry *entry;
> >
> > + if (!is_tcg2_protocol_installed())
> > + return EFI_NOT_READY;
> > +
> > if (tcg2_efi_app_invoked)
> > return EFI_SUCCESS;
> >
> > @@ -1809,6 +1829,9 @@ efi_status_t efi_tcg2_measure_efi_app_exit(void)
> > efi_status_t ret;
> > struct udevice *dev;
> >
> > + if (!is_tcg2_protocol_installed())
> > + return EFI_NOT_READY;
> > +
> > ret = platform_get_tpm2_device(&dev);
> > if (ret != EFI_SUCCESS)
> > return ret;
> > @@ -1833,6 +1856,11 @@ efi_tcg2_notify_exit_boot_services(struct efi_event *event, void *context)
> >
> > EFI_ENTRY("%p, %p", event, context);
> >
> > + if (!is_tcg2_protocol_installed()) {
> > + ret = EFI_NOT_READY;
> > + goto out;
> > + }
> > +
> > event_log.ebs_called = true;
> > ret = platform_get_tpm2_device(&dev);
> > if (ret != EFI_SUCCESS)
> > @@ -1863,6 +1891,9 @@ efi_status_t efi_tcg2_notify_exit_boot_services_failed(void)
> > struct udevice *dev;
> > efi_status_t ret;
> >
> > + if (!is_tcg2_protocol_installed())
> > + return EFI_NOT_READY;
> > +
> > ret = platform_get_tpm2_device(&dev);
> > if (ret != EFI_SUCCESS)
> > goto out;
> > @@ -1932,6 +1963,45 @@ error:
> > return ret;
> > }
> >
> > +/**
> > + * efi_tcg2_setup_measurement() - setup for the measurement
> > + *
> > + * Return: status code
> > + */
> > +efi_status_t efi_tcg2_setup_measurement(void)
> > +{
> > + efi_status_t ret;
> > + struct efi_event *event;
> > +
> > + ret = efi_create_event(EVT_SIGNAL_EXIT_BOOT_SERVICES, TPL_CALLBACK,
> > + efi_tcg2_notify_exit_boot_services, NULL,
> > + NULL, &event);
> > +
> > + return ret;
> > +}
> > +
> > +/**
> > + * efi_tcg2_do_initial_measurement() - do initial measurement
> > + *
> > + * Return: status code
> > + */
> > +efi_status_t efi_tcg2_do_initial_measurement(void)
> > +{
> > + efi_status_t ret;
> > + struct udevice *dev;
> > +
> > + ret = platform_get_tpm2_device(&dev);
> > + if (ret != EFI_SUCCESS)
> > + goto out;
> > +
> > + ret = tcg2_measure_secure_boot_variable(dev);
> > + if (ret != EFI_SUCCESS)
> > + goto out;
> > +
> > +out:
> > + return ret;
> > +}
> > +
> > /**
> > * efi_tcg2_register() - register EFI_TCG2_PROTOCOL
> > *
> > @@ -1943,7 +2013,6 @@ efi_status_t efi_tcg2_register(void)
> > {
> > efi_status_t ret = EFI_SUCCESS;
> > struct udevice *dev;
> > - struct efi_event *event;
> > u32 err;
> >
> > ret = platform_get_tpm2_device(&dev);
> > @@ -1969,6 +2038,10 @@ efi_status_t efi_tcg2_register(void)
> > goto fail;
> > }
> >
> > + /*
> > + * efi_add_protocol() is called at last on purpose.
> > + * tcg2_uninit() does not uninstall the tcg2 protocol, but it is intended.
> > + */
> > ret = efi_add_protocol(efi_root, &efi_guid_tcg2_protocol,
> > (void *)&efi_tcg2_protocol);
> > if (ret != EFI_SUCCESS) {
> > @@ -1976,20 +2049,6 @@ efi_status_t efi_tcg2_register(void)
> > goto fail;
> > }
> >
> > - ret = efi_create_event(EVT_SIGNAL_EXIT_BOOT_SERVICES, TPL_CALLBACK,
> > - efi_tcg2_notify_exit_boot_services, NULL,
> > - NULL, &event);
> > - if (ret != EFI_SUCCESS) {
> > - tcg2_uninit();
> > - goto fail;
> > - }
> > -
> > - ret = tcg2_measure_secure_boot_variable(dev);
> > - if (ret != EFI_SUCCESS) {
> > - tcg2_uninit();
> > - goto fail;
> > - }
> > -
> > return ret;
> >
> > fail:
> > --
> > 2.17.1
> >
>
> This looks reasonable. I've just finished reviewing Ruchika's
> patchset adding TF-A eventlog support though [1]. Can you please
> rebase this on top of that series?
I have sent the rebased v2 patch.
Thanks,
Masahisa Kojima
>
>
> [1] https://lore.kernel.org/u-boot/CAC_iWjLPfwos2_x9e536jxwufQ3g7JhuzyEBf8s70MBEqfOadA@mail.gmail.com/
>
> Thanks
> /Ilias
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