| Message ID | 20211126013116.3781-1-masahisa.kojima@linaro.org |
|---|---|
| State | New |
| Headers | show |
| Series | [v3] efi_loader: check tcg2 protocol installation outside the TCG protocol | expand |
Hi Kojima-san, On Fri, Nov 26, 2021 at 10:31:16AM +0900, Masahisa Kojima 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@linaro.org> > --- > Changes in v3: > - add static qualifier to is_tcg2_protocol_installed() > - simplify is_tcg2_protocol_installed() return handling > > Changes in v2: > - rebased on top of the TF-A eventlog handover support > > 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 b44eed0ec9..2196af49a6 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 s/chech/check > + * > + * @Return: true if tcg2 protocol is installed, false if not > + */ > +static 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); > +} > + > static u32 tcg_event_final_size(struct tpml_digest_values *digest_list) > { > u32 len; > @@ -962,6 +976,9 @@ 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; > @@ -2140,6 +2157,9 @@ 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; > > @@ -2190,6 +2210,9 @@ 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; > @@ -2214,6 +2237,11 @@ 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) > @@ -2244,6 +2272,9 @@ 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; > @@ -2313,6 +2344,45 @@ 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; > +} > + Unfortunately always returning EFI_SUCCESS from efi_tcg2_register() creates a dependency hell for us. If we want to keep this code don't we need to check is_tcg2_protocol_installed() here as well? If we don't the call chain here is: tcg2_measure_secure_boot_variable() -> tcg2_measure_variable() -> tcg2_measure_event() -> tcg2_agile_log_append(). Won't this still crash if for some reason efi_tcg2_register() failed? We could also avoid it by adding a similar check to tcg2_agile_log_append(). Or we do something like: diff --git a/lib/efi_loader/efi_tcg2.c b/lib/efi_loader/efi_tcg2.c index 117bf9add631..92ea8937cc60 100644 --- a/lib/efi_loader/efi_tcg2.c +++ b/lib/efi_loader/efi_tcg2.c @@ -325,6 +325,16 @@ static efi_status_t tcg2_agile_log_append(u32 pcr_index, u32 event_type, u32 event_size = size + tcg_event_final_size(digest_list); struct efi_tcg2_final_events_table *final_event; efi_status_t ret = EFI_SUCCESS; + /* + * This should never happen. This function should only be invoked if + * the TCG2 protocol has been installed. However since we always + * return EFI_SUCCESS from efi_tcg2_register shield callers against + * crashing and complain + */ + if (!event_log.buffer) { + log_err("EFI TCG2 protocol not installed correctly\n"); + return EFI_INVALID_PARAMETER; + } /* if ExitBootServices hasn't been called update the normal log */ if (!event_log.ebs_called) { @@ -341,6 +351,10 @@ static efi_status_t tcg2_agile_log_append(u32 pcr_index, u32 event_type, if (!event_log.get_event_called) return ret; + if (!event_log.final_buffer) { + log_err("EFI TCG2 protocol not installed correctly\n"); + return EFI_INVALID_PARAMETER; + } /* if GetEventLog has been called update FinalEventLog as well */ if (event_log.final_pos + event_size > TPM2_EVENT_LOG_SIZE) return EFI_VOLUME_FULL; But at this point I think this is an error waiting to happen. I'd much prefer just refusing to boot if the TCG protocol installation failed. > /** > * efi_tcg2_register() - register EFI_TCG2_PROTOCOL > * > @@ -2324,7 +2394,6 @@ 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); > @@ -2344,6 +2413,10 @@ efi_status_t efi_tcg2_register(void) > if (ret != EFI_SUCCESS) > 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) { > @@ -2351,20 +2424,6 @@ 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 > > return 0; Regards /Ilias
Hi Ilias, On Fri, 26 Nov 2021 at 23:55, Ilias Apalodimas <ilias.apalodimas@linaro.org> wrote: > > Hi Kojima-san, > > On Fri, Nov 26, 2021 at 10:31:16AM +0900, Masahisa Kojima 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@linaro.org> > > --- > > Changes in v3: > > - add static qualifier to is_tcg2_protocol_installed() > > - simplify is_tcg2_protocol_installed() return handling > > > > Changes in v2: > > - rebased on top of the TF-A eventlog handover support > > > > 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 b44eed0ec9..2196af49a6 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 > > s/chech/check > > > + * > > + * @Return: true if tcg2 protocol is installed, false if not > > + */ > > +static 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); > > +} > > + > > static u32 tcg_event_final_size(struct tpml_digest_values *digest_list) > > { > > u32 len; > > @@ -962,6 +976,9 @@ 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; > > @@ -2140,6 +2157,9 @@ 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; > > > > @@ -2190,6 +2210,9 @@ 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; > > @@ -2214,6 +2237,11 @@ 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) > > @@ -2244,6 +2272,9 @@ 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; > > @@ -2313,6 +2344,45 @@ 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; > > +} > > + > > Unfortunately always returning EFI_SUCCESS from efi_tcg2_register() creates > a dependency hell for us. If we want to keep this code don't we need to > check is_tcg2_protocol_installed() here as well? If we don't the call > chain here is: > tcg2_measure_secure_boot_variable() -> tcg2_measure_variable() -> > tcg2_measure_event() -> tcg2_agile_log_append(). > Won't this still crash if for some reason efi_tcg2_register() failed? Yes, you are correct. efi_tcg2_setup_measurement() and efi_tcg2_do_initial_measurement() expects that efi_tcg2_register() returns the correct error code, instead of EFI_SUCCESS, so this patch will not work as expected. In addition, I think again that calling is_tcg2_protocol_installed() in the outside of EFI Protocol functions such as tcg2_measure_pe_image() is also wrong. tcg2_measure_pe_image() shall be handled even if TCG2 EFI Protocol is not installed. > > We could also avoid it by adding a similar check to > tcg2_agile_log_append(). Or we do something like: > > diff --git a/lib/efi_loader/efi_tcg2.c b/lib/efi_loader/efi_tcg2.c > index 117bf9add631..92ea8937cc60 100644 > --- a/lib/efi_loader/efi_tcg2.c > +++ b/lib/efi_loader/efi_tcg2.c > @@ -325,6 +325,16 @@ static efi_status_t tcg2_agile_log_append(u32 pcr_index, u32 event_type, > u32 event_size = size + tcg_event_final_size(digest_list); > struct efi_tcg2_final_events_table *final_event; > efi_status_t ret = EFI_SUCCESS; > + /* > + * This should never happen. This function should only be invoked if > + * the TCG2 protocol has been installed. However since we always > + * return EFI_SUCCESS from efi_tcg2_register shield callers against > + * crashing and complain > + */ > + if (!event_log.buffer) { > + log_err("EFI TCG2 protocol not installed correctly\n"); > + return EFI_INVALID_PARAMETER; > + } > > /* if ExitBootServices hasn't been called update the normal log */ > if (!event_log.ebs_called) { > @@ -341,6 +351,10 @@ static efi_status_t tcg2_agile_log_append(u32 pcr_index, u32 event_type, > if (!event_log.get_event_called) > return ret; > > + if (!event_log.final_buffer) { > + log_err("EFI TCG2 protocol not installed correctly\n"); > + return EFI_INVALID_PARAMETER; > + } > /* if GetEventLog has been called update FinalEventLog as well */ > if (event_log.final_pos + event_size > TPM2_EVENT_LOG_SIZE) > return EFI_VOLUME_FULL; > > But at this point I think this is an error waiting to happen. I'd much > prefer just refusing to boot if the TCG protocol installation failed. I agree. So I think what should we do for this issue is: - Add null check of eventlog buffer in tcg2_agile_log_append() ===> You have already sent this patch. - return appropriate error code in efi_tcg2_register() - remove efi_create_event() and tcg2_measure_secure_boot_variable() from efi_tcg2_register() and create separate function as this patch, to make efi_tcg2_register() implementation simple. What do you think? Thanks, Masahisa Kojima > > > /** > > * efi_tcg2_register() - register EFI_TCG2_PROTOCOL > > * > > @@ -2324,7 +2394,6 @@ 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); > > @@ -2344,6 +2413,10 @@ efi_status_t efi_tcg2_register(void) > > if (ret != EFI_SUCCESS) > > 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) { > > @@ -2351,20 +2424,6 @@ 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 > > > > return 0; > > > Regards > /Ilias
Hi Kojima-san [...] > > > +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; > > > +} > > > + > > > > Unfortunately always returning EFI_SUCCESS from efi_tcg2_register() creates > > a dependency hell for us. If we want to keep this code don't we need to > > check is_tcg2_protocol_installed() here as well? If we don't the call > > chain here is: > > tcg2_measure_secure_boot_variable() -> tcg2_measure_variable() -> > > tcg2_measure_event() -> tcg2_agile_log_append(). > > Won't this still crash if for some reason efi_tcg2_register() failed? > > Yes, you are correct. efi_tcg2_setup_measurement() and > efi_tcg2_do_initial_measurement() expects that efi_tcg2_register() > returns > the correct error code, instead of EFI_SUCCESS, so this patch will not > work as expected. > > In addition, I think again that calling is_tcg2_protocol_installed() in the > outside of EFI Protocol functions such as tcg2_measure_pe_image() > is also wrong. tcg2_measure_pe_image() shall be handled even if > TCG2 EFI Protocol is not installed. > > > > > We could also avoid it by adding a similar check to > > tcg2_agile_log_append(). Or we do something like: > > > > diff --git a/lib/efi_loader/efi_tcg2.c b/lib/efi_loader/efi_tcg2.c > > index 117bf9add631..92ea8937cc60 100644 > > --- a/lib/efi_loader/efi_tcg2.c > > +++ b/lib/efi_loader/efi_tcg2.c > > @@ -325,6 +325,16 @@ static efi_status_t tcg2_agile_log_append(u32 pcr_index, u32 event_type, > > u32 event_size = size + tcg_event_final_size(digest_list); > > struct efi_tcg2_final_events_table *final_event; > > efi_status_t ret = EFI_SUCCESS; > > + /* > > + * This should never happen. This function should only be invoked if > > + * the TCG2 protocol has been installed. However since we always > > + * return EFI_SUCCESS from efi_tcg2_register shield callers against > > + * crashing and complain > > + */ > > + if (!event_log.buffer) { > > + log_err("EFI TCG2 protocol not installed correctly\n"); > > + return EFI_INVALID_PARAMETER; > > + } > > > > /* if ExitBootServices hasn't been called update the normal log */ > > if (!event_log.ebs_called) { > > @@ -341,6 +351,10 @@ static efi_status_t tcg2_agile_log_append(u32 pcr_index, u32 event_type, > > if (!event_log.get_event_called) > > return ret; > > > > + if (!event_log.final_buffer) { > > + log_err("EFI TCG2 protocol not installed correctly\n"); > > + return EFI_INVALID_PARAMETER; > > + } > > /* if GetEventLog has been called update FinalEventLog as well */ > > if (event_log.final_pos + event_size > TPM2_EVENT_LOG_SIZE) > > return EFI_VOLUME_FULL; > > > > But at this point I think this is an error waiting to happen. I'd much > > prefer just refusing to boot if the TCG protocol installation failed. > > I agree. > So I think what should we do for this issue is: > - Add null check of eventlog buffer in tcg2_agile_log_append() > ===> You have already sent this patch. > - return appropriate error code in efi_tcg2_register() > - remove efi_create_event() and tcg2_measure_secure_boot_variable() > from efi_tcg2_register() and create separate function as this patch, > to make efi_tcg2_register() implementation simple. > > What do you think? Yes I think this is the best say forward. Feel free to pick up the null checking patchset. > > Thanks, > Masahisa Kojima > > > Cheers /Ilias [...]
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 b44eed0ec9..2196af49a6 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 + */ +static 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); +} + static u32 tcg_event_final_size(struct tpml_digest_values *digest_list) { u32 len; @@ -962,6 +976,9 @@ 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; @@ -2140,6 +2157,9 @@ 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; @@ -2190,6 +2210,9 @@ 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; @@ -2214,6 +2237,11 @@ 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) @@ -2244,6 +2272,9 @@ 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; @@ -2313,6 +2344,45 @@ 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 * @@ -2324,7 +2394,6 @@ 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); @@ -2344,6 +2413,10 @@ efi_status_t efi_tcg2_register(void) if (ret != EFI_SUCCESS) 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) { @@ -2351,20 +2424,6 @@ 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:
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@linaro.org> --- Changes in v3: - add static qualifier to is_tcg2_protocol_installed() - simplify is_tcg2_protocol_installed() return handling Changes in v2: - rebased on top of the TF-A eventlog handover support 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(-)