Add the TEE-backed runtime SetVariable() implementation for the FF-A/MM variable backend. The runtime path uses EFI runtime-safe memory helpers and the shared MM communication path so SetVariable() can reach the MM secure partition after ExitBootServices().
Add runtime-safe variable-property helpers for the SetVariable() path and use the original data_size argument when restoring the read-only property maxsize, instead of relying on the MM response buffer. Reviewed-by: Simon Glass <[email protected]> Signed-off-by: Harsimran Singh Tungal <[email protected]> --- lib/efi_loader/efi_variable_tee.c | 147 ++++++++++++++++++++++++++++-- 1 file changed, 140 insertions(+), 7 deletions(-) diff --git a/lib/efi_loader/efi_variable_tee.c b/lib/efi_loader/efi_variable_tee.c index 5c7104662e9..d04b8dc1376 100644 --- a/lib/efi_loader/efi_variable_tee.c +++ b/lib/efi_loader/efi_variable_tee.c @@ -717,6 +717,38 @@ out: return ret; } +static efi_status_t __efi_runtime set_property_int_runtime(const u16 *variable_name, + efi_uintn_t name_size, + const efi_guid_t *vendor, + struct var_check_property *var_property) +{ + struct smm_variable_var_check_property *smm_property; + efi_uintn_t payload_size; + u8 *comm_buf = NULL; + efi_status_t ret; + + payload_size = sizeof(*smm_property) + name_size; + if (payload_size > max_payload_size) { + ret = EFI_INVALID_PARAMETER; + return ret; + } + comm_buf = setup_mm_hdr((void **)&smm_property, payload_size, + SMM_VARIABLE_FUNCTION_VAR_CHECK_VARIABLE_PROPERTY_SET, + &ret); + if (!comm_buf) + return ret; + + efi_memcpy_runtime(&smm_property->guid, vendor, sizeof(*vendor)); + smm_property->name_size = name_size; + efi_memcpy_runtime(&smm_property->property, var_property, + sizeof(smm_property->property)); + efi_memcpy_runtime(smm_property->name, variable_name, name_size); + + ret = mm_communicate(comm_buf, payload_size); + + return ret; +} + static efi_status_t get_property_int(const u16 *variable_name, efi_uintn_t name_size, const efi_guid_t *vendor, @@ -762,6 +794,49 @@ out: return ret; } +static efi_status_t __efi_runtime get_property_int_runtime(const u16 *variable_name, + efi_uintn_t name_size, + const efi_guid_t *vendor, + struct var_check_property *var_property) +{ + struct smm_variable_var_check_property *smm_property; + efi_uintn_t payload_size; + u8 *comm_buf = NULL; + efi_status_t ret; + + efi_memset_runtime(var_property, 0, sizeof(*var_property)); + payload_size = sizeof(*smm_property) + name_size; + if (payload_size > max_payload_size) { + ret = EFI_INVALID_PARAMETER; + return ret; + } + comm_buf = setup_mm_hdr((void **)&smm_property, payload_size, + SMM_VARIABLE_FUNCTION_VAR_CHECK_VARIABLE_PROPERTY_GET, + &ret); + if (!comm_buf) + return ret; + + efi_memcpy_runtime(&smm_property->guid, vendor, sizeof(smm_property->guid)); + smm_property->name_size = name_size; + efi_memcpy_runtime(smm_property->name, variable_name, name_size); + + ret = mm_communicate(comm_buf, payload_size); + /* + * Currently only R/O property is supported in StMM. + * Variables that are not set to R/O will not set the property in StMM + * and the call will return EFI_NOT_FOUND. We are setting the + * properties to 0x0 so checking against that is enough for the + * EFI_NOT_FOUND case. + */ + if (ret == EFI_NOT_FOUND) + return EFI_SUCCESS; + if (ret != EFI_SUCCESS) + return ret; + efi_memcpy_runtime(var_property, &smm_property->property, sizeof(*var_property)); + + return EFI_SUCCESS; +} + efi_status_t efi_get_variable_int(const u16 *variable_name, const efi_guid_t *vendor, u32 *attributes, efi_uintn_t *data_size, @@ -995,7 +1070,7 @@ efi_status_t efi_set_variable_int(const u16 *variable_name, var_property.property |= VAR_CHECK_VARIABLE_PROPERTY_READ_ONLY; var_property.attributes = attributes; var_property.minsize = 1; - var_property.maxsize = var_acc->data_size; + var_property.maxsize = data_size; ret = set_property_int(variable_name, name_size, vendor, &var_property); } @@ -1072,7 +1147,7 @@ efi_query_variable_info_runtime(u32 attributes, u64 *max_variable_storage_size, } /** - * efi_set_variable_runtime() - runtime implementation of SetVariable() + * efi_set_variable_int_runtime() - runtime implementation of SetVariable() * * @variable_name: name of the variable * @guid: vendor GUID @@ -1082,11 +1157,69 @@ efi_query_variable_info_runtime(u32 attributes, u64 *max_variable_storage_size, * Return: status code */ static efi_status_t __efi_runtime EFIAPI -efi_set_variable_runtime(u16 *variable_name, const efi_guid_t *guid, - u32 attributes, efi_uintn_t data_size, - const void *data) +efi_set_variable_int_runtime(u16 *variable_name, const efi_guid_t *guid, + u32 attributes, efi_uintn_t data_size, + const void *data) { - return EFI_UNSUPPORTED; + efi_status_t ret, mm_communicate_ret = EFI_SUCCESS; + struct var_check_property var_property; + struct smm_variable_access *var_acc; + efi_uintn_t payload_size; + efi_uintn_t name_size; + u8 *comm_buf = NULL; + bool ro; + + if (!variable_name || variable_name[0] == 0 || !guid) + return EFI_INVALID_PARAMETER; + + if (data_size > 0 && !data) + return EFI_INVALID_PARAMETER; + + /* Check payload size */ + name_size = u16_strsize(variable_name); + payload_size = MM_VARIABLE_ACCESS_HEADER_SIZE + name_size + data_size; + if (payload_size > max_payload_size) + return EFI_INVALID_PARAMETER; + + ro = !!(attributes & EFI_VARIABLE_READ_ONLY); + attributes &= EFI_VARIABLE_MASK; + + ret = get_property_int_runtime(variable_name, name_size, guid, + &var_property); + if (ret != EFI_SUCCESS) + return ret; + + if (var_property.property & VAR_CHECK_VARIABLE_PROPERTY_READ_ONLY) + return EFI_WRITE_PROTECTED; + + comm_buf = setup_mm_hdr((void **)&var_acc, payload_size, + SMM_VARIABLE_FUNCTION_SET_VARIABLE, &ret); + if (!comm_buf) + return ret; + + /* Fill in contents */ + efi_memcpy_runtime(&var_acc->guid, guid, sizeof(*guid)); + var_acc->data_size = data_size; + var_acc->name_size = name_size; + var_acc->attr = attributes; + efi_memcpy_runtime(var_acc->name, variable_name, name_size); + efi_memcpy_runtime((u8 *)var_acc->name + name_size, data, data_size); + + /* Communicate */ + ret = mm_communicate(comm_buf, payload_size); + if (ret != EFI_SUCCESS) + mm_communicate_ret = ret; + + if (ro && !(var_property.property & VAR_CHECK_VARIABLE_PROPERTY_READ_ONLY)) { + var_property.revision = VAR_CHECK_VARIABLE_PROPERTY_REVISION; + var_property.property |= VAR_CHECK_VARIABLE_PROPERTY_READ_ONLY; + var_property.attributes = attributes; + var_property.minsize = 1; + var_property.maxsize = data_size; + ret = set_property_int_runtime(variable_name, name_size, guid, &var_property); + } + + return (mm_communicate_ret == EFI_SUCCESS) ? ret : mm_communicate_ret; } /** @@ -1123,7 +1256,7 @@ void efi_variables_boot_exit_notify(void) efi_runtime_services.get_variable = efi_get_variable_runtime; efi_runtime_services.get_next_variable_name = efi_get_next_variable_name_runtime; - efi_runtime_services.set_variable = efi_set_variable_runtime; + efi_runtime_services.set_variable = efi_set_variable_int_runtime; efi_update_table_header_crc32(&efi_runtime_services.hdr); /* Record that ExitBootServices() has been called */ -- 2.34.1
