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// Copyright (c) Microsoft Corporation.
// Licensed under the MIT License.
//! An implementation of UEFI spec 8.2 - Variable Services
//!
//! This implementation is a direct implementation / transcription of the UEFI
//! spec, and does not contain any Hyper-V specific features* (i.e: injecting
//! various nvram vars related to secure boot, boot order, etc...).
//!
//! *that isn't _entirely_ true just yet, as there is one bit of code
//! that enforce read-only access to certain Hyper-V specific vars, but if the
//! need arises, those code paths can be refactored.
pub use nvram_services_ext::NvramServicesExt;
use bitfield_struct::bitfield;
use guid::Guid;
use inspect::Inspect;
use mesh::payload::Protobuf;
use std::borrow::Cow;
use thiserror::Error;
use ucs2::Ucs2LeSlice;
use ucs2::Ucs2ParseError;
use uefi_nvram_specvars::signature_list;
use uefi_nvram_specvars::signature_list::ParseSignatureLists;
use uefi_nvram_storage::InspectableNvramStorage;
use uefi_nvram_storage::NextVariable;
use uefi_nvram_storage::NvramStorageError;
use uefi_specs::uefi::common::EfiStatus;
use uefi_specs::uefi::nvram::EfiVariableAttributes;
use uefi_specs::uefi::time::EFI_TIME;
use zerocopy::FromBytes;
use zerocopy::FromZeroes;
#[cfg(feature = "fuzzing")]
pub mod auth_var_crypto;
#[cfg(not(feature = "fuzzing"))]
mod auth_var_crypto;
mod nvram_services_ext;
#[derive(Debug, Error)]
pub enum NvramError {
#[error("storage backend error")]
NvramStorage(#[source] NvramStorageError),
#[error("variable name cannot be null/None")]
NameNull,
#[error("variable data of non-zero len cannot be null")]
DataNull,
#[error("variable name validation failed")]
NameValidation(#[from] Ucs2ParseError),
#[error("cannot pass empty string to SetVariable")]
NameEmpty,
#[error("attributes include non-spec values")]
AttributeNonSpec,
#[error("invalid runtime access")]
InvalidRuntimeAccess,
#[error("invalid attr: hardware error records are not supported")]
UnsupportedHardwareErrorRecord,
#[error("invalid attr: enhanced authenticated access unsupported")]
UnsupportedEnhancedAuthAccess,
#[error("invalid attr: volatile variables unsupported")]
UnsupportedVolatile,
#[error("attribute mismatch with existing variable")]
AttributeMismatch,
#[error("authenticated variable error")]
AuthError(#[from] AuthError),
#[error("updating SetupMode variable")]
UpdateSetupMode(#[source] NvramStorageError),
#[error("parsing signature list")]
SignatureList(#[from] signature_list::ParseError),
}
#[derive(Debug, Error)]
pub enum AuthError {
#[error("data too short (cannot extract EFI_VARIABLE_AUTHENTICATION_2 header)")]
NotEnoughHdrData,
#[error("data too short (cannot extract WIN_CERTIFICATE_UEFI_GUID cert)")]
NotEnoughCertData,
#[error("invalid WIN_CERTIFICATE Header")]
InvalidWinCertHeader,
#[error("invalid WIN_CERTIFICATE_UEFI_GUID Header")]
InvalidWinCertUefiGuidHeader,
#[error("incorrect cert type (must be WIN_CERTIFICATE_UEFI_GUID)")]
IncorrectCertType,
#[error("incorrect timestamp values")]
IncorrectTimestamp,
#[error("new timestamp is not later than current timestamp")]
OldTimestamp,
#[error("current implementation cannot authenticate specified var")]
UnsupportedAuthVar,
#[error("could not verify auth var")]
CryptoError,
#[cfg(feature = "auth-var-verify-crypto")]
#[error("error in crypto payload format")]
CryptoFormat(#[from] auth_var_crypto::FormatError),
}
/// `SetVariable` validation is incredibly tricky, since there are a _lot_ of
/// subtle logic branches that are predicated on the presence (or lack thereof)
/// of various attribute bits.
///
/// In order to make the implementation a bit easier to understand and maintain,
/// we switch from using the full-featured `EfiVariableAttributes` bitflags type
/// to a restricted subset of these flags described by `SupportedAttrs` part-way
/// through SetVariable.
#[bitfield(u32)]
#[derive(PartialEq)]
pub struct SupportedAttrs {
pub non_volatile: bool,
pub bootservice_access: bool,
pub runtime_access: bool,
pub hardware_error_record: bool,
_reserved: bool,
pub time_based_authenticated_write_access: bool,
#[bits(26)]
_reserved2: u32,
}
impl SupportedAttrs {
pub fn contains_unsupported_bits(&self) -> bool {
u32::from(*self)
& !u32::from(
Self::new()
.with_non_volatile(true)
.with_bootservice_access(true)
.with_runtime_access(true)
.with_hardware_error_record(true)
.with_time_based_authenticated_write_access(true),
)
!= 0
}
}
/// Helper struct to collect various properties of a parsed authenticated var
#[cfg_attr(not(feature = "auth-var-verify-crypto"), allow(dead_code))]
#[derive(Debug, Clone, Copy)]
pub struct ParsedAuthVar<'a> {
pub name: &'a Ucs2LeSlice,
pub vendor: Guid,
pub attr: u32,
pub timestamp: EFI_TIME,
pub pkcs7_data: &'a [u8],
pub var_data: &'a [u8],
}
/// Unlike a typical result type, NvramErrors contain _both_ a payload _and_ an
/// error code. Depending on the error code, an optional `NvramError` might be
/// included as well, which provides more context.
///
/// Notably, **this result types cannot be propagated via the `?` operator!**
#[derive(Debug)]
pub struct NvramResult<T>(pub T, pub EfiStatus, pub Option<NvramError>);
impl<T> NvramResult<T> {
pub fn is_success(&self) -> bool {
matches!(self.1, EfiStatus::SUCCESS)
}
}
impl<T> std::fmt::Display for NvramResult<T> {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
match &self.2 {
Some(_) => write!(f, "{:?} (with error context)", self.1),
None => write!(f, "{:?}", self.1),
}
}
}
impl<T> std::error::Error for NvramResult<T>
where
T: std::fmt::Debug,
{
fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
self.2
.as_ref()
.map(|s| s as &(dyn std::error::Error + 'static))
}
}
#[derive(Clone, Copy, Debug, Protobuf, Inspect)]
enum RuntimeState {
/// Implementation-specific state, whereby certain read-only and
/// authenticated variable checks are bypassed.
///
/// Transitions into `Boot` once all pre-boot nvram variables have been
/// successfully injected.
PreBoot,
/// UEFI firmware hasn't called `ExitBootServices`
Boot,
/// UEFI firmware has called `ExitBootServices`
Runtime,
}
impl RuntimeState {
fn is_pre_boot(&self) -> bool {
matches!(&self, RuntimeState::PreBoot)
}
fn is_boot(&self) -> bool {
matches!(&self, RuntimeState::Boot)
}
fn is_runtime(&self) -> bool {
matches!(&self, RuntimeState::Runtime)
}
}
/// An implementation of UEFI spec 8.2 - Variable Services
///
/// This API tries to match the API defined by the UEFI spec 1:1, hence why it
/// doesn't look very "Rust-y".
///
/// If you need to interact with `NvramServices` outside the context of the UEFI
/// device itself, consider importing the [`NvramServicesExt`] trait. This trait
/// provides various helper methods that make it easier to get/set nvram
/// variables, without worrying about the nitty-gritty details of UCS-2 string
/// encoding, pointer sizes/nullness, etc...
///
/// Instead of returning a typical `Result` type, these methods all return a
/// tuple of `(Option<T>, EfiStatus, Option<NvramError>)`, where the `EfiStatus`
/// field should be unconditionally returned to the guest, while the
/// `NvramError` type provides additional context as to what error occurred in
/// OpenVMM (i.e: for logging purposes).
#[derive(Debug, Inspect)]
pub struct NvramSpecServices<S: InspectableNvramStorage> {
storage: S,
runtime_state: RuntimeState,
}
impl<S: InspectableNvramStorage> NvramSpecServices<S> {
/// Construct a new NvramServices instance from an existing storage backend.
pub fn new(storage: S) -> NvramSpecServices<S> {
NvramSpecServices {
storage,
runtime_state: RuntimeState::PreBoot,
}
}
/// Check if the nvram store is empty.
pub async fn is_empty(&mut self) -> Result<bool, NvramStorageError> {
self.storage.is_empty().await
}
/// Update "SetupMode" based on the current value of "PK"
///
/// From UEFI spec section 32.3
///
/// While no Platform Key is enrolled, the SetupMode variable shall be equal
/// to 1. While SetupMode == 1, the platform firmware shall not require
/// authentication in order to modify the Platform Key, Key Enrollment Key,
/// OsRecoveryOrder, OsRecovery####, and image security databases.
///
/// After the Platform Key is enrolled, the SetupMode variable shall be
/// equal to 0. While SetupMode == 0, the platform firmware shall require
/// authentication in order to modify the Platform Key, Key Enrollment Key,
/// OsRecoveryOrder, OsRecovery####, and image security databases.
pub async fn update_setup_mode(&mut self) -> Result<(), NvramStorageError> {
use uefi_specs::uefi::nvram::vars::PK;
use uefi_specs::uefi::nvram::vars::SETUP_MODE;
let (pk_vendor, pk_name) = PK();
let (setup_mode_vendor, setup_mode_name) = SETUP_MODE();
let attr = EfiVariableAttributes::DEFAULT_ATTRIBUTES;
let timestamp = EFI_TIME::new_zeroed();
let data = match self.storage.get_variable(pk_name, pk_vendor).await? {
Some(_) => [0x00],
None => [0x01],
};
self.storage
.set_variable(
setup_mode_name,
setup_mode_vendor,
attr.into(),
data.to_vec(),
timestamp,
)
.await?;
Ok(())
}
/// Nvram behavior changes after the guest signals that ExitBootServices has
/// been called (e.g: hiding variables that are only accessible at
/// boot-time).
pub fn exit_boot_services(&mut self) {
assert!(self.runtime_state.is_boot());
tracing::trace!("NVRAM has entered runtime mode");
self.runtime_state = RuntimeState::Runtime;
}
/// Called when the VM resets to return to the preboot state.
pub fn reset(&mut self) {
self.runtime_state = RuntimeState::PreBoot;
}
/// Called after injecting any pre-boot nvram vars, transitioning the nvram
/// store to start accepting calls from guest UEFI.
pub fn prepare_for_boot(&mut self) {
assert!(self.runtime_state.is_pre_boot());
tracing::trace!("NVRAM has entered boot mode");
self.runtime_state = RuntimeState::Boot;
}
async fn get_setup_mode(&mut self) -> Result<bool, NvramStorageError> {
use uefi_specs::uefi::nvram::vars::SETUP_MODE;
let (setup_mode_vendor, setup_mode_name) = SETUP_MODE();
let in_setup_mode = match self
.storage
.get_variable(setup_mode_name, setup_mode_vendor)
.await?
{
None => false,
Some((_, data, _)) => data.first().map(|b| *b == 0x01).unwrap_or(false),
};
Ok(in_setup_mode)
}
/// Get a variable identified by `name` + `vendor`, returning the variable's
/// attributes and data.
///
/// - `in_name`
/// - (In) Variable name (a null-terminated UTF-16 string, or `None` if
/// the guest passed a `nullptr`)
/// - `in_vendor`
/// - (In) Variable vendor guid
/// - `out_attr`
/// - (Out) Variable's attributes
/// - _Note:_ According to the UEFI spec: `attr` will be populated on
/// both EFI_SUCCESS _and_ when EFI_BUFFER_TOO_SMALL is returned.
/// - `in_out_data_size`
/// - (In) Size of available data buffer (provided by guest)
/// - (Out) Size of data to be written into buffer
/// - _Note:_ If `data_is_null` is `true`, and `in_out_data_size` is set
/// to `0`, `in_out_data_size` will be updated with the size required
/// to store the variable.
/// - `data_is_null`
/// - (In) bool indicating if guest passed `nullptr` as the data addr
pub async fn uefi_get_variable(
&mut self,
name: Option<&[u8]>,
in_vendor: Guid,
out_attr: &mut u32,
in_out_data_size: &mut u32,
data_is_null: bool,
) -> NvramResult<Option<Vec<u8>>> {
let name = match name {
Some(name) => {
Ucs2LeSlice::from_slice_with_nul(name).map_err(NvramError::NameValidation)
}
None => Err(NvramError::NameNull),
};
let name = match name {
Ok(name) => name,
Err(e) => return NvramResult(None, EfiStatus::INVALID_PARAMETER, Some(e)),
};
tracing::trace!(
?in_vendor,
?name,
in_out_data_size,
data_is_null,
"Get NVRAM variable",
);
let (attr, data) = match self.get_variable_inner(name, in_vendor).await {
Ok(Some((attr, data, _))) => (attr, data),
Ok(None) => return NvramResult(None, EfiStatus::NOT_FOUND, None),
Err((status, err)) => return NvramResult(None, status, err),
};
if self.runtime_state.is_runtime() && !attr.runtime_access() {
// From UEFI spec section 8.2:
//
// If EFI_BOOT_SERVICES.ExitBootServices() has already been
// executed, data variables without the EFI_VARIABLE_RUNTIME_ACCESS
// attribute set will not be visible to GetVariable() and will
// return an EFI_NOT_FOUND error.
return NvramResult(
None,
EfiStatus::NOT_FOUND,
Some(NvramError::InvalidRuntimeAccess),
);
}
*out_attr = attr.into();
match (*in_out_data_size, data_is_null) {
(0, true) => *in_out_data_size = data.len() as u32,
(_, true) => return NvramResult(None, EfiStatus::INVALID_PARAMETER, None),
(_, false) => {
let guest_buf_len = *in_out_data_size as usize;
*in_out_data_size = data.len() as u32;
if guest_buf_len < data.len() {
return NvramResult(None, EfiStatus::BUFFER_TOO_SMALL, None);
}
}
}
NvramResult(Some(data), EfiStatus::SUCCESS, None)
}
async fn get_variable_inner(
&mut self,
name: &Ucs2LeSlice,
vendor: Guid,
) -> Result<Option<(SupportedAttrs, Vec<u8>, EFI_TIME)>, (EfiStatus, Option<NvramError>)> {
match self.storage.get_variable(name, vendor).await {
Ok(None) => Ok(None),
Ok(Some((attr, data, timestamp))) => {
let attr = SupportedAttrs::from(attr);
assert!(
!attr.contains_unsupported_bits(),
"underlying storage should only ever contain valid attributes"
);
Ok(Some((attr, data, timestamp)))
}
Err(e) => {
let status = match &e {
NvramStorageError::Deserialize => EfiStatus::DEVICE_ERROR,
_ => panic!("unexpected NvramStorageError from get_variable"),
};
Err((status, Some(NvramError::NvramStorage(e))))
}
}
}
/// Set a variable identified by `name` + `vendor` with the specified `attr`
/// and `data`
///
/// - `name`
/// - (In) Variable name (a null-terminated UTF-16 string, or `None` if
/// the guest passed a `nullptr`)
/// - _Note:_ `name` must contain one or more character.
/// - `in_vendor`
/// - (In) Variable vendor guid
/// - `in_attr`
/// - (In) Variable's attributes
/// - `in_data_size`
/// - (In) Length of data to be written
/// - If len in `0`, and the EFI_VARIABLE_APPEND_WRITE,
/// EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS,
/// EFI_VARIABLE_ENHANCED_AUTHENTICATED_ACCESS, or
/// EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS are not set,
/// the variable will be deleted.
/// - `data`
/// - (In) Variable data (or `None` if the guest passed a `nullptr`)
pub async fn uefi_set_variable(
&mut self,
name: Option<&[u8]>,
in_vendor: Guid,
in_attr: u32,
in_data_size: u32,
data: Option<Vec<u8>>,
) -> NvramResult<()> {
let name = match name {
Some(name) => {
Ucs2LeSlice::from_slice_with_nul(name).map_err(NvramError::NameValidation)
}
None => Err(NvramError::NameNull),
};
let name = match name {
Ok(name) => name,
Err(e) => return NvramResult((), EfiStatus::INVALID_PARAMETER, Some(e)),
};
if name.as_bytes() == [0, 0] {
return NvramResult(
(),
EfiStatus::INVALID_PARAMETER,
Some(NvramError::NameEmpty),
);
}
tracing::trace!(
%in_vendor,
%name,
in_attr,
in_data_size,
data = if data.is_some() { "Some([..])" } else { "None" },
"Set NVRAM variable",
);
// Perform some basic attribute validation
let attr = {
// Validate that set bits correspond to valid attribute flags
let attr = EfiVariableAttributes::from(in_attr);
if attr.contains_unsupported_bits() {
return NvramResult(
(),
EfiStatus::INVALID_PARAMETER,
Some(NvramError::AttributeNonSpec),
);
}
// From UEFI spec section 8.2:
//
// Runtime access to a data variable implies boot service access.
// Attributes that have EFI_VARIABLE_RUNTIME_ACCESS set must also
// have EFI_VARIABLE_BOOTSERVICE_ACCESS set. The caller is
// responsible for following this rule.
if attr.runtime_access() && !attr.bootservice_access() {
return NvramResult((), EfiStatus::INVALID_PARAMETER, None);
}
// From UEFI spec section 8.2:
//
// If both the EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS
// and the EFI_VARIABLE_ENHANCED_AUTHENTICATED_ACCESS attribute are
// set in a SetVariable() call, then the firmware must return
// EFI_INVALID_PARAMETER.
if attr.time_based_authenticated_write_access() && attr.enhanced_authenticated_access()
{
return NvramResult((), EfiStatus::INVALID_PARAMETER, None);
}
attr
};
// Report EFI_UNSUPPORTED for any attributes our implementation doesn't
// support
{
if attr.hardware_error_record() {
return NvramResult(
(),
EfiStatus::UNSUPPORTED,
Some(NvramError::UnsupportedHardwareErrorRecord),
);
}
if attr.enhanced_authenticated_access() {
return NvramResult(
(),
EfiStatus::UNSUPPORTED,
Some(NvramError::UnsupportedEnhancedAuthAccess),
);
}
// From UEFI spec section 8.2:
//
// EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS is deprecated and should
// not be used. Platforms should return EFI_UNSUPPORTED if a caller
// to SetVariable() specifies this attribute.
if attr.authenticated_write_access() {
return NvramResult((), EfiStatus::UNSUPPORTED, None);
}
}
// From UEFI spec section 32.3, Figure 32-4
//
// There are various nvram variables that determine what part of secure
// boot flow we are in. These get used later on in validation, but we'll
// go ahead and fetch them here...
//
// TODO: implement logic around AuditMode and DeployedMode
let in_setup_mode = match self.get_setup_mode().await {
Ok(val) => val,
Err(err) => {
return NvramResult(
(),
EfiStatus::DEVICE_ERROR,
Some(NvramError::NvramStorage(err)),
)
}
};
// From UEFI spec section 8.2:
//
// Once ExitBootServices() is performed, only variables that have
// EFI_VARIABLE_RUNTIME_ACCESS and EFI_VARIABLE_NON_VOLATILE set can be
// set with SetVariable(). Variables that have runtime access but that
// are not nonvolatile are readonly data variables once
// ExitBootServices() is performed.
if self.runtime_state.is_runtime() {
// At first glance, this seems like a pretty straightforward
// conditional, but unfortunately, we need to consider the
// interaction with this other clause:
//
// From UEFI spec section 8.2:
//
// If a preexisting variable is rewritten with no access
// attributes specified, the variable will be deleted.
//
// As such, if neither access attribute is set, we punt this runtime
// access check to the implementation of the delete operation,
// whereby it will make sure the variable being deleted has the
// correct attributes.
let missing_access_attrs = !(attr.runtime_access() || attr.bootservice_access());
if !missing_access_attrs {
if !attr.runtime_access() || !attr.non_volatile() {
return NvramResult(
(),
EfiStatus::INVALID_PARAMETER,
Some(NvramError::InvalidRuntimeAccess),
);
}
}
}
// Check if variable being set is read-only from the Guest
//
// Note: these checks are bypassed during pre-boot in order to set the
// vars' initial values.
if !self.runtime_state.is_pre_boot() {
use uefi_specs::hyperv::nvram::vars as hyperv_vars;
use uefi_specs::uefi::nvram::vars as spec_vars;
// In true UEFI spec fashion, there are always exceptions...
enum Exception {
None,
SetupMode,
// TODO: add more exception variants as new RO vars are added
}
#[rustfmt::skip]
let read_only_vars = [
// UEFI Spec - Table 3-1 Global Variables
//
// NOTE: Does not implement all of the read-only
// variables defined by the UEFI spec in section 3.3
(spec_vars::SECURE_BOOT(), Exception::None),
(spec_vars::SETUP_MODE(), Exception::None),
(spec_vars::KEK(), Exception::SetupMode),
(spec_vars::PK(), Exception::SetupMode),
(spec_vars::DBDEFAULT(), Exception::None),
// Hyper-V also uses some read-only vars that aren't specified
// in the UEFI spec
(hyperv_vars::SECURE_BOOT_ENABLE(), Exception::None),
(hyperv_vars::CURRENT_POLICY(), Exception::None),
(hyperv_vars::OS_LOADER_INDICATIONS_SUPPORTED(), Exception::None),
];
let is_readonly = read_only_vars.into_iter().any(|(v, exception)| {
let skip_check = match exception {
Exception::None => false,
Exception::SetupMode => in_setup_mode,
};
// NOTE: The HCL and worker process implementations perform a
// case-insensitive comparisons here. A better fix would've
// been to make all comparisons case _sensitive_, rather than
// introducing bits of case _insensitivity_ around the nvram
// implementation. Hindsight is 20-20.
//
// In OpenVMM, we don't consider nvram variable names as strings
// with semantic meaning. Instead, they are akin to a
// bag-of-bytes that _just so happen_ to have a convenient debug
// representation when printed out at a UCS-2 string.
//
// Case-sensitive comparisons has been confirmed correct with
// the UEFI team, and as such, it may be worthwhile to backport
// this change into the C++ implementation as well.
if !skip_check {
v == (in_vendor, name)
} else {
false
}
});
if is_readonly {
return NvramResult((), EfiStatus::WRITE_PROTECTED, None);
}
}
// The behavior of various operations changes depending on whether or
// not the specified variable already exists, so go ahead and try to
// fetch it
let existing_var = match self.get_variable_inner(name, in_vendor).await {
Ok(v) => v,
Err((status, err)) => return NvramResult((), status, err),
};
let (in_data_size, data, timestamp) = {
if !attr.time_based_authenticated_write_access() {
// nothing fancy here, just some regular 'ol data...
let timestamp = EFI_TIME::new_zeroed();
(in_data_size, data, timestamp)
} else {
// the payload includes an authenticated variable header
//
// UEFI spec 8.2.2 - Using the EFI_VARIABLE_AUTHENTICATION_2 descriptor
use uefi_specs::uefi::nvram::EFI_VARIABLE_AUTHENTICATION_2;
use uefi_specs::uefi::signing::EFI_CERT_TYPE_PKCS7_GUID;
use uefi_specs::uefi::signing::WIN_CERTIFICATE_UEFI_GUID;
use uefi_specs::uefi::signing::WIN_CERT_TYPE_EFI_GUID;
tracing::trace!(
"variable is attempting to use TIME_BASED_AUTHENTICATED_WRITE_ACCESS"
);
// data cannot be null
let data = match data {
Some(data) => data,
None => {
return NvramResult(
(),
EfiStatus::INVALID_PARAMETER,
Some(NvramError::DataNull),
)
}
};
// extract EFI_VARIABLE_AUTHENTICATION_2 header
let auth_hdr =
match EFI_VARIABLE_AUTHENTICATION_2::read_from_prefix(data.as_slice()) {
Some(hdr) => hdr,
None => {
return NvramResult(
(),
EfiStatus::SECURITY_VIOLATION,
Some(NvramError::AuthError(AuthError::NotEnoughHdrData)),
)
}
};
let timestamp = auth_hdr.timestamp;
let auth_info = auth_hdr.auth_info;
// split off the variable-length WIN_CERTIFICATE_UEFI_GUID cert
// data from the variable length payload
let (pkcs7_data, var_data) = {
let auth_info_offset = size_of_val(&auth_hdr.timestamp);
// use the header's length value to extract the
// WIN_CERTIFICATE_UEFI_GUID struct + variable length payload
if data[auth_info_offset..].len() < (auth_info.header.length as usize) {
return NvramResult(
(),
EfiStatus::SECURITY_VIOLATION,
Some(NvramError::AuthError(AuthError::NotEnoughCertData)),
);
}
let (auth_info_hdr_and_cert, var_data) =
data[auth_info_offset..].split_at(auth_info.header.length as usize);
// ...and then strip off the WIN_CERTIFICATE_UEFI_GUID
// struct from the variable length payload
let pkcs7_data = match auth_info_hdr_and_cert
.get(size_of::<WIN_CERTIFICATE_UEFI_GUID>()..)
{
Some(data) => data,
None => {
return NvramResult(
(),
EfiStatus::SECURITY_VIOLATION,
Some(NvramError::AuthError(AuthError::NotEnoughCertData)),
);
}
};
(pkcs7_data, var_data)
};
// validate WIN_CERTIFICATE header construction
if auth_info.header.revision != 0x0200 {
return NvramResult(
(),
EfiStatus::SECURITY_VIOLATION,
Some(NvramError::AuthError(AuthError::InvalidWinCertHeader)),
);
}
// validate correct cert type is being used
if auth_info.header.certificate_type != WIN_CERT_TYPE_EFI_GUID
|| auth_info.cert_type != EFI_CERT_TYPE_PKCS7_GUID
{
return NvramResult(
(),
EfiStatus::SECURITY_VIOLATION,
Some(NvramError::AuthError(AuthError::IncorrectCertType)),
);
}
// validate timestamp according to spec
if timestamp.pad1 != 0
|| timestamp.nanosecond != 0
|| timestamp.timezone.0 != 0
|| u8::from(timestamp.daylight) != 0
|| timestamp.pad2 != 0
{
return NvramResult(
(),
EfiStatus::SECURITY_VIOLATION,
Some(NvramError::AuthError(AuthError::IncorrectTimestamp)),
);
}
// if a variable already exists, make sure the timestamp is
// newer (or in the case of Append, clamp the timestamp to the
// existing timestamp)
let orig_timestamp = timestamp; // original value must be used when performing variable auth
let timestamp = {
let mut timestamp = timestamp;
if let Some((_, _, existing_timestamp)) = existing_var {
let is_newer = (
timestamp.year,
timestamp.month,
timestamp.day,
timestamp.hour,
timestamp.minute,
timestamp.second,
timestamp.nanosecond,
)
.cmp(&(
existing_timestamp.year,
existing_timestamp.month,
existing_timestamp.day,
existing_timestamp.hour,
existing_timestamp.minute,
existing_timestamp.second,
existing_timestamp.nanosecond,
))
.is_gt();
if !is_newer {
if !attr.append_write() {
return NvramResult(
(),
EfiStatus::SECURITY_VIOLATION,
Some(NvramError::AuthError(AuthError::OldTimestamp)),
);
} else {
timestamp = existing_timestamp
}
}
}
timestamp
};
// If PK is present, then we need to authenticate the payload with KEK or PK.
let pk_var = {
let (pk_vendor, pk_name) = uefi_specs::uefi::nvram::vars::PK();
match self.get_variable_inner(pk_name, pk_vendor).await {
Ok(v) => v,
Err((status, err)) => return NvramResult((), status, err),
}
};
// From UEFI spec section 8.2.2:
//
// If the variable SetupMode==1, and the variable is a secure
// boot policy variable, then the firmware implementation shall
// consider the checks in the following steps 4 and 5 to have
// passed, and proceed with updating the variable value as
// outlined below.
//
// (our implementation extends this condition to include
// "is nvram currently in the pre-boot state")
let bypass_auth = self.runtime_state.is_pre_boot()
|| (in_setup_mode
&& uefi_specs::uefi::nvram::is_secure_boot_policy_var(in_vendor, name));
if pk_var.is_some() && !bypass_auth {
tracing::trace!("pk exists, attempting to actually authenticate var...");
let parsed_auth_var = ParsedAuthVar {
name,
vendor: in_vendor,
attr: attr.into(),
timestamp: orig_timestamp,
pkcs7_data,
var_data,
};
// The UEFI spec has several special-cased authenticated vars.
// At the moment, our implementation only supports a handful of these cases.
enum AuthVarKind {
Db,
PkKek,
Unsupported,
}
let var_kind = match (in_vendor, name) {
v if v == uefi_specs::uefi::nvram::vars::DB() => AuthVarKind::Db,
v if v == uefi_specs::uefi::nvram::vars::DBX() => AuthVarKind::Db,
v if v == uefi_specs::uefi::nvram::vars::PK() => AuthVarKind::PkKek,
v if v == uefi_specs::uefi::nvram::vars::KEK() => AuthVarKind::PkKek,
// TODO: add support for:
// - dbr, dbt
// - OsRecoveryOrder, OsRecovery####
// - private auth vars
_ => AuthVarKind::Unsupported,
};
let auth_res = match var_kind {
AuthVarKind::Db => {
// UEFI Spec - 8.2.2 Using the EFI_VARIABLE_AUTHENTICATION_2 descriptor
//
// If the variable is the “db”, “dbt”, “dbr”, or “dbx” variable mentioned
// in step 3, verify that the signer’s certificate chains to a certificate
// in the Key Exchange Key database (or that the signature was made with
// the current Platform Key).
match self
.authenticate_var(
uefi_specs::uefi::nvram::vars::KEK(),
parsed_auth_var,
)
.await
{
Ok(res) => Ok(res),
// If authentication with KEK fails, then try PK authentication.
Err(_) => {
self.authenticate_var(
uefi_specs::uefi::nvram::vars::PK(),
parsed_auth_var,
)
.await
}
}
}
AuthVarKind::PkKek => {
// UEFI Spec - 8.2.2 Using the EFI_VARIABLE_AUTHENTICATION_2 descriptor
//
// If the variable is the global PK variable or the global KEK variable,
// verify that the signature has been made with the current Platform Key.
self.authenticate_var(
uefi_specs::uefi::nvram::vars::PK(),
parsed_auth_var,
)
.await
}
AuthVarKind::Unsupported => {
// TODO: the HCL treats this case the same as the `PkKek` case, but that
// seems wrong...
return NvramResult(
(),
EfiStatus::SECURITY_VIOLATION,
Some(NvramError::AuthError(AuthError::UnsupportedAuthVar)),
);
}
};
if let Err((status, err)) = auth_res {
return NvramResult((), status, err);
}
}
// now that everything has been validated, we can strip off the
// auth header and go on to actually performing the requested
// operation of the remaining payload.
let total_auth_hdr_len =
size_of_val(&auth_hdr.timestamp) + (auth_info.header.length as usize);
(
in_data_size - total_auth_hdr_len as u32,
Some({
let mut data = data;
data.drain(..total_auth_hdr_len);
data
}),
timestamp,
)
}
};
// SetVariable is pretty weird, as it overloads a single method to
// perform a whole bunch of different variable operations, such as
// removing, updating, appending, and setting variables.
//
// Determining which specific operation is being requested requires
// navigating a hodgepodge of various rules and indicators, such as the
// length of the data passed in, what attributes are set, etc...
#[derive(Debug)]
enum VariableOperation {
Set,
Append,
Delete,
}
let op = {
let is_doing_append = attr.append_write();
let is_doing_delete = {
// From UEFI spec section 8.2:
//
// If a preexisting variable is rewritten with no access attributes
// specified, the variable will be deleted.
let missing_access_attrs = !(attr.runtime_access() || attr.bootservice_access());
// From UEFI spec section 8.2:
//
// Unless the EFI_VARIABLE_APPEND_WRITE,
// EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS, or
// EFI_VARIABLE_ENHANCED_AUTHENTICATED_ACCESS attribute is set (see
// below), using SetVariable() with a DataSize of zero will cause the
// entire variable to be deleted
let zero_data_size = in_data_size == 0 && !is_doing_append;
missing_access_attrs || zero_data_size
};
// append takes precedence over delete/set
if is_doing_append {
VariableOperation::Append
} else if is_doing_delete {
VariableOperation::Delete
} else {
VariableOperation::Set
}
};
tracing::trace!(?op, "SetVariable is performing");
// normalize attr bits (i.e: strip off APPEND_WRITE indicator)
let attr = attr.with_append_write(false);
// Drop down to using `SupportedAttrs` instead of
// `EfiVariableAttributes` to make things easier to follow.
let attr = SupportedAttrs::from(u32::from(attr));
let res = match op {
VariableOperation::Append => {
// This implementation only supports non-volatile variables.
// Volatile variables should be handled within UEFI itself.
if !attr.non_volatile() {
return NvramResult(
(),
EfiStatus::UNSUPPORTED,
Some(NvramError::UnsupportedVolatile),
);
}
// data *might* get modified in the case that it contains an
// EFI_SIGNATURE_LIST, and duplicates need to get filtered out
// (hence the use of `mut`)
let mut data = match (in_data_size, data) {
// Appending with zero data will silently do nothing,
// regardless if a variable already exists
(0, _) => return NvramResult((), EfiStatus::SUCCESS, None),
// If data len is non-zero, data cannot be nullptr
(_, None) => {
return NvramResult((), EfiStatus::SUCCESS, Some(NvramError::DataNull))
}
(_, Some(data)) => data,
};
if let Some((existing_attr, existing_data, _)) = existing_var {
// attempting to fetch a boot-time variable at runtime
if self.runtime_state.is_runtime() && !existing_attr.runtime_access() {
// ...will fail, since the variable "doesn't exist" at runtime
return NvramResult(
(),
EfiStatus::NOT_FOUND,
Some(NvramError::InvalidRuntimeAccess),
);
}
// From UEFI spec section 8.2:
//
// If a preexisting variable is rewritten with different
// attributes, SetVariable() shall not modify the variable
// and shall return EFI_INVALID_PARAMETER.
if attr != existing_attr {
return NvramResult(
(),
EfiStatus::INVALID_PARAMETER,
Some(NvramError::AttributeMismatch),
);
}
// From UEFI spec section 8.2:
//
// For variables with the GUID EFI_IMAGE_SECURITY_DATABASE_GUID
// (i.e. where the data buffer is formatted as EFI_SIGNATURE_LIST),
// the driver shall not perform an append of EFI_SIGNATURE_DATA
// values that are already part of the existing variable value.
//
// Note: This situation is not considered an error, and shall in itself
// not cause a status code other than EFI_SUCCESS to be returned or the
// timestamp associated with the variable not to be updated.
if attr.time_based_authenticated_write_access() {
use signature_list::SignatureDataPayload;
let existing_signatures = ParseSignatureLists::new(&existing_data)
.collect_signature_set()
.expect("existing var must contain valid list of EFI_SIGNATURE_LIST");
// NOTE: the Hyper-V implementation filter signature lists in-place. While
// that *would* be more efficient, it also makes the code a _lot_ harder to
// understand, so in OpenVMM, lets keep things simple and just allocate a new
// buffer for the filtered signatures.
let filtered_signatures = ParseSignatureLists::new(&data)
.collect_signature_lists(|header, sig| {
let sig: &[u8] = match sig {
SignatureDataPayload::X509(buf) => buf,
SignatureDataPayload::Sha256(buf) => buf,
};
!existing_signatures.contains(&(header, Cow::Borrowed(sig)))
});
// it *is* an error if the provided signature list is malformed
let filtered_signatures = match filtered_signatures {
Ok(sigs) => sigs,
Err(e) => {
return NvramResult(
(),
EfiStatus::INVALID_PARAMETER,
Some(NvramError::SignatureList(e)),
)
}
};
let mut new_data = Vec::new();
for list in filtered_signatures {
list.extend_as_spec_signature_list(&mut new_data);
}
// update data to point at the new signature list we just created
data = new_data;
}
}
// All validation checks have passed, so perform the operation
match self
.storage
.append_variable(name, in_vendor, data.to_vec(), timestamp)
.await
{
Ok(true) => NvramResult((), EfiStatus::SUCCESS, None),
Ok(false) => NvramResult((), EfiStatus::NOT_FOUND, None),
Err(e) => {
let status = match &e {
NvramStorageError::Commit(_) => EfiStatus::DEVICE_ERROR,
NvramStorageError::OutOfSpace => EfiStatus::OUT_OF_RESOURCES,
NvramStorageError::VariableNameTooLong => EfiStatus::INVALID_PARAMETER,
NvramStorageError::VariableDataTooLong => EfiStatus::INVALID_PARAMETER,
_ => {
panic!("unexpected NvramStorageError from append_variable")
}
};
NvramResult((), status, Some(NvramError::NvramStorage(e)))
}
}
}
VariableOperation::Delete => {
if let Some((existing_attr, _, _)) = existing_var {
// attempting to delete an existing boot-time variable at runtime
if self.runtime_state.is_runtime() && !existing_attr.runtime_access() {
// ...will fail, since the variable "doesn't exist" at runtime
return NvramResult(
(),
EfiStatus::NOT_FOUND,
Some(NvramError::InvalidRuntimeAccess),
);
}
}
// All validation checks have passed, so perform the operation
match self.storage.remove_variable(name, in_vendor).await {
Ok(true) => NvramResult((), EfiStatus::SUCCESS, None),
Ok(false) => NvramResult((), EfiStatus::NOT_FOUND, None),
Err(e) => {
let status = match &e {
NvramStorageError::Commit(_) => EfiStatus::DEVICE_ERROR,
NvramStorageError::OutOfSpace => EfiStatus::OUT_OF_RESOURCES,
NvramStorageError::VariableNameTooLong => EfiStatus::INVALID_PARAMETER,
NvramStorageError::VariableDataTooLong => EfiStatus::INVALID_PARAMETER,
_ => {
panic!("unexpected NvramStorageError from remove_variable")
}
};
NvramResult((), status, Some(NvramError::NvramStorage(e)))
}
}
}
VariableOperation::Set => {
// This implementation only supports non-volatile variables.
// Volatile variables should be handled within UEFI itself.
//
// The exceptions are variables that are controlled/injected by the loader.
// This includes secure boot enablement (volatile by specification),
// as well as the private Hyper-V OsLoaderIndications and
// OsLoaderIndicationsSupported variables, which are volatile variables
// that are injected via the non-volatile store. The dbDefault variable
// is also an exception.
if !attr.non_volatile() {
use uefi_specs::hyperv::nvram::vars as hyperv_vars;
use uefi_specs::uefi::nvram::vars::DBDEFAULT;
use uefi_specs::uefi::nvram::vars::SECURE_BOOT;
let allowed_volatile = [
hyperv_vars::OS_LOADER_INDICATIONS(),
hyperv_vars::OS_LOADER_INDICATIONS_SUPPORTED(),
DBDEFAULT(),
SECURE_BOOT(),
];
let is_allowed = allowed_volatile.into_iter().any(|v| v == (in_vendor, name));
if !is_allowed {
return NvramResult(
(),
EfiStatus::UNSUPPORTED,
Some(NvramError::UnsupportedVolatile),
);
}
}
// if we are doing a variable set, then data cannot be a nullptr
let data = match data {
Some(data) => data,
None => {
return NvramResult(
(),
EfiStatus::INVALID_PARAMETER,
Some(NvramError::DataNull),
)
}
};
if let Some((existing_attr, _, _)) = existing_var {
// attempting to overwrite an existing boot-time variable
if self.runtime_state.is_runtime() && !existing_attr.runtime_access() {
// This is a weird case, since calling GetVariable would
// actually return `EFI_NOT_FOUND` (as the variable is
// "hidden" at runtime), implying that it should be
// _fine_ to set the variable.
//
// It seems that unless we have some kind of "runtime
// shadow variable" support, it's possible to use
// `SetVariable` as a way to check if boot-time
// variables _actually_ exist...
//
// The UEFI folks seem to think this gap is _fine_, as
// it doesn't give access to protected data - just the
// fact that that the boot time var exists.
//
// So... while this isn't a _great_ solution, it matches
// all existing implementations (both within and outside
// Hyper-V)
return NvramResult(
(),
EfiStatus::WRITE_PROTECTED,
Some(NvramError::InvalidRuntimeAccess),
);
}
// From UEFI spec section 8.2:
//
// If a preexisting variable is rewritten with different
// attributes, SetVariable() shall not modify the
// variable and shall return EFI_INVALID_PARAMETER.
if attr != existing_attr {
return NvramResult(
(),
EfiStatus::INVALID_PARAMETER,
Some(NvramError::AttributeMismatch),
);
}
}
// All validation checks have passed, so perform the operation
match self
.storage
.set_variable(name, in_vendor, attr.into(), data.to_vec(), timestamp)
.await
{
Ok(_) => NvramResult((), EfiStatus::SUCCESS, None),
Err(e) => {
let status = match &e {
NvramStorageError::Commit(_) => EfiStatus::DEVICE_ERROR,
NvramStorageError::OutOfSpace => EfiStatus::OUT_OF_RESOURCES,
NvramStorageError::VariableNameTooLong => EfiStatus::INVALID_PARAMETER,
NvramStorageError::VariableDataTooLong => EfiStatus::INVALID_PARAMETER,
_ => panic!("unexpected NvramStorageError from set_variable"),
};
NvramResult((), status, Some(NvramError::NvramStorage(e)))
}
}
}
};
// If we modified the PK variable, we need to update the SetupMode
// variable accordingly.
if res.is_success() && (in_vendor, name) == uefi_specs::uefi::nvram::vars::PK() {
if let Err(e) = self.update_setup_mode().await {
return NvramResult(
(),
EfiStatus::DEVICE_ERROR,
Some(NvramError::UpdateSetupMode(e)),
);
}
}
res
}
#[cfg(not(feature = "auth-var-verify-crypto"))]
async fn authenticate_var(
&mut self,
// NOTE: Due to a compiler limitation with async fn, 'static bound was removed here
// https://github.com/rust-lang/rust/issues/63033#issuecomment-521234696
_: (Guid, &Ucs2LeSlice),
_: ParsedAuthVar<'_>,
) -> Result<(), (EfiStatus, Option<NvramError>)> {
tracing::warn!("compiled without 'auth-var-verify-crypto' - unconditionally failing auth var validation!");
Err((EfiStatus::SECURITY_VIOLATION, None))
}
/// Authenticate the given variable against the signatures stored in the
/// specified EFI_SIGNATURE_LIST
#[cfg(feature = "auth-var-verify-crypto")]
async fn authenticate_var(
&mut self,
// NOTE: Due to a compiler limitation with async fn, 'static bound was removed here
// https://github.com/rust-lang/rust/issues/63033#issuecomment-521234696
(key_var_name, key_var_vendor): (Guid, &Ucs2LeSlice),
auth_var: ParsedAuthVar<'_>,
) -> Result<(), (EfiStatus, Option<NvramError>)> {
let signature_lists = match self
.get_variable_inner(key_var_vendor, key_var_name)
.await?
{
Some((_, data, _)) => data,
None => return Err((EfiStatus::SECURITY_VIOLATION, None)),
};
// the nitty-gritty of how authentication works is best left to a separate module...
match auth_var_crypto::authenticate_variable(&signature_lists, auth_var) {
Ok(true) => Ok(()),
Ok(false) => Err((
EfiStatus::SECURITY_VIOLATION,
Some(NvramError::AuthError(AuthError::CryptoError)),
)),
Err(e) if e.key_var_error() => {
panic!("existing signature list must contain valid data: {}", e)
}
// all other errors are due to malformed auth_var data
Err(e) => Err((
EfiStatus::SECURITY_VIOLATION,
Some(NvramError::AuthError(AuthError::CryptoFormat(e))),
)),
}
}
/// Return the variable immediately following the variable identified by
/// `name` + `vendor` `key`.
///
/// If `name` is an empty string, the first variable is returned.
///
/// - `name`
/// - (In) Variable name (a null-terminated UTF-16 string, or `None` if
/// the guest passed a `nullptr`)
/// - `in_out_name_size`
/// - (In) Length of the provided `name`
/// - (Out) Length of the next variable name
/// - _Note:_ If there is insufficient space in the name buffer to store
/// the next variable, `in_out_name_size` will be updated with the
/// size required to store the variable.
/// - `vendor`
/// - (In) Variable vendor guid
pub async fn uefi_get_next_variable(
&mut self,
in_out_name_size: &mut u32,
name: Option<&[u8]>,
vendor: Guid,
) -> NvramResult<Option<(Vec<u8>, Guid)>> {
let name = match name {
Some(name) => {
Ucs2LeSlice::from_slice_with_nul(name).map_err(NvramError::NameValidation)
}
None => Err(NvramError::NameNull),
};
let name = match name {
Ok(name) => name,
Err(e) => return NvramResult(None, EfiStatus::INVALID_PARAMETER, Some(e)),
};
tracing::trace!(?vendor, ?name, in_out_name_size, "Next NVRAM variable",);
// As per UEFI spec: if an empty null-terminated string is passed to
// GetNextVariable, the first variable should be returned
let mut res = if name.as_bytes() == [0, 0] {
self.storage.next_variable(None).await
} else {
self.storage.next_variable(Some((name, vendor))).await
};
loop {
match res {
Ok(NextVariable::EndOfList) => {
return NvramResult(None, EfiStatus::NOT_FOUND, None)
}
Ok(NextVariable::InvalidKey) => {
return NvramResult(None, EfiStatus::INVALID_PARAMETER, None);
}
Ok(NextVariable::Exists { name, vendor, attr }) => {
let attr = EfiVariableAttributes::from(attr);
assert!(
!attr.contains_unsupported_bits(),
"underlying storage should only ever contain valid attributes"
);
// From UEFI spec section 8.2:
//
// Once EFI_BOOT_SERVICES.ExitBootServices() is performed,
// variables that are only visible during boot services will
// no longer be returned.
//
// i.e: continue iterating
if self.runtime_state.is_runtime() && !attr.runtime_access() {
res = self
.storage
.next_variable(Some((name.as_ref(), vendor)))
.await;
continue;
}
let guest_buf_len = *in_out_name_size as usize;
*in_out_name_size = name.as_bytes().len() as u32;
if guest_buf_len < name.as_bytes().len() {
return NvramResult(None, EfiStatus::BUFFER_TOO_SMALL, None);
}
return NvramResult(
Some((name.into_inner(), vendor)),
EfiStatus::SUCCESS,
None,
);
}
Err(e) => {
let status = match &e {
NvramStorageError::Deserialize => EfiStatus::DEVICE_ERROR,
_ => panic!("unexpected NvramStorageError from next_variable"),
};
return NvramResult(None, status, Some(NvramError::NvramStorage(e)));
}
}
}
}
}
mod save_restore {
use super::*;
use vmcore::save_restore::RestoreError;
use vmcore::save_restore::SaveError;
use vmcore::save_restore::SaveRestore;
mod state {
use mesh::payload::Protobuf;
#[derive(Protobuf)]
#[mesh(package = "firmware.uefi.nvram.spec")]
pub enum SavedRuntimeState {
#[mesh(1)]
PreBoot,
#[mesh(2)]
Boot,
#[mesh(3)]
Runtime,
}
#[derive(Protobuf)]
#[mesh(package = "firmware.uefi.nvram.spec")]
pub struct SavedState {
#[mesh(1)]
pub runtime_state: SavedRuntimeState,
}
}
impl<S: InspectableNvramStorage> SaveRestore for NvramSpecServices<S> {
type SavedState = state::SavedState;
fn save(&mut self) -> Result<Self::SavedState, SaveError> {
Ok(state::SavedState {
runtime_state: match self.runtime_state {
RuntimeState::PreBoot => state::SavedRuntimeState::PreBoot,
RuntimeState::Boot => state::SavedRuntimeState::Boot,
RuntimeState::Runtime => state::SavedRuntimeState::Runtime,
},
})
}
fn restore(&mut self, state: Self::SavedState) -> Result<(), RestoreError> {
let state::SavedState { runtime_state } = state;
self.runtime_state = match runtime_state {
state::SavedRuntimeState::PreBoot => RuntimeState::PreBoot,
state::SavedRuntimeState::Boot => RuntimeState::Boot,
state::SavedRuntimeState::Runtime => RuntimeState::Runtime,
};
Ok(())
}
}
}
#[cfg(test)]
mod test {
use super::*;
use uefi_nvram_storage::in_memory::InMemoryNvram;
// TODO: wchz returns UTF-16 strings, _not_ UCS-2 strings. This works fine
// when using english variable names, but things will _not_ work as expected
// if one tries to use any particularly "exotic" chars (that cannot be
// represented in UCS-2).
use pal_async::async_test;
use wchar::wchz;
use zerocopy::AsBytes;
/// Extension trait around `NvramServices` that makes it easier to use the
/// API outside the context of the UEFI device
#[async_trait::async_trait]
trait NvramServicesTestExt {
async fn set_test_var(&mut self, name: &[u8], attr: u32, data: &[u8]) -> NvramResult<()>;
async fn get_test_var(&mut self, name: &[u8]) -> NvramResult<(u32, Option<Vec<u8>>)>;
async fn get_next_test_var(
&mut self,
name: Option<Vec<u8>>,
) -> NvramResult<Option<Vec<u8>>>;
}
#[async_trait::async_trait]
impl<S: InspectableNvramStorage> NvramServicesTestExt for NvramSpecServices<S> {
async fn set_test_var(&mut self, name: &[u8], attr: u32, data: &[u8]) -> NvramResult<()> {
let vendor = Guid::default();
self.uefi_set_variable(
Some(name),
vendor,
attr,
data.len() as u32,
Some(data.to_vec()),
)
.await
}
async fn get_test_var(&mut self, name: &[u8]) -> NvramResult<(u32, Option<Vec<u8>>)> {
let vendor = Guid::default();
let mut attr = 0;
let NvramResult(data, status, err) = self
.uefi_get_variable(Some(name), vendor, &mut attr, &mut 256, false)
.await;
NvramResult((attr, data), status, err)
}
async fn get_next_test_var(
&mut self,
name: Option<Vec<u8>>,
) -> NvramResult<Option<Vec<u8>>> {
let vendor = Guid::default();
let NvramResult(name_guid, status, err) = self
.uefi_get_next_variable(&mut 256, name.as_deref(), vendor)
.await;
NvramResult(name_guid.map(|(n, _)| n.to_vec()), status, err)
}
}
trait NvramRetTestExt<T> {
fn unwrap_efi_success(self) -> T;
}
impl<T> NvramRetTestExt<T> for NvramResult<T> {
#[track_caller]
fn unwrap_efi_success(self) -> T {
let NvramResult(val, status, err) = self;
if let Some(err) = err {
panic!("{}", err)
}
assert_eq!(status, EfiStatus::SUCCESS);
val
}
}
#[async_test]
async fn runtime_vars() {
let nvram_storage = InMemoryNvram::new();
let mut nvram = NvramSpecServices::new(nvram_storage);
nvram.prepare_for_boot();
let name1 = wchz!(u16, "var1").as_bytes();
let name2 = wchz!(u16, "var2").as_bytes();
let name3 = wchz!(u16, "var3").as_bytes();
let name4 = wchz!(u16, "var4").as_bytes();
let dummy_data = b"dummy data".to_vec();
let runtime_attr = (EfiVariableAttributes::DEFAULT_ATTRIBUTES).into();
let no_runtime_attr = EfiVariableAttributes::DEFAULT_ATTRIBUTES
.with_runtime_access(false)
.into();
// set some vars
nvram
.set_test_var(name1, runtime_attr, &dummy_data)
.await
.unwrap_efi_success();
nvram
.set_test_var(name2, no_runtime_attr, &dummy_data)
.await
.unwrap_efi_success();
nvram
.set_test_var(name3, runtime_attr, &dummy_data)
.await
.unwrap_efi_success();
nvram
.set_test_var(name4, no_runtime_attr, &dummy_data)
.await
.unwrap_efi_success();
// ensure they can all be accessed in pre-runtime environment
// access them individually
let (attr, data) = nvram.get_test_var(name1).await.unwrap_efi_success();
assert_eq!(attr, runtime_attr);
assert_eq!(data, Some(dummy_data.clone()));
let (attr, data) = nvram.get_test_var(name2).await.unwrap_efi_success();
assert_eq!(attr, no_runtime_attr);
assert_eq!(data, Some(dummy_data.clone()));
let (attr, data) = nvram.get_test_var(name3).await.unwrap_efi_success();
assert_eq!(attr, runtime_attr);
assert_eq!(data, Some(dummy_data.clone()));
let (attr, data) = nvram.get_test_var(name4).await.unwrap_efi_success();
assert_eq!(attr, no_runtime_attr);
assert_eq!(data, Some(dummy_data.clone()));
// access them sequentially
let mut name = Some(wchz!(u16, "").as_bytes().into());
name = nvram.get_next_test_var(name).await.unwrap_efi_success();
assert_eq!(name, Some(name1.into()));
name = nvram.get_next_test_var(name).await.unwrap_efi_success();
assert_eq!(name, Some(name2.into()));
name = nvram.get_next_test_var(name).await.unwrap_efi_success();
assert_eq!(name, Some(name3.into()));
name = nvram.get_next_test_var(name).await.unwrap_efi_success();
assert_eq!(name, Some(name4.into()));
let NvramResult(name, status, err) = nvram.get_next_test_var(name).await;
assert!(name.is_none());
assert_eq!(status, EfiStatus::NOT_FOUND);
assert!(err.is_none());
// ensure vars are hidden once runtime toggle is set
nvram.exit_boot_services();
// try to set non-runtime access var
let NvramResult(_, status, err) = nvram
.set_test_var(
wchz!(u16, "non-volatile").as_bytes(),
no_runtime_attr,
&dummy_data,
)
.await;
assert_eq!(status, EfiStatus::INVALID_PARAMETER);
assert!(matches!(err, Some(NvramError::InvalidRuntimeAccess)));
// access them individually
let (attr, data) = nvram.get_test_var(name1).await.unwrap_efi_success();
assert_eq!(attr, runtime_attr);
assert_eq!(data, Some(dummy_data.clone()));
let NvramResult((attr, data), status, err) = nvram.get_test_var(name2).await;
assert_eq!(attr, 0);
assert_eq!(data, None);
assert_eq!(status, EfiStatus::NOT_FOUND);
assert!(matches!(err, Some(NvramError::InvalidRuntimeAccess)));
let (attr, data) = nvram.get_test_var(name3).await.unwrap_efi_success();
assert_eq!(attr, runtime_attr);
assert_eq!(data, Some(dummy_data));
let NvramResult((attr, data), status, err) = nvram.get_test_var(name4).await;
assert_eq!(attr, 0);
assert_eq!(data, None);
assert_eq!(status, EfiStatus::NOT_FOUND);
assert!(matches!(err, Some(NvramError::InvalidRuntimeAccess)));
// access them sequentially
let mut name = Some(wchz!(u16, "").as_bytes().into());
name = nvram.get_next_test_var(name).await.unwrap_efi_success();
assert_eq!(name, Some(name1.into()));
// DON'T read name2
name = nvram.get_next_test_var(name).await.unwrap_efi_success();
assert_eq!(name, Some(name3.into()));
// DON'T read name4
let NvramResult(name, status, err) = nvram.get_next_test_var(name).await;
assert!(name.is_none());
assert_eq!(status, EfiStatus::NOT_FOUND);
assert!(err.is_none());
}
}