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Merge pull request #1505 from rmja/split-firmware-updater

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Split the FirmwareUpdater into blocking and async
This commit is contained in:
Dario Nieuwenhuis 2023-05-29 19:48:44 +00:00 committed by GitHub
commit 3b38079490
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4 changed files with 543 additions and 543 deletions
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543
embassy-boot/boot/src/firmware_updater.rs
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use digest::Digest;
use embedded_storage::nor_flash::{NorFlash, NorFlashError, NorFlashErrorKind};
#[cfg(feature = "nightly")]
use embedded_storage_async::nor_flash::NorFlash as AsyncNorFlash;
use crate::{Partition, State, BOOT_MAGIC, SWAP_MAGIC};
/// Errors returned by FirmwareUpdater
#[derive(Debug)]
pub enum FirmwareUpdaterError {
/// Error from flash.
Flash(NorFlashErrorKind),
/// Signature errors.
Signature(signature::Error),
}
#[cfg(feature = "defmt")]
impl defmt::Format for FirmwareUpdaterError {
fn format(&self, fmt: defmt::Formatter) {
match self {
FirmwareUpdaterError::Flash(_) => defmt::write!(fmt, "FirmwareUpdaterError::Flash(_)"),
FirmwareUpdaterError::Signature(_) => defmt::write!(fmt, "FirmwareUpdaterError::Signature(_)"),
}
}
}
impl<E> From<E> for FirmwareUpdaterError
where
E: NorFlashError,
{
fn from(error: E) -> Self {
FirmwareUpdaterError::Flash(error.kind())
}
}
/// FirmwareUpdater is an application API for interacting with the BootLoader without the ability to
/// 'mess up' the internal bootloader state
pub struct FirmwareUpdater {
state: Partition,
dfu: Partition,
}
#[cfg(target_os = "none")]
impl Default for FirmwareUpdater {
fn default() -> Self {
extern "C" {
static __bootloader_state_start: u32;
static __bootloader_state_end: u32;
static __bootloader_dfu_start: u32;
static __bootloader_dfu_end: u32;
}
let dfu = unsafe {
Partition::new(
&__bootloader_dfu_start as *const u32 as u32,
&__bootloader_dfu_end as *const u32 as u32,
)
};
let state = unsafe {
Partition::new(
&__bootloader_state_start as *const u32 as u32,
&__bootloader_state_end as *const u32 as u32,
)
};
trace!("DFU: 0x{:x} - 0x{:x}", dfu.from, dfu.to);
trace!("STATE: 0x{:x} - 0x{:x}", state.from, state.to);
FirmwareUpdater::new(dfu, state)
}
}
impl FirmwareUpdater {
/// Create a firmware updater instance with partition ranges for the update and state partitions.
pub const fn new(dfu: Partition, state: Partition) -> Self {
Self { dfu, state }
}
/// Obtain the current state.
///
/// This is useful to check if the bootloader has just done a swap, in order
/// to do verifications and self-tests of the new image before calling
/// `mark_booted`.
#[cfg(feature = "nightly")]
pub async fn get_state<F: AsyncNorFlash>(
&mut self,
state_flash: &mut F,
aligned: &mut [u8],
) -> Result<State, FirmwareUpdaterError> {
self.state.read(state_flash, 0, aligned).await?;
if !aligned.iter().any(|&b| b != SWAP_MAGIC) {
Ok(State::Swap)
} else {
Ok(State::Boot)
}
}
/// Verify the DFU given a public key. If there is an error then DO NOT
/// proceed with updating the firmware as it must be signed with a
/// corresponding private key (otherwise it could be malicious firmware).
///
/// Mark to trigger firmware swap on next boot if verify suceeds.
///
/// If the "ed25519-salty" feature is set (or another similar feature) then the signature is expected to have
/// been generated from a SHA-512 digest of the firmware bytes.
///
/// If no signature feature is set then this method will always return a
/// signature error.
///
/// # Safety
///
/// The `_aligned` buffer must have a size of F::WRITE_SIZE, and follow the alignment rules for the flash being read from
/// and written to.
#[cfg(all(feature = "_verify", feature = "nightly"))]
pub async fn verify_and_mark_updated<F: AsyncNorFlash>(
&mut self,
_state_and_dfu_flash: &mut F,
_public_key: &[u8],
_signature: &[u8],
_update_len: u32,
_aligned: &mut [u8],
) -> Result<(), FirmwareUpdaterError> {
assert_eq!(_aligned.len(), F::WRITE_SIZE);
assert!(_update_len <= self.dfu.size());
#[cfg(feature = "ed25519-dalek")]
{
use ed25519_dalek::{PublicKey, Signature, SignatureError, Verifier};
use crate::digest_adapters::ed25519_dalek::Sha512;
let into_signature_error = |e: SignatureError| FirmwareUpdaterError::Signature(e.into());
let public_key = PublicKey::from_bytes(_public_key).map_err(into_signature_error)?;
let signature = Signature::from_bytes(_signature).map_err(into_signature_error)?;
let mut message = [0; 64];
self.hash::<_, Sha512>(_state_and_dfu_flash, _update_len, _aligned, &mut message)
.await?;
public_key.verify(&message, &signature).map_err(into_signature_error)?
}
#[cfg(feature = "ed25519-salty")]
{
use salty::constants::{PUBLICKEY_SERIALIZED_LENGTH, SIGNATURE_SERIALIZED_LENGTH};
use salty::{PublicKey, Signature};
use crate::digest_adapters::salty::Sha512;
fn into_signature_error<E>(_: E) -> FirmwareUpdaterError {
FirmwareUpdaterError::Signature(signature::Error::default())
}
let public_key: [u8; PUBLICKEY_SERIALIZED_LENGTH] = _public_key.try_into().map_err(into_signature_error)?;
let public_key = PublicKey::try_from(&public_key).map_err(into_signature_error)?;
let signature: [u8; SIGNATURE_SERIALIZED_LENGTH] = _signature.try_into().map_err(into_signature_error)?;
let signature = Signature::try_from(&signature).map_err(into_signature_error)?;
let mut message = [0; 64];
self.hash::<_, Sha512>(_state_and_dfu_flash, _update_len, _aligned, &mut message)
.await?;
let r = public_key.verify(&message, &signature);
trace!(
"Verifying with public key {}, signature {} and message {} yields ok: {}",
public_key.to_bytes(),
signature.to_bytes(),
message,
r.is_ok()
);
r.map_err(into_signature_error)?
}
self.set_magic(_aligned, SWAP_MAGIC, _state_and_dfu_flash).await
}
/// Verify the update in DFU with any digest.
#[cfg(feature = "nightly")]
pub async fn hash<F: AsyncNorFlash, D: Digest>(
&mut self,
dfu_flash: &mut F,
update_len: u32,
chunk_buf: &mut [u8],
output: &mut [u8],
) -> Result<(), FirmwareUpdaterError> {
let mut digest = D::new();
for offset in (0..update_len).step_by(chunk_buf.len()) {
self.dfu.read(dfu_flash, offset, chunk_buf).await?;
let len = core::cmp::min((update_len - offset) as usize, chunk_buf.len());
digest.update(&chunk_buf[..len]);
}
output.copy_from_slice(digest.finalize().as_slice());
Ok(())
}
/// Mark to trigger firmware swap on next boot.
///
/// # Safety
///
/// The `aligned` buffer must have a size of F::WRITE_SIZE, and follow the alignment rules for the flash being written to.
#[cfg(all(feature = "nightly", not(feature = "_verify")))]
pub async fn mark_updated<F: AsyncNorFlash>(
&mut self,
state_flash: &mut F,
aligned: &mut [u8],
) -> Result<(), FirmwareUpdaterError> {
assert_eq!(aligned.len(), F::WRITE_SIZE);
self.set_magic(aligned, SWAP_MAGIC, state_flash).await
}
/// Mark firmware boot successful and stop rollback on reset.
///
/// # Safety
///
/// The `aligned` buffer must have a size of F::WRITE_SIZE, and follow the alignment rules for the flash being written to.
#[cfg(feature = "nightly")]
pub async fn mark_booted<F: AsyncNorFlash>(
&mut self,
state_flash: &mut F,
aligned: &mut [u8],
) -> Result<(), FirmwareUpdaterError> {
assert_eq!(aligned.len(), F::WRITE_SIZE);
self.set_magic(aligned, BOOT_MAGIC, state_flash).await
}
#[cfg(feature = "nightly")]
async fn set_magic<F: AsyncNorFlash>(
&mut self,
aligned: &mut [u8],
magic: u8,
state_flash: &mut F,
) -> Result<(), FirmwareUpdaterError> {
self.state.read(state_flash, 0, aligned).await?;
if aligned.iter().any(|&b| b != magic) {
// Read progress validity
self.state.read(state_flash, F::WRITE_SIZE as u32, aligned).await?;
// FIXME: Do not make this assumption.
const STATE_ERASE_VALUE: u8 = 0xFF;
if aligned.iter().any(|&b| b != STATE_ERASE_VALUE) {
// The current progress validity marker is invalid
} else {
// Invalidate progress
aligned.fill(!STATE_ERASE_VALUE);
self.state.write(state_flash, F::WRITE_SIZE as u32, aligned).await?;
}
// Clear magic and progress
self.state.wipe(state_flash).await?;
// Set magic
aligned.fill(magic);
self.state.write(state_flash, 0, aligned).await?;
}
Ok(())
}
/// Write data to a flash page.
///
/// The buffer must follow alignment requirements of the target flash and a multiple of page size big.
///
/// # Safety
///
/// Failing to meet alignment and size requirements may result in a panic.
#[cfg(feature = "nightly")]
pub async fn write_firmware<F: AsyncNorFlash>(
&mut self,
offset: usize,
data: &[u8],
dfu_flash: &mut F,
) -> Result<(), FirmwareUpdaterError> {
assert!(data.len() >= F::ERASE_SIZE);
self.dfu
.erase(dfu_flash, offset as u32, (offset + data.len()) as u32)
.await?;
self.dfu.write(dfu_flash, offset as u32, data).await?;
Ok(())
}
/// Prepare for an incoming DFU update by erasing the entire DFU area and
/// returning its `Partition`.
///
/// Using this instead of `write_firmware` allows for an optimized API in
/// exchange for added complexity.
#[cfg(feature = "nightly")]
pub async fn prepare_update<F: AsyncNorFlash>(
&mut self,
dfu_flash: &mut F,
) -> Result<Partition, FirmwareUpdaterError> {
self.dfu.wipe(dfu_flash).await?;
Ok(self.dfu)
}
//
// Blocking API
//
/// Obtain the current state.
///
/// This is useful to check if the bootloader has just done a swap, in order
/// to do verifications and self-tests of the new image before calling
/// `mark_booted`.
pub fn get_state_blocking<F: NorFlash>(
&mut self,
state_flash: &mut F,
aligned: &mut [u8],
) -> Result<State, FirmwareUpdaterError> {
self.state.read_blocking(state_flash, 0, aligned)?;
if !aligned.iter().any(|&b| b != SWAP_MAGIC) {
Ok(State::Swap)
} else {
Ok(State::Boot)
}
}
/// Verify the DFU given a public key. If there is an error then DO NOT
/// proceed with updating the firmware as it must be signed with a
/// corresponding private key (otherwise it could be malicious firmware).
///
/// Mark to trigger firmware swap on next boot if verify suceeds.
///
/// If the "ed25519-salty" feature is set (or another similar feature) then the signature is expected to have
/// been generated from a SHA-512 digest of the firmware bytes.
///
/// If no signature feature is set then this method will always return a
/// signature error.
///
/// # Safety
///
/// The `_aligned` buffer must have a size of F::WRITE_SIZE, and follow the alignment rules for the flash being read from
/// and written to.
#[cfg(feature = "_verify")]
pub fn verify_and_mark_updated_blocking<F: NorFlash>(
&mut self,
_state_and_dfu_flash: &mut F,
_public_key: &[u8],
_signature: &[u8],
_update_len: u32,
_aligned: &mut [u8],
) -> Result<(), FirmwareUpdaterError> {
assert_eq!(_aligned.len(), F::WRITE_SIZE);
assert!(_update_len <= self.dfu.size());
#[cfg(feature = "ed25519-dalek")]
{
use ed25519_dalek::{PublicKey, Signature, SignatureError, Verifier};
use crate::digest_adapters::ed25519_dalek::Sha512;
let into_signature_error = |e: SignatureError| FirmwareUpdaterError::Signature(e.into());
let public_key = PublicKey::from_bytes(_public_key).map_err(into_signature_error)?;
let signature = Signature::from_bytes(_signature).map_err(into_signature_error)?;
let mut message = [0; 64];
self.hash_blocking::<_, Sha512>(_state_and_dfu_flash, _update_len, _aligned, &mut message)?;
public_key.verify(&message, &signature).map_err(into_signature_error)?
}
#[cfg(feature = "ed25519-salty")]
{
use salty::constants::{PUBLICKEY_SERIALIZED_LENGTH, SIGNATURE_SERIALIZED_LENGTH};
use salty::{PublicKey, Signature};
use crate::digest_adapters::salty::Sha512;
fn into_signature_error<E>(_: E) -> FirmwareUpdaterError {
FirmwareUpdaterError::Signature(signature::Error::default())
}
let public_key: [u8; PUBLICKEY_SERIALIZED_LENGTH] = _public_key.try_into().map_err(into_signature_error)?;
let public_key = PublicKey::try_from(&public_key).map_err(into_signature_error)?;
let signature: [u8; SIGNATURE_SERIALIZED_LENGTH] = _signature.try_into().map_err(into_signature_error)?;
let signature = Signature::try_from(&signature).map_err(into_signature_error)?;
let mut message = [0; 64];
self.hash_blocking::<_, Sha512>(_state_and_dfu_flash, _update_len, _aligned, &mut message)?;
let r = public_key.verify(&message, &signature);
trace!(
"Verifying with public key {}, signature {} and message {} yields ok: {}",
public_key.to_bytes(),
signature.to_bytes(),
message,
r.is_ok()
);
r.map_err(into_signature_error)?
}
self.set_magic_blocking(_aligned, SWAP_MAGIC, _state_and_dfu_flash)
}
/// Verify the update in DFU with any digest.
pub fn hash_blocking<F: NorFlash, D: Digest>(
&mut self,
dfu_flash: &mut F,
update_len: u32,
chunk_buf: &mut [u8],
output: &mut [u8],
) -> Result<(), FirmwareUpdaterError> {
let mut digest = D::new();
for offset in (0..update_len).step_by(chunk_buf.len()) {
self.dfu.read_blocking(dfu_flash, offset, chunk_buf)?;
let len = core::cmp::min((update_len - offset) as usize, chunk_buf.len());
digest.update(&chunk_buf[..len]);
}
output.copy_from_slice(digest.finalize().as_slice());
Ok(())
}
/// Mark to trigger firmware swap on next boot.
///
/// # Safety
///
/// The `aligned` buffer must have a size of F::WRITE_SIZE, and follow the alignment rules for the flash being written to.
#[cfg(not(feature = "_verify"))]
pub fn mark_updated_blocking<F: NorFlash>(
&mut self,
state_flash: &mut F,
aligned: &mut [u8],
) -> Result<(), FirmwareUpdaterError> {
assert_eq!(aligned.len(), F::WRITE_SIZE);
self.set_magic_blocking(aligned, SWAP_MAGIC, state_flash)
}
/// Mark firmware boot successful and stop rollback on reset.
///
/// # Safety
///
/// The `aligned` buffer must have a size of F::WRITE_SIZE, and follow the alignment rules for the flash being written to.
pub fn mark_booted_blocking<F: NorFlash>(
&mut self,
state_flash: &mut F,
aligned: &mut [u8],
) -> Result<(), FirmwareUpdaterError> {
assert_eq!(aligned.len(), F::WRITE_SIZE);
self.set_magic_blocking(aligned, BOOT_MAGIC, state_flash)
}
fn set_magic_blocking<F: NorFlash>(
&mut self,
aligned: &mut [u8],
magic: u8,
state_flash: &mut F,
) -> Result<(), FirmwareUpdaterError> {
self.state.read_blocking(state_flash, 0, aligned)?;
if aligned.iter().any(|&b| b != magic) {
// Read progress validity
self.state.read_blocking(state_flash, F::WRITE_SIZE as u32, aligned)?;
// FIXME: Do not make this assumption.
const STATE_ERASE_VALUE: u8 = 0xFF;
if aligned.iter().any(|&b| b != STATE_ERASE_VALUE) {
// The current progress validity marker is invalid
} else {
// Invalidate progress
aligned.fill(!STATE_ERASE_VALUE);
self.state.write_blocking(state_flash, F::WRITE_SIZE as u32, aligned)?;
}
// Clear magic and progress
self.state.wipe_blocking(state_flash)?;
// Set magic
aligned.fill(magic);
self.state.write_blocking(state_flash, 0, aligned)?;
}
Ok(())
}
/// Write data to a flash page.
///
/// The buffer must follow alignment requirements of the target flash and a multiple of page size big.
///
/// # Safety
///
/// Failing to meet alignment and size requirements may result in a panic.
pub fn write_firmware_blocking<F: NorFlash>(
&mut self,
offset: usize,
data: &[u8],
dfu_flash: &mut F,
) -> Result<(), FirmwareUpdaterError> {
assert!(data.len() >= F::ERASE_SIZE);
self.dfu
.erase_blocking(dfu_flash, offset as u32, (offset + data.len()) as u32)?;
self.dfu.write_blocking(dfu_flash, offset as u32, data)?;
Ok(())
}
/// Prepare for an incoming DFU update by erasing the entire DFU area and
/// returning its `Partition`.
///
/// Using this instead of `write_firmware_blocking` allows for an optimized
/// API in exchange for added complexity.
pub fn prepare_update_blocking<F: NorFlash>(&mut self, flash: &mut F) -> Result<Partition, FirmwareUpdaterError> {
self.dfu.wipe_blocking(flash)?;
Ok(self.dfu)
}
}
#[cfg(test)]
mod tests {
use futures::executor::block_on;
use sha1::{Digest, Sha1};
use super::*;
use crate::mem_flash::MemFlash;
#[test]
#[cfg(feature = "nightly")]
fn can_verify_sha1() {
const STATE: Partition = Partition::new(0, 4096);
const DFU: Partition = Partition::new(65536, 131072);
let mut flash = MemFlash::<131072, 4096, 8>::default();
let update = [0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66];
let mut to_write = [0; 4096];
to_write[..7].copy_from_slice(update.as_slice());
let mut updater = FirmwareUpdater::new(DFU, STATE);
block_on(updater.write_firmware(0, to_write.as_slice(), &mut flash)).unwrap();
let mut chunk_buf = [0; 2];
let mut hash = [0; 20];
block_on(updater.hash::<_, Sha1>(&mut flash, update.len() as u32, &mut chunk_buf, &mut hash)).unwrap();
assert_eq!(Sha1::digest(update).as_slice(), hash);
}
}

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embassy-boot/boot/src/firmware_updater/asynch.rs Normal file
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use digest::Digest;
use embedded_storage_async::nor_flash::NorFlash as AsyncNorFlash;
use crate::{FirmwareUpdater, FirmwareUpdaterError, Partition, State, BOOT_MAGIC, SWAP_MAGIC};
impl FirmwareUpdater {
/// Obtain the current state.
///
/// This is useful to check if the bootloader has just done a swap, in order
/// to do verifications and self-tests of the new image before calling
/// `mark_booted`.
pub async fn get_state<F: AsyncNorFlash>(
&mut self,
state_flash: &mut F,
aligned: &mut [u8],
) -> Result<State, FirmwareUpdaterError> {
self.state.read(state_flash, 0, aligned).await?;
if !aligned.iter().any(|&b| b != SWAP_MAGIC) {
Ok(State::Swap)
} else {
Ok(State::Boot)
}
}
/// Verify the DFU given a public key. If there is an error then DO NOT
/// proceed with updating the firmware as it must be signed with a
/// corresponding private key (otherwise it could be malicious firmware).
///
/// Mark to trigger firmware swap on next boot if verify suceeds.
///
/// If the "ed25519-salty" feature is set (or another similar feature) then the signature is expected to have
/// been generated from a SHA-512 digest of the firmware bytes.
///
/// If no signature feature is set then this method will always return a
/// signature error.
///
/// # Safety
///
/// The `_aligned` buffer must have a size of F::WRITE_SIZE, and follow the alignment rules for the flash being read from
/// and written to.
#[cfg(all(feature = "_verify", feature = "nightly"))]
pub async fn verify_and_mark_updated<F: AsyncNorFlash>(
&mut self,
_state_and_dfu_flash: &mut F,
_public_key: &[u8],
_signature: &[u8],
_update_len: u32,
_aligned: &mut [u8],
) -> Result<(), FirmwareUpdaterError> {
assert_eq!(_aligned.len(), F::WRITE_SIZE);
assert!(_update_len <= self.dfu.size());
#[cfg(feature = "ed25519-dalek")]
{
use ed25519_dalek::{PublicKey, Signature, SignatureError, Verifier};
use crate::digest_adapters::ed25519_dalek::Sha512;
let into_signature_error = |e: SignatureError| FirmwareUpdaterError::Signature(e.into());
let public_key = PublicKey::from_bytes(_public_key).map_err(into_signature_error)?;
let signature = Signature::from_bytes(_signature).map_err(into_signature_error)?;
let mut message = [0; 64];
self.hash::<_, Sha512>(_state_and_dfu_flash, _update_len, _aligned, &mut message)
.await?;
public_key.verify(&message, &signature).map_err(into_signature_error)?
}
#[cfg(feature = "ed25519-salty")]
{
use salty::constants::{PUBLICKEY_SERIALIZED_LENGTH, SIGNATURE_SERIALIZED_LENGTH};
use salty::{PublicKey, Signature};
use crate::digest_adapters::salty::Sha512;
fn into_signature_error<E>(_: E) -> FirmwareUpdaterError {
FirmwareUpdaterError::Signature(signature::Error::default())
}
let public_key: [u8; PUBLICKEY_SERIALIZED_LENGTH] = _public_key.try_into().map_err(into_signature_error)?;
let public_key = PublicKey::try_from(&public_key).map_err(into_signature_error)?;
let signature: [u8; SIGNATURE_SERIALIZED_LENGTH] = _signature.try_into().map_err(into_signature_error)?;
let signature = Signature::try_from(&signature).map_err(into_signature_error)?;
let mut message = [0; 64];
self.hash::<_, Sha512>(_state_and_dfu_flash, _update_len, _aligned, &mut message)
.await?;
let r = public_key.verify(&message, &signature);
trace!(
"Verifying with public key {}, signature {} and message {} yields ok: {}",
public_key.to_bytes(),
signature.to_bytes(),
message,
r.is_ok()
);
r.map_err(into_signature_error)?
}
self.set_magic(_aligned, SWAP_MAGIC, _state_and_dfu_flash).await
}
/// Verify the update in DFU with any digest.
pub async fn hash<F: AsyncNorFlash, D: Digest>(
&mut self,
dfu_flash: &mut F,
update_len: u32,
chunk_buf: &mut [u8],
output: &mut [u8],
) -> Result<(), FirmwareUpdaterError> {
let mut digest = D::new();
for offset in (0..update_len).step_by(chunk_buf.len()) {
self.dfu.read(dfu_flash, offset, chunk_buf).await?;
let len = core::cmp::min((update_len - offset) as usize, chunk_buf.len());
digest.update(&chunk_buf[..len]);
}
output.copy_from_slice(digest.finalize().as_slice());
Ok(())
}
/// Mark to trigger firmware swap on next boot.
///
/// # Safety
///
/// The `aligned` buffer must have a size of F::WRITE_SIZE, and follow the alignment rules for the flash being written to.
#[cfg(all(feature = "nightly", not(feature = "_verify")))]
pub async fn mark_updated<F: AsyncNorFlash>(
&mut self,
state_flash: &mut F,
aligned: &mut [u8],
) -> Result<(), FirmwareUpdaterError> {
assert_eq!(aligned.len(), F::WRITE_SIZE);
self.set_magic(aligned, SWAP_MAGIC, state_flash).await
}
/// Mark firmware boot successful and stop rollback on reset.
///
/// # Safety
///
/// The `aligned` buffer must have a size of F::WRITE_SIZE, and follow the alignment rules for the flash being written to.
pub async fn mark_booted<F: AsyncNorFlash>(
&mut self,
state_flash: &mut F,
aligned: &mut [u8],
) -> Result<(), FirmwareUpdaterError> {
assert_eq!(aligned.len(), F::WRITE_SIZE);
self.set_magic(aligned, BOOT_MAGIC, state_flash).await
}
async fn set_magic<F: AsyncNorFlash>(
&mut self,
aligned: &mut [u8],
magic: u8,
state_flash: &mut F,
) -> Result<(), FirmwareUpdaterError> {
self.state.read(state_flash, 0, aligned).await?;
if aligned.iter().any(|&b| b != magic) {
// Read progress validity
self.state.read(state_flash, F::WRITE_SIZE as u32, aligned).await?;
// FIXME: Do not make this assumption.
const STATE_ERASE_VALUE: u8 = 0xFF;
if aligned.iter().any(|&b| b != STATE_ERASE_VALUE) {
// The current progress validity marker is invalid
} else {
// Invalidate progress
aligned.fill(!STATE_ERASE_VALUE);
self.state.write(state_flash, F::WRITE_SIZE as u32, aligned).await?;
}
// Clear magic and progress
self.state.wipe(state_flash).await?;
// Set magic
aligned.fill(magic);
self.state.write(state_flash, 0, aligned).await?;
}
Ok(())
}
/// Write data to a flash page.
///
/// The buffer must follow alignment requirements of the target flash and a multiple of page size big.
///
/// # Safety
///
/// Failing to meet alignment and size requirements may result in a panic.
pub async fn write_firmware<F: AsyncNorFlash>(
&mut self,
offset: usize,
data: &[u8],
dfu_flash: &mut F,
) -> Result<(), FirmwareUpdaterError> {
assert!(data.len() >= F::ERASE_SIZE);
self.dfu
.erase(dfu_flash, offset as u32, (offset + data.len()) as u32)
.await?;
self.dfu.write(dfu_flash, offset as u32, data).await?;
Ok(())
}
/// Prepare for an incoming DFU update by erasing the entire DFU area and
/// returning its `Partition`.
///
/// Using this instead of `write_firmware` allows for an optimized API in
/// exchange for added complexity.
pub async fn prepare_update<F: AsyncNorFlash>(
&mut self,
dfu_flash: &mut F,
) -> Result<Partition, FirmwareUpdaterError> {
self.dfu.wipe(dfu_flash).await?;
Ok(self.dfu)
}
}
#[cfg(test)]
mod tests {
use futures::executor::block_on;
use sha1::{Digest, Sha1};
use super::*;
use crate::mem_flash::MemFlash;
#[test]
fn can_verify_sha1() {
const STATE: Partition = Partition::new(0, 4096);
const DFU: Partition = Partition::new(65536, 131072);
let mut flash = MemFlash::<131072, 4096, 8>::default();
let update = [0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66];
let mut to_write = [0; 4096];
to_write[..7].copy_from_slice(update.as_slice());
let mut updater = FirmwareUpdater::new(DFU, STATE);
block_on(updater.write_firmware(0, to_write.as_slice(), &mut flash)).unwrap();
let mut chunk_buf = [0; 2];
let mut hash = [0; 20];
block_on(updater.hash::<_, Sha1>(&mut flash, update.len() as u32, &mut chunk_buf, &mut hash)).unwrap();
assert_eq!(Sha1::digest(update).as_slice(), hash);
}
}

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embassy-boot/boot/src/firmware_updater/blocking.rs Normal file
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use digest::Digest;
use embedded_storage::nor_flash::NorFlash;
use crate::{FirmwareUpdater, FirmwareUpdaterError, Partition, State, BOOT_MAGIC, SWAP_MAGIC};
impl FirmwareUpdater {
/// Create a firmware updater instance with partition ranges for the update and state partitions.
pub const fn new(dfu: Partition, state: Partition) -> Self {
Self { dfu, state }
}
/// Obtain the current state.
///
/// This is useful to check if the bootloader has just done a swap, in order
/// to do verifications and self-tests of the new image before calling
/// `mark_booted`.
pub fn get_state_blocking<F: NorFlash>(
&mut self,
state_flash: &mut F,
aligned: &mut [u8],
) -> Result<State, FirmwareUpdaterError> {
self.state.read_blocking(state_flash, 0, aligned)?;
if !aligned.iter().any(|&b| b != SWAP_MAGIC) {
Ok(State::Swap)
} else {
Ok(State::Boot)
}
}
/// Verify the DFU given a public key. If there is an error then DO NOT
/// proceed with updating the firmware as it must be signed with a
/// corresponding private key (otherwise it could be malicious firmware).
///
/// Mark to trigger firmware swap on next boot if verify suceeds.
///
/// If the "ed25519-salty" feature is set (or another similar feature) then the signature is expected to have
/// been generated from a SHA-512 digest of the firmware bytes.
///
/// If no signature feature is set then this method will always return a
/// signature error.
///
/// # Safety
///
/// The `_aligned` buffer must have a size of F::WRITE_SIZE, and follow the alignment rules for the flash being read from
/// and written to.
#[cfg(feature = "_verify")]
pub fn verify_and_mark_updated_blocking<F: NorFlash>(
&mut self,
_state_and_dfu_flash: &mut F,
_public_key: &[u8],
_signature: &[u8],
_update_len: u32,
_aligned: &mut [u8],
) -> Result<(), FirmwareUpdaterError> {
assert_eq!(_aligned.len(), F::WRITE_SIZE);
assert!(_update_len <= self.dfu.size());
#[cfg(feature = "ed25519-dalek")]
{
use ed25519_dalek::{PublicKey, Signature, SignatureError, Verifier};
use crate::digest_adapters::ed25519_dalek::Sha512;
let into_signature_error = |e: SignatureError| FirmwareUpdaterError::Signature(e.into());
let public_key = PublicKey::from_bytes(_public_key).map_err(into_signature_error)?;
let signature = Signature::from_bytes(_signature).map_err(into_signature_error)?;
let mut message = [0; 64];
self.hash_blocking::<_, Sha512>(_state_and_dfu_flash, _update_len, _aligned, &mut message)?;
public_key.verify(&message, &signature).map_err(into_signature_error)?
}
#[cfg(feature = "ed25519-salty")]
{
use salty::constants::{PUBLICKEY_SERIALIZED_LENGTH, SIGNATURE_SERIALIZED_LENGTH};
use salty::{PublicKey, Signature};
use crate::digest_adapters::salty::Sha512;
fn into_signature_error<E>(_: E) -> FirmwareUpdaterError {
FirmwareUpdaterError::Signature(signature::Error::default())
}
let public_key: [u8; PUBLICKEY_SERIALIZED_LENGTH] = _public_key.try_into().map_err(into_signature_error)?;
let public_key = PublicKey::try_from(&public_key).map_err(into_signature_error)?;
let signature: [u8; SIGNATURE_SERIALIZED_LENGTH] = _signature.try_into().map_err(into_signature_error)?;
let signature = Signature::try_from(&signature).map_err(into_signature_error)?;
let mut message = [0; 64];
self.hash_blocking::<_, Sha512>(_state_and_dfu_flash, _update_len, _aligned, &mut message)?;
let r = public_key.verify(&message, &signature);
trace!(
"Verifying with public key {}, signature {} and message {} yields ok: {}",
public_key.to_bytes(),
signature.to_bytes(),
message,
r.is_ok()
);
r.map_err(into_signature_error)?
}
self.set_magic_blocking(_aligned, SWAP_MAGIC, _state_and_dfu_flash)
}
/// Verify the update in DFU with any digest.
pub fn hash_blocking<F: NorFlash, D: Digest>(
&mut self,
dfu_flash: &mut F,
update_len: u32,
chunk_buf: &mut [u8],
output: &mut [u8],
) -> Result<(), FirmwareUpdaterError> {
let mut digest = D::new();
for offset in (0..update_len).step_by(chunk_buf.len()) {
self.dfu.read_blocking(dfu_flash, offset, chunk_buf)?;
let len = core::cmp::min((update_len - offset) as usize, chunk_buf.len());
digest.update(&chunk_buf[..len]);
}
output.copy_from_slice(digest.finalize().as_slice());
Ok(())
}
/// Mark to trigger firmware swap on next boot.
///
/// # Safety
///
/// The `aligned` buffer must have a size of F::WRITE_SIZE, and follow the alignment rules for the flash being written to.
#[cfg(not(feature = "_verify"))]
pub fn mark_updated_blocking<F: NorFlash>(
&mut self,
state_flash: &mut F,
aligned: &mut [u8],
) -> Result<(), FirmwareUpdaterError> {
assert_eq!(aligned.len(), F::WRITE_SIZE);
self.set_magic_blocking(aligned, SWAP_MAGIC, state_flash)
}
/// Mark firmware boot successful and stop rollback on reset.
///
/// # Safety
///
/// The `aligned` buffer must have a size of F::WRITE_SIZE, and follow the alignment rules for the flash being written to.
pub fn mark_booted_blocking<F: NorFlash>(
&mut self,
state_flash: &mut F,
aligned: &mut [u8],
) -> Result<(), FirmwareUpdaterError> {
assert_eq!(aligned.len(), F::WRITE_SIZE);
self.set_magic_blocking(aligned, BOOT_MAGIC, state_flash)
}
fn set_magic_blocking<F: NorFlash>(
&mut self,
aligned: &mut [u8],
magic: u8,
state_flash: &mut F,
) -> Result<(), FirmwareUpdaterError> {
self.state.read_blocking(state_flash, 0, aligned)?;
if aligned.iter().any(|&b| b != magic) {
// Read progress validity
self.state.read_blocking(state_flash, F::WRITE_SIZE as u32, aligned)?;
// FIXME: Do not make this assumption.
const STATE_ERASE_VALUE: u8 = 0xFF;
if aligned.iter().any(|&b| b != STATE_ERASE_VALUE) {
// The current progress validity marker is invalid
} else {
// Invalidate progress
aligned.fill(!STATE_ERASE_VALUE);
self.state.write_blocking(state_flash, F::WRITE_SIZE as u32, aligned)?;
}
// Clear magic and progress
self.state.wipe_blocking(state_flash)?;
// Set magic
aligned.fill(magic);
self.state.write_blocking(state_flash, 0, aligned)?;
}
Ok(())
}
/// Write data to a flash page.
///
/// The buffer must follow alignment requirements of the target flash and a multiple of page size big.
///
/// # Safety
///
/// Failing to meet alignment and size requirements may result in a panic.
pub fn write_firmware_blocking<F: NorFlash>(
&mut self,
offset: usize,
data: &[u8],
dfu_flash: &mut F,
) -> Result<(), FirmwareUpdaterError> {
assert!(data.len() >= F::ERASE_SIZE);
self.dfu
.erase_blocking(dfu_flash, offset as u32, (offset + data.len()) as u32)?;
self.dfu.write_blocking(dfu_flash, offset as u32, data)?;
Ok(())
}
/// Prepare for an incoming DFU update by erasing the entire DFU area and
/// returning its `Partition`.
///
/// Using this instead of `write_firmware_blocking` allows for an optimized
/// API in exchange for added complexity.
pub fn prepare_update_blocking<F: NorFlash>(&mut self, flash: &mut F) -> Result<Partition, FirmwareUpdaterError> {
self.dfu.wipe_blocking(flash)?;
Ok(self.dfu)
}
}

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#[cfg(feature = "nightly")]
mod asynch;
mod blocking;
use embedded_storage::nor_flash::{NorFlashError, NorFlashErrorKind};
use crate::Partition;
/// Errors returned by FirmwareUpdater
#[derive(Debug)]
pub enum FirmwareUpdaterError {
/// Error from flash.
Flash(NorFlashErrorKind),
/// Signature errors.
Signature(signature::Error),
}
#[cfg(feature = "defmt")]
impl defmt::Format for FirmwareUpdaterError {
fn format(&self, fmt: defmt::Formatter) {
match self {
FirmwareUpdaterError::Flash(_) => defmt::write!(fmt, "FirmwareUpdaterError::Flash(_)"),
FirmwareUpdaterError::Signature(_) => defmt::write!(fmt, "FirmwareUpdaterError::Signature(_)"),
}
}
}
impl<E> From<E> for FirmwareUpdaterError
where
E: NorFlashError,
{
fn from(error: E) -> Self {
FirmwareUpdaterError::Flash(error.kind())
}
}
/// FirmwareUpdater is an application API for interacting with the BootLoader without the ability to
/// 'mess up' the internal bootloader state
pub struct FirmwareUpdater {
state: Partition,
dfu: Partition,
}
#[cfg(target_os = "none")]
impl Default for FirmwareUpdater {
fn default() -> Self {
extern "C" {
static __bootloader_state_start: u32;
static __bootloader_state_end: u32;
static __bootloader_dfu_start: u32;
static __bootloader_dfu_end: u32;
}
let dfu = unsafe {
Partition::new(
&__bootloader_dfu_start as *const u32 as u32,
&__bootloader_dfu_end as *const u32 as u32,
)
};
let state = unsafe {
Partition::new(
&__bootloader_state_start as *const u32 as u32,
&__bootloader_state_end as *const u32 as u32,
)
};
trace!("DFU: 0x{:x} - 0x{:x}", dfu.from, dfu.to);
trace!("STATE: 0x{:x} - 0x{:x}", state.from, state.to);
FirmwareUpdater::new(dfu, state)
}
}