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Refactor firmware updater

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* Allow manipulating state without accessing DFU partition.
* Provide aligned buffer when creating updater to reduce potential wrong parameters passed.
This commit is contained in:
Ulf Lilleengen
2023-08-03 20:56:04 +02:00
parent a40daa923b
commit a34331ae5f
16 changed files with 307 additions and 255 deletions
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194
embassy-boot/boot/src/firmware_updater/asynch.rs
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@ -10,9 +10,9 @@ use crate::{FirmwareUpdaterError, State, BOOT_MAGIC, STATE_ERASE_VALUE, SWAP_MAG
/// FirmwareUpdater is an application API for interacting with the BootLoader without the ability to
/// 'mess up' the internal bootloader state
pub struct FirmwareUpdater<DFU: NorFlash, STATE: NorFlash> {
pub struct FirmwareUpdater<'d, DFU: NorFlash, STATE: NorFlash> {
dfu: DFU,
state: STATE,
state: FirmwareState<'d, STATE>,
}
#[cfg(target_os = "none")]
@ -47,22 +47,12 @@ impl<'a, FLASH: NorFlash>
}
}
impl<DFU: NorFlash, STATE: NorFlash> FirmwareUpdater<DFU, STATE> {
impl<'d, DFU: NorFlash, STATE: NorFlash> FirmwareUpdater<'d, DFU, STATE> {
/// Create a firmware updater instance with partition ranges for the update and state partitions.
pub fn new(config: FirmwareUpdaterConfig<DFU, STATE>) -> Self {
pub fn new(config: FirmwareUpdaterConfig<DFU, STATE>, aligned: &'d mut [u8]) -> Self {
Self {
dfu: config.dfu,
state: config.state,
}
}
// Make sure we are running a booted firmware to avoid reverting to a bad state.
async fn verify_booted(&mut self, aligned: &mut [u8]) -> Result<(), FirmwareUpdaterError> {
assert_eq!(aligned.len(), STATE::WRITE_SIZE);
if self.get_state(aligned).await? == State::Boot {
Ok(())
} else {
Err(FirmwareUpdaterError::BadState)
state: FirmwareState::new(config.state, aligned),
}
}
@ -71,14 +61,8 @@ impl<DFU: NorFlash, STATE: NorFlash> FirmwareUpdater<DFU, 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(&mut self, aligned: &mut [u8]) -> Result<State, FirmwareUpdaterError> {
self.state.read(0, aligned).await?;
if !aligned.iter().any(|&b| b != SWAP_MAGIC) {
Ok(State::Swap)
} else {
Ok(State::Boot)
}
pub async fn get_state(&mut self) -> Result<State, FirmwareUpdaterError> {
self.state.get_state().await
}
/// Verify the DFU given a public key. If there is an error then DO NOT
@ -92,23 +76,16 @@ impl<DFU: NorFlash, STATE: NorFlash> FirmwareUpdater<DFU, STATE> {
///
/// If no signature feature is set then this method will always return a
/// signature error.
///
/// # Safety
///
/// The `_aligned` buffer must have a size of STATE::WRITE_SIZE, and follow the alignment rules for the flash being read from
/// and written to.
#[cfg(feature = "_verify")]
pub async fn verify_and_mark_updated(
&mut self,
_public_key: &[u8],
_signature: &[u8],
_update_len: u32,
_aligned: &mut [u8],
) -> Result<(), FirmwareUpdaterError> {
assert_eq!(_aligned.len(), STATE::WRITE_SIZE);
assert!(_update_len <= self.dfu.capacity() as u32);
self.verify_booted(_aligned).await?;
self.state.verify_booted().await?;
#[cfg(feature = "ed25519-dalek")]
{
@ -121,8 +98,9 @@ impl<DFU: NorFlash, STATE: NorFlash> FirmwareUpdater<DFU, STATE> {
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 chunk_buf = [0; 2];
let mut message = [0; 64];
self.hash::<Sha512>(_update_len, _aligned, &mut message).await?;
self.hash::<Sha512>(_update_len, &mut chunk_buf, &mut message).await?;
public_key.verify(&message, &signature).map_err(into_signature_error)?
}
@ -143,7 +121,8 @@ impl<DFU: NorFlash, STATE: NorFlash> FirmwareUpdater<DFU, STATE> {
let signature = Signature::try_from(&signature).map_err(into_signature_error)?;
let mut message = [0; 64];
self.hash::<Sha512>(_update_len, _aligned, &mut message).await?;
let mut chunk_buf = [0; 2];
self.hash::<Sha512>(_update_len, &mut chunk_buf, &mut message).await?;
let r = public_key.verify(&message, &signature);
trace!(
@ -156,7 +135,7 @@ impl<DFU: NorFlash, STATE: NorFlash> FirmwareUpdater<DFU, STATE> {
r.map_err(into_signature_error)?
}
self.set_magic(_aligned, SWAP_MAGIC).await
self.state.mark_updated().await
}
/// Verify the update in DFU with any digest.
@ -177,49 +156,14 @@ impl<DFU: NorFlash, STATE: NorFlash> FirmwareUpdater<DFU, STATE> {
}
/// Mark to trigger firmware swap on next boot.
///
/// # Safety
///
/// The `aligned` buffer must have a size of STATE::WRITE_SIZE, and follow the alignment rules for the flash being written to.
#[cfg(not(feature = "_verify"))]
pub async fn mark_updated(&mut self, aligned: &mut [u8]) -> Result<(), FirmwareUpdaterError> {
assert_eq!(aligned.len(), STATE::WRITE_SIZE);
self.set_magic(aligned, SWAP_MAGIC).await
pub async fn mark_updated(&mut self) -> Result<(), FirmwareUpdaterError> {
self.state.mark_updated().await
}
/// Mark firmware boot successful and stop rollback on reset.
///
/// # Safety
///
/// The `aligned` buffer must have a size of STATE::WRITE_SIZE, and follow the alignment rules for the flash being written to.
pub async fn mark_booted(&mut self, aligned: &mut [u8]) -> Result<(), FirmwareUpdaterError> {
assert_eq!(aligned.len(), STATE::WRITE_SIZE);
self.set_magic(aligned, BOOT_MAGIC).await
}
async fn set_magic(&mut self, aligned: &mut [u8], magic: u8) -> Result<(), FirmwareUpdaterError> {
self.state.read(0, aligned).await?;
if aligned.iter().any(|&b| b != magic) {
// Read progress validity
self.state.read(STATE::WRITE_SIZE as u32, aligned).await?;
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::WRITE_SIZE as u32, aligned).await?;
}
// Clear magic and progress
self.state.erase(0, self.state.capacity() as u32).await?;
// Set magic
aligned.fill(magic);
self.state.write(0, aligned).await?;
}
Ok(())
pub async fn mark_booted(&mut self) -> Result<(), FirmwareUpdaterError> {
self.state.mark_booted().await
}
/// Write data to a flash page.
@ -229,16 +173,10 @@ impl<DFU: NorFlash, STATE: NorFlash> FirmwareUpdater<DFU, STATE> {
/// # Safety
///
/// Failing to meet alignment and size requirements may result in a panic.
pub async fn write_firmware(
&mut self,
aligned: &mut [u8],
offset: usize,
data: &[u8],
) -> Result<(), FirmwareUpdaterError> {
pub async fn write_firmware(&mut self, offset: usize, data: &[u8]) -> Result<(), FirmwareUpdaterError> {
assert!(data.len() >= DFU::ERASE_SIZE);
assert_eq!(aligned.len(), STATE::WRITE_SIZE);
self.verify_booted(aligned).await?;
self.state.verify_booted().await?;
self.dfu.erase(offset as u32, (offset + data.len()) as u32).await?;
@ -252,20 +190,94 @@ impl<DFU: NorFlash, STATE: NorFlash> FirmwareUpdater<DFU, STATE> {
///
/// Using this instead of `write_firmware` allows for an optimized API in
/// exchange for added complexity.
///
/// # Safety
///
/// The `aligned` buffer must have a size of STATE::WRITE_SIZE, and follow the alignment rules for the flash being written to.
pub async fn prepare_update(&mut self, aligned: &mut [u8]) -> Result<&mut DFU, FirmwareUpdaterError> {
assert_eq!(aligned.len(), STATE::WRITE_SIZE);
self.verify_booted(aligned).await?;
pub async fn prepare_update(&mut self) -> Result<&mut DFU, FirmwareUpdaterError> {
self.state.verify_booted().await?;
self.dfu.erase(0, self.dfu.capacity() as u32).await?;
Ok(&mut self.dfu)
}
}
/// Manages the state partition of the firmware update.
///
/// Can be used standalone for more fine grained control, or as part of the updater.
pub struct FirmwareState<'d, STATE> {
state: STATE,
aligned: &'d mut [u8],
}
impl<'d, STATE: NorFlash> FirmwareState<'d, STATE> {
/// Create a firmware state instance with a buffer for magic content and state partition.
///
/// # Safety
///
/// The `aligned` buffer must have a size of STATE::WRITE_SIZE, and follow the alignment rules for the flash being read from
/// and written to.
pub fn new(state: STATE, aligned: &'d mut [u8]) -> Self {
assert_eq!(aligned.len(), STATE::WRITE_SIZE);
Self { state, aligned }
}
// Make sure we are running a booted firmware to avoid reverting to a bad state.
async fn verify_booted(&mut self) -> Result<(), FirmwareUpdaterError> {
if self.get_state().await? == State::Boot {
Ok(())
} else {
Err(FirmwareUpdaterError::BadState)
}
}
/// 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(&mut self) -> Result<State, FirmwareUpdaterError> {
self.state.read(0, &mut self.aligned).await?;
if !self.aligned.iter().any(|&b| b != SWAP_MAGIC) {
Ok(State::Swap)
} else {
Ok(State::Boot)
}
}
/// Mark to trigger firmware swap on next boot.
pub async fn mark_updated(&mut self) -> Result<(), FirmwareUpdaterError> {
self.set_magic(SWAP_MAGIC).await
}
/// Mark firmware boot successful and stop rollback on reset.
pub async fn mark_booted(&mut self) -> Result<(), FirmwareUpdaterError> {
self.set_magic(BOOT_MAGIC).await
}
async fn set_magic(&mut self, magic: u8) -> Result<(), FirmwareUpdaterError> {
self.state.read(0, &mut self.aligned).await?;
if self.aligned.iter().any(|&b| b != magic) {
// Read progress validity
self.state.read(STATE::WRITE_SIZE as u32, &mut self.aligned).await?;
if self.aligned.iter().any(|&b| b != STATE_ERASE_VALUE) {
// The current progress validity marker is invalid
} else {
// Invalidate progress
self.aligned.fill(!STATE_ERASE_VALUE);
self.state.write(STATE::WRITE_SIZE as u32, &self.aligned).await?;
}
// Clear magic and progress
self.state.erase(0, self.state.capacity() as u32).await?;
// Set magic
self.aligned.fill(magic);
self.state.write(0, &self.aligned).await?;
}
Ok(())
}
}
#[cfg(test)]
mod tests {
use embassy_embedded_hal::flash::partition::Partition;
@ -288,8 +300,8 @@ mod tests {
let mut to_write = [0; 4096];
to_write[..7].copy_from_slice(update.as_slice());
let mut updater = FirmwareUpdater::new(FirmwareUpdaterConfig { dfu, state });
block_on(updater.write_firmware(&mut aligned, 0, to_write.as_slice())).unwrap();
let mut updater = FirmwareUpdater::new(FirmwareUpdaterConfig { dfu, state }, &mut aligned);
block_on(updater.write_firmware(0, to_write.as_slice())).unwrap();
let mut chunk_buf = [0; 2];
let mut hash = [0; 20];
block_on(updater.hash::<Sha1>(update.len() as u32, &mut chunk_buf, &mut hash)).unwrap();