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embassy-boot: add nightly feature gates

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This commit is contained in:
sander 2023-04-11 13:49:32 +02:00
parent c309797488
commit f51cbebffd
4 changed files with 265 additions and 250 deletions
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2
embassy-boot/boot/Cargo.toml
View File

@ -45,7 +45,7 @@ default_features = false
features = ["rand", "std", "u32_backend"]
[features]
default = ["nightly"]
#default = ["nightly"]
ed25519-dalek = ["dep:ed25519-dalek", "_verify"]
ed25519-salty = ["dep:salty", "_verify"]

440
embassy-boot/boot/src/firmware_updater.rs
View File

@ -1,5 +1,6 @@
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};
@ -73,222 +74,6 @@ impl FirmwareUpdater {
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 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(feature = "_verify")]
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(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)
}
//
// Blocking API
//
@ -504,7 +289,228 @@ impl FirmwareUpdater {
}
}
#[cfg(test)]
// Async API
#[cfg(feature = "nightly")]
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(feature = "_verify")]
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(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};

3
embassy-boot/boot/src/mem_flash.rs
View File

@ -3,6 +3,7 @@
use core::ops::{Bound, Range, RangeBounds};
use embedded_storage::nor_flash::{ErrorType, NorFlash, NorFlashError, NorFlashErrorKind, ReadNorFlash};
#[cfg(feature = "nightly")]
use embedded_storage_async::nor_flash::{NorFlash as AsyncNorFlash, ReadNorFlash as AsyncReadNorFlash};
pub struct MemFlash<const SIZE: usize, const ERASE_SIZE: usize, const WRITE_SIZE: usize> {
@ -134,6 +135,7 @@ impl<const SIZE: usize, const ERASE_SIZE: usize, const WRITE_SIZE: usize> NorFla
}
}
#[cfg(feature = "nightly")]
impl<const SIZE: usize, const ERASE_SIZE: usize, const WRITE_SIZE: usize> AsyncReadNorFlash
for MemFlash<SIZE, ERASE_SIZE, WRITE_SIZE>
{
@ -148,6 +150,7 @@ impl<const SIZE: usize, const ERASE_SIZE: usize, const WRITE_SIZE: usize> AsyncR
}
}
#[cfg(feature = "nightly")]
impl<const SIZE: usize, const ERASE_SIZE: usize, const WRITE_SIZE: usize> AsyncNorFlash
for MemFlash<SIZE, ERASE_SIZE, WRITE_SIZE>
{

70
embassy-boot/boot/src/partition.rs
View File

@ -1,4 +1,5 @@
use embedded_storage::nor_flash::{NorFlash, ReadNorFlash};
#[cfg(feature = "nightly")]
use embedded_storage_async::nor_flash::{NorFlash as AsyncNorFlash, ReadNorFlash as AsyncReadNorFlash};
/// A region in flash used by the bootloader.
@ -22,6 +23,43 @@ impl Partition {
self.to - self.from
}
/// Read from the partition on the provided flash
pub fn read_blocking<F: ReadNorFlash>(&self, flash: &mut F, offset: u32, bytes: &mut [u8]) -> Result<(), F::Error> {
let offset = self.from as u32 + offset;
flash.read(offset, bytes)
}
/// Write to the partition on the provided flash
pub fn write_blocking<F: NorFlash>(&self, flash: &mut F, offset: u32, bytes: &[u8]) -> Result<(), F::Error> {
let offset = self.from as u32 + offset;
flash.write(offset, bytes)?;
trace!("Wrote from 0x{:x} len {}", offset, bytes.len());
Ok(())
}
/// Erase part of the partition on the provided flash
pub fn erase_blocking<F: NorFlash>(&self, flash: &mut F, from: u32, to: u32) -> Result<(), F::Error> {
let from = self.from as u32 + from;
let to = self.from as u32 + to;
flash.erase(from, to)?;
trace!("Erased from 0x{:x} to 0x{:x}", from, to);
Ok(())
}
/// Erase the entire partition
pub(crate) fn wipe_blocking<F: NorFlash>(&self, flash: &mut F) -> Result<(), F::Error> {
let from = self.from as u32;
let to = self.to as u32;
flash.erase(from, to)?;
trace!("Wiped from 0x{:x} to 0x{:x}", from, to);
Ok(())
}
}
// Async API
#[cfg(feature = "nightly")]
impl Partition {
/// Read from the partition on the provided flash
pub async fn read<F: AsyncReadNorFlash>(
&self,
@ -58,38 +96,6 @@ impl Partition {
trace!("Wiped from 0x{:x} to 0x{:x}", from, to);
Ok(())
}
/// Read from the partition on the provided flash
pub fn read_blocking<F: ReadNorFlash>(&self, flash: &mut F, offset: u32, bytes: &mut [u8]) -> Result<(), F::Error> {
let offset = self.from as u32 + offset;
flash.read(offset, bytes)
}
/// Write to the partition on the provided flash
pub fn write_blocking<F: NorFlash>(&self, flash: &mut F, offset: u32, bytes: &[u8]) -> Result<(), F::Error> {
let offset = self.from as u32 + offset;
flash.write(offset, bytes)?;
trace!("Wrote from 0x{:x} len {}", offset, bytes.len());
Ok(())
}
/// Erase part of the partition on the provided flash
pub fn erase_blocking<F: NorFlash>(&self, flash: &mut F, from: u32, to: u32) -> Result<(), F::Error> {
let from = self.from as u32 + from;
let to = self.from as u32 + to;
flash.erase(from, to)?;
trace!("Erased from 0x{:x} to 0x{:x}", from, to);
Ok(())
}
/// Erase the entire partition
pub(crate) fn wipe_blocking<F: NorFlash>(&self, flash: &mut F) -> Result<(), F::Error> {
let from = self.from as u32;
let to = self.to as u32;
flash.erase(from, to)?;
trace!("Wiped from 0x{:x} to 0x{:x}", from, to);
Ok(())
}
}
#[cfg(test)]