From 7c6936a2e398e43ea3dc89736dc385402822933f Mon Sep 17 00:00:00 2001 From: Rasmus Melchior Jacobsen Date: Tue, 4 Apr 2023 12:24:30 +0200 Subject: [PATCH] Let hash functions take a digest::Digest trait ... and add adapters for current Sha512 implementations that does not inplement the Digest trait --- embassy-boot/boot/Cargo.toml | 4 +- .../boot/src/digest_adapters/ed25519_dalek.rs | 30 +++++ embassy-boot/boot/src/digest_adapters/mod.rs | 5 + .../boot/src/digest_adapters/salty.rs | 29 +++++ embassy-boot/boot/src/firmware_updater.rs | 108 ++++++++++++------ embassy-boot/boot/src/lib.rs | 1 + 6 files changed, 140 insertions(+), 37 deletions(-) create mode 100644 embassy-boot/boot/src/digest_adapters/ed25519_dalek.rs create mode 100644 embassy-boot/boot/src/digest_adapters/mod.rs create mode 100644 embassy-boot/boot/src/digest_adapters/salty.rs diff --git a/embassy-boot/boot/Cargo.toml b/embassy-boot/boot/Cargo.toml index 3312c2f9..c4ebdaff 100644 --- a/embassy-boot/boot/Cargo.toml +++ b/embassy-boot/boot/Cargo.toml @@ -24,6 +24,7 @@ features = ["defmt"] [dependencies] defmt = { version = "0.3", optional = true } +digest = "0.10" log = { version = "0.4", optional = true } ed25519-dalek = { version = "1.0.1", default_features = false, features = ["u32_backend"], optional = true } embassy-sync = { version = "0.1.0", path = "../../embassy-sync" } @@ -37,6 +38,7 @@ log = "0.4" env_logger = "0.9" rand = "0.7" # ed25519-dalek v1.0.1 depends on this exact version futures = { version = "0.3", features = ["executor"] } +sha1 = "0.10.5" [dev-dependencies.ed25519-dalek] default_features = false @@ -47,4 +49,4 @@ ed25519-dalek = ["dep:ed25519-dalek", "_verify"] ed25519-salty = ["dep:salty", "_verify"] #Internal features -_verify = [] \ No newline at end of file +_verify = [] diff --git a/embassy-boot/boot/src/digest_adapters/ed25519_dalek.rs b/embassy-boot/boot/src/digest_adapters/ed25519_dalek.rs new file mode 100644 index 00000000..a184d1c5 --- /dev/null +++ b/embassy-boot/boot/src/digest_adapters/ed25519_dalek.rs @@ -0,0 +1,30 @@ +use digest::typenum::U64; +use digest::{FixedOutput, HashMarker, OutputSizeUser, Update}; +use ed25519_dalek::Digest as _; + +pub struct Sha512(ed25519_dalek::Sha512); + +impl Default for Sha512 { + fn default() -> Self { + Self(ed25519_dalek::Sha512::new()) + } +} + +impl Update for Sha512 { + fn update(&mut self, data: &[u8]) { + self.0.update(data) + } +} + +impl FixedOutput for Sha512 { + fn finalize_into(self, out: &mut digest::Output) { + let result = self.0.finalize(); + out.as_mut_slice().copy_from_slice(result.as_slice()) + } +} + +impl OutputSizeUser for Sha512 { + type OutputSize = U64; +} + +impl HashMarker for Sha512 {} diff --git a/embassy-boot/boot/src/digest_adapters/mod.rs b/embassy-boot/boot/src/digest_adapters/mod.rs new file mode 100644 index 00000000..9b4b4b60 --- /dev/null +++ b/embassy-boot/boot/src/digest_adapters/mod.rs @@ -0,0 +1,5 @@ +#[cfg(feature = "ed25519-dalek")] +pub(crate) mod ed25519_dalek; + +#[cfg(feature = "ed25519-salty")] +pub(crate) mod salty; diff --git a/embassy-boot/boot/src/digest_adapters/salty.rs b/embassy-boot/boot/src/digest_adapters/salty.rs new file mode 100644 index 00000000..2b5dcf3a --- /dev/null +++ b/embassy-boot/boot/src/digest_adapters/salty.rs @@ -0,0 +1,29 @@ +use digest::typenum::U64; +use digest::{FixedOutput, HashMarker, OutputSizeUser, Update}; + +pub struct Sha512(salty::Sha512); + +impl Default for Sha512 { + fn default() -> Self { + Self(salty::Sha512::new()) + } +} + +impl Update for Sha512 { + fn update(&mut self, data: &[u8]) { + self.0.update(data) + } +} + +impl FixedOutput for Sha512 { + fn finalize_into(self, out: &mut digest::Output) { + let result = self.0.finalize(); + out.as_mut_slice().copy_from_slice(result.as_slice()) + } +} + +impl OutputSizeUser for Sha512 { + type OutputSize = U64; +} + +impl HashMarker for Sha512 {} diff --git a/embassy-boot/boot/src/firmware_updater.rs b/embassy-boot/boot/src/firmware_updater.rs index 22e3e6b0..2d1b2698 100644 --- a/embassy-boot/boot/src/firmware_updater.rs +++ b/embassy-boot/boot/src/firmware_updater.rs @@ -1,3 +1,4 @@ +use digest::Digest; use embedded_storage::nor_flash::{NorFlash, NorFlashError, NorFlashErrorKind}; use embedded_storage_async::nor_flash::NorFlash as AsyncNorFlash; @@ -128,25 +129,27 @@ impl FirmwareUpdater { #[cfg(feature = "ed25519-dalek")] { - use ed25519_dalek::{Digest, PublicKey, Sha512, Signature, SignatureError, Verifier}; + 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 digest = Sha512::new(); - self.incremental_hash(_state_and_dfu_flash, _update_len, _aligned, |x| digest.update(x)) + let mut message = [0; 64]; + self.hash::<_, Sha512>(_state_and_dfu_flash, _update_len, _aligned, &mut message) .await?; - public_key - .verify(&digest.finalize(), &signature) - .map_err(into_signature_error)? + 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, Sha512, Signature}; + use salty::{PublicKey, Signature}; + + use crate::digest_adapters::salty::Sha512; fn into_signature_error(_: E) -> FirmwareUpdaterError { FirmwareUpdaterError::Signature(signature::Error::default()) @@ -157,11 +160,10 @@ impl FirmwareUpdater { 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 digest = Sha512::new(); - self.incremental_hash(_state_and_dfu_flash, _update_len, _aligned, |x| digest.update(x)) + let mut message = [0; 64]; + self.hash::<_, Sha512>(_state_and_dfu_flash, _update_len, _aligned, &mut message) .await?; - let message = digest.finalize(); let r = public_key.verify(&message, &signature); trace!( "Verifying with public key {}, signature {} and message {} yields ok: {}", @@ -176,19 +178,21 @@ impl FirmwareUpdater { self.set_magic(_aligned, SWAP_MAGIC, _state_and_dfu_flash).await } - /// Iterate through the DFU and process all bytes with the provided closure. - pub async fn incremental_hash( + /// Verify the update in DFU with any digest. + pub async fn hash( &mut self, dfu_flash: &mut F, update_len: u32, - aligned: &mut [u8], - mut update: impl FnMut(&[u8]), + chunk_buf: &mut [u8], + output: &mut [u8], ) -> Result<(), FirmwareUpdaterError> { - for offset in (0..update_len).step_by(aligned.len()) { - self.dfu.read(dfu_flash, offset, aligned).await?; - let len = core::cmp::min((update_len - offset) as usize, aligned.len()); - update(&aligned[..len]); + 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(()) } @@ -334,24 +338,26 @@ impl FirmwareUpdater { #[cfg(feature = "ed25519-dalek")] { - use ed25519_dalek::{Digest, PublicKey, Sha512, Signature, SignatureError, Verifier}; + 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 digest = Sha512::new(); - self.incremental_hash_blocking(_state_and_dfu_flash, _update_len, _aligned, |x| digest.update(x))?; + let mut message = [0; 64]; + self.hash_blocking::<_, Sha512>(_state_and_dfu_flash, _update_len, _aligned, &mut message)?; - public_key - .verify(&digest.finalize(), &signature) - .map_err(into_signature_error)? + 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, Sha512, Signature}; + use salty::{PublicKey, Signature}; + + use crate::digest_adapters::salty::Sha512; fn into_signature_error(_: E) -> FirmwareUpdaterError { FirmwareUpdaterError::Signature(signature::Error::default()) @@ -362,10 +368,9 @@ impl FirmwareUpdater { 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 digest = Sha512::new(); - self.incremental_hash_blocking(_state_and_dfu_flash, _update_len, _aligned, |x| digest.update(x))?; + let mut message = [0; 64]; + self.hash_blocking::<_, Sha512>(_state_and_dfu_flash, _update_len, _aligned, &mut message)?; - let message = digest.finalize(); let r = public_key.verify(&message, &signature); trace!( "Verifying with public key {}, signature {} and message {} yields ok: {}", @@ -380,19 +385,21 @@ impl FirmwareUpdater { self.set_magic_blocking(_aligned, SWAP_MAGIC, _state_and_dfu_flash) } - /// Iterate through the DFU and process all bytes with the provided closure. - pub fn incremental_hash_blocking( + /// Verify the update in DFU with any digest. + pub fn hash_blocking( &mut self, dfu_flash: &mut F, update_len: u32, - aligned: &mut [u8], - mut update: impl FnMut(&[u8]), + chunk_buf: &mut [u8], + output: &mut [u8], ) -> Result<(), FirmwareUpdaterError> { - for offset in (0..update_len).step_by(aligned.len()) { - self.dfu.read_blocking(dfu_flash, offset, aligned)?; - let len = core::cmp::min((update_len - offset) as usize, aligned.len()); - update(&aligned[..len]); + 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(()) } @@ -479,3 +486,32 @@ impl FirmwareUpdater { Ok(self.dfu) } } + +#[cfg(test)] +mod tests { + use futures::executor::block_on; + use sha1::{Digest, Sha1}; + + use super::*; + use crate::tests::MemFlash; + + #[test] + fn can_verify() { + const STATE: Partition = Partition::new(0, 4096); + const DFU: Partition = Partition::new(65536, 131072); + + let mut flash = MemFlash::<131072, 4096, 8>([0xFF; 131072]); + + 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); + } +} diff --git a/embassy-boot/boot/src/lib.rs b/embassy-boot/boot/src/lib.rs index 6888a805..da905547 100644 --- a/embassy-boot/boot/src/lib.rs +++ b/embassy-boot/boot/src/lib.rs @@ -6,6 +6,7 @@ mod fmt; mod boot_loader; +mod digest_adapters; mod firmware_updater; mod partition;