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New metadata format (#539)

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* new metadata format is used

* Update bootloader/src/main.rs

Co-authored-by: ztoked <zhalvorsen@google.com>

* splits the metadata signed and unsigned parts evenly

* fixes pylint

Co-authored-by: ztoked <zhalvorsen@google.com>
This commit is contained in:
kaczmarczyck
2022-08-31 14:35:45 +02:00
committed by GitHub
parent 932924ea85
commit 598c21071e
7 changed files with 190 additions and 260 deletions
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34
bootloader/src/main.rs
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@@ -34,6 +34,7 @@ use rtt_target::{rprintln, rtt_init_print};
/// Size of a flash page in bytes.
const PAGE_SIZE: usize = 0x1000;
const METADATA_SIGN_OFFSET: usize = 0x800;
/// A flash page.
type Page = [u8; PAGE_SIZE];
@@ -48,21 +49,19 @@ unsafe fn read_page(address: usize) -> Page {
/// Parsed metadata for a firmware partition.
struct Metadata {
checksum: [u8; 32],
timestamp: u32,
_signature: [u8; 64],
version: u64,
address: u32,
}
impl Metadata {
pub const DATA_LEN: usize = 40;
}
/// Reads the metadata from a flash page.
impl From<Page> for Metadata {
fn from(page: Page) -> Self {
Metadata {
checksum: page[0..32].try_into().unwrap(),
timestamp: LittleEndian::read_u32(&page[32..36]),
address: LittleEndian::read_u32(&page[36..Metadata::DATA_LEN]),
_signature: page[32..96].try_into().unwrap(),
version: LittleEndian::read_u64(&page[METADATA_SIGN_OFFSET..][..8]),
address: LittleEndian::read_u32(&page[METADATA_SIGN_OFFSET + 8..][..4]),
}
}
}
@@ -76,15 +75,15 @@ struct BootPartition {
impl BootPartition {
const FIRMWARE_LENGTH: usize = 0x00040000;
/// Reads the metadata, returns the timestamp if all checks pass.
pub fn read_timestamp(&self) -> Result<u32, ()> {
/// Reads the metadata, returns the firmware version if all checks pass.
pub fn read_version(&self) -> Result<u64, ()> {
let metadata_page = unsafe { read_page(self.metadata_address) };
let hash_value = self.compute_upgrade_hash(&metadata_page);
let metadata = Metadata::from(metadata_page);
if self.firmware_address != metadata.address as usize {
#[cfg(debug_assertions)]
rprintln!(
"Firmware address mismatch: expected 0x{:08X}, metadata 0x{:08X}",
"Partition address mismatch: expected 0x{:08X}, metadata 0x{:08X}",
self.firmware_address,
metadata.address as usize
);
@@ -95,7 +94,7 @@ impl BootPartition {
rprintln!("Hash mismatch");
return Err(());
}
Ok(metadata.timestamp)
Ok(metadata.version)
}
/// Computes the SHA256 of metadata information and partition data.
@@ -107,11 +106,14 @@ impl BootPartition {
debug_assert!(self.firmware_address % PAGE_SIZE == 0);
debug_assert!(BootPartition::FIRMWARE_LENGTH % PAGE_SIZE == 0);
let cc310 = crypto_cell::CryptoCell310::new();
cc310.update(&metadata_page[METADATA_SIGN_OFFSET..], false);
for page_offset in (0..BootPartition::FIRMWARE_LENGTH).step_by(PAGE_SIZE) {
let page = unsafe { read_page(self.firmware_address + page_offset) };
cc310.update(&page, false);
cc310.update(
&page,
page_offset + PAGE_SIZE == BootPartition::FIRMWARE_LENGTH,
);
}
cc310.update(&metadata_page[32..Metadata::DATA_LEN], true);
cc310.finalize_and_clear()
}
@@ -156,12 +158,12 @@ fn main() -> ! {
};
#[cfg(debug_assertions)]
rprintln!("Reading partition A");
let timestamp_a = partition_a.read_timestamp();
let version_a = partition_a.read_version();
#[cfg(debug_assertions)]
rprintln!("Reading partition B");
let timestamp_b = partition_b.read_timestamp();
let version_b = partition_b.read_version();
match (timestamp_a, timestamp_b) {
match (version_a, version_b) {
(Ok(t1), Ok(t2)) => {
if t1 >= t2 {
partition_a.boot()