New feature: ota TLV and ota-packer utility

.cargo/config.toml

@@ -28,6 +28,14 @@ run-esp32c6 = "run --release --target riscv32imac-unknown-none-elf --no-default-
 run-esp32s2 = "run --profile esp32s2 --target xtensa-esp32s2-none-elf --no-default-features --features esp32s2 "
 run-esp32s3 = "run --release --target xtensa-esp32s3-none-elf --no-default-features --features esp32s3 "
 
+# Test alias
+test-ota = "test --package ota --target x86_64-unknown-linux-gnu"
+
+# ota-packer aliases
+build-ota-packer = "build --package ota --bin ota-packer --target x86_64-unknown-linux-gnu"
+ota-packer = "run --package ota --bin ota-packer --target x86_64-unknown-linux-gnu"
+
+
 [target.xtensa-esp32-none-elf]
 runner = "espflash flash --baud=921600 --monitor --chip esp32"
 rustflags = ["-C", "link-arg=-nostartfiles", '--cfg=feature="esp32"']

.github/workflows/build.yml

@@ -10,8 +10,8 @@ on:
   workflow_dispatch:
 
 jobs:
-  build:
-    name: Build ${{ matrix.device.soc }}
+  espressif-targets:
+    name: Espressif target ${{ matrix.device.soc }}
     runs-on: ubuntu-latest
     strategy:
       fail-fast: false
@@ -53,4 +53,19 @@ jobs:
         if: ${{ contains(fromJson('["esp32c6"]'), matrix.device.soc) }}
         run: |
           cargo +${{ matrix.device.toolchain }} clippy --features ${{ matrix.device.soc }} --target riscv32imac-unknown-none-elf -- -D warnings
-          cargo +${{ matrix.device.toolchain }} fmt -- --check
+          cargo +${{ matrix.device.toolchain }} fmt -- --check
+  ota-packer:
+    name: OTA Packer
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+      - name: Setup Stable Rust Toolchain
+        uses: dtolnay/rust-toolchain@v1
+        with:
+          target: riscv32imac-unknown-none-elf
+          toolchain: stable
+      - name: Build utility
+        run: cargo build-ota-packer

.github/workflows/tests.yml

@@ -0,0 +1,27 @@
+name: Std tests
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+    branches:
+      - main
+  workflow_dispatch:
+
+jobs:
+  ota-packer:
+    name: OTA tests
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+      - name: Setup Stable Rust Toolchain
+        uses: dtolnay/rust-toolchain@v1
+        with:
+          target: riscv32imac-unknown-none-elf
+          toolchain: stable
+      - name: Package test
+        run: cargo test-ota

ota/Cargo.toml

@@ -8,3 +8,16 @@ default = []
 std = []
 
 [dependencies]
+sunset.workspace = true
+sunset-async.workspace = true
+
+log.workspace = true
+sha2.workspace = true
+
+# Only for helpers and tests
+[target.'cfg(not(target_os = "none"))'.dependencies]
+clap = "4.5"
+
+[[bin]]
+name = "ota-packer"
+path = "src/bin/ota-packer.rs"

ota/src/bin/README.md

@@ -0,0 +1,49 @@
+# Purpose of ota-packer
+
+The content of this file is provided for illustrative purposes. For a complete understanding of what this utility does read `ota-packer.rs`.
+
+This binary is a helper cli application to pack binary files together with a header to allow for the sftp-ota procedure to validate the binary before applying the OTA.
+
+## What this tool does
+
+It takes one binary file and adds the following Type Length Value fields (TLV):
+
+- ota type: SSH-Stamp "magic number" used to identify the ota file as SSH-Stamp. Any other value should be rejected in a OTA procedure by an SSH-Stamp binary.
+- checksum: SHA256 checksum of the binary. SSH-Stamp will calculate the checksum of the binary uploaded and will abort the OTA if it does not match this field.
+- binary length: Additional validation step. SSH-Stamp will only write/validate the announced bytes into flash memory. A target chip with an ota partition smaller than the announced binary length should abort the OTA.
+
+## What this tool does not...
+
+... and it might do in the future:
+
+- Sign the binary
+- Add information about the target architecture to help the target instance aborting a wrong binary.
+
+... and will definitely not do:
+
+- Upload the OTA to the target device (The user does this with any standard SFTP client and the appropriate credentials)
+- Validate or test in any way the binary
+
+## Usage
+
+For updated information on how to use this tool build and run the binary from the `ssh-stamp/ota` directory
+
+```sh
+ssh-stamp/ota$ cargo run --bin ota-packer -- --help
+```
+
+At the moment of redaction, this command outputs:
+
+```sh
+SSH-Stamp utility 0.1.0 to pack (unpack) OTA update files adding the required metadata.
+
+Usage: ota-packer [OPTIONS] <FILE>
+
+Arguments:
+  <FILE>  The file to process
+
+Options:
+  -u, --unpack  Unpacks a OTA file. Will save to <file> with .ota.npkd extension
+  -p, --pack    (default) Packs a binary file as an OTA file. Will save to <file>.ota
+  -h, --help    Print help
+```