Files

Michael Chus a38c35ce2d docs: add three LiveCD/embedded patterns from bee project

- alpine-livecd: mkimage profile rules, apkovl mechanics, workdir caching,
  squashfs compression, NIC firmware, long build survival via screen
- vendor-installer-verification: checksum-before-download, cache validation,
  version URL verification before writing build scripts
- unattended-boot-services: OpenRC invariants for headless environments,
  network-independent SSH, persistent DHCP, graceful degradation

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

2026-03-05 18:18:22 +03:00

2.3 KiB

Raw Blame History

Contract: Vendor Installer Verification

Version: 1.0

Purpose

Rules for downloading and verifying proprietary vendor installers (.run, .exe, .tar.gz) where the vendor publishes a checksum alongside the binary. Applies to: NVIDIA drivers, vendor CLI tools, firmware packages.

Download Order

Always download the checksum file before the installer:

BASE_URL="https://vendor.example.com/downloads/${VERSION}"
BIN_FILE="/var/cache/vendor-${VERSION}.run"
SHA_FILE="/var/cache/vendor-${VERSION}.run.sha256sum"

# 1. Download checksum first
wget -q -O "$SHA_FILE" "${BASE_URL}/vendor-${VERSION}.run.sha256sum"

# 2. Download installer
wget --show-progress -O "$BIN_FILE" "${BASE_URL}/vendor-${VERSION}.run"

# 3. Verify
cd /var/cache
sha256sum -c "$SHA_FILE" || { echo "ERROR: sha256 mismatch"; rm -f "$BIN_FILE"; exit 1; }

Reason: if the download is interrupted, you have the expected checksum to verify against on retry.

Cache with Verification

Never assume a cached file is valid — a previous download may have been interrupted (0-byte file):

verify_cached() {
    [ -s "$SHA_FILE" ] || return 1   # sha256 file missing or empty
    [ -s "$BIN_FILE" ] || return 1   # binary missing or empty
    cd "$(dirname "$BIN_FILE")"
    sha256sum -c "$SHA_FILE" --status 2>/dev/null
}

if ! verify_cached; then
    rm -f "$BIN_FILE" "$SHA_FILE"
    # ... download and verify
else
    echo "verified from cache"
fi

Never check only for file existence. Check that the file is non-empty (-s) AND passes checksum.

Version Validation

Before writing build scripts, verify the version URL actually exists:

curl -sIL "https://vendor.example.com/downloads/${VERSION}/installer.run" \
    | grep -i 'http/\|content-length'

A 404 or content-length: 0 means the version does not exist on that CDN. Vendor version numbering may have gaps (e.g. NVIDIA skips minor versions on some CDNs).

Rules

Download checksum before installer — never after.
Verify checksum before extracting or executing.
On mismatch: delete the file, exit with error. Never proceed with a bad installer.
Cache by version + any secondary key (e.g. kernel version for compiled modules).
Never commit installer files to git — always download at build time.
Log the expected hash when downloading so failures are diagnosable.

2.3 KiB Raw Blame History