debsmith

debsmith builds Debian and Ubuntu packages from one declarative manifest. It writes the .deb, audits it against Debian Policy, generates a 3.0 (quilt) source package, produces a CycloneDX SBOM, proves the build is reproducible and turns a directory of artifacts into a signed APT repository.

Everything is implemented in Go. dpkg-deb, ar, tar, gzip, xz, zstd, gpg and lintian are not required on the build host.

$ debsmith build examples/hello --epoch 1700000000
==> Building package
  ✓ hello 1.0.0-1 (all)
    artifact: examples/hello/dist/hello_1.0.0-1_all.deb (2.1 KiB)
    sha256:   9be1e664308249a519555d7c2006a06b328710f2d15e0d551b62d66c5c6987a8
    payload:  14 files, 5 KiB installed
    epoch:    1700000000

$ debsmith lint examples/hello/dist/hello_1.0.0-1_all.deb --fail-on warning
hello 1.0.0-1 (all)

0 error(s), 0 warning(s), 0 info(s) from 30 checks

Why debsmith

Debian packaging is powerful but fragmented: dpkg-deb for archives, dpkg-source for source packages, lintian for policy, apt-ftparchive for repositories, gpg for signing and a pile of shell glue to hold it together. Reproducibility is usually an afterthought.

debsmith treats packaging as a compiler problem:

Features

• Deterministic .deb writer — sorted tar members, fixed root:root ownership, zeroed gzip mtimes, SOURCE_DATE_EPOCH timestamps and reproducible ar headers.
• Four compressors — zstd (default data), gzip (default control) and xz, with read support for legacy bzip2.
• Staged payloads — copy a root filesystem, individual files, directories and symlinks; override modes per path; declare conffiles and maintainer scripts.
• 30 Debian Policy checks — names, versions, maintainers, control fields, ownership, modes, checksums, conffiles, scripts, doc files, sections, dependencies and archive safety.
• Multiple report formats — human readable, JSON and SARIF 2.1.0 for GitHub code scanning.
• Signed APT repositories — Debian pool/ layout, deterministic Packages/Release, clearsigned InRelease and armored Release.gpg.
• Source packages — 3.0 (quilt) .dsc with MD5, SHA-1 and SHA-256 checksums; works with dpkg-source -x and dpkg-buildpackage.
• CycloneDX 1.5 SBOM — deterministic serial number, payload digest and a dependency graph built from Depends/Pre-Depends.
• Reproducibility verifier — builds twice in isolated directories and compares bytes, then falls back to a structural diff when they differ.
• Safe by construction — rejects .., absolute escapes, duplicate paths, unknown control members and oversized control archives.
• Zero shell-outs — one static binary for Linux, macOS and Windows.

Installation

go install github.com/Avi6855/debsmith/cmd/debsmith@latest

Build from source:

git clone https://github.com/Avi6855/debsmith.git
cd debsmith
make build            # bin/debsmith with version metadata
sudo mv bin/debsmith /usr/local/bin/

Shell completion:

debsmith completion bash > /etc/bash_completion.d/debsmith
debsmith completion zsh  > /usr/share/zsh/site-functions/_debsmith
debsmith completion fish > ~/.config/fish/completions/debsmith.fish

Quick start

A complete working project lives in examples/hello.

1. Manifest

# debsmith.yaml
name: hello
version: "1.0.0"
revision: "1"
architecture: all
maintainer: "Avinash Rajendra Patil <avinashpatil6855@gmail.com>"
description: "Minimal Debian package built with debsmith"
extendedDescription: |
  A tiny, dependency-free package that demonstrates the full pipeline.
homepage: "https://github.com/Avi6855/debsmith"
section: utils
priority: optional
license: MIT

root: rootfs
permissions:
  /usr/bin/hello: "0755"
conffiles:
  - /etc/hello/hello.conf
scripts:
  postinst: packaging/postinst

source:
  upstream: src

2. Payload

rootfs/
├── etc/hello/hello.conf
├── usr/bin/hello
├── usr/share/doc/hello/changelog.Debian.gz
├── usr/share/doc/hello/copyright
└── usr/share/man/man1/hello.1.gz

3. Build

debsmith build examples/hello --epoch 1700000000 --sbom
debsmith inspect examples/hello/dist/hello_1.0.0-1_all.deb --contents
debsmith lint examples/hello/dist/hello_1.0.0-1_all.deb --fail-on warning
debsmith verify-repro examples/hello --epoch 1700000000

hello 1.0.0-1 (all)
  format:        debian-binary 2.0
  control:       gzip
  data:          zstd
  size:          2.1 KiB
  sha256:        9be1e664308249a519555d7c2006a06b328710f2d15e0d551b62d66c5c6987a8

Control:
  Package: hello
  Version: 1.0.0-1
  Architecture: all
  Maintainer: Avinash Rajendra Patil <avinashpatil6855@gmail.com>
  Installed-Size: 5
  Section: utils
  Priority: optional
  Homepage: https://github.com/Avi6855/debsmith
  Description: Minimal Debian package built with debsmith
    A tiny, dependency-free package that demonstrates the full debsmith
    pipeline: deterministic archives, Debian Policy linting, source package
    generation, SBOM output and signed APT repositories.

Commands

Global flags: --verbose, --quiet, --no-color.

build

debsmith build .                                   # dist/<name>_<ver>_<arch>.deb
debsmith build . -o /srv/packages/app.deb
debsmith build . --compression xz --control-compression gzip
debsmith build . --sbom --epoch 1700000000 --json

lint

debsmith lint pkg.deb                              # exit 1 on errors
debsmith lint pkg.deb --fail-on warning            # strict CI gate
debsmith lint pkg.deb --json
debsmith lint pkg.deb --sarif > debsmith.sarif
debsmith lint --list-checks

repo

debsmith repo dist                                 # pool/ + dists/stable
debsmith repo dist --suite bookworm --component main --arch amd64 --arch arm64
debsmith repo dist --sign-key ~/.config/debsmith/release.asc

dist/
├── dists/stable/
│   ├── InRelease
│   ├── Release
│   ├── Release.gpg
│   └── main/binary-amd64/Packages{,.gz}
└── pool/main/h/hello/hello_1.0.0-1_amd64.deb

Client configuration:

curl -fsSL https://example.com/repo/release.asc \
  | sudo gpg --dearmor -o /usr/share/keyrings/debsmith.gpg
echo "deb [signed-by=/usr/share/keyrings/debsmith.gpg] https://example.com/repo stable main" \
  | sudo tee /etc/apt/sources.list.d/debsmith.list
sudo apt update && sudo apt install hello

Manifest reference

The complete schema, defaults and validation rules are in docs/manifest.md. Highlights:

All modes are octal ("0755"). Payload paths are absolute (/usr/bin/app).

Reproducible builds

debsmith is deterministic by construction:

1. Every tar member is sorted by path and written with PAX headers.
2. Ownership is forced to uid=0, gid=0, uname=root, gname=root.
3. Every timestamp is the build epoch (--epoch or SOURCE_DATE_EPOCH).
4. gzip headers carry no filename and a zero mtime (OS=255).
5. zstd runs with a single encoder goroutine and a fixed window.
6. ar headers use fixed modes, zero uid/gid and the build epoch.
7. Repository indexes are sorted and checksummed in a fixed order.
8. OpenPGP signatures are created at the build epoch, not wall-clock time.

debsmith verify-repro examples/hello --epoch 1700000000

==> Verifying reproducibility
  ✓ reproducible: identical SHA-256 9be1e664308249a519555d7c2006a06b328710f2d15e0d551b62d66c5c6987a8
    size: 2.1 KiB

If two artifacts differ, verify-repro compares ar members and payload entries and reports the first structural differences (mode, size, content, link targets) instead of a bare hash mismatch.

Debian Policy linting

30 checks cover the failures that matter most in review:

$ debsmith lint hello.deb --fail-on warning
hello 1.0.0-1 (all)
  warning DSM010  mode 0666  etc/hello/hello.conf
  warning DSM016  file has no md5sums entry  usr/bin/hello

0 error(s), 2 warning(s), 0 info(s) from 30 checks

The full catalog is in docs/checks.md and at debsmith lint --list-checks. Each finding has a stable DSM### code, a severity, an optional payload path and remediation advice. --sarif produces a SARIF 2.1.0 log that GitHub code scanning accepts directly.

Source packages

debsmith source examples/hello --epoch 1700000000

examples/hello/dist/
├── hello_1.0.0.orig.tar.gz
├── hello_1.0.0-1.debian.tar.xz
└── hello_1.0.0-1.dsc

The .dsc lists MD5, SHA-1 and SHA-256 checksums for both tarballs and is compatible with dpkg-source:

dpkg-source -x hello_1.0.0-1.dsc hello
cd hello && dpkg-buildpackage -b -us -uc

If source.debian is missing, debsmith generates a minimal debian/ scaffold (control, changelog, copyright, rules, source/format). For real packages, ship your own directory; it is validated for debian/control, debian/rules and debian/source/format.

Use --sign-key to clearsign the .dsc for upload.

SBOM

debsmith build examples/hello --sbom

{
  "bomFormat": "CycloneDX",
  "specVersion": "1.5",
  "serialNumber": "urn:uuid:…",
  "metadata": {
    "timestamp": "2023-11-14T22:13:20Z",
    "component": {
      "type": "application",
      "name": "hello",
      "version": "1.0.0-1",
      "purl": "pkg:deb/hello@1.0.0-1?arch=all"
    }
  },
  "components": [
    { "type": "library", "name": "libc6", "version": "2.38" }
  ]
}

The serial number is derived from the artifact digest, so repeated builds of the same bytes produce identical BOMs.

Verified against the real Debian toolchain

The repository ships scripts/verify-container.sh, which runs the artifacts through dpkg, lintian, dpkg-source, dpkg-buildpackage and apt inside Ubuntu 24.04:

docker run --rm -v "$PWD:/work" -w /work ubuntu:24.04 \
  bash scripts/verify-container.sh

Verified in this repository:

• dpkg-deb --info and --contents parse the archive and its modes.
• dpkg -i installs the package; the maintainer script runs; conffiles are registered; the binary works.
• lintian reports 0 errors (one expected initial-upload-closes-no-bugs warning for a first upload).
• dpkg-source -x extracts the .dsc.
• dpkg-buildpackage -b -us -uc rebuilds a working binary package from the generated source package.
• apt-get install hello=1.0.0-1 from the generated repository installs the exact artifact built by debsmith.

Architecture

debsmith.yaml ──▶ manifest.Load ──▶ manifest.Stage ──▶ deb.Write ──▶ .deb
                                      │                  │
                                      │                  ├──▶ policy.Lint ──▶ text/JSON/SARIF
                                      │                  ├──▶ sbom.Generate ──▶ .cdx.json
                                      │                  └──▶ repro.Compare ──▶ proof
                                      │
                                      └──▶ sourcepkg.Build ──▶ .dsc + tarballs

.deb files ──▶ aptrepo.Build ──▶ Packages / Release / InRelease / Release.gpg

Design notes and the reproducibility contract are in docs/architecture.md.

Development

Requirements: Go 1.25+.

make build        # bin/debsmith
make test         # go test ./...
make cover        # coverage.html
make fmt vet      # formatting and static checks
make verify       # build, lint, SBOM, source package and repository
make e2e          # Ubuntu 24.04 container verification (Docker)

Coverage on the current tree:

internal/deb        78.3%
internal/policy     87.5%
internal/sbom       82.8%
internal/sourcepkg  76.3%
internal/manifest   73.5%
internal/tarutil    75.6%
internal/repro      72.8%
internal/aptrepo    72.4%
internal/build      70.5%

Limitations

• debsmith packages a staged payload, it does not run debhelper; use it for prebuilt binaries, scripts, configuration and documentation trees.
• Source packages contain one binary stanza per manifest; multi-binary source packaging still belongs in debian/control and your debian/rules.
• Debug symbol packages, Build-Ids splitting and dh_dwz are not generated.
• One component per repository run (main by default).
• Installed-Size is an estimate: one KiB per file rounded up, as dpkg does.
• Maintainer scripts are stored, never executed, during packaging.
• APT Acquire-By-Hash is not emitted.
• Signing reads armored or binary OpenPGP private keys; passphrases come from a file or DEBSMITH_GPG_PASSPHRASE, never from a command-line argument.

Contributing

See CONTRIBUTING.md. Security reports are covered by SECURITY.md.

License

MIT — see LICENSE.

Author

Avinash Rajendra Patil — author and maintainer.

Built with Go, Cobra, ProtonMail go-crypto and klauspost/compress.