Document security verdict versus Docker

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

CHANGELOG.md

@@ -2,6 +2,9 @@
 
 **Docs:** [README](README.md) · [SPEC](SPEC.md) · [ARCHITECTURE](docs/ARCHITECTURE.md) · [RESEARCH](docs/RESEARCH.md) · [COMPARISON](COMPARISON.md) · [AGENTS](AGENTS.md) · [CHANGELOG](CHANGELOG.md)
 
+## 1.1.4 - 2026-10-23
+- Docs: [COMPARISON](COMPARISON.md) section 6.1 answers whether doos is a security-wise Docker replacement (same class as rootless Podman, not for untrusted code), summarized in the README safety summary.
+
 ## 1.1.3 - 2026-10-23
 - Charts: startup time, executable size and CPU limit as SVG (light and dark palettes, doos highlighted), embedded in [COMPARISON](COMPARISON.md) and [RESEARCH](docs/RESEARCH.md).
 - Reproducible measurements: `scripts/bench.sh` writes `docs/charts/bench.json`; `docs/charts/make_charts.py` builds the charts and rewrites every generated number and table in the documents from it, so text, tables and charts cannot drift apart.

COMPARISON.md

@@ -151,6 +151,21 @@ Podman is the closest comparison, since both are daemonless and rootless.
 - **Missing layers.** Docker applies an AppArmor profile (`docker-default`) on this machine [M: `docker info` lists apparmor]. doos installs no AppArmor or SELinux profile of its own; its only profile exists to *permit* user namespaces on Ubuntu 24.04+ [D].
 - **Supply chain.** doos pins publisher signing keys for Alpine and Ubuntu and checks digests for Debian [D][M]. Registry-based tools rely on registry trust, content trust or external signing tools [K].
 
+### 6.1 Is doos a security-wise Docker replacement?
+
+Short answer: it is in the same class as rootless Podman and rootless Docker by design, but it is not a replacement for running untrusted code.
+
+| Question | Answer |
+|---|---|
+| Better than rootful Docker on privilege? | Yes. No root daemon, nothing runs as root on the host, so an escape yields the invoking user's rights, not root [D][S]. |
+| Equal to rootless Podman or Docker? | Not proven. The mechanism is the same (user namespaces, seccomp, dropped capabilities, cgroup v2), the maturity is not [D][K]. |
+| What the default confines | 14 capabilities (Docker's default set, `CapEff` `a80425fb`), `no_new_privs`, seccomp denylist of 48 syscalls, cgroup memory/pids/cpu limits, a written-data cap, no host `/home`, host loopback blocked in `slirp` [M]. |
+| Weaker than Docker or Podman | Denylist instead of an allowlist (a new dangerous syscall is allowed by default); no per-container AppArmor or SELinux profile; host mode uses the host's own `/usr` and an `/etc` allowlist; `--net host` shares abstract unix sockets [D]. |
+| Kernel exposure | Shared kernel, and user namespaces enlarge the reachable kernel surface, which is why Ubuntu 24.04 restricts them by default [S]. |
+| Assurance | One developer, one machine (Linux x86_64), no external audit, no CVE history, Debian images verified by digest only [M][D]. |
+
+Use doos for your own tools, builds and experiments, where you accept the risk. For code you do not trust, or for several tenants, use rootless Podman with its default seccomp and SELinux or AppArmor, and gVisor or Kata when the kernel must not be shared (see the conclusion table in section 8). Functionally it is also not a drop-in replacement: see section 7.
+
 Full list of what doos does not cover is at the end of [RESEARCH](docs/RESEARCH.md); the exact hardening is in [SPEC](SPEC.md) under Hardening.
 
 ## 7. What doos lacks, and which code would change

README.md

@@ -168,6 +168,11 @@ run with Docker's default capability set and a seccomp filter. Memory, pids, cpu
 `--net host` removes network isolation and is opt-in (`--net pasta` is the safer host-like choice).
 What is still not covered is listed at the end of `docs/RESEARCH.md`.
 
+Is it a security-wise Docker replacement? Same class as rootless Podman by design (no root daemon, user namespaces,
+seccomp, dropped capabilities, cgroup limits), but unaudited, tested on one machine, with a seccomp denylist and no
+per-container AppArmor/SELinux profile. Fine for your own tools; for untrusted code use rootless Podman, gVisor or Kata.
+Details: [COMPARISON](COMPARISON.md) section 6.1.
+
 ## Development
 
 `make help` lists the targets: `make build`, `make test` (end-to-end, needs network), `make bench` (re-measure startup, sizes and the cpu limit), `make charts` (rebuild the SVG charts and the generated numbers in the comparison), `make docs`, `make release KIND=patch MSG="..."`. Build and test details are in [AGENTS](AGENTS.md); the charts and how they are generated are in [COMPARISON](COMPARISON.md) section 3 and `docs/charts/`.

VERSION

@@ -1 +1 @@
-1.1.3
+1.1.4