- AppArmor network rules must use socket types (stream/dgram),
not protocol names (tcp/udp/icmp): the parser rejected the
profile (Invalid network entry) until fixed.
- Tinyproxy has no 'Upstream none' syntax; the line failed the
service at startup. Direct connection is the default, so the
line is removed.
- Tinyproxy Filter is POSIX BASIC regex, not extended: the
extended-style anchored patterns denied even allowed domains
(verified: xcmapi.org got 403). Rewritten in basic syntax
(\(...\)* groups); the anchored form still blocks
evilgithub.com and xcmapi.org.evil.com (verified on host).
- Filter file must be world-readable (was 640 root:root, so
tinyproxy could not read it and exited on reload); install
steps now chmod 644 (documented in the filter header via
the install note in tinyproxy.conf).
Host already runs these exact files (proxy allow/block
verified: xcmapi/github/api.github 200, example/evilgithub/
xcmapi.org.evil.com 403).
Inner codex sandbox stays danger-full-access by choice (bwrap
path is a separate decision); this hardens everything around it:
- DockerExecutor: --security-opt plumbing (repeatable, dedups
no-new-privileges), --pids-limit (CLI default 512, fork-bomb
guard), per-call extra_env (-e NAME=VALUE, non-secrets only,
e.g. proxy URLs; the model key still goes by -e NAME only).
- Worker: --egress-proxy-port (0 = off). When on, Docker task
containers get HTTP(S)_PROXY pointing at the host filtering
proxy via their network gateway IP (tenant network gateway
or default bridge gateway). Gateway unresolvable => the
attempt fails instead of running unproxied (fail closed,
same rule as tenant network creation failure).
- AppArmor profile deploy/apparmor/docker-codex: docker-default
base + deny network raw/packet, deny ptrace, deny mount/
umount/pivot_root, deny dangerous capabilities, deny writes
to /proc/sys, /sys, /proc/keys. Deliberately NO userns rule
(that would enable the bwrap path, not this one). File rules
mirror docker-default (broad + sensitive denies); a strict
file allowlist would need profiling codex's file access set
and is not claimed here.
- Egress proxy deploy/egress/: Tinyproxy with
FilterDefaultDeny + anchored domain allowlist (relay,
github, pypi, npm). Anchoring matters: an unanchored
'github.com' regex would also match 'evilgithub.com'.
- Seccomp honesty (README): Docker default seccomp already
enforces on all task containers; no new stricter allowlist
is claimed in this change (building one from memory risks
silently breaking the toolchain; it needs syscall profiling
first).
Tests: 3 outer-hardening tests (security-opt dedup, pids
limit, proxy env without leaking the key value, gateway
parse/fail, proxy fail-closed). Full suites pass.
host