Robert Allan JamesandClaude Sonnet 5
2fc55f47e1
First attempt shelled out to `openssl pkeyutl -sign` (fork/execlp, not system() -- avoided shell string interpolation of the key path). Corrected on request: no new external host binary dependency when the repo's own code can do the job -- same standing preference as the earlier anti-file correction. Rewritten to link ed25519_sign() (already verified against OpenSSL in Phase B) directly into mkcapsule. New tools/pkcs8_ed25519.c: a narrow DER walker (same shape as x509_ed25519.c, deliberately not shared -- small enough that duplicating a few TLV-walking lines beat threading a header between the kernel crypto tree and host tooling) extracting the raw seed from the intermediate's PKCS#8 private key, plus a minimal self-written base64 decoder (PEM is openssl genpkey's default output; no decoder existed anywhere in the repo). Verified end-to-end before wiring anything in: the extracted seed's derived pubkey matches the cert's exactly, and a full self-contained sign+verify round-trip (zero openssl) passes. CapsuleDesc had no spare bytes, so signatures live in a new parallel CapsuleSigEntry array, emitted by a new `mkcapsule --sign-key <path>` flag (omitted/missing key -> has_sig=0 everywhere, graceful, not a build failure -- CI has no access to the offline key). New capsule_sig.c/.h: capsule_verify_signature(), a separate function, not folded into the already-tested capsule_validate(). Finds and caches the embedded intermediate cert's pubkey once per boot, then verifies against it. Wired into all three capsule_validate() call sites in capsule_birth.c via log_message(LOG_WARN, ...) -- never refuses yet, per the earlier staged-rollout decision. Verified independently, both directions, live in the real kernel: a full clean build (38 signed capsules) boots clean on all three architectures with zero warnings. Separately, hand-corrupted one byte of Mama's own init.4th capsule's stored signature (not its payload/hash, which capsule_validate() already catches and would have masked the test) and rebuilt just the changed object: produced exactly "capsule sig: init.4th: INVALID -- signature does not verify" on boot, and the kernel still reached ok> -- proving warn-only doesn't refuse anything yet. Reverted before the final, untampered 3-arch acceptance pass. Still open: flipping WARN to hard-refuse (separate, deliberate step) and the BLOCK_MAP.md signature-status column. Documented in FABRIC-3.md. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01U14ET9CWAtbQMbYqomKgXd
capsules/
FORTH personality files loaded by the VM at boot. A capsule is an immutable, content-addressed payload; its XXHash64 hash is its identity. Any mutation changes the hash and the birth protocol rejects the image.
Key files
| File | Type | Purpose |
|---|---|---|
init.4th |
(m) MAMA_INIT |
Default Mama VM personality — loaded at LBN 2048 |
ACL.4th |
user | Word-level ACL system; self-activating at boot |
zuse.4th |
user | Bootstrap superuser; loaded by ACL.4th |
doe.4th |
user | DoE workload words (EXEC-DOE) — opt-in |
init-0.4th … init-9.4th |
(p) |
Numbered personality variants |
init-l8-*.4th |
(p) |
L8 Jacquard mode variants (stable/volatile/diverse/temporal/transition/omni) |
hermes/init.4th |
(p) |
Hermes baby VM personality |
artemis/init.4th |
(p) |
Artemis baby VM personality |
Block namespace
Block ranges are shared across all loaded capsules — collisions cause silent word-definition overwrites.
| Range | Owner |
|---|---|
| 2048–2099 | init.4th |
| 2100–2199 | doe.4th |
| 3000–3999 | workload capsules |
| 4000+ | user-defined (ACL.4th, zuse.4th, …) |
Each block is limited to 1024 bytes. Verify with wc -c before committing.
See also
experiments/bare_metal/README.md— DoE protocols and block namespace rulesdocs/03-architecture/word-acl/DESIGN.md— ACL system designtools/mkcapsule.c— assembles capsules intocapsule_generated.c- Project root