Root CA + snakeoil intermediate generated entirely offline
(/home/rajames/CLionProjects/lithosananke-ca/, outside this repo,
private keys chmod 600) per this milestone's own requirement: Ed25519,
root self-signed 20-year validity, intermediate real-CA-signed
(CA:TRUE, pathlen:0), chain verified via openssl.
Snakeoil intermediate embedded as a capsule (capsules/pki/
snakeoil-intermediate.der) -- confirmed the font-capsule precedent
needed zero new infrastructure, any non-.4th file under capsules/
embeds verbatim already.
New x509_ed25519.c: a from-scratch, narrow DER walker (not general
ASN.1/X.509, per this milestone's design decision) extracting the raw
Ed25519 pubkey from a cert's SubjectPublicKeyInfo -- handles the
optional v3 version field, verifies the AlgorithmIdentifier OID is
Ed25519 rather than assuming, handles both DER length forms. Verified
against ground truth: the extracted key from the real embedded cert
matches openssl's own reported pubkey byte-for-byte; refusal path
checked against truncated/garbage/empty/wrong-algorithm (real RSA cert)
input. Compiles clean on all three architectures.
Still open: mkcapsule signing step, wiring ed25519_verify() into
capsule_birth.c's three validate call sites (landing warn-only first,
per decision -- a bug here could stop every capsule from birthing,
including Mama's own, on all three arches), 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
Extends the previously verify-only ed25519.c with ed25519_keygen() and
ed25519_sign() per RFC 8032 5.1.5/5.1.6, reusing every point-arithmetic
primitive verify already had -- only seed expansion/clamping and
per-message nonce derivation are new. Signing is deterministic; only
keygen ever touches entropy, via a caller-supplied seed (virtio_rng,
Phase A) -- keygen still generates nothing itself.
New scalar_muladd() (scalar25519.c) for signing's S = (k*a + r) mod L,
the one scalar op verify never needed. Schoolbook multiply into a u128
wide accumulator with one final carry pass -- deliberately the same
shape as fe25519.c's existing multiply, which has a documented history
of a real bug from carrying mid-accumulation instead of in one pass.
Verified against an independent implementation, not self-consistency:
a throwaway host harness against Python's cryptography library (OpenSSL-
backed) across 6 trials (5 random seed/message pairs + the empty-message
case) produced byte-for-byte identical pubkeys and signatures every
time. Clean compile on all three architectures and a full 3-arch QEMU
acceptance boot, conservation intact, no panics or guest errors.
Nothing calls the new functions from the live kernel path yet -- that's
Phase C (the MINT word itself), still open, documented in FABRIC-3.md.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01U14ET9CWAtbQMbYqomKgXd
New freestanding, verify-only Ed25519 (RFC 8032) implementation:
include/starkernel/{sha512,fe25519,scalar25519,ed25519}.h +
src/starkernel/crypto/{sha512,fe25519,scalar25519,ed25519}.c, wired into
Makefile.starkernel. Kernel never signs or generates keys -- only
ed25519_verify() is needed; signing happens in the host-side mkcapsule
build tool via libsodium/OpenSSL.
Confirmed __int128 multiply/add/shift-by-constant compile with zero
undefined symbols on all three target toolchains (only division needs
libgcc's __udivti3, per timer.c's existing documented finding -- that
file's comment updated to narrow the claim, since it had been read as
"avoid __int128 entirely"). This enabled the standard 5-limb radix-2^51
field arithmetic representation.
An abandoned first attempt (10-limb radix-2^26, avoiding __int128 out of
premature caution) hit two real bugs, both invisible on inspection and
found only by property-based testing against Python's own bignum
arithmetic: a non-uniform-radix limb misalignment in multiplication, and
a double-counted carry. Verification chain: SHA-512 against known +
boundary vectors (7/7); field arithmetic property-tested 25,045 cases;
scalar-mod-L arithmetic 300 cases (L confirmed prime via Miller-Rabin
first); full verify() end-to-end against 110 real signatures from
Python's cryptography library, including tampered inputs and the RFC
8032 S>=L malleability attack -- all correctly accepted/rejected.
Compiles clean (zero warnings) and links on all three architectures,
confirmed via the mandatory three-arch QEMU boot. The code is linked but
not yet called from anywhere -- wiring into capsule_birth.c needs a
from-scratch X.509/DER parser first (Captain Bob chose real X.509 over a
raw-blob cert format this session), which is the next open item.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HZ8kNoTuP63pbQtro4qvrm
