Two research passes confirmed the identity record itself (seed/pubkey/
cert) is already unreachable from any FORTH primitive -- only C-level
read_devblock/write_devblock touch it. But a device's ordinary user block
content CAN be copied between two attached devices today, using only
stock, unpinned words: <src> BLOCK <dst> BUFFER 1024 MOVE UPDATE
SAVE-BUFFERS, or the dedicated RELOCATE-BLOCK word (whose own doc comment
already admits "performs no policy validation of its own"). Checked
whether the existing per-block owner_fp/BLK-ACL-ALLOW@ metadata already
solves this -- it doesn't: owner_fp encodes who (a VM identity pubkey),
never where (physical device), and blk_get_buffer()/blk_update() never
consult acl_allow/acl_ttl at all -- those fields are completely inert.
Small, targeted fix, no rearchitecture:
- blk_subsys_relocate_block() (block_subsystem.c): same-device check.
Its own documented purpose is wear-leveling (relocate on the SAME
device) -- never stated as cross-device, and nothing enforced that
until now.
- New public blk_lbn_device_handle() (block_subsystem.c/.h): the missing
LBN-to-device direction (blk_get_device_range() already goes the other
way). Opaque, stable, == comparable.
- MOVE (memory_words.c) and CMOVE/CMOVE> (string_words.c): refuse when
both addresses are block-window addresses backed by two different
devices -- the exact shape of the composed attack. A copy where either
end is ordinary VM memory (the overwhelming common case: staging text
from PAD, editing a block in place) is untouched.
- blk_vm_check_epoch()/blk_vm_slot_for_addr() exposed (block_words.h) so
the two new call sites share the same window-slot invalidation contract
rather than a second, divergent copy of it.
Verified live on all three architectures, not just boot-clean: same-
device MOVE/RELOCATE-BLOCK still succeed exactly as before; cross-device
MOVE/CMOVE/RELOCATE-BLOCK all refused. Zero UNKNOWN WORD, identical
dict_hash across all three (this change adds no FORTH-visible word, only
internal refusal conditions, as predicted).
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Maintainability sweep (prompted by "this is getting hard to maintain"):
fixed the remaining three warning classes after the missing-field-
initializers commit -- 2x -Wsign-compare (control_words.c, cast at the
comparison site rather than changing cf_last_mode's type, which
deliberately holds a -999 sentinel outside vm_mode_t's valid range),
2x -Wstringop-truncation (mkcapsule.c, strncpy+manual-null-terminate
replaced with the idiomatic snprintf equivalent), and 26x
-Wunused-parameter (mostly documented stubs, silenced with the repo's
existing (void)param; idiom).
One of the unused-parameter warnings was not a deliberate stub -- a
real bug. restore_vm_state() (test_common.c) is named, documented, and
called by nine real call sites (acl_words_test.c x8 plus its own
internal use) as "restore saved VM state", but ignored all four of its
parameters and hard-reset to a fixed baseline instead, silently not
restoring what any caller actually saved. Fixed to actually assign the
passed-in dsp/rsp/error/mode. Found while fixing warnings, reported
before touching it, fixed/tested/documented/committed on explicit
instruction.
Verified: all three architectures build with zero C-compiler warnings
(amd64: 3040 -> 0; aarch64's one remaining note is lld-link's own
unrelated linker warning, not a C warning). Full amd64 acceptance boot
post-fix: POST 1003/965/0/0/38 (total/passed/failed/errors/stubs),
"ALL IMPLEMENTED TESTS PASSED!", contract checks (A4'/A1) all passed,
dict_hash=0x24b4279f0670aa3a -- an exact match to this document's own
previously-recorded baseline hash.
.claude/CLAUDE.md corrected to describe the real -Wno-error= exemption
list instead of the "-Wall -Werror" oversimplification. FABRIC-2.md
Section J records the full sweep, including doc-tree staleness findings
flagged but not fixed this pass (docs/lithosananke/ROADMAP.md branch
topology, docs/03-architecture/word-acl/DESIGN.md's Phase 7 claim
contradicting CLAUDE.md, top-level ROADMAP.md's stale StarForth-era
status, the Isabelle pipeline-metrics model mismatch).
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
