Files
stack/packages/mosaic/framework/tools/git/test-wrapper-guard.sh
T
Hermes Agent 8b7ac5b51e
ci/woodpecker/pr/ci Pipeline was canceled
guard: close four fail-open holes found by independent review
An independent reviewer broke all three new controls before they shipped.
Every finding is reproduced as a fixture or a repro, because the class is
recurring rather than incidental: each hole was a case where the answer was
"allow" because something was ABSENT rather than because it was CHECKED.

1. wrapper-guard read only the spellings it knew. `curl -d@body` (no space),
   `--request=POST` (equals form), and a URL path assembled from shell
   variables each carried a real provider write straight through. Write
   detection now covers every body and method form curl accepts, and the
   endpoint match no longer anchors on a literal host path that a variable
   can dissolve.

2. wrapper-guard blocked only when the wrapper FILE existed. A host with a
   broken or partial install therefore permitted exactly the raw writes the
   guard exists to stop. Blocking is now on the endpoint; a missing wrapper
   changes the remedy text, not the verdict — a broken install is not
   permission to bypass gate 7.

3. mosaic-worktree read a worktree's safety from two questions, and a clean,
   fully-pushed tree holding a gitignored `local.secret` answered both with
   zero. `git worktree remove` then deleted the one copy in existence. A file
   is gitignored precisely so nothing else holds it, so ignored-but-not-
   disposable files are now a third evidence question. Build junk
   (node_modules, .venv, dist, caches, *.pyc) stays disposable, so the common
   case still reads SAFE.

4. check-tools-index counted a documented tool as discoverable at mode 0644.
   Every caller tests `[ -x ]`, so a non-executable tool is a missing tool;
   it now fails the gate with its own message.

Local gates green: sanitization, resident budget, test enumeration,
tools-index (4/4 self-test, 100% on the enforced git suite), and
wrapper-guard 20/20.
2026-08-12 17:20:11 -05:00

84 lines
5.1 KiB
Bash
Executable File

#!/usr/bin/env bash
# test-wrapper-guard.sh — hermetic behavioural regression for wrapper-guard.sh.
#
# Resolves no credentials, touches no network, and creates no repository: the
# guard reads a hook payload on stdin and answers with an exit code, so the whole
# contract is testable from fixtures.
#
# The fixtures are written to a temp file rather than passed inline, and this is
# not stylistic. The guard inspects the literal text of the Bash command it is
# handed. A test that embeds `git clone ... $HOME` inside its own command line
# trips the guard on the harness instead of on the fixture — which is exactly
# what happened the first time this was checked by hand. Substring matching over
# whole command text is the guard's deliberate fail-closed posture; a test that
# does not account for it silently measures the wrong thing.
#
# Exit: 0 = every fixture behaved as specified · 1 = at least one did not
set -uo pipefail
HERE="$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd)"
GUARD="${1:-$HERE/wrapper-guard.sh}"
[ -x "$GUARD" ] || { printf 'test-wrapper-guard: not executable: %s\n' "$GUARD" >&2; exit 2; }
TMP="$(mktemp -d)"; trap 'rm -rf "$TMP"' EXIT
FIXTURES="$TMP/fixtures.tsv"
# Each line: <expected-exit> TAB <hook payload> TAB <what it proves>
# 0 = allowed, 2 = blocked.
{
printf '2\t{"tool_input":{"command":"git clone https://example.invalid/x ~/wt"}}\tcheckout into $HOME is refused\n'
printf '2\t{"tool_input":{"command":"git worktree add ~/wt topic"}}\tworktree into $HOME is refused\n'
printf '0\t{"tool_input":{"command":"git clone https://example.invalid/x /src/wt"}}\tcheckout onto a work filesystem is fine\n'
printf '0\t{"tool_input":{"command":"curl -s -X GET https://git.example.invalid/api/v1/repos/a/b/pulls/1"}}\treads are never blocked\n'
printf '2\t{"tool_input":{"command":"curl -X POST -d @b https://git.example.invalid/api/v1/repos/a/b/pulls/1/reviews"}}\treview write has a wrapper\n'
printf '2\t{"tool_input":{"command":"curl -X POST -d @b https://git.example.invalid/api/v1/repos/a/b/pulls/1/merge"}}\tmerge write has a wrapper\n'
printf '2\t{"tool_input":{"command":"curl -X POST -d @b https://api.github.com/repos/a/b/issues"}}\tGitHub host is covered too\n'
printf '0\t{"tool_input":{"command":"curl -X POST -d @b https://git.example.invalid/api/v1/repos/a/b/releases"}}\tan endpoint with no wrapper passes\n'
printf '2\t{"tool_input":{"command":"curl -X POST -d {\\"event\\":\\"APPROVE\\"} https://example.invalid/x"}}\tthe APPROVE token is caught anywhere\n'
printf '0\t{"tool_input":{"command":"ls -la /src"}}\tordinary commands are untouched\n'
printf '0\t{"tool_input":{"command":"MOSAIC_WRAPPER_OVERRIDE=1 curl -X POST -d @b https://git.example.invalid/api/v1/repos/a/b/pulls"}}\tbreak-glass works\n'
printf '0\t{"tool_input":{}}\tan empty payload does not block the session\n'
# --- bypasses an independent reviewer demonstrated against the first version.
# Each of these returned 0 (allowed) and each is a real write. They are pinned
# as fixtures rather than fixed-and-forgotten because the class is recurring:
# the guard reads text, so every spelling it does not know is a hole.
printf '2\t{"tool_input":{"command":"curl -d@b https://git.example.invalid/api/v1/repos/a/b/pulls/1/reviews"}}\t-d@body with no space is still a body\n'
printf '2\t{"tool_input":{"command":"curl --request=POST -d@b https://git.example.invalid/api/v1/repos/a/b/pulls/1/reviews"}}\t--request=POST equals-form is still a method\n'
printf '2\t{"tool_input":{"command":"p=/api/v1/repo; q=s/a/b/pulls/1/reviews; curl -d@b https://git.example.invalid${p}${q}"}}\ta path split across variables is still that path\n'
printf '2\t{"tool_input":{"command":"curl --data-binary @b https://git.example.invalid/api/v1/repos/a/b/issues/1/comments"}}\t--data-binary is a body\n'
printf '2\t{"tool_input":{"command":"curl -F f=@b https://git.example.invalid/api/v1/repos/a/b/issues"}}\t-F multipart is a body\n'
# Reads must survive every one of those broadenings, or the guard gets disabled.
printf '0\t{"tool_input":{"command":"curl -s https://git.example.invalid/api/v1/repos/a/b/pulls/1/reviews"}}\tno body and no verb is a read\n'
printf '0\t{"tool_input":{"command":"grep -rn /pulls/ src/ | head -20"}}\ta path fragment in a grep is not an API call\n'
printf '0\t{"tool_input":{"command":"curl -X POST -d @b https://registry.example.invalid/v2/x/manifests/latest"}}\tan unwrapped API is not this guard'"'"'s business\n'
} > "$FIXTURES"
fail=0 n=0
while IFS=$'\t' read -r want payload why; do
[ -n "${want:-}" ] || continue
n=$((n + 1))
printf '%s' "$payload" | "$GUARD" >/dev/null 2>&1
got=$?
if [ "$got" = "$want" ]; then
printf 'ok %s\n' "$why"
else
printf 'FAIL %s (want exit %s, got %s)\n' "$why" "$want" "$got"
fail=1
fi
done < "$FIXTURES"
printf '\n'
if [ "$fail" -eq 0 ]; then
printf 'wrapper-guard: %d/%d fixtures behaved as specified.\n' "$n" "$n"
else
cat <<'EOF'
wrapper-guard drifted from its contract.
A guard that blocks too much gets routed around, and a guard that blocks too
little is decoration. Both directions are failures here, which is why the
allowed cases are asserted as hard as the blocked ones.
EOF
fi
exit "$fail"