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Garry TanandClaude Fable 5
455c805125
Freeze boundary hook had four verified bugs: the grep-first JSON extractor truncated at escaped quotes and failed OPEN on unparseable payloads; the deny JSON was printf-interpolated so a quote- or newline-bearing path silently no-oped the block; the freeze path read stripped INTERNAL spaces (a boundary like ~/My Project could never match); and the path resolver skipped the final component, letting an in-boundary symlink write through to an out-of-boundary target. Fixes, structurally: one shared sourced helper (careful/bin/hook-extract.sh) now owns JSON extraction and JSON-encoded decision envelopes for BOTH hooks -- the two-copy drift is how freeze kept a broken extractor after careful's was fixed. Freeze is now deny-tier fail-closed (unparseable payload denies, parsed-but-no-file_path still allows), trims only leading/trailing whitespace, and resolves symlinks through the final path component. Careful gains a HIGH tier (hard deny, simple commands only): recursive delete of /, ~, or $HOME, and force-push to the repo's default branch. Compound commands always fall through to the MEDIUM ask; --force-with-lease is never HIGH. Documented as a best-effort advisory hard-stop, not a policy boundary. Plus additive-only project patterns (~/.gstack/careful-patterns.txt + per-project file): config can only ADD warn rules, never suppress a baseline family. test/hook-scripts.test.ts: 89 tests incl. malformed-payload deny, parseable deny JSON for hostile paths, space-bearing boundaries, symlink escape, HIGH tier splits, additive invariant, invalid-regex resilience. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
65 lines
3.3 KiB
Bash
65 lines
3.3 KiB
Bash
#!/usr/bin/env bash
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# hook-extract.sh — SHARED JSON helpers for gstack PreToolUse hooks.
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# Sourced (never executed) by careful/bin/check-careful.sh and
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# freeze/bin/check-freeze.sh via a path relative to each hook script.
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#
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# ONE copy on purpose. These two hooks previously carried separate extractor
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# copies; the escaped-quote truncation bug got fixed in careful's copy while
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# freeze silently kept the broken one. Any future parsing fix lands here and
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# reaches both hooks by construction.
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# gstack_hook_extract_field PAYLOAD FIELD
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# Prints tool_input.FIELD when PAYLOAD is valid JSON and the field is a
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# string ("" when absent or non-string). Returns 1 when no parser is
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# available or the payload is not parseable JSON — the CALLER decides the
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# polarity for that case (careful asks, freeze denies).
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#
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# python3 is tried first because it ships with macOS and most Linux distros
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# and is reliably on PATH in a hook environment; node is the fallback.
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gstack_hook_extract_field() {
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_ghef_payload="$1"
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_ghef_field="$2"
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if command -v python3 >/dev/null 2>&1; then
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printf '%s' "$_ghef_payload" | python3 -c 'import sys,json
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field = sys.argv[1]
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d = json.loads(sys.stdin.read())
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c = d.get("tool_input", {}).get(field, "")
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sys.stdout.write(c if isinstance(c, str) else "")' "$_ghef_field" 2>/dev/null && return 0
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fi
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if command -v node >/dev/null 2>&1; then
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printf '%s' "$_ghef_payload" | node -e 'let s="";process.stdin.on("data",d=>s+=d).on("end",()=>{try{const j=JSON.parse(s);const c=(j&&j.tool_input&&j.tool_input[process.argv[1]])||"";process.stdout.write(typeof c==="string"?c:"")}catch(e){process.exit(3)}})' "$_ghef_field" 2>/dev/null && return 0
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fi
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return 1
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}
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# gstack_hook_json_string TEXT
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# Prints TEXT as a JSON string literal (surrounding quotes included),
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# encoding quotes, backslashes, control characters and newlines. Never build
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# hook JSON with printf/sed interpolation: a path containing a quote or a
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# newline produces malformed JSON, and Claude Code silently ignores the
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# whole decision — a deny that no-ops exactly when it matters.
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gstack_hook_json_string() {
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_ghjs_text="$1"
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if command -v python3 >/dev/null 2>&1; then
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printf '%s' "$_ghjs_text" | python3 -c 'import sys,json; sys.stdout.write(json.dumps(sys.stdin.read()))' 2>/dev/null && return 0
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fi
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if command -v node >/dev/null 2>&1; then
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printf '%s' "$_ghjs_text" | node -e 'let s="";process.stdin.on("data",d=>s+=d).on("end",()=>process.stdout.write(JSON.stringify(s)))' 2>/dev/null && return 0
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fi
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# Last-resort fallback (no parser on PATH): strip to a safe charset so the
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# envelope stays valid JSON even if the message loses characters.
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printf '"%s"' "$(printf '%s' "$_ghjs_text" | tr -cd 'a-zA-Z0-9 ._/:@=+-' )"
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}
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# gstack_hook_decision DECISION REASON
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# Emits the full PreToolUse hookSpecificOutput envelope with REASON safely
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# JSON-encoded. DECISION is "ask" or "deny". The decision MUST be nested
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# under hookSpecificOutput — Claude Code ignores a top-level
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# permissionDecision, which silently no-ops the block.
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gstack_hook_decision() {
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_ghd_decision="$1"
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_ghd_reason="$2"
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_ghd_encoded=$(gstack_hook_json_string "$_ghd_reason")
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printf '{"hookSpecificOutput":{"hookEventName":"PreToolUse","permissionDecision":"%s","permissionDecisionReason":%s}}\n' "$_ghd_decision" "$_ghd_encoded"
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}
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