[pitboss] phase 08: Track C.4 + C.5 — SinkCrash oracle + per-probe witness capture

src/dynamic/lang/python.rs

@@ -51,12 +51,66 @@ impl LangEmitter for PythonEmitter {
 /// configured a probe channel.
 pub fn probe_shim() -> &'static str {
     r#"
-# ── __nyx_probe shim (Phase 06 — Track C.1) ──────────────────────────────────
-def __nyx_probe(sink_callee, *args):
-    import os, time, json
+# ── __nyx_probe shim (Phase 06 — Track C.1, Phase 08 — Track C.4 + C.5) ──────
+# Deny-substring list mirrors crate::dynamic::policy::DENY_KEY_SUBSTRINGS; keep
+# in sync when the host-side policy gains new entries.
+_NYX_DENY_SUBSTRINGS = (
+    "TOKEN", "SECRET", "PASSWORD", "PASSWD", "API_KEY", "APIKEY",
+    "PRIVATE_KEY", "CREDENTIAL", "SESSION", "COOKIE", "AUTH", "BEARER",
+    "AWS_ACCESS", "AWS_SESSION", "GH_TOKEN", "GITHUB_TOKEN", "NPM_TOKEN",
+    "PYPI_TOKEN", "DOCKER_PASS",
+)
+_NYX_PAYLOAD_LIMIT = 16 * 1024
+_NYX_REDACTED = "<redacted-by-nyx-policy>"
+
+def __nyx_scrub_env():
+    import os
+    out = {}
+    for k, v in os.environ.items():
+        ku = str(k).upper()
+        if any(n in ku for n in _NYX_DENY_SUBSTRINGS):
+            out[k] = _NYX_REDACTED
+        else:
+            out[k] = v
+    return out
+
+def __nyx_witness(sink_callee, args):
+    import os
+    payload = os.environ.get("NYX_PAYLOAD", "")
+    payload_bytes = payload.encode("utf-8", "replace") if isinstance(payload, str) else bytes(payload)
+    if len(payload_bytes) > _NYX_PAYLOAD_LIMIT:
+        payload_bytes = payload_bytes[:_NYX_PAYLOAD_LIMIT]
+    args_repr = []
+    for a in args:
+        if isinstance(a, (bytes, bytearray)):
+            args_repr.append("<bytes:%d>" % len(a))
+        else:
+            args_repr.append(str(a))
+    try:
+        cwd = os.getcwd()
+    except OSError:
+        cwd = ""
+    return {
+        "env_snapshot": __nyx_scrub_env(),
+        "cwd": cwd,
+        "payload_bytes": list(payload_bytes),
+        "callee": str(sink_callee),
+        "args_repr": args_repr,
+    }
+
+def __nyx_emit(rec):
+    import os, json
     p = os.environ.get("NYX_PROBE_PATH")
     if not p:
         return
+    try:
+        with open(p, "a") as _f:
+            _f.write(json.dumps(rec) + "\n")
+    except OSError:
+        pass
+
+def __nyx_probe(sink_callee, *args):
+    import os, time
     serialised = []
     for a in args:
         if isinstance(a, (bytes, bytearray)):
@@ -72,12 +126,45 @@ def __nyx_probe(sink_callee, *args):
         "args": serialised,
         "captured_at_ns": time.time_ns(),
         "payload_id": os.environ.get("NYX_PAYLOAD_ID", ""),
+        "kind": {"kind": "Normal"},
+        "witness": __nyx_witness(sink_callee, args),
     }
-    try:
-        with open(p, "a") as _f:
-            _f.write(json.dumps(rec) + "\n")
-    except OSError:
-        pass
+    __nyx_emit(rec)
+
+# Phase 08: sink-site signal handler.  Call __nyx_install_crash_guard before
+# invoking the instrumented sink so a SIGSEGV / SIGABRT / etc. is captured as
+# a Crash probe (with witness) before the process aborts.  The shim re-raises
+# the signal on the default handler after writing so process-level outcome
+# observers (exit_code) still see the death.
+_NYX_SIGNAL_NAMES = {}
+
+def __nyx_install_crash_guard(sink_callee):
+    import signal, os, time
+    catchable = []
+    for nm in ("SIGSEGV", "SIGABRT", "SIGBUS", "SIGFPE", "SIGILL"):
+        s = getattr(signal, nm, None)
+        if s is not None:
+            catchable.append((nm, s))
+            _NYX_SIGNAL_NAMES[s] = nm
+    def _handler(signum, frame):
+        nm = _NYX_SIGNAL_NAMES.get(signum, "SIG?")
+        rec = {
+            "sink_callee": str(sink_callee),
+            "args": [],
+            "captured_at_ns": time.time_ns(),
+            "payload_id": os.environ.get("NYX_PAYLOAD_ID", ""),
+            "kind": {"kind": "Crash", "signal": nm},
+            "witness": __nyx_witness(sink_callee, []),
+        }
+        __nyx_emit(rec)
+        # Reset to default and re-raise so the process actually dies.
+        signal.signal(signum, signal.SIG_DFL)
+        os.kill(os.getpid(), signum)
+    for _nm, s in catchable:
+        try:
+            signal.signal(s, _handler)
+        except (OSError, ValueError):
+            pass
 "#
 }