Audit remediation: codec subprocess timeout + LICENSE

LICENSE

@@ -0,0 +1,3 @@
+NDI-compress-python is licensed under [CC BY-NC-SA 4.0](http://creativecommons.org/licenses/by-nc-sa/4.0/?ref=chooser-v1).
+
+Contact info@walthamdatascience.com for commercial licensing.

README.md

@@ -21,6 +21,11 @@ This package requires the NDI compression C executables to be present.
 By default, it looks for them in `../../C/bin` relative to the `ndi_compress` package file.
 You can override this by setting the `NDI_BIN_PATH` environment variable.
 
+Each codec executable runs in a subprocess with a timeout (default 300 seconds)
+so a hung or looping codec process cannot block indefinitely. Override it with
+the `NDI_COMPRESS_TIMEOUT` environment variable (in seconds); an invalid value
+falls back to the default with a warning.
+
 ```python
 import ndi_compress
 import numpy as np

docs/Audit_Remediation_Results_2026-06-12.md

@@ -0,0 +1,29 @@
+# NDI-compress-python Audit Remediation — Results (2026-06-12)
+
+> **Context for a reviewer / next agent.** One of **9 coordinated PRs** in the 2026-06 NDI
+> ecosystem audit; **none are merged.** This repo's PR: **Waltham-Data-Science/NDI-compress-python#2**.
+> Done here: subprocess timeout + LICENSE. **Deferred:** codec provenance/checksums + a
+> cross-language round-trip test (needs the codec source + a paired MATLAB run) — see below.
+
+Branch `audit/ndi-compress-python-2026-06`, off `origin/main`.
+
+## Findings addressed (audit §6.2-7, §6.2-8)
+
+| # | Status | Summary |
+|---|--------|---------|
+| 6.2-7 (subprocess timeout) | **Done** | `_call_c_exec` ran the C codec via `subprocess.run(...)` with no timeout, so a hung/looping codec process would block indefinitely. Added a generous default timeout (`_C_EXEC_TIMEOUT`, 300 s, overridable via the `NDI_COMPRESS_TIMEOUT` env var) and convert `TimeoutExpired` into a clear `RuntimeError`. |
+| 6.2-8 (LICENSE) | **Done** | Added `LICENSE` (CC BY-NC-SA 4.0) matching the NDI-compress-matlabp counterpart. |
+
+## FLAGGED — codec provenance + cross-language round-trip (not done here)
+
+The audit's core §6.2-7 concern is that **NDI-compress is unauditable on both
+sides**: the MATLAB side ships P-code and the Python side ships committed C
+binaries, built at different times, so binary/format drift between the two codecs
+cannot be ruled out. Resolving that requires either (a) vendoring the codec C
+**source** in-repo and building it in CI, or (b) pinning a single versioned codec
+build and committing a checksum manifest of the binaries — plus a cross-language
+round-trip fixture test (compress with one language's codec, decompress with the
+other, assert byte-identity). That work needs the codec build provenance / source
+(not available in this environment) and a paired MATLAB run, so it is flagged for
+a focused follow-up. Only the subprocess-timeout hardening and the LICENSE are
+done here.

src/ndicompress/compress.py

@@ -10,10 +10,39 @@
 
 from .utility import get_executable_path
 
+# Maximum seconds to wait for a codec subprocess before treating it as hung.
+# Compression/decompression of very large arrays can be slow, so this default is
+# generous; override via the NDI_COMPRESS_TIMEOUT environment variable.
+def _read_timeout_env(default=300.0):
+    raw = os.environ.get("NDI_COMPRESS_TIMEOUT")
+    if raw is None or raw == "":
+        return default
+    try:
+        return float(raw)
+    except (TypeError, ValueError):
+        import warnings
+
+        warnings.warn(
+            f"Invalid NDI_COMPRESS_TIMEOUT={raw!r}; using default {default:g}s.",
+            RuntimeWarning,
+        )
+        return default
+
+
+_C_EXEC_TIMEOUT = _read_timeout_env()
+
+
 def _call_c_exec(exec_name, args):
     exec_path = get_executable_path(exec_name)
     cmd = [exec_path] + args
-    result = subprocess.run(cmd, capture_output=True, text=True)
+    try:
+        result = subprocess.run(
+            cmd, capture_output=True, text=True, timeout=_C_EXEC_TIMEOUT
+        )
+    except subprocess.TimeoutExpired as exc:
+        raise RuntimeError(
+            f"C executable {exec_name} timed out after {_C_EXEC_TIMEOUT:g}s"
+        ) from exc
     if result.returncode != 0:
         raise RuntimeError(f"C executable {exec_name} failed: {result.stderr}")
     return result.stdout