1 files changed, 67 insertions, 0 deletions
diff --git a/tools/lint/trojan-source/__init__.py b/tools/lint/trojan-source/__init__.py
new file mode 100644
index 0000000000..a20c10203d
--- /dev/null
+++ b/tools/lint/trojan-source/__init__.py
@@ -0,0 +1,67 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+import sys
+import unicodedata
+
+from mozlint import result
+from mozlint.pathutils import expand_exclusions
+
+# Code inspired by Red Hat
+# https://github.com/siddhesh/find-unicode-control/
+# published under the 'BSD 3-Clause' license
+# https://access.redhat.com/security/vulnerabilities/RHSB-2021-007
+
+results = []
+
+disallowed = set(
+    chr(c) for c in range(sys.maxunicode) if unicodedata.category(chr(c)) == "Cf"
+)
+
+
+def getfiletext(config, filename):
+    # Make a text string from a file, attempting to decode from latin1 if necessary.
+    # Other non-utf-8 locales are not supported at the moment.
+    with open(filename, "rb") as infile:
+        try:
+            return infile.read().decode("utf-8")
+        except Exception as e:
+            res = {
+                "path": filename,
+                "message": "Could not open file as utf-8 - maybe an encoding error: %s"
+                % e,
+                "level": "error",
+            }
+            results.append(result.from_config(config, **res))
+            return None
+
+    return None
+
+
+def analyze_text(filename, text, disallowed):
+    line = 0
+    for t in text.splitlines():
+        line = line + 1
+        subset = [c for c in t if chr(ord(c)) in disallowed]
+        if subset:
+            return (subset, line)
+
+    return ("", 0)
+
+
+def lint(paths, config, **lintargs):
+    files = list(expand_exclusions(paths, config, lintargs["root"]))
+    for f in files:
+        text = getfiletext(config, f)
+        if text:
+            (subset, line) = analyze_text(f, text, disallowed)
+            if subset:
+                res = {
+                    "path": f,
+                    "lineno": line,
+                    "message": "disallowed characters: %s" % subset,
+                    "level": "error",
+                }
+                results.append(result.from_config(config, **res))
+
+    return {"results": results, "fixed": 0}