1 files changed, 39 insertions, 0 deletions
diff --git a/mitmproxy/libmproxy/contrib/jsbeautifier/unpackers/evalbased.py b/mitmproxy/libmproxy/contrib/jsbeautifier/unpackers/evalbased.py
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index 00000000..b17d926e
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+++ b/mitmproxy/libmproxy/contrib/jsbeautifier/unpackers/evalbased.py
@@ -0,0 +1,39 @@
+#
+# Unpacker for eval() based packers, a part of javascript beautifier
+# by Einar Lielmanis <einar@jsbeautifier.org>
+#
+#     written by Stefano Sanfilippo <a.little.coder@gmail.com>
+#
+# usage:
+#
+# if detect(some_string):
+#     unpacked = unpack(some_string)
+#
+
+"""Unpacker for eval() based packers: runs JS code and returns result.
+Works only if a JS interpreter (e.g. Mozilla's Rhino) is installed and
+properly set up on host."""
+
+from subprocess import PIPE, Popen
+
+PRIORITY = 3
+
+def detect(source):
+    """Detects if source is likely to be eval() packed."""
+    return source.strip().lower().startswith('eval(function(')
+
+def unpack(source):
+    """Runs source and return resulting code."""
+    return jseval('print %s;' % source[4:]) if detect(source) else source
+
+# In case of failure, we'll just return the original, without crashing on user.
+def jseval(script):
+    """Run code in the JS interpreter and return output."""
+    try:
+        interpreter = Popen(['js'], stdin=PIPE, stdout=PIPE)
+    except OSError:
+        return script
+    result, errors = interpreter.communicate(script)
+    if interpreter.poll() or errors:
+        return script
+    return result