Validate stdout paths

This should prevent breaking out of the search to grep /etc/shadow or similar shenanigans.

irclog.py

@@ -877,12 +877,14 @@ class WebServer:
 				yield (path, line)
 
 	def _stdout_with_path(self, stdout):
-		# Process grep output with --with-filenames, --null, and --line-number into (path, line) tuples; this blindly assumes the expected directory structure of '.../path/YYYY-MM.log'.
+		# Process grep output with --with-filenames, --null, and --line-number into (path, line) tuples.
 		# Lines are sorted by timestamp, filename, and line number to ensure a consistent and chronological order.
 		out = []
 		for line in stdout.decode('utf-8').splitlines():
 			fn, line = line.split('\0', 1)
+			assert fn.startswith(self.config['storage']['path'] + '/') and fn.count('/', len(self.config['storage']['path']) + 1) == 1
 			_, path, _ = fn.rsplit('/', 2)
+			assert path in self._paths
 			ln, line = line.split(':', 1)
 			ln = int(ln)
 			ts = float(line.split(' ', 1)[0])