Report error is post table version 2.0 is too small

Lib/fontTools/ttLib/tables/_p_o_s_t.py

@@ -87,11 +87,7 @@ class table__p_o_s_t(DefaultTable.DefaultTable):
 		indices.frombytes(data[:2*numGlyphs])
 		if sys.byteorder != "big": indices.byteswap()
 		data = data[2*numGlyphs:]
-
+		maxIndex = max(indices[:numGlyphs])
-		maxIndex = 0
-		for i in range(numGlyphs):
-			if indices[i] > maxIndex: maxIndex = indices [i]
-
 		self.extraNames = extraNames = unpackPStrings(data, maxIndex-257)
 		self.glyphOrder = glyphOrder = [""] * int(ttFont['maxp'].numGlyphs)
 		for glyphID in range(numGlyphs):
@@ -259,17 +255,34 @@ class table__p_o_s_t(DefaultTable.DefaultTable):
 			self.data = readHex(content)
 
 
-def unpackPStrings(data, nbStrings):
+def unpackPStrings(data, n):
+        # extract n Pascal strings from data.
+        # if there is not enough data, use ""
+
 	strings = []
 	index = 0
-	while nbStrings > 0:
-		length = byteord(data[index])
-		strings.append(tostr(data[index+1:index+1+length], encoding="latin1"))
-		index = index + 1 + length
-		nbStrings = nbStrings - 1
 	dataLen = len(data)
+
+	for _ in range(n):
+		if (dataLen <= index):
+			length = 0
+		else:
+			length = byteord(data[index])
+		index += 1
+
+		if (dataLen <= index + length - 1):
+			name = ""
+		else:
+			name = tostr(data[index:index+length], encoding="latin1")
+		strings.append (name)
+		index += length
+
 	if (index < dataLen):
 		log.warning("%d extra bytes in post.stringData array", dataLen - index)
+
+	elif (dataLen < index):
+		log.warning("not enough data in post.stringData array")
+
 	return strings