Add: Allow parsing CPEs with parts containing a colon

In the real world CPEs contain escaped colons in the vendor or product
parts exist. Therefore allow to parse these CPE strings. Currently
parsing a CPE string like `cpe:2.3:a:foo\\:bar:...` wouldn't work. But
as far as I can see this is neither a valid CPE nor a real world
scenario.

pontos/cpe/_cpe.py

@@ -392,7 +392,24 @@ def from_string(cpe: str) -> "CPE":
         Create a new CPE from a string
         """
         cleaned_cpe = cpe.strip().lower()
-        parts = cpe.split(":")
+        if "\\:" in cleaned_cpe:
+            # houston we have a problem
+            # the cpe string contains an escaped colon (:)
+            parts = []
+            index = 0
+            start_index = 0
+            while index < len(cleaned_cpe):
+                if (
+                    index > 0
+                    and cleaned_cpe[index] == ":"
+                    and cleaned_cpe[index - 1] != "\\"
+                ):
+                    part = cleaned_cpe[start_index:index]
+                    parts.append(part)
+                    start_index = index + 1
+                index += 1
+        else:
+            parts = cpe.split(":")
 
         if is_uri_binding(cleaned_cpe):
             values: dict[str, Optional[str]] = dict(

tests/cpe/test_cpe.py

@@ -463,14 +463,34 @@ def test_formatted_unbind_examples(self):
         self.assertEqual(cpe.target_hw, "80gb")
         self.assertEqual(cpe.other, ANY)
 
+        cpe = CPE.from_string("cpe:2.3:a:foo:bar\:mumble:1.0:*:*:*:*:*:*:*")
+        self.assertFalse(cpe.is_uri_binding())
+        self.assertTrue(cpe.is_formatted_string_binding())
+        self.assertEqual(cpe.part, Part.APPLICATION)
+        self.assertEqual(cpe.vendor, "foo")
+        self.assertEqual(cpe.product, "bar\:mumble")
+        self.assertEqual(cpe.version, "1\.0")
+        self.assertEqual(cpe.update, ANY)
+        self.assertEqual(cpe.edition, ANY)
+        self.assertEqual(cpe.language, ANY)
+        self.assertEqual(cpe.sw_edition, ANY)
+        self.assertEqual(cpe.target_sw, ANY)
+        self.assertEqual(cpe.target_hw, ANY)
+        self.assertEqual(cpe.other, ANY)
+
     def test_as_uri_binding(self):
-        cpe_string = "cpe:2.3:a:microsoft:internet_explorer:8\\.*:sp?"
-        cpe = CPE.from_string(cpe_string)
+        cpe = CPE.from_string("cpe:2.3:a:microsoft:internet_explorer:8\\.*:sp?")
         self.assertEqual(
             cpe.as_uri_binding(),
             "cpe:/a:microsoft:internet_explorer:8.%02:sp%01",
         )
 
+        cpe = CPE.from_string("cpe:2.3:a:cgiirc:cgi\:irc:0.5.7:*:*:*:*:*:*:*")
+        self.assertEqual(
+            cpe.as_uri_binding(),
+            "cpe:/a:cgiirc:cgi%3airc:0.5.7",
+        )
+
     def test_as_uri_binding_with_edition(self):
         cpe_string = "cpe:2.3:a:hp:insight_diagnostics:7.4.0.1570:-:*:*:online:win2003:x64"
         cpe = CPE.from_string(cpe_string)