Add test for usage of FTP_TLS (#1149)

* Performance improvement in blacklist function

The blacklisting function is currently using fnmatch.fnmatch()
to do matching of qualified names of blacklist calls. It seems
it is only used for telnetlib and ftplib where they are setting
the qualified name in a file glob style (telnetlib.*).

This change would slightly break backward compatibility if there
are any third-party plugins that use globbing in the qualified
names for blacklisting. I think the likelyhood is small. I also
think it is better to be more explicit in the qualified name
patterns. In the case of ftplib, FTP is insecure, but FTP_TLS is
not. So this already is resolving one false postive.

The other effect of this change is a slight boost to performance.
When scanning cpython prior to this fix, it would take around 1 min.
After the fix, closer to 50 seconds. So a nice little bump in speed.

Fixes: #438

Signed-off-by: Eric Brown <eric_wade_brown@yahoo.com>

* Add test for usage of FTP_TLS

This change adds an FTP_TLS call to the examples. A high severity
error is no longer reported as a result of the fix in PR #1148
that explicitly now matches blacklist call qualified names rather
than using a file glob.

However, you will notice that there is one more high severity
issue reported in the tests as a result of the import of
ftplib.FTP_TLS because the blacklist import is only checking for
"ftplib".

Fixes: #148

Signed-off-by: Eric Brown <eric_wade_brown@yahoo.com>

---------

Signed-off-by: Eric Brown <eric_wade_brown@yahoo.com>

examples/ftplib.py

@@ -1,9 +1,24 @@
 from ftplib import FTP
+from ftplib import FTP_TLS
 
+
+# bad
 ftp = FTP('ftp.debian.org')
 ftp.login()
 
 ftp.cwd('debian')
 ftp.retrlines('LIST')
 
-ftp.quit()
+ftp.quit()
+
+# okay
+ftp = ftplib.FTP_TLS(
+    "ftp.us.debian.org",
+    context=ssl.create_default_context(),
+)
+ftp.login()
+
+ftp.cwd("debian")
+ftp.retrlines("LIST")
+
+ftp.quit()

tests/functional/test_functional.py

@@ -246,8 +246,8 @@ def test_telnet_usage(self):
     def test_ftp_usage(self):
         """Test for `import ftplib` and FTP.* calls."""
         expect = {
-            "SEVERITY": {"UNDEFINED": 0, "LOW": 0, "MEDIUM": 0, "HIGH": 2},
-            "CONFIDENCE": {"UNDEFINED": 0, "LOW": 0, "MEDIUM": 0, "HIGH": 2},
+            "SEVERITY": {"UNDEFINED": 0, "LOW": 0, "MEDIUM": 0, "HIGH": 3},
+            "CONFIDENCE": {"UNDEFINED": 0, "LOW": 0, "MEDIUM": 0, "HIGH": 3},
         }
         self.check_example("ftplib.py", expect)