Handle corrupt and empty ZIP files.

mime.py

@@ -1,4 +1,7 @@
 # $Log$
+# Revision 1.4  2005/06/17 01:49:39  customdesigned
+# Handle zip within zip.
+#
 # Revision 1.3  2005/06/02 15:00:17  customdesigned
 # Configure banned extensions.  Scan zipfile option with test case.
 #
@@ -193,7 +196,8 @@ class MimeMessage(Message):
       for key,name in tuple(names):	# copy by converting to tuple
 	if name and name.lower().endswith('.zip'):
 	  txt = self.get_payload(decode=True)
-	  names += zipnames(txt)
+	  if txt.strip():
+	    names += zipnames(txt)
     return names
 
   def ismodified(self):
@@ -304,19 +308,25 @@ See your administrator.
 
 def check_name(msg,savname=None,ckname=check_ext,scan_zip=False):
   "Replace attachment with a warning if its name is suspicious."
-  for key,name in msg.getnames(scan_zip):
+  try:
-    badname = ckname(name)
+    for key,name in msg.getnames(scan_zip):
-    if badname:
+      badname = ckname(name)
-      hostname = socket.gethostname()
+      if badname:
-      if key == 'zipname':
+        if key == 'zipname':
-        badname = msg.get_filename()
+          badname = msg.get_filename()
-      msg.set_payload(virus_msg % (badname,hostname,savname))
+	break
-      del msg["content-type"]
+    else:
-      del msg["content-disposition"]
+      return Milter.CONTINUE
-      del msg["content-transfer-encoding"]
+  except zipfile.BadZipfile:
-      name = "WARNING.TXT"
+    # a ZIP that is not a zip is very suspicious
-      msg["Content-Type"] = "text/plain; name="+name
+    badname = msg.get_filename()
-      break
+  hostname = socket.gethostname()
+  msg.set_payload(virus_msg % (badname,hostname,savname))
+  del msg["content-type"]
+  del msg["content-disposition"]
+  del msg["content-transfer-encoding"]
+  name = "WARNING.TXT"
+  msg["Content-Type"] = "text/plain; name="+name
   return Milter.CONTINUE
 
 import email.Iterators

test/zip2

@@ -0,0 +1,49 @@
+From paulp@go2net.com  Wed Jun  1 22:35:12 2005
+Return-Path: <paulp@go2net.com>
+Received: from mail.bmsi.com (spidey.bmsi.com [192.168.9.81])
+	by bmsred.bmsi.com (8.13.1/8.12.10) with ESMTP id j522ZCQg014058
+	for <stuart@bmsred.bmsi.com>; Wed, 1 Jun 2005 22:35:12 -0400
+Received: from 127.0.0.1 ([220.117.92.241])
+	by mail.bmsi.com (8.13.1/8.13.1) with ESMTP id j522Ynjm028604
+	for stuart@bmsi.com; Wed, 1 Jun 2005 22:34:51 -0400
+Message-Id: <200506020234.j522Ynjm028604@mail.bmsi.com>
+SUBJECT: urgent
+FROM: paulp@go2net.com
+TO: stuart@bmsi.com
+DATE: [[ ¸ñ, 02 6 2005 ¿ÀÀü 11:34:47 ]]
+MIME-Version: 1.0
+Content-Type: multipart/mixed; boundary="--------bound--"
+X-DSpam-Score: 0.081200
+Received-SPF: neutral (mail.bmsi.com: guessing: 220.117.92.241 is neither permitted nor denied by domain of go2net.com)
+Status: RO
+X-Status: 
+X-Keywords: NonJunk         
+
+----------bound--
+Content-Type: text/plain; charset=us-ascii
+Content-Transfer-Encoding: 7bit
+
+Hi 
+
+Sorry, I forgot to send an important
+document to you in that last email. I had an important phone call.
+Please checkout attached doc file when you have a moment.
+
+Best Regards
+
+<!DSPAM:1043AE6B6492860536935410>
+
+
+----------bound--
+Content-Type: application/octet-stream;
+	name="Readme.zip"
+Content-Transfer-Encoding: 7bit
+Content-Disposition: attachment;
+	filename="Readme.zip"
+
+
+----------bound--
+
+
+----------bound----
+

test/zip3

@@ -0,0 +1,51 @@
+From paulp@go2net.com  Wed Jun  1 22:35:12 2005
+Return-Path: <paulp@go2net.com>
+Received: from mail.bmsi.com (spidey.bmsi.com [192.168.9.81])
+	by bmsred.bmsi.com (8.13.1/8.12.10) with ESMTP id j522ZCQg014058
+	for <stuart@bmsred.bmsi.com>; Wed, 1 Jun 2005 22:35:12 -0400
+Received: from 127.0.0.1 ([220.117.92.241])
+	by mail.bmsi.com (8.13.1/8.13.1) with ESMTP id j522Ynjm028604
+	for stuart@bmsi.com; Wed, 1 Jun 2005 22:34:51 -0400
+Message-Id: <200506020234.j522Ynjm028604@mail.bmsi.com>
+SUBJECT: urgent
+FROM: paulp@go2net.com
+TO: stuart@bmsi.com
+DATE: [[ ¸ñ, 02 6 2005 ¿ÀÀü 11:34:47 ]]
+MIME-Version: 1.0
+Content-Type: multipart/mixed; boundary="--------bound--"
+X-DSpam-Score: 0.081200
+Received-SPF: neutral (mail.bmsi.com: guessing: 220.117.92.241 is neither permitted nor denied by domain of go2net.com)
+Status: RO
+X-Status: 
+X-Keywords: NonJunk         
+
+----------bound--
+Content-Type: text/plain; charset=us-ascii
+Content-Transfer-Encoding: 7bit
+
+Hi 
+
+Sorry, I forgot to send an important
+document to you in that last email. I had an important phone call.
+Please checkout attached doc file when you have a moment.
+
+Best Regards
+
+<!DSPAM:1043AE6B6492860536935410>
+
+
+----------bound--
+Content-Type: application/x-msdownload; name="zip.zip"
+Content-Transfer-Encoding: base64
+Content-Disposition: attachment; filename="zip.zip"
+
+USsDBAoBAAAAADVVwjLaV2nEGgAAABoAAAAzABUAemlwLmRvYyAgICAgICAgICAgICAgICAg
+ICAgICAgICAgICAgICAgICAgICAgICAuZXhlVVQJAAOmGp9CphqfQlV4BACGA2UAVGhpcyBw
+cm9ncmFtIHdhcyBhIHZpcnVzLgpQSwECFwMKAAAAAAA1VcIy2ldpxBoAAAAaAAAAMwANAAAA
+AAABAAAAtIEAAAAAemlwLmRvYyAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAg
+ICAgICAuZXhlVVQFAAOmGp9CVXgAAFBLBQYAAAAAAQABAG4AAACAAAAAAAA=
+----------bound--
+
+
+----------bound----
+

testmime.py

@@ -1,4 +1,7 @@
 # $Log$
+# Revision 1.3  2005/06/17 01:49:39  customdesigned
+# Handle zip within zip.
+#
 # Revision 1.2  2005/06/02 15:00:17  customdesigned
 # Configure banned extensions.  Scan zipfile option with test case.
 #
@@ -130,9 +133,16 @@ class MimeTestCase(unittest.TestCase):
 
   def testZip(self,vname="zip1",fname='zip.zip'):
     self.testDefang(vname,1,'zip.zip')
+    # test scan_zip flag
     msg = mime.message_from_file(open('test/'+vname,"r"))
     mime.defang(msg,scan_zip=False)
     self.failIf(msg.ismodified())
+    # test ignoring empty zip (often found in DSNs)
+    msg = mime.message_from_file(open('test/zip2','r'))
+    mime.defang(msg,scan_zip=True)
+    self.failIf(msg.ismodified())
+    # test corrupt zip (often an EXE named as a ZIP)
+    self.testDefang('zip3',1,'zip.zip')
     # test zip within zip
     self.testDefang('ziploop',1,'stuart@bmsi.com.zip')