On Fri, 09 Jan 2009 00:46:27 -0800, Carl Banks wrote: > On Jan 9, 2:16 am, Steven D'Aprano <st...@remove-this- > cybersource.com.au> wrote: >> On Thu, 08 Jan 2009 16:47:39 -0800, webcomm wrote: >> > The error... >> ... >> > BadZipfile: File is not a zip file >> >> > When I look at data.zip in Windows, it appears to be a valid zip >> > file. I am able to uncompress it in Windows XP, and can also >> > uncompress it with 7-Zip. It looks like zipfile is not able to read >> > a "table of contents" in the zip file. That's not a concept I'm >> > familiar with. >> >> No, ZipFile can read table of contents: >> >> Help on method printdir in module zipfile: >> >> printdir(self) unbound zipfile.ZipFile method >> Print a table of contents for the zip file. >> >> In my experience, zip files originating from Windows sometimes have >> garbage at the end of the file. WinZip just ignores the garbage, but >> other tools sometimes don't -- if I recall correctly, Linux unzip >> successfully unzips the file but then complains that the file was >> corrupt. It's possible that you're running into a similar problem. > > > The zipfile format is kind of brain dead, you can't tell where the end > of the file is supposed to be by looking at the header. If the end of > file hasn't yet been reached there could be more data. To make matters > worse, somehow zip files came to have text comments simply appended to > the end of them. (Probably this was for the benefit of people who would > cat them to the terminal.) > > Anyway, if you see something that doesn't adhere to the zipfile format, > you don't have any foolproof way to know if it's because the file is > corrupted or if it's just an appended comment.
Yes, this has lead to a nice little attack vector, using hostile Java classes inside JAR files (a variant of ZIP). http://www.infoworld.com/article/08/08/01/ A_photo_that_can_steal_your_online_credentials_1.html or http://snipurl.com/9oh0e -- Steven -- http://mail.python.org/mailman/listinfo/python-list
