Re: How to avoid tempfile generation for uploaded file ?

[Matt Jones]

On Wednesday, 26 September 2012 03:43:15 UTC-4, Soundarapandian Rathinasamy wrote:

Hi folks,
  I am building secure web application using Ruby on Rails which scans virus in uploaded file.
Now Currently I can access the tempfile from the ActionDispatch::Http::UploadedFile instance which Rails creates for uploaded file and complete scan successfully.
But I want to avoid Rails creating the tempfile as I fear once the virus affected file stored in tempfile this may infect the system.

What my question is:

  Is there any way to tell Rails that 'Generate the IO stream instance(string) instead of Tempfile' ?

If Rails gives file as IO stream I can use this stream to scan for Virus.

I don't think this is a sensible tradeoff - there are plenty of better ways to make sure that temporary files aren't executable. For instance, putting the directory on they're in on a partition mounted with noexec (or just NOT EXECUTING them). 

On the other hand, streaming them into memory makes it trivial to completely DDOS your server, by simply sending a file larger than the available RAM.

--Matt Jones