[ruby-core:43187] [ruby-trunk - Bug #5374] Weird SecurityError with ruby1.9, File.stat/Dir.glob and $SAFE=1

Issue #5374 has been updated by Koichi Sasada.

Assignee set to Yusuke Endoh


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Bug #5374: Weird SecurityError with ruby1.9, File.stat/Dir.glob and $SAFE=1
https://bugs.ruby-lang.org/issues/5374

Author: Hleb  Valoshka
Status: Open
Priority: Normal
Assignee: Yusuke Endoh
Category: core
Target version: 2.0.0
ruby -v: ruby 1.9.2p180 (2011-02-18) [i386-mingw32]


Preface.

I've tried to find workaroud for one GetText-Ruby bug with untainted data from Dir.glob (http://rubyforge.org//tracker/?func=detail&atid=3377&aid=28336&group_id=855). 

Here it is (full text is in gettext-test.rb):

module GetText
  class MOFile
  alias :oldload :load
    def load(arg)
      arg = arg.dup.untaint if arg.kind_of? String
      oldload(arg)
    end
  end
end

It works fine with ruby 1.8, but with 1.9 with debug enabled there is a
message about exception SecurityError:

Exception `SecurityError' at /usr/lib/ruby/1.9.1/gettext/runtime/mofile.rb:75 - Insecure operation - stat

The corresponding code is
74  begin
75    st = File.stat(arg)
76    @last_modified = [st.ctime, st.mtime]
77  rescue Exception
78  end

I've put line 
warn "$SAFE == #{$SAFE}; arg.tainted? == #{arg.tainted?}"
before it, and it says:

$SAFE == 1; arg.tainted? == false

So why the exception is if arg is NOT tainted? Note: it was discovered on Debian
GNU/Linux box with 1.9.3preview1. Full log is in gettext-debian.log

Going further.

I've made very simple test program which mimics GetTExt-Ruby and workaround for
it, see test.rb in attachment.

This program was tested on Win32 box with 1.9.2-p180 and -p290.

Been run as "ruby -T1 test.rb u" output was clean. But been run as "ruby -T1
test.rb t" or "ruby -T1 test.rb t" is had an exception on files test1234.txt
and test12345.txt (see full test.log in attachment). 't' means "send tainted
object to function", 'u' means "send untainted", 'b' means "send tainted, then
untainted". But on Debian box it outputs NO error.

At last, I have run test for GetText on win box, and it failed with exception 

Exception `SecurityError' at C:/fsc.tmp/gettext/runtime/locale_path.rb:90 - Insecure operation - glob

Log is in gettext-win.log

But whether Dir.glob is insecure with $SAFE==1?




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