From: ts <decoux@...>
Date: 2003-02-14T03:01:34+09:00
Subject: Re: mod_ruby insecury op

>>>>> "D" == Daniel Carrera <dcarrera@math.umd.edu> writes:

D> Do something like:
>> 
>> Probably you make confusion with another language

D> Actually no, I'm not.

 From your previous message

D> To untaint data you use regular expressions.  In this case a directory 
D> name should only be composed of "word" charcaters and the character "/".

D> Do something like:

D> # dir tainted.
D> if dir =~ /^([\w\/]+)$/
D>     dir = $1  # Untainted.
D> else
D>     # Error...
D> end

 Now see the result

D> # external data   
D> # =============   
D> y1 = ENV["HOME"]    
D> y1.tainted?     # ->  true     
D> y2 = y1[2, 4] 
D> y2.tainted?     # ->  true      
D> y1 =~ /([a-z])/ 
D> $1.tainted?     # ->  true
   ^^^^^^^^^^^^^^^^^^^^^^^^^^

  $1 is tainted



Guy Decoux