Beefy Boxes and Bandwidth Generously Provided by pair Networks
Problems? Is your data what you think it is?
 
PerlMonks  

comment on

( #3333=superdoc: print w/replies, xml ) Need Help??
Your example code assumes that the entirety of /usr and /bin are inherently safe. I cannot answer for you whether that is true on your webserver (which, IIRC, is a shared hosting server). edit:in light of afoken's additional points, I concur that your snippet was not sufficient./edit

Further, your example code ignores the remainder of the untainting in my example snippet, and shows that you didn't read the whole of perlsec, nor even the few paragraphs in the section called Cleaning Up Your Path. The delete was there for a reason; that reason was explained in the documentation I linked, but can be summed up in the statement that those other environment variables can affect execution similar to PATH. If you do not follow the complete advice, perl will still consider $ENV{PATH} tainted until you take care of those other environment variables as well.

But if you believe the assumptions about those paths is valid, and if you have implemented but not shown the other advice mentioned, then your code seems a reasonable way of making sure that only the "safe" path elements are included. edit:struck out; see afoken's additional points for why your code still isn't a reasonable way to trim the PATH/edit

But, while cleaning up PATH (and the related variables) is advisable from an un-tainting perspective, I think that Corion's advice in Re: Insecure CPAN module in taint mode is still even better: why fork out to an external process unless necessary?

edit:see inline edits/edit


In reply to Re^3: Insecure CPAN module in taint mode by pryrt
in thread Insecure CPAN module in taint mode by Bod

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post; it's "PerlMonks-approved HTML":



  • Are you posting in the right place? Check out Where do I post X? to know for sure.
  • Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:
    <code> <a> <b> <big> <blockquote> <br /> <dd> <dl> <dt> <em> <font> <h1> <h2> <h3> <h4> <h5> <h6> <hr /> <i> <li> <nbsp> <ol> <p> <small> <strike> <strong> <sub> <sup> <table> <td> <th> <tr> <tt> <u> <ul>
  • Snippets of code should be wrapped in <code> tags not <pre> tags. In fact, <pre> tags should generally be avoided. If they must be used, extreme care should be taken to ensure that their contents do not have long lines (<70 chars), in order to prevent horizontal scrolling (and possible janitor intervention).
  • Want more info? How to link or or How to display code and escape characters are good places to start.
Log In?
Username:
Password:

What's my password?
Create A New User
Domain Nodelet?
Chatterbox?
and the web crawler heard nothing...

How do I use this? | Other CB clients
Other Users?
Others chanting in the Monastery: (6)
As of 2022-05-23 11:41 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?
    Do you prefer to work remotely?



    Results (82 votes). Check out past polls.

    Notices?