Re: Re: Re^2: use Safe ; Any Thwarted Attacks?

[scrottie]

BEGIN and use are each run immediately upon sight. Looking at the TinyWiki code I linked from my initial reply, you'll see the "use ops" strategically located - before it are subs defined that I want to provide priviledged fascilities and have input validation built in. Beyond it is code that doesn't require priviledge and things that result in evals, including evals of code in pages. To generalize, put the use ops line before unsane things. If someone can insert a BEGIN block with arbitrary contents into the code, then they could just delete the use ops line, too, couldn't they? Doing use ops then requiring another file, or using another file on a subsequent line is safe. Of course the main code would be seperate from sandboxed code. The priviledged conde contains the sandboxed code - not vice versa. Look no further than the Safe manual page for examples.

But this is far afield - the original question was whether or not Safe "thwarts" attacks. I'm not even talking about Safe.pm here. I only mentioned ops.pm because my experience is with it and I had a few footnotes to offer on it, but even with the additional safety afforded, I wanted to point out to the original author that it wasn't the correct idiom. The additional safety was too complex to implement, not completely trust-worthy, and there are better ways to do what he wants to do.

-scott