🚀 go-pugleaf

jon@vector0.SAC.CA.US  (Dazed N. Confused) writes:

>      Is there a BBS-safe version of uudecode?  Do Unix uudecodes
> do this?

Unix iteself checks for file permissions... but under Unix, doesn't
everything under waffle run under the same userid?

it'd be easy enough to write a sed script that would strip any of
/\: from a filename and add /user/%A/ onto the front of it, but
even then you'd have to be careful they didn't write to clock$, say,
and crash your system.

I posted code (in pascal) in alt.sources a few weeks ago to check
for device names (con, lpt1.os2, emm$whatever - whatever you've got installed)
by going through the device chain - that way, you can do the check without
even opening the filename.  so, you could do this:

uuscheck filename
if errorlevel 1 goto illegal
uudecode ...
goto done
:illegal
echo ...
:done

where uuscheck would do the `security' check of the file - if it was
pointing to a device driver, it'd return with errorlevel 1, otherwise
it'd fix up the filename on the `begin ' line to be in the user's home
directory.

> --Jon (thanks to Russ Schulz for pointing this hole out)

who just realized last night a security hole in rusnews - where it reads
in the `forward' file from the user/foo directory, if you send mail to
something like `../../waffle/system' and you had a waffle/system file,
it'd read in the first line - not a _big_ security hole, (nothing like
the one in v0.9 fixed long, long ago) but one nonetheless.
-- 
Russell Schulz  russell@alpha3.ersys.edmonton.ab.ca  ersys!rschulz  Shad 86c