Re: executable stacks, a few suggetions

solar@sun1.ideal.ru
Mon, 14 Apr 1997 16:55:12 -0300 (GMT)


Hello!

> plus anyone caring to exploit a setuid root executable buffer overflow
> flaw can send bogus signals to get the protection turned off.

Wrong. Read that message with the 2nd patch once again. :)

> i would suggest to turn executable stack off only for setuid exec()'s

What about daemons? These are even more important, and, as I'm going to
explain when posting the final patch, removed stack execution permission
is possible to bypass in less cases when exploiting remotely than locally.

So, if such an enable/disable bit is implemented (currently there're only
lines that you could put in a program's source code for that purpose), it
seems to be more reasonable to put it into the POSIX.6 privilege bitmask
(BTW, is anyone still working on that stuff?), or something like that,
instead of just using suid bit.

However, I don't think this is really required, since with the GPF handler
everything seems to run just fine, and the stack is non-executable where
possible.

Signed,
Solar Designer