Re: Flaws in recent Linux kernels

[Mariusz Woloszyn <emsi () ipartners pl>]

On Fri, 19 Oct 2001, Martin Kacer wrote:

>    PS: What about executing suid binary while some other process has our
> /proc/$$/mem opened for writing? Isn't there the same problem too?
> Unfortunately, I do not have enough time to investigate that.
VERY quick test: opening mem WRONLY returns EINVAL while write().

But opening /proc/%i/exe of a process that executes suid binary works
well. After exec() another process is able to read suid binary.
[Isn't it known behavior???]

Opening mem RDONLY works, but after exec() of setuid binary read() returns
"no such process".

Thinking 'bout mmaping and other tricks...

Tested on 2.2.19.

--
Mariusz Wołoszyn
Internet Security Specialist, Internet Partners