Re: trusting user-supplied data (was Re: FreeBSD Security Advisory FreeBSD-SA-02:23.stdio)

2002-04-24 Thread Steven M. Bellovin
In message <[EMAIL PROTECTED]>, Wietse Venema write s: >It is interesting to see that old problems with set-uid commands >keep coming back. Allow me to speed up the discussion a bit by >enumerating a few other channels for attack on set-uid commands. > >A quick perusal of /usr/include/sys/proc.h r

Re: trusting user-supplied data (was Re: FreeBSD Security Advisory FreeBSD-SA-02:23.stdio)

2002-04-24 Thread Wietse Venema
It is interesting to see that old problems with set-uid commands keep coming back. Allow me to speed up the discussion a bit by enumerating a few other channels for attack on set-uid commands. A quick perusal of /usr/include/sys/proc.h reveals a large number of "inputs" that a child process may i

Re: FreeBSD Security Advisory FreeBSD-SA-02:23.stdio

2002-04-23 Thread Steven M. Bellovin
It's amazing that this has taken so long to resurface. This is an ancient bug -- see, for example, Henry Spencer's suid man page from 1987 (http://groups.google.com/groups?q=checklist+security+setuid+-linux+group:alt.security&hl=en&scoring=r&selm=1991May14.101450.830%40convex.com&rnum=1 quotes

Re: FreeBSD Security Advisory FreeBSD-SA-02:23.stdio

2002-04-22 Thread bert hubert
> Credits:Joost Pol <[EMAIL PROTECTED]> Joost rules. And my apologies to Pine for always being late paying my bills. Sorry :-) This is a simple test, executing a setuid process with filedescriptor 2 closed, and then opening a file and seeing what fd it gets. Linux 2.2.16RedHat AXP

Re: FreeBSD Security Advisory FreeBSD-SA-02:23.stdio

2002-04-22 Thread Theo de Raadt
> Topic: insecure handling of stdio file descriptors They didn't say so, but this work was obviously based on: RCS file: /cvs/src/sys/kern/kern_exec.c,v ... revision 1.20 date: 1998/07/02 08:53:04; author: deraadt; state: Exp; lines: +38 -1 for sugid procs ensure that fd 0-2 are allo