Re: Beware xargs security holes

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5 total messages Started by Robert E. Stampfli Sat, 20 Oct 1990 03:27

#1577

Author: Robert E. Stampfli
Date: Sat, 20 Oct 1990 03:27

9 lines
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> In any case, I've yet to see how "a malicious user [could]
> remove every file on the system."

No user, malicious or not, can remove "every file on the system."
In fact, I contend it is impossible to remove the last instance of
an executable that contains the unlink() system call.
-- 
Rob Stampfli	/ att.com!stampfli (uucp@work) / kd8wk@w8cqk (packet radio)
614-864-9377	/ osu-cis.cis.ohio-state.edu!kd8wk!res (uucp@home)

Re: Beware xargs security holes

#1590

Author: Conor P. Cahill
Date: Tue, 23 Oct 1990 12:50

12 lines
1079 bytes

In article <1990Oct20.032718.1874@cbnews.att.com> res@cbnews.att.com (Robert E. Stampfli) writes:
>No user, malicious or not, can remove "every file on the system."
>In fact, I contend it is impossible to remove the last instance of
>an executable that contains the unlink() system call.

This is only true for system V.  BSD allows you to unlink a running executable.


-- 
Conor P. Cahill            (703)430-9247        Virtual Technologies, Inc.,
uunet!virtech!cpcahil                           46030 Manekin Plaza, Suite 160
                                                Sterling, VA 22170

Re: Beware xargs security holes

#1596

Author: Keith Gabryelski
Date: Tue, 23 Oct 1990 21:46

10 lines
885 bytes

In article <1990Oct20.032718.1874@cbnews.att.com> res@cbnews.att.com (Robert
E. Stampfli) writes:
>No user, malicious or not, can remove "every file on the system."
>In fact, I contend it is impossible to remove the last instance of
>an executable that contains the unlink() system call.

This was, infact, impossible on System V Release 3.x, but in SVR4 it
is possible.  BSD and SunOS varients get this `right', also.

Pax, Keith

Re: Beware xargs security holes

#1635

Author: Karl Lehenbauer
Date: Fri, 26 Oct 1990 17:51

11 lines
1069 bytes

In article <1990Oct20.032718.1874@cbnews.att.com> res@cbnews.att.com (Robert E. Stampfli) writes:
>No user, malicious or not, can remove "every file on the system."
>In fact, I contend it is impossible to remove the last instance of
>an executable that contains the unlink() system call.

Oh, then I guess it's not a problem...
-- 
-- uunet!sugar!ficc!karl (wk), uunet!sugar!karl (hm)
"The computer programmer is a creator of universes for which he alone is 
 responsible.  Universes of virtually unlimited complexity can be created in 
 the form of computer programs."  -- Joseph Weizenbaum

Re: Beware xargs security holes

#1815

Author: Ian Donaldson
Date: Fri, 23 Nov 1990 05:27

12 lines
946 bytes

karl@ficc.ferranti.com (Karl Lehenbauer) writes:

>In article <1990Oct20.032718.1874@cbnews.att.com> res@cbnews.att.com (Robert E. Stampfli) writes:
>>No user, malicious or not, can remove "every file on the system."
>>In fact, I contend it is impossible to remove the last instance of
>>an executable that contains the unlink() system call.

If the executable is built with non-shared text (ie unpure) then its
possible on most UNIXen.  On some UNIXen its even possible with shared
text binaries (eg: SVR4, SUNOS4.1)

Ian D

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