Date: Sun, 14 Jul 2002 12:11:47 -0700 From: "Crist J. Clark" <crist.clark@attbi.com> To: Robert Watson <rwatson@FreeBSD.org> Cc: David Malone <dwmalone@maths.tcd.ie>, Luigi Rizzo <luigi@FreeBSD.org>, Giorgos Keramidas <keramida@FreeBSD.org>, cvs-committers@FreeBSD.org, cvs-all@FreeBSD.org Subject: Re: cvs commit: src/usr.bin/talk display.c talk.1 talk.c Message-ID: <20020714191147.GE56656@blossom.cjclark.org> In-Reply-To: <Pine.NEB.3.96L.1020714123154.25880D-100000@fledge.watson.org> References: <20020714153536.GA97536@walton.maths.tcd.ie> <Pine.NEB.3.96L.1020714123154.25880D-100000@fledge.watson.org>
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On Sun, Jul 14, 2002 at 12:33:20PM -0400, Robert Watson wrote:
> On Sun, 14 Jul 2002, David Malone wrote:
[snip]
> > Isn't this what kern.ps_showallprocs is for? I've always considered ps
> > and w showing what other people are doing a good way for users to learn
> > new commands.
>
> kern.ps_showallprocs in -stable was simply a mib setting to tell ps to
> ignore other users.
kern.ps_showallprocs is enforced in the kernel. It prevents the kernel
from returning a list of all processes to ps(1) or anything else (see
src/sys/kern/kern_proc.c).
_However,_ it does not prevent one from doing,
$ ps -p <pid>
On any process, regardless of the owner. We can simulate the '-a'
switch by enumerating all PIDs,
ps-a () {
I=0
while [ $I -lt 100000 ]; do
ps -p $I
I=$(($I + 1))
done |
grep -v '^ PID'
}
'Course, that takes a few minutes to run.
This simple patch will stop that too. Think it's worth adding? I've
been running it for weeks on several RELENG_4 boxes.
Index: src/sys/kern/kern_proc.c
===================================================================
RCS file: /export/freebsd/ncvs/src/sys/kern/kern_proc.c,v
retrieving revision 1.63.2.8
diff -u -r1.63.2.8 kern_proc.c
--- src/sys/kern/kern_proc.c 1 May 2001 13:39:06 -0000 1.63.2.8
+++ src/sys/kern/kern_proc.c 20 May 2002 07:36:15 -0000
@@ -451,7 +451,8 @@
p = pfind((pid_t)name[0]);
if (!p)
return (0);
- if (!PRISON_CHECK(curproc, p))
+ if (!PRISON_CHECK(curproc, p) ||
+ (!ps_showallprocs) && p_trespass(curproc, p))
return (0);
error = sysctl_out_proc(p, req, 0);
return (error);
--
Crist J. Clark | cjclark@alum.mit.edu
| cjclark@jhu.edu
http://people.freebsd.org/~cjc/ | cjc@freebsd.org
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