Re: [PATCH][2.4-rc1] fix side effects of the kmod/ptrace secfix

From: Andreas Gietl (Listen@e-admin.de)
Date: Fri Apr 25 2003 - 09:40:22 EST

On Friday 25 April 2003 12:40, Bernhard Kaindl wrote:
> On Fri, 25 Apr 2003, Andreas Gietl wrote:
> > > system monitoring stuff this way(I've even heard shutdown is affected)
> >
> > i can confirm that shutdown (halt|reboot) does not work on my
> > 2.4.21-rc1-ac1 boxes. (gentoo + redhat).
>
> Thanks for the info!
>
> > But your patch does not seem to fix it.
>
> Very interesting also, the two liner adressed only the well-known problems.
> To fix the other not so well-known side effects, a real cleanup is the way
> to go.
>
> Can you try the attached cleanup patch instead of the two-liner?
>
> It's an inital cleanup and should fix the other side effects which
> I described in my mails.
>
> Bernhard Kaindl
>
> PS: If either patch is applied correctly, this
>
> su guest -c 'ps $PPID;wc -m </proc/$PPID/cmdline'
>
> should give:
>
> PID TTY STAT TIME COMMAND
> 2452 pts/2 S 0:00 su bin -c ps $PPID;wc -m </proc/$PPID/cmdline
> 46

it shows:
  PID TTY STAT TIME COMMAND
 2092 ttyp0 S 0:00 su guest -c ps $PPID;wc -m </proc/$PPID/cmdline
      0

but cat shows:
su guest -c 'ps $PPID; cat /proc/$PPID/cmdline'
  PID TTY STAT TIME COMMAND
 2144 ttyp0 S 0:00 su guest -c ps $PPID; cat /proc/$PPID/cmdline
suguest-cps $PPID; cat /proc/$PPID/cmdline

what happened?

>
> If it does not, access_process_vm is not fixed properly.
>
> Second, calling this as root:
>
> strace -fewrite su -c /bin/echo 2>&1 | grep pid
>
> should give:
>
> [pid 2599] --- SIGSTOP (Stopped (signal)) @ 0 (0) ---
> [pid 2599] write(1, "\n", 1

it shows:
localhost root # strace -fewrite su -c /bin/echo 2>&1 | grep pid
[pid 2159] write(1, "\n", 1

>
> If it does not, ptrace_check_attach is not fixed properly.
>
> (These are only the checks for the well known side
> effects which should be fixed even with the short
> is_dumpable() -> task_dumpable patch.)

Looks like my results are slightly diffent, Does this mean i did not apply the
patch correctly? I applied it twice manually, because patch did not succeed
and compiled the kernel 3 times... 

-- 
e-admin internet gmbh
Andreas Gietl                                            tel +49 941 3810884
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This archive was generated by hypermail 2b29 : Wed Apr 30 2003 - 22:00:21 EST