Re: F_SETOWN...

Ricky Beam (root@defiant.interpath.net)
Tue, 24 Nov 1998 03:15:48 -0500 (EST)


Letting the chips fall where they may, I quote Rene Janssen:
>At 03:09 PM 11/22/98 -0500, Ricky Beam wrote:
>>I'll assume no one else has seen this...
>><URL:http://www.rootshell.com/archive-j457nxiqi3gq59dv/199811/shits.c.html>
>
>I checked this, but I couldnt kill any process. Have you ?

Yes...

1) login
2) start up a subshell (tcsh)
3) find the pid of the subshell
4) ./shits {pid}
5) hit enter when asked
6) watch the subshell die

Under 2.1.124, the shell exists with "Pollable event" (or something like that)

>>Does no one else think that's just a little on the brain damaged side? No
>>sanity checks what-so-ever in handing a filedesc to an arbitrary process
>>number... no permissions check, no pid check, nothing.
>
>They are checked when the signal is supposed to be send.

By then, it's too late, the filp info has already been changed.

>>If they are "for sockets", then why isn't there any check to see that the
>>filp actually is a socket before screwing with it? In fact, why isn't it
>>in net/core/sock.c under sock_fcntl? And then why doesn't it set the uids
>>to match arg?
>
>No they are not just for sockets but ttys also, so the comments are a bit
>misleading yes.

Personally, I'm trying to see why it's needed in the first place? Does any
software actually use this feature?

--Ricky

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