Re: kern/45393 (core dumps are unilaterally prevented by unmounted cwd or MNT_NOCOREDUMP even if corename will be valid)

[christos%zoulas.com@localhost (Christos Zoulas)]

The following reply was made to PR kern/45393; it has been noted by GNATS.

From: christos%zoulas.com@localhost (Christos Zoulas)
To: gnats-bugs%NetBSD.org@localhost, gnats-admin%netbsd.org@localhost, 
netbsd-bugs%netbsd.org@localhost, 
        "Greg A. Woods" <woods%planix.com@localhost>
Cc: 
Subject: Re: kern/45393 (core dumps are unilaterally prevented by unmounted cwd 
or MNT_NOCOREDUMP even if corename will be valid)
Date: Sat, 24 Sep 2011 18:55:18 -0400

 On Sep 24, 10:15pm, woods%planix.com@localhost ("Greg A. Woods") wrote:
 -- Subject: Re: kern/45393 (core dumps are unilaterally prevented by unmounte
 
 |  After doing a little more research on the origins of MNT_NOCOREDUMP
 |  (first by cgd, in NetBSD, in 1996, so far as I can tell) I'm now a lot
 |  less inclined to worry about the single filesystem issue I initially
 |  raised.
 |  
 |  Indeed, as you said, if the admin doesn't want any core dumps then
 |  MNT_NOCOREDUMP is the best way to ensure that (or at least it will be
 |  after your fixes are in a release :-)).
 |  
 |  When I originally encountered the "nocoredump" option I looked to it
 |  more as a way to prevent pollution of core files in random locations,
 |  not as the security mechanism as it is described in mount(8).
 |  
 |  However my personal goal is now met by both the logging of core dumps
 |  (at least with my patch to log the directory where the core is created),
 |  and the ability to contain them all to one sub-directory by giving
 |  kern.defcorename a fully qualified pathname template.
 
 Great.
 
 |  So, with that said I'd say yes, please close this PR (though perhaps
 |  your final fix deserves a pull-up to netbsd-5?)
 
 Well, that is going to be a bit difficult because 5 is missing the simple
 namei() function that I am using :-)
   
 |  As a side note I find it interesting that not even OpenBSD has
 |  implemented MNT_NOCOREDUMP.  In fact I don't find it anywhere other than
 |  in NetBSD.
 |  
 
 I have not seen it either.
 
 |  Oh, and one more partly related thing my research revealed:  OpenBSD
 |  added a check in 2007 to prevent a core from overwriting a file owned by
 |  a different user (their kern_sig.c rev. 1.96).  I think NetBSD should
 |  gain this check as well, but perhaps it deserves a separate PR?
 
 I've added it too, thanks for mentioning it.
 
 christos