From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from sc8-sf-mx1-b.sourceforge.net ([10.3.1.11] helo=sc8-sf-mx1.sourceforge.net) by sc8-sf-list1.sourceforge.net with esmtp (Cipher TLSv1:DES-CBC3-SHA:168) (Exim 3.31-VA-mm2 #1 (Debian)) id 1A7H53-0003L5-00 for ; Wed, 08 Oct 2003 09:22:29 -0700 Received: from fed1mtao03.cox.net ([68.6.19.242]) by sc8-sf-mx1.sourceforge.net with esmtp (Exim 4.22) id 1A7H51-0007cp-Ry for user-mode-linux-devel@lists.sourceforge.net; Wed, 08 Oct 2003 09:22:27 -0700 Message-ID: <3F843A79.6060600@easyco.com> From: Doug Dumitru MIME-Version: 1.0 Subject: Re: [uml-devel] Patch for buffer overrun in serial/console device logic References: <3F830C2C.8010308@easyco.com> In-Reply-To: Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: user-mode-linux-devel-admin@lists.sourceforge.net Errors-To: user-mode-linux-devel-admin@lists.sourceforge.net List-Help: List-Post: List-Subscribe: , List-Id: The user-mode Linux development list List-Unsubscribe: , List-Archive: Date: Wed, 08 Oct 2003 09:25:29 -0700 To: Hannes Schulz , user-mode-linux-devel@lists.sourceforge.net Hannes Schulz wrote: > [...] > >> We also have a much messier, in-house patch that we apply to hostfs.c >> so that root mounts will correctly honor ownerships and rights. Is >> anyone else working on this. The 2.4.20-5um release appears to have a >> lot of missing stuff in this area, but if someone else is re-working >> this, I will put my patch down for a while and wait. Otherwise, I >> will clean it up and submit it. >> > > I did such a patch (see below). How does yours fix the problem ? > Unfortunately I have another problem with hostfs: munmap does not write > out the changes to the file. I looked at the code but I am afraid this > is beyound me. [ ... snipped ... ] My patch was quite a bit more involved. The problem that I saw was that the actual IO operations in hostfs_user.c were always being executed as the user that start UML. In order to get all of the UID/GIDs to map transparently, you have to do setegid(...) and seteuid(...) operations around all of the IO operations that have the potential to create a file or directory. This includes open and a bunch of others. Unfurtunately, the calling UID/GID is never visible to the functons in hostfs_user.c, so hostfs_kern.c needs a new call (or new parameters) to pass this down. Umask also needs to travel down to hostfs_user.c. My patch is very tangled in with my "transaction journel" that we use for replication. The replication stuff is very "non trivial" to implement from a setup point of view, so I don't want to give that to anyone at this point. Plus, the patch as stands has lots of debugging lines commented out and is just plain ugly. My reputation would not be served well to show it to anyone at this point. My real question was whether there is a need to more transparent UID/GID/UMASK processing to hostfs (with the caveat that UML must boot root or at least SUID root). -------------------------------------------------------------------- Doug Dumitru 800-470-2756 (610-237-2000) EasyCo LLC doug@easyco.com http://easyco.com -------------------------------------------------------------------- D3, U2, jBase Virtual Servers. Off-site backup over the internet. Develop/test/deploy from $20/mo. Fast, secure, cheaper than tape. http://mirroredservers.com http://mirroredbackup.com ------------------------------------------------------- This SF.net email is sponsored by: SF.net Giveback Program. SourceForge.net hosts over 70,000 Open Source Projects. See the people who have HELPED US provide better services: Click here: http://sourceforge.net/supporters.php _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel