From mboxrd@z Thu Jan 1 00:00:00 1970 From: Amerigo Wang Subject: Re: [Patch 1/2] selinux: ajust rules for ATTR_FORCE Date: Tue, 18 Aug 2009 14:56:45 +0800 Message-ID: <4A8A50AD.7030004@redhat.com> References: <20090817071001.5913.94767.sendpatchset@localhost.localdomain> <20090817071011.5913.69970.sendpatchset@localhost.localdomain> <1250511313.3629.103.camel@moss-pluto.epoch.ncsc.mil> <87prau5ld1.fsf@devron.myhome.or.jp> <1250536052.3629.154.camel@moss-pluto.epoch.ncsc.mil> <873a7q441a.fsf@devron.myhome.or.jp> <1250538981.3629.184.camel@moss-pluto.epoch.ncsc.mil> <87fxbq19qs.fsf@devron.myhome.or.jp> <87my5yxidt.fsf@devron.myhome.or.jp> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Stephen Smalley , linux-kernel@vger.kernel.org, esandeen@redhat.com, eteo@redhat.com, eparis@redhat.com, linux-fsdevel@vger.kernel.org, akpm@linux-foundation.org, viro@zeniv.linux.org.uk To: OGAWA Hirofumi Return-path: Received: from mx2.redhat.com ([66.187.237.31]:54638 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751246AbZHRGya (ORCPT ); Tue, 18 Aug 2009 02:54:30 -0400 In-Reply-To: <87my5yxidt.fsf@devron.myhome.or.jp> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: OGAWA Hirofumi wrote: > Could you review this? I've added ATTR_TIMES_SET to check explicit > utimes(), and tried it with minimum change. > > [I'm not sure this handles notify_change() usage of nfsd (and perhaps > other network fs too) correctly, and whether selinux may want to check > it. I guess network fs _may_ try to change the multiple attributes at a > time. Well, even if it's true, it would be another topic...] > > Ah, according to the discussion here, I know I misunderstood ATTR_FORCE... sorry. > OGAWA Hirofumi > > > From: Amerigo Wang > > As suggested by OGAWA Hirofumi in thread: http://lkml.org/lkml/2009/8/7/132, > we should let selinux_inode_setattr() to match our ATTR_* rules. > ATTR_FORCE should not force things like ATTR_SIZE. > > Cc: Stephen Smalley > Cc: Eric Paris > Signed-off-by: WANG Cong > [tweaks] > Signed-off-by: OGAWA Hirofumi > Great! Some comments below. > --- > > security/selinux/hooks.c | 13 +++++++++---- > 1 file changed, 9 insertions(+), 4 deletions(-) > > diff -puN security/selinux/hooks.c~selinux-truncate-fix security/selinux/hooks.c > --- linux-2.6/security/selinux/hooks.c~selinux-truncate-fix 2009-08-18 03:50:09.000000000 +0900 > +++ linux-2.6-hirofumi/security/selinux/hooks.c 2009-08-18 05:35:11.000000000 +0900 > @@ -2711,12 +2711,17 @@ static int selinux_inode_permission(stru > static int selinux_inode_setattr(struct dentry *dentry, struct iattr *iattr) > { > const struct cred *cred = current_cred(); > + unsigned int ia_valid = iattr->ia_valid; > > - if (iattr->ia_valid & ATTR_FORCE) > - return 0; > + /* ATTR_FORCE is just used for ATTR_KILL_S[UG]ID. */ > + if (ia_valid & ATTR_FORCE) { > + ia_valid &= ~(ATTR_KILL_SUID | ATTR_KILL_SGID | ATTR_MODE); > + if (!ia_valid) > + return 0; > So if I read this correctly, (ATTR_FORCE| ATTR_KILL_SUID|ATTR_MODE) will not return here, since 'ia_valid' will be ATTR_FORCE finally. I think you forgot to clear ATTR_FORCE here... > + } > > - if (iattr->ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID | > - ATTR_ATIME_SET | ATTR_MTIME_SET)) > + if (ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID | > + ATTR_ATIME_SET | ATTR_MTIME_SET | ATTR_TIMES_SET)) > return dentry_has_perm(cred, NULL, dentry, FILE__SETATTR); > > return dentry_has_perm(cred, NULL, dentry, FILE__WRITE); > _ > > I am not sure about ATTR_TIMES_SET here, but looks fine. :-/