From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Myklebust, Trond" Subject: Re: [PATCH 06/15] NFSv4: Introduce new label structure Date: Tue, 12 Feb 2013 22:40:46 +0000 Message-ID: <4FA345DA4F4AE44899BD2B03EEEC2FA91F3CE58F@sacexcmbx05-prd.hq.netapp.com> References: <1360327163-20360-1-git-send-email-SteveD@redhat.com> <1360327163-20360-7-git-send-email-SteveD@redhat.com> <20130212220741.GJ10267@fieldses.org> <4FA345DA4F4AE44899BD2B03EEEC2FA91F3CE55C@sacexcmbx05-prd.hq.netapp.com> <20130212223226.GL10267@fieldses.org> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT Cc: Steve Dickson , "J. Bruce Fields" , "David P. Quigley" , Linux NFS list , Linux FS devel list , Linux Security List , SELinux List To: "J. Bruce Fields" Return-path: In-Reply-To: <20130212223226.GL10267@fieldses.org> Content-Language: en-US Content-ID: Sender: linux-security-module-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org On Tue, 2013-02-12 at 17:32 -0500, J. Bruce Fields wrote: > On Tue, Feb 12, 2013 at 10:28:16PM +0000, Myklebust, Trond wrote: > > On Tue, 2013-02-12 at 17:07 -0500, J. Bruce Fields wrote: > > > On Fri, Feb 08, 2013 at 07:39:14AM -0500, Steve Dickson wrote: > > > > From: David Quigley > > > > > > > > In order to mimic the way that NFSv4 ACLs are implemented we have created a > > > > structure to be used to pass label data up and down the call chain. This patch > > > > adds the new structure and new members to the required NFSv4 call structures. > > > > > > > > Signed-off-by: Matthew N. Dodd > > > > Signed-off-by: Miguel Rodel Felipe > > > > Signed-off-by: Phua Eu Gene > > > > Signed-off-by: Khin Mi Mi Aung > > > > --- > > > > fs/nfs/inode.c | 33 +++++++++++++++++++++++++++++++++ > > > > include/linux/nfs4.h | 7 +++++++ > > > > include/linux/nfs_fs.h | 17 +++++++++++++++++ > > > > include/linux/nfs_xdr.h | 21 +++++++++++++++++++++ > > > > include/uapi/linux/nfs4.h | 2 +- > > > > 5 files changed, 79 insertions(+), 1 deletion(-) > > > > > > > > diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c > > > > index ebeb94c..8d5f01b 100644 > > > > --- a/fs/nfs/inode.c > > > > +++ b/fs/nfs/inode.c > > > > @@ -255,6 +255,39 @@ nfs_init_locked(struct inode *inode, void *opaque) > > > > return 0; > > > > } > > > > > > > > +#ifdef CONFIG_NFS_V4_SECURITY_LABEL > > > > +struct nfs4_label *nfs4_label_alloc(struct nfs_server *server, gfp_t flags) > > > > +{ > > > > + struct nfs4_label *label = NULL; > > > > + > > > > + if (!(server->caps & NFS_CAP_SECURITY_LABEL)) > > > > + return label; > > > > + > > > > + label = kzalloc(NFS4_MAXLABELLEN, flags); > > > > + if (label == NULL) > > > > + return ERR_PTR(-ENOMEM); > > > > + > > > > + label->label = (char *)(label + 1); > > > > + label->len = NFS4_MAXLABELLEN; > > > > > > If you're expecting to be able to store up to NFS4_MAXLABELLEN of data > > > after the end of the struct, then you want: > > > > > > label = kzalloc(sizeof(struct nfs4_label) + NFS4_MAXLABELLEN, flags); > > > > Sigh... No. > > > > I keep telling Steve that the 'label' needs to be defined as an array, > > Yeah, I know, he said in 0/15 that he couldn't do that, so I've been > reading through these on the assumption I'll find out why not at some > point.... (Still not seeing it, though.) It only makes sense to define label->label as a pointer if you need to change the pointer value at some time. However, if that is the case, then why allocate the struct nfs4_label and label string as a single memory block? It would make more sense to allocate them separately so that you can free the old label storage after you change the pointer. Trond