Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755920AbYGCMAt (ORCPT ); Thu, 3 Jul 2008 08:00:49 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755455AbYGCL7e (ORCPT ); Thu, 3 Jul 2008 07:59:34 -0400 Received: from mx1.redhat.com ([66.187.233.31]:35074 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755425AbYGCL7c (ORCPT ); Thu, 3 Jul 2008 07:59:32 -0400 Subject: Re: [patch v2] gfs2: don't call permission() From: Steven Whitehouse To: Miklos Szeredi Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, hch@infradead.org In-Reply-To: References: Content-Type: text/plain Organization: Red Hat UK Ltd Date: Thu, 03 Jul 2008 11:11:27 +0100 Message-Id: <1215079887.3598.2.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.12.3 (2.12.3-5.fc8) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7847 Lines: 235 Hi, Now in the GFS2 -nmw git tree. Thanks, Steve. On Wed, 2008-07-02 at 21:12 +0200, Miklos Szeredi wrote: > This is the updated version, with the promised renames: > > gfs2_do_permission -> gfs2_permission > gfs2_permission -> gfs2_iop_permission > > Thanks, > Miklos > > ---- > From: Miklos Szeredi > > GFS2 calls permission() to verify permissions after locks on the files > have been taken. > > For this it's sufficient to call gfs2_permission() instead. This > results in the following changes: > > - IS_RDONLY() check is not performed > - IS_IMMUTABLE() check is not performed > - devcgroup_inode_permission() is not called > - security_inode_permission() is not called > > IS_RDONLY() should be unnecessary anyway, as the per-mount read-only > flag should provide protection against read-only remounts during > operations. do_gfs2_set_flags() has been fixed to perform > mnt_want_write()/mnt_drop_write() to protect against remounting > read-only. > > IS_IMMUTABLE has been added to gfs2_permission() > > Repeating the security checks seems to be pointless, as they don't > normally change, and if they do, it's independent of the filesystem > state. > > Signed-off-by: Miklos Szeredi > --- > fs/gfs2/inode.c | 6 +++--- > fs/gfs2/inode.h | 1 + > fs/gfs2/ops_file.c | 11 +++++++++-- > fs/gfs2/ops_inode.c | 25 +++++++++++++++++-------- > 4 files changed, 30 insertions(+), 13 deletions(-) > > Index: linux-2.6/fs/gfs2/inode.c > =================================================================== > --- linux-2.6.orig/fs/gfs2/inode.c 2008-07-01 18:11:32.000000000 +0200 > +++ linux-2.6/fs/gfs2/inode.c 2008-07-01 19:15:59.000000000 +0200 > @@ -504,7 +504,7 @@ struct inode *gfs2_lookupi(struct inode > } > > if (!is_root) { > - error = permission(dir, MAY_EXEC, NULL); > + error = gfs2_permission(dir, MAY_EXEC); > if (error) > goto out; > } > @@ -667,7 +667,7 @@ static int create_ok(struct gfs2_inode * > { > int error; > > - error = permission(&dip->i_inode, MAY_WRITE | MAY_EXEC, NULL); > + error = gfs2_permission(&dip->i_inode, MAY_WRITE | MAY_EXEC); > if (error) > return error; > > @@ -1134,7 +1134,7 @@ int gfs2_unlink_ok(struct gfs2_inode *di > if (IS_APPEND(&dip->i_inode)) > return -EPERM; > > - error = permission(&dip->i_inode, MAY_WRITE | MAY_EXEC, NULL); > + error = gfs2_permission(&dip->i_inode, MAY_WRITE | MAY_EXEC); > if (error) > return error; > > Index: linux-2.6/fs/gfs2/inode.h > =================================================================== > --- linux-2.6.orig/fs/gfs2/inode.h 2008-07-01 18:11:32.000000000 +0200 > +++ linux-2.6/fs/gfs2/inode.h 2008-07-01 19:15:59.000000000 +0200 > @@ -91,6 +91,7 @@ int gfs2_rmdiri(struct gfs2_inode *dip, > struct gfs2_inode *ip); > int gfs2_unlink_ok(struct gfs2_inode *dip, const struct qstr *name, > const struct gfs2_inode *ip); > +int gfs2_permission(struct inode *inode, int mask); > int gfs2_ok_to_move(struct gfs2_inode *this, struct gfs2_inode *to); > int gfs2_readlinki(struct gfs2_inode *ip, char **buf, unsigned int *len); > int gfs2_glock_nq_atime(struct gfs2_holder *gh); > Index: linux-2.6/fs/gfs2/ops_file.c > =================================================================== > --- linux-2.6.orig/fs/gfs2/ops_file.c 2008-07-01 18:11:32.000000000 +0200 > +++ linux-2.6/fs/gfs2/ops_file.c 2008-07-01 19:15:59.000000000 +0200 > @@ -15,6 +15,7 @@ > #include > #include > #include > +#include > #include > #include > #include > @@ -220,10 +221,14 @@ static int do_gfs2_set_flags(struct file > int error; > u32 new_flags, flags; > > - error = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &gh); > + error = mnt_want_write(filp->f_path.mnt); > if (error) > return error; > > + error = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &gh); > + if (error) > + goto out_drop_write; > + > flags = ip->i_di.di_flags; > new_flags = (flags & ~mask) | (reqflags & mask); > if ((new_flags ^ flags) == 0) > @@ -242,7 +247,7 @@ static int do_gfs2_set_flags(struct file > !capable(CAP_LINUX_IMMUTABLE)) > goto out; > if (!IS_IMMUTABLE(inode)) { > - error = permission(inode, MAY_WRITE, NULL); > + error = gfs2_permission(inode, MAY_WRITE); > if (error) > goto out; > } > @@ -272,6 +277,8 @@ out_trans_end: > gfs2_trans_end(sdp); > out: > gfs2_glock_dq_uninit(&gh); > +out_drop_write: > + mnt_drop_write(filp->f_path.mnt); > return error; > } > > Index: linux-2.6/fs/gfs2/ops_inode.c > =================================================================== > --- linux-2.6.orig/fs/gfs2/ops_inode.c 2008-07-01 18:11:32.000000000 +0200 > +++ linux-2.6/fs/gfs2/ops_inode.c 2008-07-01 19:15:59.000000000 +0200 > @@ -163,7 +163,7 @@ static int gfs2_link(struct dentry *old_ > if (error) > goto out; > > - error = permission(dir, MAY_WRITE | MAY_EXEC, NULL); > + error = gfs2_permission(dir, MAY_WRITE | MAY_EXEC); > if (error) > goto out_gunlock; > > @@ -669,7 +669,7 @@ static int gfs2_rename(struct inode *odi > } > } > } else { > - error = permission(ndir, MAY_WRITE | MAY_EXEC, NULL); > + error = gfs2_permission(ndir, MAY_WRITE | MAY_EXEC); > if (error) > goto out_gunlock; > > @@ -704,7 +704,7 @@ static int gfs2_rename(struct inode *odi > /* Check out the dir to be renamed */ > > if (dir_rename) { > - error = permission(odentry->d_inode, MAY_WRITE, NULL); > + error = gfs2_permission(odentry->d_inode, MAY_WRITE); > if (error) > goto out_gunlock; > } > @@ -891,7 +891,7 @@ static void *gfs2_follow_link(struct den > * Returns: errno > */ > > -static int gfs2_permission(struct inode *inode, int mask, struct nameidata *nd) > +int gfs2_permission(struct inode *inode, int mask) > { > struct gfs2_inode *ip = GFS2_I(inode); > struct gfs2_holder i_gh; > @@ -905,13 +905,22 @@ static int gfs2_permission(struct inode > unlock = 1; > } > > - error = generic_permission(inode, mask, gfs2_check_acl); > + if ((mask & MAY_WRITE) && IS_IMMUTABLE(inode)) > + error = -EACCES; > + else > + error = generic_permission(inode, mask, gfs2_check_acl); > if (unlock) > gfs2_glock_dq_uninit(&i_gh); > > return error; > } > > +static int gfs2_iop_permission(struct inode *inode, int mask, > + struct nameidata *nd) > +{ > + return gfs2_permission(inode, mask); > +} > + > static int setattr_size(struct inode *inode, struct iattr *attr) > { > struct gfs2_inode *ip = GFS2_I(inode); > @@ -1141,7 +1150,7 @@ static int gfs2_removexattr(struct dentr > } > > const struct inode_operations gfs2_file_iops = { > - .permission = gfs2_permission, > + .permission = gfs2_iop_permission, > .setattr = gfs2_setattr, > .getattr = gfs2_getattr, > .setxattr = gfs2_setxattr, > @@ -1160,7 +1169,7 @@ const struct inode_operations gfs2_dir_i > .rmdir = gfs2_rmdir, > .mknod = gfs2_mknod, > .rename = gfs2_rename, > - .permission = gfs2_permission, > + .permission = gfs2_iop_permission, > .setattr = gfs2_setattr, > .getattr = gfs2_getattr, > .setxattr = gfs2_setxattr, > @@ -1172,7 +1181,7 @@ const struct inode_operations gfs2_dir_i > const struct inode_operations gfs2_symlink_iops = { > .readlink = gfs2_readlink, > .follow_link = gfs2_follow_link, > - .permission = gfs2_permission, > + .permission = gfs2_iop_permission, > .setattr = gfs2_setattr, > .getattr = gfs2_getattr, > .setxattr = gfs2_setxattr, -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/