- md5 fix

[packages/kernel.git] / ovl13-overlayfs-copy-up-i_uid-i_gid-from-the-underlying-in.patch

From 3d5a6482fd89423b94d8bb3a0a303f0b40bb4279 Mon Sep 17 00:00:00 2001
From: Andy Whitcroft <apw@canonical.com>
Date: Thu, 9 Aug 2012 16:47:21 +0100
Subject: [PATCH 13/13] overlayfs: copy up i_uid/i_gid from the underlying
 inode
Patch-mainline: not yet

YAMA et al rely on on i_uid/i_gid to be populated in order to perform
their checks.  While these really cannot be guarenteed as the underlying
filesystem may not even have the concept, they are expected to be filled
when possible.  To quote Al Viro:

    "Ideally, yes, we'd want to have ->i_uid used only by fs-specific
     code and helpers used by that fs (including those that are
     implicit defaults). [...]   In practice we have enough places
     where uid/gid is used directly to make setting them practically
     a requirement - places like /proc/<pid>/ can get away with
     not doing that, but only because shitloads of syscalls are
     not allowed on those anyway, permissions or no permissions.
     In anything general-purpose you really need to set it."

Copy up the underlying filesystem information into the overlayfs inode
when we create it.

Buglink: http://bugs.launchpad.net/bugs/944386
Signed-off-by: Andy Whitcroft <apw@canonical.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
---
 fs/overlayfs/dir.c       |    2 ++
 fs/overlayfs/inode.c     |    2 ++
 fs/overlayfs/overlayfs.h |    6 ++++++
 fs/overlayfs/super.c     |    1 +
 4 files changed, 11 insertions(+)

Index: linux-3.6-rc7-master/fs/overlayfs/dir.c
===================================================================
--- linux-3.6-rc7-master.orig/fs/overlayfs/dir.c	2012-09-28 13:37:04.000000000 +0200
+++ linux-3.6-rc7-master/fs/overlayfs/dir.c	2012-09-28 13:37:10.000000000 +0200
@@ -304,6 +304,7 @@ static int ovl_create_object(struct dent
 		}
 	}
 	ovl_dentry_update(dentry, newdentry);
+	ovl_copyattr(newdentry->d_inode, inode);
 	d_instantiate(dentry, inode);
 	inode = NULL;
 	newdentry = NULL;
@@ -446,6 +447,7 @@ static int ovl_link(struct dentry *old,
 				new->d_fsdata);
 		if (!newinode)
 			goto link_fail;
+		ovl_copyattr(upperdir->d_inode, newinode);
 
 		ovl_dentry_version_inc(new->d_parent);
 		ovl_dentry_update(new, newdentry);
Index: linux-3.6-rc7-master/fs/overlayfs/inode.c
===================================================================
--- linux-3.6-rc7-master.orig/fs/overlayfs/inode.c	2012-09-28 13:37:08.000000000 +0200
+++ linux-3.6-rc7-master/fs/overlayfs/inode.c	2012-09-28 13:37:10.000000000 +0200
@@ -31,6 +31,8 @@ int ovl_setattr(struct dentry *dentry, s
 
 	mutex_lock(&upperdentry->d_inode->i_mutex);
 	err = notify_change(upperdentry, attr);
+	if (!err)
+		ovl_copyattr(upperdentry->d_inode, dentry->d_inode);
 	mutex_unlock(&upperdentry->d_inode->i_mutex);
 
 	return err;
Index: linux-3.6-rc7-master/fs/overlayfs/overlayfs.h
===================================================================
--- linux-3.6-rc7-master.orig/fs/overlayfs/overlayfs.h	2012-09-28 13:36:53.000000000 +0200
+++ linux-3.6-rc7-master/fs/overlayfs/overlayfs.h	2012-09-28 13:37:10.000000000 +0200
@@ -56,6 +56,12 @@ int ovl_removexattr(struct dentry *dentr
 
 struct inode *ovl_new_inode(struct super_block *sb, umode_t mode,
 			    struct ovl_entry *oe);
+static inline void ovl_copyattr(struct inode *from, struct inode *to)
+{
+	to->i_uid = from->i_uid;
+	to->i_gid = from->i_gid;
+}
+
 /* dir.c */
 extern const struct inode_operations ovl_dir_inode_operations;
 
Index: linux-3.6-rc7-master/fs/overlayfs/super.c
===================================================================
--- linux-3.6-rc7-master.orig/fs/overlayfs/super.c	2012-09-28 13:37:00.000000000 +0200
+++ linux-3.6-rc7-master/fs/overlayfs/super.c	2012-09-28 13:37:10.000000000 +0200
@@ -347,6 +347,7 @@ static int ovl_do_lookup(struct dentry *
 				      oe);
 		if (!inode)
 			goto out_dput;
+		ovl_copyattr(realdentry->d_inode, inode);
 	}
 
 	if (upperdentry)