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From: Dave Hansen <haveblue@us.ibm.com>
To: akpm@osdl.org
Cc: linux-kernel@vger.kernel.org, hch@infradead.org,
	Dave Hansen <haveblue@us.ibm.com>
Subject: [PATCH 13/25] elevate mount count for extended attributes
Date: Thu, 20 Sep 2007 12:53:05 -0700	[thread overview]
Message-ID: <20070920195305.2369B8F3@kernel> (raw)
In-Reply-To: <20070920195249.852667D5@kernel>


This basically audits the callers of xattr_permission(), which
calls permission() and can perform writes to the filesystem.

This conflicts with the current (~2.6.23-rc7) audit 
git tree in -mm.  wiggle'ing the patch merges it.

Acked-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
---

 lxc-dave/fs/nfsd/nfs4proc.c |    7 ++++++-
 lxc-dave/fs/xattr.c         |   16 ++++++++++++++--
 2 files changed, 20 insertions(+), 3 deletions(-)

diff -puN fs/nfsd/nfs4proc.c~elevate-mount-count-for-extended-attributes fs/nfsd/nfs4proc.c
--- lxc/fs/nfsd/nfs4proc.c~elevate-mount-count-for-extended-attributes	2007-09-20 12:16:16.000000000 -0700
+++ lxc-dave/fs/nfsd/nfs4proc.c	2007-09-20 12:16:16.000000000 -0700
@@ -658,14 +658,19 @@ nfsd4_setattr(struct svc_rqst *rqstp, st
 			return status;
 		}
 	}
+	status = mnt_want_write(cstate->current_fh.fh_export->ex_mnt);
+	if (status)
+		return status;
 	status = nfs_ok;
 	if (setattr->sa_acl != NULL)
 		status = nfsd4_set_nfs4_acl(rqstp, &cstate->current_fh,
 					    setattr->sa_acl);
 	if (status)
-		return status;
+		goto out;
 	status = nfsd_setattr(rqstp, &cstate->current_fh, &setattr->sa_iattr,
 				0, (time_t)0);
+out:
+	mnt_drop_write(cstate->current_fh.fh_export->ex_mnt);
 	return status;
 }
 
diff -puN fs/xattr.c~elevate-mount-count-for-extended-attributes fs/xattr.c
--- lxc/fs/xattr.c~elevate-mount-count-for-extended-attributes	2007-09-20 12:16:16.000000000 -0700
+++ lxc-dave/fs/xattr.c	2007-09-20 12:16:16.000000000 -0700
@@ -11,6 +11,7 @@
 #include <linux/slab.h>
 #include <linux/file.h>
 #include <linux/xattr.h>
+#include <linux/mount.h>
 #include <linux/namei.h>
 #include <linux/security.h>
 #include <linux/syscalls.h>
@@ -32,8 +33,6 @@ xattr_permission(struct inode *inode, co
 	 * filesystem  or on an immutable / append-only inode.
 	 */
 	if (mask & MAY_WRITE) {
-		if (IS_RDONLY(inode))
-			return -EROFS;
 		if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
 			return -EPERM;
 	}
@@ -235,7 +234,11 @@ sys_setxattr(char __user *path, char __u
 	error = user_path_walk(path, &nd);
 	if (error)
 		return error;
+	error = mnt_want_write(nd.mnt);
+	if (error)
+		return error;
 	error = setxattr(nd.dentry, name, value, size, flags);
+	mnt_drop_write(nd.mnt);
 	path_release(&nd);
 	return error;
 }
@@ -250,7 +253,11 @@ sys_lsetxattr(char __user *path, char __
 	error = user_path_walk_link(path, &nd);
 	if (error)
 		return error;
+	error = mnt_want_write(nd.mnt);
+	if (error)
+		return error;
 	error = setxattr(nd.dentry, name, value, size, flags);
+	mnt_drop_write(nd.mnt);
 	path_release(&nd);
 	return error;
 }
@@ -266,9 +273,14 @@ sys_fsetxattr(int fd, char __user *name,
 	f = fget(fd);
 	if (!f)
 		return error;
+	error = mnt_want_write(f->f_vfsmnt);
+	if (error)
+		goto out_fput;
 	dentry = f->f_path.dentry;
 	audit_inode(NULL, dentry->d_inode);
 	error = setxattr(dentry, name, value, size, flags);
+	mnt_drop_write(f->f_vfsmnt);
+out_fput:
 	fput(f);
 	return error;
 }
_

  parent reply	other threads:[~2007-09-20 19:59 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-09-20 19:52 [PATCH 00/25] Read-only bind mounts Dave Hansen
2007-09-20 19:52 ` [PATCH 01/25] filesystem helpers for custom 'struct file's Dave Hansen
2007-09-20 19:52 ` [PATCH 02/25] rearrange may_open() to be r/o friendly Dave Hansen
2007-09-20 19:52 ` [PATCH 03/25] give may_open() a local 'mnt' variable Dave Hansen
2007-09-20 19:57   ` Christoph Hellwig
2007-09-20 19:52 ` [PATCH 04/25] create cleanup helper svc_msnfs() Dave Hansen
2007-09-20 19:52 ` [PATCH 05/25] r/o bind mounts: stub functions Dave Hansen
2007-09-20 19:52 ` [PATCH 06/25] elevate write count open()'d files Dave Hansen
2007-11-28  8:41   ` Andrew Morton
2007-11-28 17:33     ` Dave Hansen
2007-09-20 19:52 ` [PATCH 07/25] r/o bind mounts: elevate write count for some ioctls Dave Hansen
2007-09-21  8:17   ` Andrew Morton
2007-09-21 21:15     ` Dave Hansen
2007-09-26  1:34     ` [RFC] detect missed mnt_want_write() calls Dave Hansen
2007-09-21 23:03   ` [PATCH 07/25] r/o bind mounts: elevate write count for some ioctls Andrew Morton
2007-09-21 23:39     ` Dave Hansen
2007-09-21 23:47       ` Andrew Morton
2007-09-20 19:52 ` [PATCH 08/25] elevate writer count for chown and friends Dave Hansen
2007-09-20 19:53 ` [PATCH 09/25] make access() use mnt check Dave Hansen
2007-09-20 19:53 ` [PATCH 10/25] elevate mnt writers for callers of vfs_mkdir() Dave Hansen
2007-09-20 19:53 ` [PATCH 11/25] elevate write count during entire ncp_ioctl() Dave Hansen
2007-09-20 19:53 ` [PATCH 12/25] elevate write count for link and symlink calls Dave Hansen
2007-09-20 19:53 ` Dave Hansen [this message]
2007-09-20 19:53 ` [PATCH 14/25] elevate write count for file_update_time() Dave Hansen
2007-09-20 19:53 ` [PATCH 15/25] unix_find_other() elevate write count for touch_atime() Dave Hansen
2007-09-20 19:53 ` [PATCH 16/25] elevate write count over calls to vfs_rename() Dave Hansen
2007-09-20 19:53 ` [PATCH 17/25] nfs: check mnt instead of superblock directly Dave Hansen
2007-09-20 19:53 ` [PATCH 18/25] elevate writer count for do_sys_truncate() Dave Hansen
2007-09-20 19:53 ` [PATCH 19/25] elevate write count for do_utimes() Dave Hansen
2007-09-20 19:53 ` [PATCH 20/25] elevate write count for do_sys_utime() and touch_atime() Dave Hansen
2007-09-20 19:53 ` [PATCH 21/25] sys_mknodat(): elevate write count for vfs_mknod/create() Dave Hansen
2007-09-20 19:53 ` [PATCH 22/25] elevate mnt writers for vfs_unlink() callers Dave Hansen
2007-09-20 19:53 ` [PATCH 23/25] do_rmdir(): elevate write count Dave Hansen
2007-09-20 19:53 ` [PATCH 24/25] r/o bind mounts: track number of mount writers Dave Hansen
2007-09-24  6:17   ` Andrew Morton
2007-09-24 14:34     ` Arjan van de Ven
2007-09-24 22:06     ` Dave Hansen
2007-09-24 22:25       ` Andrew Morton
2007-09-24 23:05         ` Dave Hansen
2007-09-24 23:15           ` Andrew Morton
2007-09-25 16:10             ` Dave Hansen
2007-09-24 17:54   ` Christoph Hellwig
2007-09-24 19:10     ` Andrew Morton
2007-09-24 19:24       ` Christoph Hellwig
2007-09-24 19:28     ` Dave Hansen
2007-09-24 19:42       ` Andrew Morton
2007-10-01 18:06         ` Dave Hansen
2007-09-20 19:53 ` [PATCH 25/25] honor r/w changes at do_remount() time Dave Hansen

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