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From: Dave Hansen <haveblue@us.ibm.com>
To: akpm@osdl.org
Cc: linux-kernel@vger.kernel.org, miklos@szeredi.hu,
	hch@infradead.org, Dave Hansen <haveblue@us.ibm.com>
Subject: [PATCH 10/27] r-o-bind-mounts-elevate-mount-count-for-extended-attributes
Date: Thu, 01 Nov 2007 16:08:39 -0700	[thread overview]
Message-ID: <20071101230839.D1B0DBB9@kernel> (raw)
In-Reply-To: <20071101230826.9A4F6E00@kernel>


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

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

 linux-2.6.git-dave/fs/nfsd/nfs4proc.c |    7 ++++++-
 linux-2.6.git-dave/fs/xattr.c         |   16 ++++++++++++++--
 2 files changed, 20 insertions(+), 3 deletions(-)

diff -puN fs/nfsd/nfs4proc.c~r-o-bind-mounts-elevate-mount-count-for-extended-attributes fs/nfsd/nfs4proc.c
--- linux-2.6.git/fs/nfsd/nfs4proc.c~r-o-bind-mounts-elevate-mount-count-for-extended-attributes	2007-11-01 14:46:11.000000000 -0700
+++ linux-2.6.git-dave/fs/nfsd/nfs4proc.c	2007-11-01 14:46:11.000000000 -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~r-o-bind-mounts-elevate-mount-count-for-extended-attributes fs/xattr.c
--- linux-2.6.git/fs/xattr.c~r-o-bind-mounts-elevate-mount-count-for-extended-attributes	2007-11-01 14:46:11.000000000 -0700
+++ linux-2.6.git-dave/fs/xattr.c	2007-11-01 14:46:11.000000000 -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);
 	error = setxattr(dentry, name, value, size, flags);
+	mnt_drop_write(f->f_vfsmnt);
+out_fput:
 	fput(f);
 	return error;
 }
_

  parent reply	other threads:[~2007-11-01 23:11 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-11-01 23:08 [PATCH 00/27] Read-only bind mounts (-mm resend) Dave Hansen
2007-11-01 23:08 ` [PATCH 01/27] do namei_flags calculation inside open_namei() Dave Hansen
2007-11-01 23:08 ` [PATCH 02/27] make open_namei() return a filp Dave Hansen
2007-11-01 23:08 ` [PATCH 03/27] kill do_filp_open() Dave Hansen
2007-11-01 23:08 ` [PATCH 04/27] kill filp_open() Dave Hansen
2008-01-16  8:52   ` Andrew Morton
2008-01-16 17:04     ` Dave Hansen
2008-01-16 17:10       ` Christoph Hellwig
2008-01-16 17:41         ` Dave Hansen
2008-01-16 17:47           ` Christoph Hellwig
2008-01-16 17:12       ` Bryn M. Reeves
2007-11-01 23:08 ` [PATCH 05/27] rename open_namei() to open_pathname() Dave Hansen
2007-11-26 14:33   ` Christoph Hellwig
2007-11-01 23:08 ` [PATCH 06/27] r-o-bind-mounts-stub-functions Dave Hansen
2007-11-01 23:08 ` [PATCH 07/27] r-o-bind-mounts-do_rmdir-elevate-write-count Dave Hansen
2007-11-01 23:08 ` [PATCH 08/27] r-o-bind-mounts-elevate-mnt-writers-for-callers-of-vfs_mkdir Dave Hansen
2007-11-01 23:08 ` [PATCH 09/27] r-o-bind-mounts-elevate-mnt-writers-for-vfs_unlink-callers Dave Hansen
2007-11-01 23:08 ` Dave Hansen [this message]
2007-11-01 23:08 ` [PATCH 11/27] r-o-bind-mounts-elevate-write-count-during-entire-ncp_ioctl Dave Hansen
2007-11-01 23:08 ` [PATCH 12/27] r-o-bind-mounts-elevate-write-count-for-do_sys_utime-and-touch_atime Dave Hansen
2007-11-01 23:08 ` [PATCH 13/27] r-o-bind-mounts-elevate-write-count-for-do_utimes Dave Hansen
2007-11-01 23:08 ` [PATCH 14/27] r-o-bind-mounts-elevate-write-count-for-file_update_time Dave Hansen
2007-11-01 23:08 ` [PATCH 15/27] r-o-bind-mounts-elevate-write-count-for-link-and-symlink-calls Dave Hansen
2007-11-01 23:08 ` [PATCH 16/27] r-o-bind-mounts-elevate-write-count-for-some-ioctls Dave Hansen
2007-11-05 23:23   ` Andrew Morton
2007-11-06  9:01     ` Jan Kara
2007-11-06  9:12       ` Andrew Morton
2007-11-01 23:08 ` [PATCH 17/27] r-o-bind-mounts-elevate-write-count-opend-files Dave Hansen
2007-11-01 23:08 ` [PATCH 18/27] r-o-bind-mounts-elevate-write-count-over-calls-to-vfs_rename Dave Hansen
2007-11-01 23:08 ` [PATCH 19/27] r-o-bind-mounts-elevate-writer-count-for-chown-and-friends Dave Hansen
2007-11-01 23:08 ` [PATCH 20/27] r-o-bind-mounts-elevate-writer-count-for-do_sys_truncate Dave Hansen
2007-11-01 23:08 ` [PATCH 21/27] r-o-bind-mounts-make-access-use-mnt-check Dave Hansen
2007-11-01 23:08 ` [PATCH 22/27] r-o-bind-mounts-nfs-check-mnt-instead-of-superblock-directly Dave Hansen
2007-11-01 23:08 ` [PATCH 23/27] r-o-bind-mounts-sys_mknodat-elevate-write-count-for-vfs_mknod-create Dave Hansen
2007-11-01 23:08 ` [PATCH 24/27] r-o-bind-mounts-track-number-of-mount-writers Dave Hansen
2007-11-01 23:09 ` [PATCH 25/27] r-o-bind-mounts-track-number-of-mount-writers-make-lockdep-happy-with-r-o-bind-mounts Dave Hansen
2007-11-05 23:35   ` Andrew Morton
2007-11-01 23:09 ` [PATCH 26/27] r-o-bind-mounts-honor-r-w-changes-at-do_remount-time Dave Hansen
2007-11-01 23:09 ` [PATCH 27/27] keep track of mnt_writer state of struct file Dave Hansen

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