The patch titled
r/o bind mounts: elevate write count for xattr_permission() callers
has been added to the -mm tree. Its filename is
r-o-bind-mounts-elevate-write-count-for-xattr_permission-callers.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: r/o bind mounts: elevate write count for xattr_permission() callers
From: Dave Hansen <haveblue@xxxxxxxxxx>
This basically audits the callers of xattr_permission(), which calls
permission() and can perform writes to the filesystem.
Acked-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Dave Hansen <haveblue@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/nfsd/nfs4proc.c | 7 ++++++-
fs/xattr.c | 16 ++++++++++++++--
2 files changed, 20 insertions(+), 3 deletions(-)
diff -puN fs/nfsd/nfs4proc.c~r-o-bind-mounts-elevate-write-count-for-xattr_permission-callers fs/nfsd/nfs4proc.c
--- a/fs/nfsd/nfs4proc.c~r-o-bind-mounts-elevate-write-count-for-xattr_permission-callers
+++ a/fs/nfsd/nfs4proc.c
@@ -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-write-count-for-xattr_permission-callers fs/xattr.c
--- a/fs/xattr.c~r-o-bind-mounts-elevate-write-count-for-xattr_permission-callers
+++ a/fs/xattr.c
@@ -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;
}
@@ -262,7 +261,11 @@ sys_setxattr(char __user *path, char __u
error = user_path_walk(path, &nd);
if (error)
return error;
+ error = mnt_want_write(nd.path.mnt);
+ if (error)
+ return error;
error = setxattr(nd.path.dentry, name, value, size, flags);
+ mnt_drop_write(nd.path.mnt);
path_put(&nd.path);
return error;
}
@@ -277,7 +280,11 @@ sys_lsetxattr(char __user *path, char __
error = user_path_walk_link(path, &nd);
if (error)
return error;
+ error = mnt_want_write(nd.path.mnt);
+ if (error)
+ return error;
error = setxattr(nd.path.dentry, name, value, size, flags);
+ mnt_drop_write(nd.path.mnt);
path_put(&nd.path);
return error;
}
@@ -293,9 +300,14 @@ 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;
}
_
Patches currently in -mm which might be from haveblue@xxxxxxxxxx are
enable-hotplug-memory-remove-for-ppc64.patch
reiserfs-eliminate-private-use-of-struct-file-in-xattr.patch
hppfs-pass-vfsmount-to-dentry_open.patch
check-for-null-vfsmount-in-dentry_open.patch
fix-up-new-filp-allocators.patch
do-namei_flags-calculation-inside-open_namei.patch
merge-open_namei-and-do_filp_open.patch
r-o-bind-mounts-stub-functions.patch
r-o-bind-mounts-create-helper-to-drop-file-write-access.patch
r-o-bind-mounts-drop-write-during-emergency-remount.patch
r-o-bind-mounts-elevate-write-count-for-vfs_rmdir.patch
r-o-bind-mounts-elevate-write-count-for-callers-of-vfs_mkdir.patch
r-o-bind-mounts-elevate-mnt_writers-for-unlink-callers.patch
r-o-bind-mounts-elevate-write-count-for-xattr_permission-callers.patch
r-o-bind-mounts-elevate-write-count-for-ncp_ioctl.patch
r-o-bind-mounts-write-counts-for-time-functions.patch
r-o-bind-mounts-elevate-write-count-for-do_utimes.patch
r-o-bind-mounts-write-count-for-file_update_time.patch
r-o-bind-mounts-write-counts-for-link-symlink.patch
r-o-bind-mounts-elevate-write-count-for-ioctls.patch
r-o-bind-mounts-elevate-write-count-for-opens.patch
r-o-bind-mounts-get-write-access-for-vfs_rename-callers.patch
r-o-bind-mounts-elevate-write-count-for-chmod-chown-callers.patch
r-o-bind-mounts-write-counts-for-truncate.patch
r-o-bind-mounts-elevate-count-for-xfs-timestamp-updates.patch
r-o-bind-mounts-make-access-use-new-r-o-helper.patch
r-o-bind-mounts-check-mnt-instead-of-superblock-directly.patch
r-o-bind-mounts-get-callers-of-vfs_mknod-create.patch
r-o-bind-mounts-track-numbers-of-writers-to-mounts.patch
r-o-bind-mounts-honor-mount-writer-counts-at-remount.patch
r-o-bind-mounts-debugging-for-missed-calls.patch
reiser4.patch
page-owner-tracking-leak-detector.patch
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