The patch titled
r/o bind mounts: sys_mknodat(): elevate write count for vfs_mknod/create()
has been added to the -mm tree. Its filename is
r-o-bind-mounts-sys_mknodat-elevate-write-count-for-vfs_mknod-create.patch
*** 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
------------------------------------------------------
Subject: r/o bind mounts: sys_mknodat(): elevate write count for vfs_mknod/create()
From: Dave Hansen <hansendc@xxxxxxxxxx>
This takes care of all of the direct callers of vfs_mknod(). Since a few of
these cases also handle normal file creation as well, this also covers some
calls to vfs_create().
Signed-off-by: Dave Hansen <haveblue@xxxxxxxxxx>
Cc: Miklos Szeredi <miklos@xxxxxxxxxx>
Cc: Ram Pai <linuxram@xxxxxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/namei.c | 12 ++++++++++++
fs/nfsd/vfs.c | 4 ++++
net/unix/af_unix.c | 4 ++++
3 files changed, 20 insertions(+)
diff -puN fs/namei.c~r-o-bind-mounts-sys_mknodat-elevate-write-count-for-vfs_mknod-create fs/namei.c
--- a/fs/namei.c~r-o-bind-mounts-sys_mknodat-elevate-write-count-for-vfs_mknod-create
+++ a/fs/namei.c
@@ -1899,14 +1899,26 @@ asmlinkage long sys_mknodat(int dfd, con
if (!IS_ERR(dentry)) {
switch (mode & S_IFMT) {
case 0: case S_IFREG:
+ error = mnt_want_write(nd.mnt);
+ if (error)
+ break;
error = vfs_create(nd.dentry->d_inode,dentry,mode,&nd);
+ mnt_drop_write(nd.mnt);
break;
case S_IFCHR: case S_IFBLK:
+ error = mnt_want_write(nd.mnt);
+ if (error)
+ break;
error = vfs_mknod(nd.dentry->d_inode,dentry,mode,
new_decode_dev(dev));
+ mnt_drop_write(nd.mnt);
break;
case S_IFIFO: case S_IFSOCK:
+ error = mnt_want_write(nd.mnt);
+ if (error)
+ break;
error = vfs_mknod(nd.dentry->d_inode,dentry,mode,0);
+ mnt_drop_write(nd.mnt);
break;
case S_IFDIR:
error = -EPERM;
diff -puN fs/nfsd/vfs.c~r-o-bind-mounts-sys_mknodat-elevate-write-count-for-vfs_mknod-create fs/nfsd/vfs.c
--- a/fs/nfsd/vfs.c~r-o-bind-mounts-sys_mknodat-elevate-write-count-for-vfs_mknod-create
+++ a/fs/nfsd/vfs.c
@@ -664,6 +664,9 @@ nfsd_open(struct svc_rqst *rqstp, struct
/* Disallow write access to files with the append-only bit set
* or any access when mandatory locking enabled
*/
+ err = mnt_want_write(fhp->fh_export->ex_mnt);
+ if (err)
+ goto out_nfserr;
err = nfserr_perm;
if (IS_APPEND(inode) && (access & MAY_WRITE))
goto out;
@@ -1199,6 +1202,7 @@ nfsd_create(struct svc_rqst *rqstp, stru
printk("nfsd: bad file type %o in nfsd_create\n", type);
host_err = -EINVAL;
}
+ mnt_drop_write(fhp->fh_export->ex_mnt);
if (host_err < 0)
goto out_nfserr;
diff -puN net/unix/af_unix.c~r-o-bind-mounts-sys_mknodat-elevate-write-count-for-vfs_mknod-create net/unix/af_unix.c
--- a/net/unix/af_unix.c~r-o-bind-mounts-sys_mknodat-elevate-write-count-for-vfs_mknod-create
+++ a/net/unix/af_unix.c
@@ -816,7 +816,11 @@ static int unix_bind(struct socket *sock
*/
mode = S_IFSOCK |
(SOCK_INODE(sock)->i_mode & ~current->fs->umask);
+ err = mnt_want_write(nd.mnt);
+ if (err)
+ goto out_mknod_dput;
err = vfs_mknod(nd.dentry->d_inode, dentry, mode, 0);
+ mnt_drop_write(nd.mnt);
if (err)
goto out_mknod_dput;
mutex_unlock(&nd.dentry->d_inode->i_mutex);
_
Patches currently in -mm which might be from hansendc@xxxxxxxxxx are
r-o-bind-mounts-filesystem-helpers-for-custom-struct-files.patch
r-o-bind-mounts-add-vfsmount-writer-counts.patch
r-o-bind-mounts-record-when-sb_writer_count-elevated-for-inode.patch
r-o-bind-mounts-elevate-writer-count-for-chown-and-friends.patch
r-o-bind-mounts-elevate-mnt-writers-for-callers-of-vfs_mkdir.patch
r-o-bind-mounts-elevate-write-count-during-entire-ncp_ioctl.patch
r-o-bind-mounts-elevate-write-count-for-link-and-symlink-calls.patch
r-o-bind-mounts-elevate-mount-count-for-extended-attributes.patch
r-o-bind-mounts-mount_is_safe-add-comment.patch
r-o-bind-mounts-unix_find_other-elevate-write-count-for-touch_atime.patch
r-o-bind-mounts-elevate-write-count-over-calls-to-vfs_rename.patch
r-o-bind-mounts-elevate-write-count-files-are-opened.patch
r-o-bind-mounts-elevate-writer-count-for-do_sys_truncate.patch
r-o-bind-mounts-elevate-write-count-for-do_utimes.patch
r-o-bind-mounts-elevate-write-count-for-do_sys_utime-and-touch_atime.patch
r-o-bind-mounts-sys_mknodat-elevate-write-count-for-vfs_mknod-create.patch
r-o-bind-mounts-elevate-mnt-writers-for-vfs_unlink-callers.patch
r-o-bind-mounts-do_rmdir-elevate-write-count.patch
r-o-bind-mounts-elevate-writer-count-for-custom-struct_file.patch
r-o-bind-mounts-gfs-check-nlink-count.patch
r-o-bind-mounts-honor-r-w-changes-at-do_remount-time.patch
r-o-bind-mounts-kill-open-files-traverse-on-remount-ro.patch
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