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https://github.com/torvalds/linux
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4609e1f18e
Convert to struct mnt_idmap.
Last cycle we merged the necessary infrastructure in
256c8aed2b ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.
Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.
Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.
Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
89 lines
2.2 KiB
C
89 lines
2.2 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Pioctl operations for Coda.
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* Original version: (C) 1996 Peter Braam
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* Rewritten for Linux 2.1: (C) 1997 Carnegie Mellon University
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*
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* Carnegie Mellon encourages users of this code to contribute improvements
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* to the Coda project. Contact Peter Braam <coda@cs.cmu.edu>.
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*/
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/time.h>
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#include <linux/fs.h>
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#include <linux/stat.h>
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#include <linux/errno.h>
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#include <linux/string.h>
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#include <linux/namei.h>
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#include <linux/module.h>
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#include <linux/uaccess.h>
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#include <linux/coda.h>
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#include "coda_psdev.h"
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#include "coda_linux.h"
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/* pioctl ops */
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static int coda_ioctl_permission(struct mnt_idmap *idmap,
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struct inode *inode, int mask);
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static long coda_pioctl(struct file *filp, unsigned int cmd,
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unsigned long user_data);
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/* exported from this file */
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const struct inode_operations coda_ioctl_inode_operations = {
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.permission = coda_ioctl_permission,
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.setattr = coda_setattr,
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};
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const struct file_operations coda_ioctl_operations = {
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.unlocked_ioctl = coda_pioctl,
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.llseek = noop_llseek,
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};
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/* the coda pioctl inode ops */
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static int coda_ioctl_permission(struct mnt_idmap *idmap,
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struct inode *inode, int mask)
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{
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return (mask & MAY_EXEC) ? -EACCES : 0;
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}
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static long coda_pioctl(struct file *filp, unsigned int cmd,
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unsigned long user_data)
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{
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struct path path;
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int error;
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struct PioctlData data;
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struct inode *inode = file_inode(filp);
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struct inode *target_inode = NULL;
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struct coda_inode_info *cnp;
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/* get the Pioctl data arguments from user space */
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if (copy_from_user(&data, (void __user *)user_data, sizeof(data)))
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return -EINVAL;
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/*
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* Look up the pathname. Note that the pathname is in
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* user memory, and namei takes care of this
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*/
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error = user_path_at(AT_FDCWD, data.path,
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data.follow ? LOOKUP_FOLLOW : 0, &path);
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if (error)
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return error;
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target_inode = d_inode(path.dentry);
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/* return if it is not a Coda inode */
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if (target_inode->i_sb != inode->i_sb) {
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error = -EINVAL;
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goto out;
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}
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/* now proceed to make the upcall */
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cnp = ITOC(target_inode);
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error = venus_pioctl(inode->i_sb, &(cnp->c_fid), cmd, &data);
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out:
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path_put(&path);
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return error;
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}
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