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path: root/fs/configfs

Age	Commit message (Expand)	Author
2020-06-01	Merge tag 'docs-5.8' of git://git.lwn.net/linux	Linus Torvalds
2020-05-05	docs: filesystems: convert configfs.txt to ReST	Mauro Carvalho Chehab
2020-04-27	configfs: fix config_item refcnt leak in configfs_rmdir()	Xiyu Yang
2019-12-08	utimes: Clamp the timestamps in notify_change()	Amir Goldstein
2019-11-06	configfs: calculate the depth of parent item	Honggang Li
2019-09-19	Merge tag 'configfs-for-5.4' of git://git.infradead.org/users/hch/configfs	Linus Torvalds
2019-09-19	Merge tag 'y2038-vfs' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/p...	Linus Torvalds
2019-09-11	configfs: calculate the symlink target only once	Al Viro
2019-09-11	configfs: make configfs_create() return inode	Al Viro
2019-09-11	configfs: factor dirent removal into helpers	Christoph Hellwig
2019-09-11	configfs: fix a deadlock in configfs_symlink()	Al Viro
2019-09-04	configfs: provide exclusion between IO and removals	Al Viro
2019-09-02	configfs: new object reprsenting tree fragments	Al Viro
2019-09-02	configfs_register_group() shouldn't be (and isn't) called in rmdirable parts	Al Viro
2019-09-02	configfs: stash the data we need into configfs_buffer at open time	Al Viro
2019-08-30	timestamp_truncate: Replace users of timespec64_trunc	Deepa Dinamani
2019-07-19	Merge branch 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/v...	Linus Torvalds
2019-07-10	Merge tag 'fsnotify_for_v5.3-rc1' of git://git.kernel.org/pub/scm/linux/kerne...	Linus Torvalds
2019-07-04	vfs: Convert configfs to use the new mount API	David Howells
2019-06-20	configfs: call fsnotify_rmdir() hook	Amir Goldstein
2019-05-31	Merge tag 'spdx-5.2-rc3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/g...	Linus Torvalds
2019-05-30	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 145	Thomas Gleixner
2019-05-28	configfs: Fix use-after-free when accessing sd->s_dentry	Sahitya Tummala
2019-05-21	treewide: Add SPDX license identifier - Makefile/Kconfig	Thomas Gleixner
2019-05-16	Merge tag 'configfs-for-5.2' of git://git.infradead.org/users/hch/configfs	Linus Torvalds
2019-05-08	configfs: fix possible use-after-free in configfs_register_group	YueHaibing
2019-04-08	fs: mark expected switch fall-throughs	Gustavo A. R. Silva
2018-07-17	configfs: fix registered group removal	Mike Christie
2018-07-02	configfs: replace strncpy with memcpy	Guenter Roeck
2018-06-19	configfs: use kvasprintf() instead of open-coding it	Bart Van Assche
2018-06-05	vfs: change inode times to use struct timespec64	Deepa Dinamani
2017-10-19	configfs: make ci_type field, some pointers and function arguments const	Bhumika Goyal
2017-10-19	configfs: Fix bool initialization/comparison	Thomas Meyer
2017-06-12	configfs: Introduce config_item_get_unless_zero()	Bart Van Assche
2017-06-12	configfs: Fix race between create_link and configfs_rmdir	Nicholas Bellinger
2016-12-24	Replace <asm/uaccess.h> with <linux/uaccess.h> globally	Linus Torvalds
2016-12-09	vfs: remove ".readlink = generic_readlink" assignments	Miklos Szeredi
2016-10-10	Merge remote-tracking branch 'ovl/rename2' into for-linus	Al Viro
2016-09-27	fs: Replace current_fs_time() with current_time()	Deepa Dinamani
2016-09-16	configfs: Return -EFBIG from configfs_write_bin_file.	Phil Turnbull
2016-07-10	configfs: don't set buffer_needs_fill to zero if show() returns error	Tal Shorer
2016-06-30	configfs: Remove ppos increment in configfs_write_bin_file	Marek Vasut
2016-05-09	configfs_readdir(): make safe under shared lock	Al Viro
2016-05-02	parallel lookups: actual switch to rwsem	Al Viro
2016-05-02	configfs_detach_prep(): make sure that wait_mutex won't go away	Al Viro
2016-04-04	mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros	Kirill A. Shutemov
2016-03-19	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/vir...	Linus Torvalds
2016-03-14	configfs: move d_rehash() into configfs_create() for regular files	Al Viro
2016-03-06	configfs: switch ->default groups to a linked list	Christoph Hellwig
2016-02-26	configfs: Replace CURRENT_TIME by current_fs_time()	Deepa Dinamani

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generated by cgit v1.2.3 (git 2.25.1) at 2024-09-10 10:06:02 +0000

// SPDX-License-Identifier: GPL-2.0-or-later
/* Filesystem access-by-fd.
 *
 * Copyright (C) 2017 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 */

#include <linux/fs_context.h>
#include <linux/fs_parser.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/syscalls.h>
#include <linux/security.h>
#include <linux/anon_inodes.h>
#include <linux/namei.h>
#include <linux/file.h>
#include <uapi/linux/mount.h>
#include "internal.h"
#include "mount.h"

/*
 * Allow the user to read back any error, warning or informational messages.
 */
static ssize_t fscontext_read(struct file *file,
			      char __user *_buf, size_t len, loff_t *pos)
{
	struct fs_context *fc = file->private_data;
	struct fc_log *log = fc->log.log;
	unsigned int logsize = ARRAY_SIZE(log->buffer);
	ssize_t ret;
	char *p;
	bool need_free;
	int index, n;

	ret = mutex_lock_interruptible(&fc->uapi_mutex);
	if (ret < 0)
		return ret;

	if (log->head == log->tail) {
		mutex_unlock(&fc->uapi_mutex);
		return -ENODATA;
	}

	index = log->tail & (logsize - 1);
	p = log->buffer[index];
	need_free = log->need_free & (1 << index);
	log->buffer[index] = NULL;
	log->need_free &= ~(1 << index);
	log->tail++;
	mutex_unlock(&fc->uapi_mutex);

	ret = -EMSGSIZE;
	n = strlen(p);
	if (n > len)
		goto err_free;
	ret = -EFAULT;
	if (copy_to_user(_buf, p, n) != 0)
		goto err_free;
	ret = n;

err_free:
	if (need_free)
		kfree(p);
	return ret;
}

static int fscontext_release(struct inode *inode, struct file *file)
{
	struct fs_context *fc = file->private_data;

	if (fc) {
		file->private_data = NULL;
		put_fs_context(fc);
	}
	return 0;
}

const struct file_operations fscontext_fops = {
	.read		= fscontext_read,
	.release	= fscontext_release,
	.llseek		= no_llseek,
};

/*
 * Attach a filesystem context to a file and an fd.
 */
static int fscontext_create_fd(struct fs_context *fc, unsigned int o_flags)
{
	int fd;

	fd = anon_inode_getfd("[fscontext]", &fscontext_fops, fc,
			      O_RDWR | o_flags);
	if (fd < 0)
		put_fs_context(fc);
	return fd;
}

static int fscontext_alloc_log(struct fs_context *fc)
{
	fc->log.log = kzalloc(sizeof(*fc->log.log), GFP_KERNEL);
	if (!fc->log.log)
		return -ENOMEM;
	refcount_set(&fc->log.log->usage, 1);
	fc->log.log->owner = fc->fs_type->owner;
	return 0;
}

/*
 * Open a filesystem by name so that it can be configured for mounting.
 *
 * We are allowed to specify a container in which the filesystem will be
 * opened, thereby indicating which namespaces will be used (notably, which
 * network namespace will be used for network filesystems).
 */
SYSCALL_DEFINE2(fsopen, const char __user *, _fs_name, unsigned int, flags)
{
	struct file_system_type *fs_type;
	struct fs_context *fc;
	const char *fs_name;
	int ret;

	if (!ns_capable(current->nsproxy->mnt_ns->user_ns, CAP_SYS_ADMIN))
		return -EPERM;

	if (flags & ~FSOPEN_CLOEXEC)
		return -EINVAL;

	fs_name = strndup_user(_fs_name, PAGE_SIZE);
	if (IS_ERR(fs_name))
		return PTR_ERR(fs_name);

	fs_type = get_fs_type(fs_name);
	kfree(fs_name);
	if (!fs_type)
		return -ENODEV;

	fc = fs_context_for_mount(fs_type, 0);
	put_filesystem(fs_type);
	if (IS_ERR(fc))
		return PTR_ERR(fc);

	fc->phase = FS_CONTEXT_CREATE_PARAMS;

	ret = fscontext_alloc_log(fc);
	if (ret < 0)
		goto err_fc;

	return fscontext_create_fd(fc, flags & FSOPEN_CLOEXEC ? O_CLOEXEC : 0);

err_fc:
	put_fs_context(fc);
	return ret;
}

/*
 * Pick a superblock into a context for reconfiguration.
 */
SYSCALL_DEFINE3(fspick, int, dfd, const char __user *, path, unsigned int, flags)
{
	struct fs_context *fc;
	struct path target;
	unsigned int lookup_flags;
	int ret;

	if (!ns_capable(current->nsproxy->mnt_ns->user_ns, CAP_SYS_ADMIN))
		return -EPERM;

	if ((flags & ~(FSPICK_CLOEXEC |
		       FSPICK_SYMLINK_NOFOLLOW |
		       FSPICK_NO_AUTOMOUNT |
		       FSPICK_EMPTY_PATH)) != 0)
		return -EINVAL;

	lookup_flags = LOOKUP_FOLLOW | LOOKUP_AUTOMOUNT;
	if (flags & FSPICK_SYMLINK_NOFOLLOW)
		lookup_flags &= ~LOOKUP_FOLLOW;
	if (flags & FSPICK_NO_AUTOMOUNT)
		lookup_flags &= ~LOOKUP_AUTOMOUNT;
	if (flags & FSPICK_EMPTY_PATH)
		lookup_flags |= LOOKUP_EMPTY;
	ret = user_path_at(dfd, path, lookup_flags, &target);
	if (ret < 0)
		goto err;

	ret = -EINVAL;
	if (target.mnt->mnt_root != target.dentry)
		goto err_path;

	fc = fs_context_for_reconfigure(target.dentry, 0, 0);
	if (IS_ERR(fc)) {
		ret = PTR_ERR(fc);
		goto err_path;
	}

	fc->phase = FS_CONTEXT_RECONF_PARAMS;

	ret = fscontext_alloc_log(fc);
	if (ret < 0)
		goto err_fc;

	path_put(&target);
	return fscontext_create_fd(fc, flags & FSPICK_CLOEXEC ? O_CLOEXEC : 0);

err_fc:
	put_fs_context(fc);
err_path:
	path_put(&target);
err:
	return ret;
}

/*
 * Check the state and apply the configuration.  Note that this function is
 * allowed to 'steal' the value by setting param->xxx to NULL before returning.
 */
static int vfs_fsconfig_locked(struct fs_context *fc, int cmd,
			       struct fs_parameter *param)
{
	struct super_block *sb;
	int ret;

	ret = finish_clean_context(fc);
	if (ret)
		return ret;
	switch (cmd) {
	case FSCONFIG_CMD_CREATE:
		if (fc->phase != FS_CONTEXT_CREATE_PARAMS)
			return -EBUSY;
		if (!mount_capable(fc))
			return -EPERM;
		fc->phase = FS_CONTEXT_CREATING;
		ret = vfs_get_tree(fc);
		if (ret)
			break;
		sb = fc->root->d_sb;
		ret = security_sb_kern_mount(sb);
		if (unlikely(ret)) {
			fc_drop_locked(fc);
			break;
		}
		up_write(&sb->s_umount);
		fc->phase = FS_CONTEXT_AWAITING_MOUNT;
		return 0;
	case FSCONFIG_CMD_RECONFIGURE:
		if (fc->phase != FS_CONTEXT_RECONF_PARAMS)
			return -EBUSY;
		fc->phase = FS_CONTEXT_RECONFIGURING;
		sb = fc->root->d_sb;
		if (!ns_capable(sb<