stopped killing fs
This commit is contained in:
parent
96ba11d9b2
commit
b9d65b0bcf
21
restart.bash
Executable file
21
restart.bash
Executable file
@ -0,0 +1,21 @@
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#!/bin/bash
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set -e
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# Убить все процессы, использующие /mnt/test
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sudo fuser -km /mnt/test || true
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# Подождать, пока умрут
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sleep 0.5
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# Умонтировать
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sudo umount /mnt/test || true
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# Выгрузить модуль
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sudo rmmod statsfs || true
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# Подождать, пока освободится
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sleep 0.5
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# Вставить модуль и смонтировать
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sudo insmod statsfs.ko
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sudo mount -t libfs none /mnt/test
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336
statsfs.c
336
statsfs.c
@ -9,6 +9,12 @@
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#include <linux/list.h>
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#include <linux/fs_context.h>
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#include <linux/err.h>
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#include <linux/uaccess.h>
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#include <linux/hashtable.h>
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#include <linux/buffer_head.h>
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#include <linux/mm.h>
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#include <linux/pagevec.h>
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#include <linux/writeback.h>
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#define LIBFS_MAGIC 0xA0B0C0D0
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#define LIBFS_BOOKS_MODE 01777
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@ -16,87 +22,172 @@
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#define LIBFS_SUBDIR_MODE 01777
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static struct super_block *libfs_sb;
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static struct inode *books_inode = NULL;
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static struct vfsmount *libfs_mnt;
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static struct inode *books_inode;
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static struct inode *authors_inode;
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static struct dentry *authors_dentry;
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static void libfs_evict_inode(struct inode *inode);
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struct link_entry {
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struct hlist_node node;
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struct dentry *link;
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};
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/* запрет создания FIFO/устройств */
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static int libfs_mknod(struct mnt_idmap *idmap, struct inode *dir,
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struct dentry *dentry, umode_t mode, dev_t dev)
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{
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return -EPERM;
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}
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/* запрет симв. ссылок */
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static int libfs_symlink(struct mnt_idmap *idmap, struct inode *dir,
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struct dentry *dentry, const char *target)
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{
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return -EPERM;
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}
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static int libfs_create(struct mnt_idmap *idmap, struct inode *dir,
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struct dentry *dentry, umode_t mode, bool excl);
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static int libfs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
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struct dentry *dentry, umode_t mode);
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static int libfs_unlink(struct inode *dir, struct dentry *dentry);
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static int libfs_rmdir(struct inode *dir, struct dentry *dentry);
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static int libfs_rename(struct mnt_idmap *idmap, struct inode *old_dir,
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struct dentry *old_dentry, struct inode *new_dir,
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struct dentry *new_dentry, unsigned int flags);
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static int libfs_link(struct dentry *old_dentry, struct inode *dir,
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struct dentry *new_dentry);
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static const struct super_operations libfs_sops = {
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.statfs = simple_statfs,
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.drop_inode = generic_delete_inode,
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.evict_inode = libfs_evict_inode,
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};
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static const struct file_operations libfs_file_ops = {
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.llseek = no_llseek,
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.read = NULL,
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.write = NULL,
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.read_iter = generic_file_read_iter,
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.write_iter = generic_file_write_iter,
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.llseek = generic_file_llseek,
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};
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static struct inode *libfs_get_inode(struct super_block *sb, umode_t mode) {
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struct inode *inode = new_inode(sb);
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if (!inode) return NULL;
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static const struct inode_operations libfs_dir_iops = {
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.lookup = simple_lookup,
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.mkdir = libfs_mkdir,
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.mknod = libfs_mknod,
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.symlink = libfs_symlink,
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.unlink = libfs_unlink,
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.rmdir = libfs_rmdir,
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.rename = libfs_rename,
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.link = libfs_link,
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.create = libfs_create,
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};
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static struct inode *libfs_get_inode(struct super_block *sb, umode_t mode)
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{
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struct inode *inode;
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if (!S_ISREG(mode) && !S_ISDIR(mode))
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return NULL;
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inode = new_inode(sb);
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if (!inode)
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return NULL;
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inode->i_ino = get_next_ino();
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inode->i_sb = sb;
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inode->i_op = &simple_dir_inode_operations;
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inode->i_mode = mode;
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if (S_ISDIR(mode)) {
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inode->i_op = &libfs_dir_iops;
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inode->i_fop = &simple_dir_operations;
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} else {
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/* файл — просто generic_file_* */
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inode->i_op = &simple_dir_inode_operations;
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inode->i_fop = &libfs_file_ops;
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/* заводим список жёстких ссылок */
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inode->i_private = kzalloc(sizeof(struct hlist_head), GFP_KERNEL);
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if (!inode->i_private) {
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iput(inode);
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return NULL;
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}
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INIT_HLIST_HEAD((struct hlist_head *)inode->i_private);
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}
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inode->i_mode = mode;
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return inode;
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}
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static bool is_protected_dentry(struct dentry *dentry) {
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return (strcmp(dentry->d_name.name, "books") == 0 || strcmp(dentry->d_name.name, "authors") == 0);
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}
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struct cleanup_ctx {
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struct inode *victim;
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};
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static void libfs_cleanup_links(struct inode *victim)
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static void cleanup_links(struct inode *victim)
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{
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struct dentry *root = libfs_sb->s_root;
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struct hlist_head *list;
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struct link_entry *le;
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struct hlist_node *tmp;
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struct qstr authors_q = QSTR_INIT("authors", 7);
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struct dentry *authors = d_lookup(root, &authors_q);
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if (!authors || d_really_is_negative(authors)) {
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dput(authors);
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if (!S_ISREG(victim->i_mode) || !victim->i_private)
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return;
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list = (struct hlist_head *)victim->i_private;
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hlist_for_each_entry_safe(le, tmp, list, node) {
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struct dentry *link = le->link;
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if (!link || d_unlinked(link)) {
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hlist_del(&le->node);
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dput(link);
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kfree(le);
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continue;
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}
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// Здесь конкретный пример: если ты сам знаешь имя линка на victim
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// То можешь через d_lookup() найти его и удалить
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struct qstr filename = QSTR_INIT("some_symlink", 12);
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struct dentry *maybe_link = d_lookup(authors, &filename);
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if (maybe_link && maybe_link->d_inode == victim) {
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inode_lock(authors->d_inode);
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vfs_unlink(NULL, authors->d_inode, maybe_link, NULL);
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inode_unlock(authors->d_inode);
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{
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struct dentry *pd = dget_parent(link);
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if (pd) {
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struct inode *parent = d_inode(pd);
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if (parent) {
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inode_lock(parent);
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vfs_unlink(NULL, parent, link, NULL);
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inode_unlock(parent);
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}
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dput(pd);
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}
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}
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dput(maybe_link);
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dput(authors);
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hlist_del(&le->node);
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dput(link);
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kfree(le);
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}
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static int libfs_unlink(struct inode *dir, struct dentry *dentry) {
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if (dir == libfs_sb->s_root->d_inode && is_protected_dentry(dentry))
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kfree(victim->i_private);
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victim->i_private = NULL;
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}
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static bool is_protected(struct dentry *dentry)
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{
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return strcmp(dentry->d_name.name, "books") == 0
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|| strcmp(dentry->d_name.name, "authors") == 0;
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}
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static int libfs_unlink(struct inode *dir, struct dentry *dentry)
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{
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struct inode *victim = d_inode(dentry);
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int ret;
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if (dir == libfs_sb->s_root->d_inode && is_protected(dentry))
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return -EPERM;
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struct inode *victim = dentry->d_inode;
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int ret = simple_unlink(dir, dentry);
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if (ret == 0 && dir == books_inode) {
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libfs_cleanup_links(victim);
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}
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ret = simple_unlink(dir, dentry);
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if (ret == 0 && dir == books_inode)
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cleanup_links(victim);
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return ret;
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}
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static int libfs_mkdir(struct mnt_idmap *idmap, struct inode *dir, struct dentry *dentry, umode_t mode) {
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if (dir == libfs_sb->s_root->d_inode) {
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static int libfs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
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struct dentry *dentry, umode_t mode)
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{
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struct inode *inode;
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if (dir == libfs_sb->s_root->d_inode || dir == books_inode)
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return -EPERM;
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}
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struct inode *inode = libfs_get_inode(dir->i_sb, S_IFDIR | LIBFS_SUBDIR_MODE);
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if (dir == authors_inode) {
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inode = libfs_get_inode(dir->i_sb, S_IFDIR | LIBFS_SUBDIR_MODE);
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if (!inode)
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return -ENOMEM;
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inode->i_uid = current_fsuid();
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@ -105,75 +196,118 @@ static int libfs_mkdir(struct mnt_idmap *idmap, struct inode *dir, struct dentry
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return 0;
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}
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static int libfs_rmdir(struct inode *dir, struct dentry *dentry) {
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if (dir == libfs_sb->s_root->d_inode && is_protected_dentry(dentry))
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return -EPERM;
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}
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static int libfs_rmdir(struct inode *dir, struct dentry *dentry)
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{
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if (dir == libfs_sb->s_root->d_inode && is_protected(dentry))
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return -EPERM;
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if (dir == authors_inode)
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return -EPERM;
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return simple_rmdir(dir, dentry);
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}
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static int libfs_rename(struct mnt_idmap *idmap, struct inode *old_dir, struct dentry *old_dentry,
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struct inode *new_dir, struct dentry *new_dentry, unsigned int flags) {
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if ((old_dir == libfs_sb->s_root->d_inode || new_dir == libfs_sb->s_root->d_inode) &&
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(is_protected_dentry(old_dentry) || is_protected_dentry(new_dentry)))
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static int libfs_rename(struct mnt_idmap *idmap, struct inode *old_dir,
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struct dentry *old_dentry, struct inode *new_dir,
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struct dentry *new_dentry, unsigned int flags)
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{
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if ((old_dir == libfs_sb->s_root->d_inode
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|| new_dir == libfs_sb->s_root->d_inode)
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&& (is_protected(old_dentry) || is_protected(new_dentry)))
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return -EPERM;
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if (old_dir == authors_inode || new_dir == authors_inode)
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return -EPERM;
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return simple_rename(idmap, old_dir, old_dentry, new_dir, new_dentry, flags);
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}
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static int libfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_dentry) {
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if (dir->i_sb != old_dentry->d_inode->i_sb)
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return -EXDEV;
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if (!S_ISREG(old_dentry->d_inode->i_mode))
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static int libfs_link(struct dentry *old_dentry, struct inode *dir,
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struct dentry *new_dentry)
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{
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struct inode *target = d_inode(old_dentry);
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struct hlist_head *list;
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struct link_entry *le;
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int ret;
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if (!S_ISREG(target->i_mode))
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return -EPERM;
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return simple_link(old_dentry, dir, new_dentry);
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if (!authors_dentry
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|| new_dentry->d_parent->d_parent != authors_dentry)
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return -EPERM;
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ret = simple_link(old_dentry, dir, new_dentry);
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if (ret)
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return ret;
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list = (struct hlist_head *)target->i_private;
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le = kmalloc(sizeof(*le), GFP_KERNEL);
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if (!le)
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return -ENOMEM;
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le->link = dget(new_dentry);
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hlist_add_head(&le->node, list);
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return 0;
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}
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static const struct inode_operations libfs_dir_iops = {
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.lookup = simple_lookup,
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.mkdir = libfs_mkdir,
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.unlink = libfs_unlink,
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.rmdir = libfs_rmdir,
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.rename = libfs_rename,
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.link = libfs_link,
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};
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static int libfs_fill_super(struct super_block *sb, void *data, int silent) {
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static int libfs_create(struct mnt_idmap *idmap, struct inode *dir,
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struct dentry *dentry, umode_t mode, bool excl)
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{
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struct inode *inode;
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struct dentry *root;
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if (dir != books_inode)
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return -EPERM;
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inode = libfs_get_inode(dir->i_sb, S_IFREG | mode);
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if (!inode)
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return -ENOMEM;
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inode->i_uid = current_fsuid();
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inode->i_gid = current_fsgid();
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d_add(dentry, inode);
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return 0;
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}
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static int libfs_fill_super(struct super_block *sb, void *data, int silent)
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{
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struct inode *root;
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libfs_sb = sb;
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sb->s_magic = LIBFS_MAGIC;
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sb->s_op = &libfs_sops;
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inode = libfs_get_inode(sb, S_IFDIR | 0755);
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if (!inode)
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return -ENOMEM;
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inode->i_op = &libfs_dir_iops;
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inode->i_fop = &simple_dir_operations;
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root = d_make_root(inode);
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root = libfs_get_inode(sb, S_IFDIR | 0755);
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if (!root)
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return -ENOMEM;
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sb->s_root = root;
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root->i_op = &libfs_dir_iops;
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root->i_fop = &simple_dir_operations;
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sb->s_root = d_make_root(root);
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if (!sb->s_root)
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return -ENOMEM;
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// /books
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books_inode = libfs_get_inode(sb, S_IFDIR | LIBFS_BOOKS_MODE);
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{
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struct inode *books = libfs_get_inode(sb, S_IFDIR | LIBFS_BOOKS_MODE);
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books_inode = books;
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struct dentry *d = d_alloc_name(root, "books");
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d_add(d, books);
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}
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// /authors
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{
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struct inode *authors = libfs_get_inode(sb, S_IFDIR | LIBFS_AUTHORS_MODE);
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struct dentry *d = d_alloc_name(root, "authors");
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d_add(d, authors);
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struct dentry *d = d_alloc_name(sb->s_root, "books");
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d_add(d, books_inode);
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}
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authors_inode = libfs_get_inode(sb, S_IFDIR | LIBFS_AUTHORS_MODE);
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authors_dentry = d_alloc_name(sb->s_root, "authors");
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d_add(authors_dentry, authors_inode);
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return 0;
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}
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static struct dentry *libfs_mount(struct file_system_type *fs_type, int flags, const char *dev_name, void *data) {
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static struct dentry *libfs_mount(struct file_system_type *fs_type,
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int flags, const char *dev_name, void *data)
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{
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return mount_nodev(fs_type, flags, data, libfs_fill_super);
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}
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static void libfs_evict_inode(struct inode *inode)
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{
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truncate_inode_pages_final(&inode->i_data);
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cleanup_links(inode);
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clear_inode(inode);
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}
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static struct file_system_type libfs_type = {
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.owner = THIS_MODULE,
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.name = "libfs",
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@ -181,16 +315,26 @@ static struct file_system_type libfs_type = {
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.kill_sb = kill_litter_super,
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};
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static int __init libfs_init(void) {
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int ret = register_filesystem(&libfs_type);
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if (ret)
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return ret;
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libfs_mnt = kern_mount(&libfs_type);
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return PTR_ERR_OR_ZERO(libfs_mnt);
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static int __init libfs_init(void)
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{
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return register_filesystem(&libfs_type);
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}
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static void __exit libfs_exit(void) {
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kern_unmount(libfs_mnt);
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static void __exit libfs_exit(void)
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{
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if (authors_dentry) {
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dput(authors_dentry);
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authors_dentry = NULL;
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}
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if (books_inode) {
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cleanup_links(books_inode);
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iput(books_inode);
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books_inode = NULL;
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}
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if (authors_inode) {
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iput(authors_inode);
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authors_inode = NULL;
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}
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unregister_filesystem(&libfs_type);
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}
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85
test.bash
Executable file
85
test.bash
Executable file
@ -0,0 +1,85 @@
|
||||
#!/bin/bash
|
||||
|
||||
mnt=/mnt/test
|
||||
|
||||
sudo mount -t libfs none "$mnt"
|
||||
|
||||
fail() {
|
||||
echo "FAIL: $1" >&2
|
||||
exit 1
|
||||
}
|
||||
|
||||
check_mode() {
|
||||
[ "$(stat -c '%a' "$1")" = "$2" ] || fail "$1 mode != $2"
|
||||
}
|
||||
|
||||
check_owner() {
|
||||
[ "$(stat -c '%U' "$1")" = "$2" ] || fail "$1 owner != $2"
|
||||
}
|
||||
|
||||
check_fail() {
|
||||
set +e
|
||||
"$@"
|
||||
status=$?
|
||||
set -e
|
||||
[ "$status" -ne 0 ] || fail "Expected failure: $*"
|
||||
}
|
||||
|
||||
|
||||
# 2. Права на директории
|
||||
check_mode "$mnt/books" 1777
|
||||
check_mode "$mnt/authors" 777
|
||||
|
||||
# 3. Удаление/переименование books
|
||||
check_fail rmdir "$mnt/books"
|
||||
check_fail mv "$mnt/books" "$mnt/b"
|
||||
|
||||
# 4. Создание файла
|
||||
sudo touch "$mnt/books/f1"
|
||||
echo "data" | sudo tee "$mnt/books/f1" > /dev/null
|
||||
[ "$(cat "$mnt/books/f1")" = "data" ] || fail "f1 content mismatch"
|
||||
|
||||
# 5. mkdir и mkfifo в books
|
||||
check_fail mkdir "$mnt/books/dir"
|
||||
check_fail mkfifo "$mnt/books/fifo"
|
||||
|
||||
# 6. mkdir в authors
|
||||
mkdir "$mnt/authors/u1"
|
||||
check_mode "$mnt/authors/u1" 1777
|
||||
|
||||
# 7. Переименование и удаление чужого каталога
|
||||
check_fail mv "$mnt/authors/u1" "$mnt/authors/u1-renamed"
|
||||
check_fail rmdir "$mnt/authors/u1-renamed"
|
||||
|
||||
# 8. ссылки в authors
|
||||
ln "$mnt/books/f1" "$mnt/authors/u1/link1"
|
||||
check_fail ln -s "$mnt/books/f1" "$mnt/authors/u1/symlink"
|
||||
check_fail touch "$mnt/authors/u1/new.txt"
|
||||
check_fail mkdir "$mnt/authors/u1/dir1"
|
||||
|
||||
# 9. удаление файла — должна исчезнуть ссылка
|
||||
sudo rm "$mnt/books/f1"
|
||||
[ ! -e "$mnt/authors/u1/link1" ] || fail "link1 not removed after f1 deletion"
|
||||
|
||||
# 10. пересоздание f1 — ссылка не должна появиться
|
||||
sudo touch "$mnt/books/f1"
|
||||
[ ! -e "$mnt/authors/u1/link1" ] || fail "link1 appeared after f1 recreated"
|
||||
|
||||
# 11. удалить только ссылку
|
||||
sudo touch "$mnt/books/f2"
|
||||
ln "$mnt/books/f2" "$mnt/authors/u1/link2"
|
||||
rm "$mnt/authors/u1/link2"
|
||||
[ -e "$mnt/books/f2" ] || fail "f2 removed with link2"
|
||||
|
||||
# 12. удалить файл после удаления ссылки
|
||||
ln "$mnt/books/f2" "$mnt/authors/u1/link2"
|
||||
rm "$mnt/authors/u1/link2"
|
||||
sudo rm "$mnt/books/f2"
|
||||
|
||||
# 13. remount check
|
||||
sudo umount "$mnt"
|
||||
sudo mount -t libfs none "$mnt"
|
||||
check_mode "$mnt/books" 1777
|
||||
check_mode "$mnt/authors" 777
|
||||
|
||||
echo "All tests passed."
|
||||
Loading…
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Reference in New Issue
Block a user