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950cc0d2be
The handle_inode_event() interface was added as (quoting comment):
"a simple variant of handle_event() for groups that only have inode
marks and don't have ignore mask".
In other words, all backends except fanotify. The inotify backend
also falls under this category, but because it required extra arguments
it was left out of the initial pass of backends conversion to the
simple interface.
This results in code duplication between the generic helper
fsnotify_handle_event() and the inotify_handle_event() callback
which also happen to be buggy code.
Generalize the handle_inode_event() arguments and add the check for
FS_EXCL_UNLINK flag to the generic helper, so inotify backend could
be converted to use the simple interface.
Link: https://lore.kernel.org/r/20201202120713.702387-2-amir73il@gmail.com
CC: stable@vger.kernel.org
Fixes: b9a1b97725
("fsnotify: create method handle_inode_event() in fsnotify_operations")
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
193 lines
5.2 KiB
C
193 lines
5.2 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/* audit_fsnotify.c -- tracking inodes
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*
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* Copyright 2003-2009,2014-2015 Red Hat, Inc.
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* Copyright 2005 Hewlett-Packard Development Company, L.P.
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* Copyright 2005 IBM Corporation
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*/
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#include <linux/kernel.h>
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#include <linux/audit.h>
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#include <linux/kthread.h>
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#include <linux/mutex.h>
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#include <linux/fs.h>
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#include <linux/fsnotify_backend.h>
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#include <linux/namei.h>
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#include <linux/netlink.h>
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include <linux/security.h>
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#include "audit.h"
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/*
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* this mark lives on the parent directory of the inode in question.
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* but dev, ino, and path are about the child
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*/
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struct audit_fsnotify_mark {
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dev_t dev; /* associated superblock device */
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unsigned long ino; /* associated inode number */
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char *path; /* insertion path */
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struct fsnotify_mark mark; /* fsnotify mark on the inode */
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struct audit_krule *rule;
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};
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/* fsnotify handle. */
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static struct fsnotify_group *audit_fsnotify_group;
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/* fsnotify events we care about. */
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#define AUDIT_FS_EVENTS (FS_MOVE | FS_CREATE | FS_DELETE | FS_DELETE_SELF |\
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FS_MOVE_SELF)
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static void audit_fsnotify_mark_free(struct audit_fsnotify_mark *audit_mark)
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{
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kfree(audit_mark->path);
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kfree(audit_mark);
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}
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static void audit_fsnotify_free_mark(struct fsnotify_mark *mark)
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{
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struct audit_fsnotify_mark *audit_mark;
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audit_mark = container_of(mark, struct audit_fsnotify_mark, mark);
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audit_fsnotify_mark_free(audit_mark);
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}
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char *audit_mark_path(struct audit_fsnotify_mark *mark)
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{
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return mark->path;
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}
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int audit_mark_compare(struct audit_fsnotify_mark *mark, unsigned long ino, dev_t dev)
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{
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if (mark->ino == AUDIT_INO_UNSET)
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return 0;
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return (mark->ino == ino) && (mark->dev == dev);
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}
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static void audit_update_mark(struct audit_fsnotify_mark *audit_mark,
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const struct inode *inode)
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{
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audit_mark->dev = inode ? inode->i_sb->s_dev : AUDIT_DEV_UNSET;
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audit_mark->ino = inode ? inode->i_ino : AUDIT_INO_UNSET;
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}
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struct audit_fsnotify_mark *audit_alloc_mark(struct audit_krule *krule, char *pathname, int len)
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{
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struct audit_fsnotify_mark *audit_mark;
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struct path path;
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struct dentry *dentry;
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struct inode *inode;
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int ret;
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if (pathname[0] != '/' || pathname[len-1] == '/')
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return ERR_PTR(-EINVAL);
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dentry = kern_path_locked(pathname, &path);
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if (IS_ERR(dentry))
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return (void *)dentry; /* returning an error */
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inode = path.dentry->d_inode;
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inode_unlock(inode);
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audit_mark = kzalloc(sizeof(*audit_mark), GFP_KERNEL);
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if (unlikely(!audit_mark)) {
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audit_mark = ERR_PTR(-ENOMEM);
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goto out;
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}
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fsnotify_init_mark(&audit_mark->mark, audit_fsnotify_group);
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audit_mark->mark.mask = AUDIT_FS_EVENTS;
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audit_mark->path = pathname;
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audit_update_mark(audit_mark, dentry->d_inode);
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audit_mark->rule = krule;
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ret = fsnotify_add_inode_mark(&audit_mark->mark, inode, true);
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if (ret < 0) {
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fsnotify_put_mark(&audit_mark->mark);
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audit_mark = ERR_PTR(ret);
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}
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out:
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dput(dentry);
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path_put(&path);
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return audit_mark;
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}
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static void audit_mark_log_rule_change(struct audit_fsnotify_mark *audit_mark, char *op)
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{
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struct audit_buffer *ab;
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struct audit_krule *rule = audit_mark->rule;
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if (!audit_enabled)
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return;
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ab = audit_log_start(audit_context(), GFP_NOFS, AUDIT_CONFIG_CHANGE);
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if (unlikely(!ab))
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return;
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audit_log_session_info(ab);
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audit_log_format(ab, " op=%s path=", op);
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audit_log_untrustedstring(ab, audit_mark->path);
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audit_log_key(ab, rule->filterkey);
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audit_log_format(ab, " list=%d res=1", rule->listnr);
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audit_log_end(ab);
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}
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void audit_remove_mark(struct audit_fsnotify_mark *audit_mark)
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{
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fsnotify_destroy_mark(&audit_mark->mark, audit_fsnotify_group);
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fsnotify_put_mark(&audit_mark->mark);
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}
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void audit_remove_mark_rule(struct audit_krule *krule)
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{
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struct audit_fsnotify_mark *mark = krule->exe;
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audit_remove_mark(mark);
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}
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static void audit_autoremove_mark_rule(struct audit_fsnotify_mark *audit_mark)
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{
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struct audit_krule *rule = audit_mark->rule;
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struct audit_entry *entry = container_of(rule, struct audit_entry, rule);
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audit_mark_log_rule_change(audit_mark, "autoremove_rule");
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audit_del_rule(entry);
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}
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/* Update mark data in audit rules based on fsnotify events. */
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static int audit_mark_handle_event(struct fsnotify_mark *inode_mark, u32 mask,
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struct inode *inode, struct inode *dir,
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const struct qstr *dname, u32 cookie)
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{
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struct audit_fsnotify_mark *audit_mark;
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audit_mark = container_of(inode_mark, struct audit_fsnotify_mark, mark);
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if (WARN_ON_ONCE(inode_mark->group != audit_fsnotify_group) ||
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WARN_ON_ONCE(!inode))
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return 0;
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if (mask & (FS_CREATE|FS_MOVED_TO|FS_DELETE|FS_MOVED_FROM)) {
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if (audit_compare_dname_path(dname, audit_mark->path, AUDIT_NAME_FULL))
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return 0;
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audit_update_mark(audit_mark, inode);
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} else if (mask & (FS_DELETE_SELF|FS_UNMOUNT|FS_MOVE_SELF)) {
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audit_autoremove_mark_rule(audit_mark);
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}
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return 0;
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}
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static const struct fsnotify_ops audit_mark_fsnotify_ops = {
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.handle_inode_event = audit_mark_handle_event,
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.free_mark = audit_fsnotify_free_mark,
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};
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static int __init audit_fsnotify_init(void)
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{
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audit_fsnotify_group = fsnotify_alloc_group(&audit_mark_fsnotify_ops);
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if (IS_ERR(audit_fsnotify_group)) {
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audit_fsnotify_group = NULL;
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audit_panic("cannot create audit fsnotify group");
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}
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return 0;
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}
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device_initcall(audit_fsnotify_init);
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