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ad982c3be4
Audit_alloc_mark() assign pathname to audit_mark->path, on error path
from fsnotify_add_inode_mark(), fsnotify_put_mark will free memory
of audit_mark->path, but the caller of audit_alloc_mark will free
the pathname again, so there will be double free problem.
Fix this by resetting audit_mark->path to NULL pointer on error path
from fsnotify_add_inode_mark().
Cc: stable@vger.kernel.org
Fixes: 7b12932340
("fsnotify: Add group pointer in fsnotify_init_mark()")
Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Paul Moore <paul@paul-moore.com>
194 lines
5.3 KiB
C
194 lines
5.3 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 ERR_CAST(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, 0);
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if (ret < 0) {
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audit_mark->path = NULL;
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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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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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FSNOTIFY_GROUP_DUPS);
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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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