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kernel/audit_fsnotify.c
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// SPDX-License-Identifier: GPL-2.0-or-later /* audit_fsnotify.c -- tracking inodes * * Copyright 2003-2009,2014-2015 Red Hat, Inc. * Copyright 2005 Hewlett-Packard Development Company, L.P. * Copyright 2005 IBM Corporation */ #include <linux/kernel.h> #include <linux/audit.h> #include <linux/kthread.h> #include <linux/mutex.h> #include <linux/fs.h> #include <linux/fsnotify_backend.h> #include <linux/namei.h> #include <linux/netlink.h> #include <linux/sched.h> #include <linux/slab.h> #include <linux/security.h> #include "audit.h" /* * this mark lives on the parent directory of the inode in question. * but dev, ino, and path are about the child */ struct audit_fsnotify_mark { dev_t dev; /* associated superblock device */ unsigned long ino; /* associated inode number */ char *path; /* insertion path */ struct fsnotify_mark mark; /* fsnotify mark on the inode */ struct audit_krule *rule; }; /* fsnotify handle. */ static struct fsnotify_group *audit_fsnotify_group; /* fsnotify events we care about. */ #define AUDIT_FS_EVENTS (FS_MOVE | FS_CREATE | FS_DELETE | FS_DELETE_SELF |\ FS_MOVE_SELF | FS_EVENT_ON_CHILD) static void audit_fsnotify_mark_free(struct audit_fsnotify_mark *audit_mark) { kfree(audit_mark->path); kfree(audit_mark); } static void audit_fsnotify_free_mark(struct fsnotify_mark *mark) { struct audit_fsnotify_mark *audit_mark; audit_mark = container_of(mark, struct audit_fsnotify_mark, mark); audit_fsnotify_mark_free(audit_mark); } char *audit_mark_path(struct audit_fsnotify_mark *mark) { return mark->path; } int audit_mark_compare(struct audit_fsnotify_mark *mark, unsigned long ino, dev_t dev) { if (mark->ino == AUDIT_INO_UNSET) return 0; return (mark->ino == ino) && (mark->dev == dev); } static void audit_update_mark(struct audit_fsnotify_mark *audit_mark, const struct inode *inode) { audit_mark->dev = inode ? inode->i_sb->s_dev : AUDIT_DEV_UNSET; audit_mark->ino = inode ? inode->i_ino : AUDIT_INO_UNSET; } struct audit_fsnotify_mark *audit_alloc_mark(struct audit_krule *krule, char *pathname, int len) { struct audit_fsnotify_mark *audit_mark; struct path path; struct dentry *dentry; struct inode *inode; int ret; if (pathname[0] != '/' || pathname[len-1] == '/') return ERR_PTR(-EINVAL); dentry = kern_path_locked(pathname, &path); if (IS_ERR(dentry)) return (void *)dentry; /* returning an error */ inode = path.dentry->d_inode; inode_unlock(inode); audit_mark = kzalloc(sizeof(*audit_mark), GFP_KERNEL); if (unlikely(!audit_mark)) { audit_mark = ERR_PTR(-ENOMEM); goto out; } fsnotify_init_mark(&audit_mark->mark, audit_fsnotify_group); audit_mark->mark.mask = AUDIT_FS_EVENTS; audit_mark->path = pathname; audit_update_mark(audit_mark, dentry->d_inode); audit_mark->rule = krule; ret = fsnotify_add_inode_mark(&audit_mark->mark, inode, true); if (ret < 0) { fsnotify_put_mark(&audit_mark->mark); audit_mark = ERR_PTR(ret); } out: dput(dentry); path_put(&path); return audit_mark; } static void audit_mark_log_rule_change(struct audit_fsnotify_mark *audit_mark, char *op) { struct audit_buffer *ab; struct audit_krule *rule = audit_mark->rule; if (!audit_enabled) return; ab = audit_log_start(audit_context(), GFP_NOFS, AUDIT_CONFIG_CHANGE); if (unlikely(!ab)) return; audit_log_session_info(ab); audit_log_format(ab, " op=%s path=", op); audit_log_untrustedstring(ab, audit_mark->path); audit_log_key(ab, rule->filterkey); audit_log_format(ab, " list=%d res=1", rule->listnr); audit_log_end(ab); } void audit_remove_mark(struct audit_fsnotify_mark *audit_mark) { fsnotify_destroy_mark(&audit_mark->mark, audit_fsnotify_group); fsnotify_put_mark(&audit_mark->mark); } void audit_remove_mark_rule(struct audit_krule *krule) { struct audit_fsnotify_mark *mark = krule->exe; audit_remove_mark(mark); } static void audit_autoremove_mark_rule(struct audit_fsnotify_mark *audit_mark) { struct audit_krule *rule = audit_mark->rule; struct audit_entry *entry = container_of(rule, struct audit_entry, rule); audit_mark_log_rule_change(audit_mark, "autoremove_rule"); audit_del_rule(entry); } /* Update mark data in audit rules based on fsnotify events. */ static int audit_mark_handle_event(struct fsnotify_group *group, struct inode *to_tell, u32 mask, const void *data, int data_type, const struct qstr *dname, u32 cookie, struct fsnotify_iter_info *iter_info) { struct fsnotify_mark *inode_mark = fsnotify_iter_inode_mark(iter_info); struct audit_fsnotify_mark *audit_mark; const struct inode *inode = NULL; audit_mark = container_of(inode_mark, struct audit_fsnotify_mark, mark); BUG_ON(group != audit_fsnotify_group); switch (data_type) { case (FSNOTIFY_EVENT_PATH): inode = ((const struct path *)data)->dentry->d_inode; break; case (FSNOTIFY_EVENT_INODE): inode = (const struct inode *)data; break; default: BUG(); return 0; } if (mask & (FS_CREATE|FS_MOVED_TO|FS_DELETE|FS_MOVED_FROM)) { if (audit_compare_dname_path(dname, audit_mark->path, AUDIT_NAME_FULL)) return 0; audit_update_mark(audit_mark, inode); } else if (mask & (FS_DELETE_SELF|FS_UNMOUNT|FS_MOVE_SELF)) audit_autoremove_mark_rule(audit_mark); return 0; } static const struct fsnotify_ops audit_mark_fsnotify_ops = { .handle_event = audit_mark_handle_event, .free_mark = audit_fsnotify_free_mark, }; static int __init audit_fsnotify_init(void) { audit_fsnotify_group = fsnotify_alloc_group(&audit_mark_fsnotify_ops); if (IS_ERR(audit_fsnotify_group)) { audit_fsnotify_group = NULL; audit_panic("cannot create audit fsnotify group"); } return 0; } device_initcall(audit_fsnotify_init); |