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#include "audit.h"#include <linux/fsnotify_backend.h>#include <linux/namei.h>#include <linux/mount.h>#include <linux/kthread.h>#include <linux/slab.h> struct audit_tree;struct audit_chunk; struct audit_tree {	atomic_t count;	int goner;	struct audit_chunk *root;	struct list_head chunks;	struct list_head rules;	struct list_head list;	struct list_head same_root;	struct rcu_head head;	char pathname[];}; struct audit_chunk {	struct list_head hash;	struct fsnotify_mark mark;	struct list_head trees;		/* with root here */	int dead;	int count;	atomic_long_t refs;	struct rcu_head head;	struct node {		struct list_head list;		struct audit_tree *owner;		unsigned index;		/* index; upper bit indicates 'will prune' */	} owners[];}; static LIST_HEAD(tree_list);static LIST_HEAD(prune_list);static struct task_struct *prune_thread; /* * One struct chunk is attached to each inode of interest. * We replace struct chunk on tagging/untagging. * Rules have pointer to struct audit_tree. * Rules have struct list_head rlist forming a list of rules over * the same tree. * References to struct chunk are collected at audit_inode{,_child}() * time and used in AUDIT_TREE rule matching. * These references are dropped at the same time we are calling * audit_free_names(), etc. * * Cyclic lists galore: * tree.chunks anchors chunk.owners[].list			hash_lock * tree.rules anchors rule.rlist				audit_filter_mutex * chunk.trees anchors tree.same_root				hash_lock * chunk.hash is a hash with middle bits of watch.inode as * a hash function.						RCU, hash_lock * * tree is refcounted; one reference for "some rules on rules_list refer to * it", one for each chunk with pointer to it. * * chunk is refcounted by embedded fsnotify_mark + .refs (non-zero refcount * of watch contributes 1 to .refs). * * node.index allows to get from node.list to containing chunk. * MSB of that sucker is stolen to mark taggings that we might have to * revert - several operations have very unpleasant cleanup logics and * that makes a difference.  Some. */ static struct fsnotify_group *audit_tree_group; static struct audit_tree *alloc_tree(const char *s){	struct audit_tree *tree; 	tree = kmalloc(sizeof(struct audit_tree) + strlen(s) + 1, GFP_KERNEL);	if (tree) {		atomic_set(&tree->count, 1);		tree->goner = 0;		INIT_LIST_HEAD(&tree->chunks);		INIT_LIST_HEAD(&tree->rules);		INIT_LIST_HEAD(&tree->list);		INIT_LIST_HEAD(&tree->same_root);		tree->root = NULL;		strcpy(tree->pathname, s);	}	return tree;} static inline void get_tree(struct audit_tree *tree){	atomic_inc(&tree->count);} static inline void put_tree(struct audit_tree *tree){	if (atomic_dec_and_test(&tree->count))		kfree_rcu(tree, head);} /* to avoid bringing the entire thing in audit.h */const char *audit_tree_path(struct audit_tree *tree){	return tree->pathname;} static void free_chunk(struct audit_chunk *chunk){	int i; 	for (i = 0; i < chunk->count; i++) {		if (chunk->owners[i].owner)			put_tree(chunk->owners[i].owner);	}	kfree(chunk);} void audit_put_chunk(struct audit_chunk *chunk){	if (atomic_long_dec_and_test(&chunk->refs))		free_chunk(chunk);} static void __put_chunk(struct rcu_head *rcu){	struct audit_chunk *chunk = container_of(rcu, struct audit_chunk, head);	audit_put_chunk(chunk);} static void audit_tree_destroy_watch(struct fsnotify_mark *entry){	struct audit_chunk *chunk = container_of(entry, struct audit_chunk, mark);	call_rcu(&chunk->head, __put_chunk);} static struct audit_chunk *alloc_chunk(int count){	struct audit_chunk *chunk;	size_t size;	int i; 	size = offsetof(struct audit_chunk, owners) + count * sizeof(struct node);	chunk = kzalloc(size, GFP_KERNEL);	if (!chunk)		return NULL; 	INIT_LIST_HEAD(&chunk->hash);	INIT_LIST_HEAD(&chunk->trees);	chunk->count = count;	atomic_long_set(&chunk->refs, 1);	for (i = 0; i < count; i++) {		INIT_LIST_HEAD(&chunk->owners[i].list);		chunk->owners[i].index = i;	}	fsnotify_init_mark(&chunk->mark, audit_tree_destroy_watch);	chunk->mark.mask = FS_IN_IGNORED;	return chunk;} enum {HASH_SIZE = 128};static struct list_head chunk_hash_heads[HASH_SIZE];static __cacheline_aligned_in_smp DEFINE_SPINLOCK(hash_lock); static inline struct list_head *chunk_hash(const struct inode *inode){	unsigned long n = (unsigned long)inode / L1_CACHE_BYTES;	return chunk_hash_heads + n % HASH_SIZE;} /* hash_lock & entry->lock is held by caller */static void insert_hash(struct audit_chunk *chunk){	struct fsnotify_mark *entry = &chunk->mark;	struct list_head *list; 	if (!entry->inode)		return;	list = chunk_hash(entry->inode);	list_add_rcu(&chunk->hash, list);} /* called under rcu_read_lock */struct audit_chunk *audit_tree_lookup(const struct inode *inode){	struct list_head *list = chunk_hash(inode);	struct audit_chunk *p; 	list_for_each_entry_rcu(p, list, hash) {		/* mark.inode may have gone NULL, but who cares? */		if (p->mark.inode == inode) {			atomic_long_inc(&p->refs);			return p;		}	}	return NULL;} int audit_tree_match(struct audit_chunk *chunk, struct audit_tree *tree){	int n;	for (n = 0; n < chunk->count; n++)		if (chunk->owners[n].owner == tree)			return 1;	return 0;} /* tagging and untagging inodes with trees */ static struct audit_chunk *find_chunk(struct node *p){	int index = p->index & ~(1U<<31);	p -= index;	return container_of(p, struct audit_chunk, owners[0]);} static void untag_chunk(struct node *p){	struct audit_chunk *chunk = find_chunk(p);	struct fsnotify_mark *entry = &chunk->mark;	struct audit_chunk *new = NULL;	struct audit_tree *owner;	int size = chunk->count - 1;	int i, j; 	fsnotify_get_mark(entry); 	spin_unlock(&hash_lock); 	if (size)		new = alloc_chunk(size); 	spin_lock(&entry->lock);	if (chunk->dead || !entry->inode) {		spin_unlock(&entry->lock);		if (new)			free_chunk(new);		goto out;	} 	owner = p->owner; 	if (!size) {		chunk->dead = 1;		spin_lock(&hash_lock);		list_del_init(&chunk->trees);		if (owner->root == chunk)			owner->root = NULL;		list_del_init(&p->list);		list_del_rcu(&chunk->hash);		spin_unlock(&hash_lock);		spin_unlock(&entry->lock);		fsnotify_destroy_mark(entry, audit_tree_group);		goto out;	} 	if (!new)		goto Fallback; 	fsnotify_duplicate_mark(&new->mark, entry);	if (fsnotify_add_mark(&new->mark, new->mark.group, new->mark.inode, NULL, 1)) {		fsnotify_put_mark(&new->mark);		goto Fallback;	} 	chunk->dead = 1;	spin_lock(&hash_lock);	list_replace_init(&chunk->trees, &new->trees);	if (owner->root == chunk) {		list_del_init(&owner->same_root);		owner->root = NULL;	} 	for (i = j = 0; j <= size; i++, j++) {		struct audit_tree *s;		if (&chunk->owners[j] == p) {			list_del_init(&p->list);			i--;			continue;		}		s = chunk->owners[j].owner;		new->owners[i].owner = s;		new->owners[i].index = chunk->owners[j].index - j + i;		if (!s) /* result of earlier fallback */			continue;		get_tree(s);		list_replace_init(&chunk->owners[j].list, &new->owners[i].list);	} 	list_replace_rcu(&chunk->hash, &new->hash);	list_for_each_entry(owner, &new->trees, same_root)		owner->root = new;	spin_unlock(&hash_lock);	spin_unlock(&entry->lock);	fsnotify_destroy_mark(entry, audit_tree_group);	fsnotify_put_mark(&new->mark);	/* drop initial reference */	goto out; Fallback:	// do the best we can	spin_lock(&hash_lock);	if (owner->root == chunk) {		list_del_init(&owner->same_root);		owner->root = NULL;	}	list_del_init(&p->list);	p->owner = NULL;	put_tree(owner);	spin_unlock(&hash_lock);	spin_unlock(&entry->lock);out:	fsnotify_put_mark(entry);	spin_lock(&hash_lock);} static int create_chunk(struct inode *inode, struct audit_tree *tree){	struct fsnotify_mark *entry;	struct audit_chunk *chunk = alloc_chunk(1);	if (!chunk)		return -ENOMEM; 	entry = &chunk->mark;	if (fsnotify_add_mark(entry, audit_tree_group, inode, NULL, 0)) {		fsnotify_put_mark(entry);		return -ENOSPC;	} 	spin_lock(&entry->lock);	spin_lock(&hash_lock);	if (tree->goner) {		spin_unlock(&hash_lock);		chunk->dead = 1;		spin_unlock(&entry->lock);		fsnotify_destroy_mark(entry, audit_tree_group);		fsnotify_put_mark(entry);		return 0;	}	chunk->owners[0].index = (1U << 31);	chunk->owners[0].owner = tree;	get_tree(tree);	list_add(&chunk->owners[0].list, &tree->chunks);	if (!tree->root) {		tree->root = chunk;		list_add(&tree->same_root, &chunk->trees);	}	insert_hash(chunk);	spin_unlock(&hash_lock);	spin_unlock(&entry->lock);	fsnotify_put_mark(entry);	/* drop initial reference */	return 0;} /* the first tagged inode becomes root of tree */static int tag_chunk(struct inode *inode, struct audit_tree *tree){	struct fsnotify_mark *old_entry, *chunk_entry;	struct audit_tree *owner;	struct audit_chunk *chunk, *old;	struct node *p;	int n; 	old_entry = fsnotify_find_inode_mark(audit_tree_group, inode);	if (!old_entry)		return create_chunk(inode, tree); 	old = container_of(old_entry, struct audit_chunk, mark); 	/* are we already there? */	spin_lock(&hash_lock);	for (n = 0; n < old->count; n++) {		if (old->owners[n].owner == tree) {			spin_unlock(&hash_lock);			fsnotify_put_mark(old_entry);			return 0;		}	}	spin_unlock(&hash_lock); 	chunk = alloc_chunk(old->count + 1);	if (!chunk) {		fsnotify_put_mark(old_entry);		return -ENOMEM;	} 	chunk_entry = &chunk->mark; 	spin_lock(&old_entry->lock);	if (!old_entry->inode) {		/* old_entry is being shot, lets just lie */		spin_unlock(&old_entry->lock);		fsnotify_put_mark(old_entry);		free_chunk(chunk);		return -ENOENT;	} 	fsnotify_duplicate_mark(chunk_entry, old_entry);	if (fsnotify_add_mark(chunk_entry, chunk_entry->group, chunk_entry->inode, NULL, 1)) {		spin_unlock(&old_entry->lock);		fsnotify_put_mark(chunk_entry);		fsnotify_put_mark(old_entry);		return -ENOSPC;	} 	/* even though we hold old_entry->lock, this is safe since chunk_entry->lock could NEVER have been grabbed before */	spin_lock(&chunk_entry->lock);	spin_lock(&hash_lock); 	/* we now hold old_entry->lock, chunk_entry->lock, and hash_lock */	if (tree->goner) {		spin_unlock(&hash_lock);		chunk->dead = 1;		spin_unlock(&chunk_entry->lock);		spin_unlock(&old_entry->lock); 		fsnotify_destroy_mark(chunk_entry, audit_tree_group); 		fsnotify_put_mark(chunk_entry);		fsnotify_put_mark(old_entry);		return 0;	}	list_replace_init(&old->trees, &chunk->trees);	for (n = 0, p = chunk->owners; n < old->count; n++, p++) {		struct audit_tree *s = old->owners[n].owner;		p->owner = s;		p->index = old->owners[n].index;		if (!s) /* result of fallback in untag */			continue;		get_tree(s);		list_replace_init(&old->owners[n].list, &p->list);	}	p->index = (chunk->count - 1) | (1U<<31);	p->owner = tree;	get_tree(tree);	list_add(&p->list, &tree->chunks);	list_replace_rcu(&old->hash, &chunk->hash);	list_for_each_entry(owner, &chunk->trees, same_root)		owner->root = chunk;	old->dead = 1;	if (!tree->root) {		tree->root = chunk;		list_add(&tree->same_root, &chunk->trees);	}	spin_unlock(&hash_lock);	spin_unlock(&chunk_entry->lock);	spin_unlock(&old_entry->lock);	fsnotify_destroy_mark(old_entry, audit_tree_group);	fsnotify_put_mark(chunk_entry);	/* drop initial reference */	fsnotify_put_mark(old_entry); /* pair to fsnotify_find mark_entry */	return 0;} static void audit_tree_log_remove_rule(struct audit_krule *rule){	struct audit_buffer *ab; 	ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);	if (unlikely(!ab))		return;	audit_log_format(ab, "op=");	audit_log_string(ab, "remove_rule");	audit_log_format(ab, " dir=");	audit_log_untrustedstring(ab, rule->tree->pathname);	audit_log_key(ab, rule->filterkey);	audit_log_format(ab, " list=%d res=1", rule->listnr);	audit_log_end(ab);} static void kill_rules(struct audit_tree *tree){	struct audit_krule *rule, *next;	struct audit_entry *entry; 	list_for_each_entry_safe(rule, next, &tree->rules, rlist) {		entry = container_of(rule, struct audit_entry, rule); 		list_del_init(&rule->rlist);		if (rule->tree) {			/* not a half-baked one */			audit_tree_log_remove_rule(rule);			if (entry->rule.exe)				audit_remove_mark(entry->rule.exe);			rule->tree = NULL;			list_del_rcu(&entry->list);			list_del(&entry->rule.list);			call_rcu(&entry->rcu, audit_free_rule_rcu);		}	}} /* * finish killing struct audit_tree */static void prune_one(struct audit_tree *victim){	spin_lock(&hash_lock);	while (!list_empty(&victim->chunks)) {		struct node *p; 

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