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![Amir Goldstein](/assets/img/avatar_default.png)
audit inode marks pin the inode so there is no need to set the FSNOTIFY_GROUP_NOFS flag. Link: https://lore.kernel.org/r/20220422120327.3459282-9-amir73il@gmail.com Suggested-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/20220321112310.vpr7oxro2xkz5llh@quack3.lan/ Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Jan Kara <jack@suse.cz>
1086 lines
26 KiB
C
1086 lines
26 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include "audit.h"
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#include <linux/fsnotify_backend.h>
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#include <linux/namei.h>
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#include <linux/mount.h>
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#include <linux/kthread.h>
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#include <linux/refcount.h>
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#include <linux/slab.h>
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struct audit_tree;
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struct audit_chunk;
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struct audit_tree {
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refcount_t count;
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int goner;
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struct audit_chunk *root;
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struct list_head chunks;
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struct list_head rules;
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struct list_head list;
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struct list_head same_root;
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struct rcu_head head;
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char pathname[];
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};
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struct audit_chunk {
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struct list_head hash;
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unsigned long key;
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struct fsnotify_mark *mark;
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struct list_head trees; /* with root here */
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int count;
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atomic_long_t refs;
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struct rcu_head head;
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struct audit_node {
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struct list_head list;
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struct audit_tree *owner;
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unsigned index; /* index; upper bit indicates 'will prune' */
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} owners[];
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};
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struct audit_tree_mark {
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struct fsnotify_mark mark;
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struct audit_chunk *chunk;
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};
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static LIST_HEAD(tree_list);
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static LIST_HEAD(prune_list);
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static struct task_struct *prune_thread;
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/*
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* One struct chunk is attached to each inode of interest through
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* audit_tree_mark (fsnotify mark). We replace struct chunk on tagging /
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* untagging, the mark is stable as long as there is chunk attached. The
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* association between mark and chunk is protected by hash_lock and
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* audit_tree_group->mark_mutex. Thus as long as we hold
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* audit_tree_group->mark_mutex and check that the mark is alive by
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* FSNOTIFY_MARK_FLAG_ATTACHED flag check, we are sure the mark points to
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* the current chunk.
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*
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* Rules have pointer to struct audit_tree.
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* Rules have struct list_head rlist forming a list of rules over
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* the same tree.
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* References to struct chunk are collected at audit_inode{,_child}()
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* time and used in AUDIT_TREE rule matching.
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* These references are dropped at the same time we are calling
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* audit_free_names(), etc.
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*
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* Cyclic lists galore:
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* tree.chunks anchors chunk.owners[].list hash_lock
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* tree.rules anchors rule.rlist audit_filter_mutex
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* chunk.trees anchors tree.same_root hash_lock
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* chunk.hash is a hash with middle bits of watch.inode as
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* a hash function. RCU, hash_lock
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*
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* tree is refcounted; one reference for "some rules on rules_list refer to
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* it", one for each chunk with pointer to it.
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*
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* chunk is refcounted by embedded .refs. Mark associated with the chunk holds
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* one chunk reference. This reference is dropped either when a mark is going
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* to be freed (corresponding inode goes away) or when chunk attached to the
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* mark gets replaced. This reference must be dropped using
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* audit_mark_put_chunk() to make sure the reference is dropped only after RCU
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* grace period as it protects RCU readers of the hash table.
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*
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* node.index allows to get from node.list to containing chunk.
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* MSB of that sucker is stolen to mark taggings that we might have to
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* revert - several operations have very unpleasant cleanup logics and
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* that makes a difference. Some.
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*/
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static struct fsnotify_group *audit_tree_group;
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static struct kmem_cache *audit_tree_mark_cachep __read_mostly;
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static struct audit_tree *alloc_tree(const char *s)
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{
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struct audit_tree *tree;
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tree = kmalloc(struct_size(tree, pathname, strlen(s) + 1), GFP_KERNEL);
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if (tree) {
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refcount_set(&tree->count, 1);
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tree->goner = 0;
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INIT_LIST_HEAD(&tree->chunks);
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INIT_LIST_HEAD(&tree->rules);
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INIT_LIST_HEAD(&tree->list);
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INIT_LIST_HEAD(&tree->same_root);
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tree->root = NULL;
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strcpy(tree->pathname, s);
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}
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return tree;
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}
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static inline void get_tree(struct audit_tree *tree)
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{
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refcount_inc(&tree->count);
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}
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static inline void put_tree(struct audit_tree *tree)
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{
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if (refcount_dec_and_test(&tree->count))
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kfree_rcu(tree, head);
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}
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/* to avoid bringing the entire thing in audit.h */
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const char *audit_tree_path(struct audit_tree *tree)
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{
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return tree->pathname;
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}
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static void free_chunk(struct audit_chunk *chunk)
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{
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int i;
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for (i = 0; i < chunk->count; i++) {
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if (chunk->owners[i].owner)
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put_tree(chunk->owners[i].owner);
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}
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kfree(chunk);
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}
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void audit_put_chunk(struct audit_chunk *chunk)
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{
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if (atomic_long_dec_and_test(&chunk->refs))
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free_chunk(chunk);
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}
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static void __put_chunk(struct rcu_head *rcu)
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{
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struct audit_chunk *chunk = container_of(rcu, struct audit_chunk, head);
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audit_put_chunk(chunk);
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}
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/*
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* Drop reference to the chunk that was held by the mark. This is the reference
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* that gets dropped after we've removed the chunk from the hash table and we
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* use it to make sure chunk cannot be freed before RCU grace period expires.
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*/
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static void audit_mark_put_chunk(struct audit_chunk *chunk)
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{
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call_rcu(&chunk->head, __put_chunk);
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}
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static inline struct audit_tree_mark *audit_mark(struct fsnotify_mark *mark)
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{
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return container_of(mark, struct audit_tree_mark, mark);
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}
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static struct audit_chunk *mark_chunk(struct fsnotify_mark *mark)
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{
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return audit_mark(mark)->chunk;
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}
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static void audit_tree_destroy_watch(struct fsnotify_mark *mark)
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{
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kmem_cache_free(audit_tree_mark_cachep, audit_mark(mark));
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}
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static struct fsnotify_mark *alloc_mark(void)
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{
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struct audit_tree_mark *amark;
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amark = kmem_cache_zalloc(audit_tree_mark_cachep, GFP_KERNEL);
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if (!amark)
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return NULL;
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fsnotify_init_mark(&amark->mark, audit_tree_group);
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amark->mark.mask = FS_IN_IGNORED;
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return &amark->mark;
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}
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static struct audit_chunk *alloc_chunk(int count)
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{
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struct audit_chunk *chunk;
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int i;
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chunk = kzalloc(struct_size(chunk, owners, count), GFP_KERNEL);
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if (!chunk)
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return NULL;
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INIT_LIST_HEAD(&chunk->hash);
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INIT_LIST_HEAD(&chunk->trees);
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chunk->count = count;
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atomic_long_set(&chunk->refs, 1);
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for (i = 0; i < count; i++) {
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INIT_LIST_HEAD(&chunk->owners[i].list);
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chunk->owners[i].index = i;
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}
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return chunk;
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}
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enum {HASH_SIZE = 128};
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static struct list_head chunk_hash_heads[HASH_SIZE];
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static __cacheline_aligned_in_smp DEFINE_SPINLOCK(hash_lock);
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/* Function to return search key in our hash from inode. */
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static unsigned long inode_to_key(const struct inode *inode)
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{
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/* Use address pointed to by connector->obj as the key */
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return (unsigned long)&inode->i_fsnotify_marks;
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}
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static inline struct list_head *chunk_hash(unsigned long key)
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{
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unsigned long n = key / L1_CACHE_BYTES;
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return chunk_hash_heads + n % HASH_SIZE;
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}
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/* hash_lock & mark->group->mark_mutex is held by caller */
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static void insert_hash(struct audit_chunk *chunk)
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{
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struct list_head *list;
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/*
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* Make sure chunk is fully initialized before making it visible in the
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* hash. Pairs with a data dependency barrier in READ_ONCE() in
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* audit_tree_lookup().
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*/
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smp_wmb();
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WARN_ON_ONCE(!chunk->key);
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list = chunk_hash(chunk->key);
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list_add_rcu(&chunk->hash, list);
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}
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/* called under rcu_read_lock */
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struct audit_chunk *audit_tree_lookup(const struct inode *inode)
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{
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unsigned long key = inode_to_key(inode);
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struct list_head *list = chunk_hash(key);
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struct audit_chunk *p;
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list_for_each_entry_rcu(p, list, hash) {
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/*
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* We use a data dependency barrier in READ_ONCE() to make sure
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* the chunk we see is fully initialized.
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*/
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if (READ_ONCE(p->key) == key) {
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atomic_long_inc(&p->refs);
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return p;
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}
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}
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return NULL;
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}
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bool audit_tree_match(struct audit_chunk *chunk, struct audit_tree *tree)
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{
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int n;
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for (n = 0; n < chunk->count; n++)
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if (chunk->owners[n].owner == tree)
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return true;
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return false;
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}
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/* tagging and untagging inodes with trees */
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static struct audit_chunk *find_chunk(struct audit_node *p)
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{
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int index = p->index & ~(1U<<31);
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p -= index;
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return container_of(p, struct audit_chunk, owners[0]);
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}
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static void replace_mark_chunk(struct fsnotify_mark *mark,
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struct audit_chunk *chunk)
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{
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struct audit_chunk *old;
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assert_spin_locked(&hash_lock);
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old = mark_chunk(mark);
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audit_mark(mark)->chunk = chunk;
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if (chunk)
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chunk->mark = mark;
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if (old)
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old->mark = NULL;
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}
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static void replace_chunk(struct audit_chunk *new, struct audit_chunk *old)
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{
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struct audit_tree *owner;
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int i, j;
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new->key = old->key;
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list_splice_init(&old->trees, &new->trees);
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list_for_each_entry(owner, &new->trees, same_root)
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owner->root = new;
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for (i = j = 0; j < old->count; i++, j++) {
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if (!old->owners[j].owner) {
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i--;
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continue;
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}
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owner = old->owners[j].owner;
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new->owners[i].owner = owner;
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new->owners[i].index = old->owners[j].index - j + i;
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if (!owner) /* result of earlier fallback */
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continue;
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get_tree(owner);
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list_replace_init(&old->owners[j].list, &new->owners[i].list);
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}
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replace_mark_chunk(old->mark, new);
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/*
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* Make sure chunk is fully initialized before making it visible in the
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* hash. Pairs with a data dependency barrier in READ_ONCE() in
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* audit_tree_lookup().
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*/
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smp_wmb();
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list_replace_rcu(&old->hash, &new->hash);
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}
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static void remove_chunk_node(struct audit_chunk *chunk, struct audit_node *p)
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{
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struct audit_tree *owner = p->owner;
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if (owner->root == chunk) {
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list_del_init(&owner->same_root);
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owner->root = NULL;
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}
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list_del_init(&p->list);
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p->owner = NULL;
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put_tree(owner);
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}
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static int chunk_count_trees(struct audit_chunk *chunk)
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{
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int i;
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int ret = 0;
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for (i = 0; i < chunk->count; i++)
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if (chunk->owners[i].owner)
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ret++;
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return ret;
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}
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static void untag_chunk(struct audit_chunk *chunk, struct fsnotify_mark *mark)
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{
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struct audit_chunk *new;
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int size;
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fsnotify_group_lock(audit_tree_group);
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/*
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* mark_mutex stabilizes chunk attached to the mark so we can check
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* whether it didn't change while we've dropped hash_lock.
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*/
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if (!(mark->flags & FSNOTIFY_MARK_FLAG_ATTACHED) ||
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mark_chunk(mark) != chunk)
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goto out_mutex;
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size = chunk_count_trees(chunk);
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if (!size) {
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spin_lock(&hash_lock);
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list_del_init(&chunk->trees);
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list_del_rcu(&chunk->hash);
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replace_mark_chunk(mark, NULL);
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spin_unlock(&hash_lock);
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fsnotify_detach_mark(mark);
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fsnotify_group_unlock(audit_tree_group);
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audit_mark_put_chunk(chunk);
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fsnotify_free_mark(mark);
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return;
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}
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new = alloc_chunk(size);
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if (!new)
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goto out_mutex;
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spin_lock(&hash_lock);
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/*
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* This has to go last when updating chunk as once replace_chunk() is
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* called, new RCU readers can see the new chunk.
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*/
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replace_chunk(new, chunk);
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spin_unlock(&hash_lock);
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fsnotify_group_unlock(audit_tree_group);
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audit_mark_put_chunk(chunk);
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return;
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out_mutex:
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fsnotify_group_unlock(audit_tree_group);
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}
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/* Call with group->mark_mutex held, releases it */
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static int create_chunk(struct inode *inode, struct audit_tree *tree)
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{
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struct fsnotify_mark *mark;
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struct audit_chunk *chunk = alloc_chunk(1);
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if (!chunk) {
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fsnotify_group_unlock(audit_tree_group);
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return -ENOMEM;
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}
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mark = alloc_mark();
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if (!mark) {
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fsnotify_group_unlock(audit_tree_group);
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kfree(chunk);
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return -ENOMEM;
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}
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if (fsnotify_add_inode_mark_locked(mark, inode, 0)) {
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fsnotify_group_unlock(audit_tree_group);
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fsnotify_put_mark(mark);
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kfree(chunk);
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return -ENOSPC;
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}
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spin_lock(&hash_lock);
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if (tree->goner) {
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spin_unlock(&hash_lock);
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fsnotify_detach_mark(mark);
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fsnotify_group_unlock(audit_tree_group);
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fsnotify_free_mark(mark);
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fsnotify_put_mark(mark);
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kfree(chunk);
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return 0;
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}
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replace_mark_chunk(mark, chunk);
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chunk->owners[0].index = (1U << 31);
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chunk->owners[0].owner = tree;
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get_tree(tree);
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list_add(&chunk->owners[0].list, &tree->chunks);
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if (!tree->root) {
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tree->root = chunk;
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list_add(&tree->same_root, &chunk->trees);
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}
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chunk->key = inode_to_key(inode);
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/*
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* Inserting into the hash table has to go last as once we do that RCU
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* readers can see the chunk.
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*/
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insert_hash(chunk);
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spin_unlock(&hash_lock);
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fsnotify_group_unlock(audit_tree_group);
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/*
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* Drop our initial reference. When mark we point to is getting freed,
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* we get notification through ->freeing_mark callback and cleanup
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* chunk pointing to this mark.
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*/
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fsnotify_put_mark(mark);
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return 0;
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}
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/* the first tagged inode becomes root of tree */
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static int tag_chunk(struct inode *inode, struct audit_tree *tree)
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{
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struct fsnotify_mark *mark;
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struct audit_chunk *chunk, *old;
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struct audit_node *p;
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int n;
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fsnotify_group_lock(audit_tree_group);
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mark = fsnotify_find_mark(&inode->i_fsnotify_marks, audit_tree_group);
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if (!mark)
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return create_chunk(inode, tree);
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/*
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* Found mark is guaranteed to be attached and mark_mutex protects mark
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* from getting detached and thus it makes sure there is chunk attached
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* to the mark.
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*/
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/* are we already there? */
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spin_lock(&hash_lock);
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old = mark_chunk(mark);
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for (n = 0; n < old->count; n++) {
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if (old->owners[n].owner == tree) {
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spin_unlock(&hash_lock);
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fsnotify_group_unlock(audit_tree_group);
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fsnotify_put_mark(mark);
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return 0;
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}
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}
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spin_unlock(&hash_lock);
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chunk = alloc_chunk(old->count + 1);
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if (!chunk) {
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fsnotify_group_unlock(audit_tree_group);
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fsnotify_put_mark(mark);
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return -ENOMEM;
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}
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spin_lock(&hash_lock);
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if (tree->goner) {
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spin_unlock(&hash_lock);
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fsnotify_group_unlock(audit_tree_group);
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fsnotify_put_mark(mark);
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kfree(chunk);
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return 0;
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}
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p = &chunk->owners[chunk->count - 1];
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p->index = (chunk->count - 1) | (1U<<31);
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p->owner = tree;
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get_tree(tree);
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list_add(&p->list, &tree->chunks);
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if (!tree->root) {
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tree->root = chunk;
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list_add(&tree->same_root, &chunk->trees);
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}
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/*
|
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* This has to go last when updating chunk as once replace_chunk() is
|
|
* called, new RCU readers can see the new chunk.
|
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*/
|
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replace_chunk(chunk, old);
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spin_unlock(&hash_lock);
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fsnotify_group_unlock(audit_tree_group);
|
|
fsnotify_put_mark(mark); /* pair to fsnotify_find_mark */
|
|
audit_mark_put_chunk(old);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void audit_tree_log_remove_rule(struct audit_context *context,
|
|
struct audit_krule *rule)
|
|
{
|
|
struct audit_buffer *ab;
|
|
|
|
if (!audit_enabled)
|
|
return;
|
|
ab = audit_log_start(context, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
|
|
if (unlikely(!ab))
|
|
return;
|
|
audit_log_format(ab, "op=remove_rule 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_context *context, 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(context, 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);
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Remove tree from chunks. If 'tagged' is set, remove tree only from tagged
|
|
* chunks. The function expects tagged chunks are all at the beginning of the
|
|
* chunks list.
|
|
*/
|
|
static void prune_tree_chunks(struct audit_tree *victim, bool tagged)
|
|
{
|
|
spin_lock(&hash_lock);
|
|
while (!list_empty(&victim->chunks)) {
|
|
struct audit_node *p;
|
|
struct audit_chunk *chunk;
|
|
struct fsnotify_mark *mark;
|
|
|
|
p = list_first_entry(&victim->chunks, struct audit_node, list);
|
|
/* have we run out of marked? */
|
|
if (tagged && !(p->index & (1U<<31)))
|
|
break;
|
|
chunk = find_chunk(p);
|
|
mark = chunk->mark;
|
|
remove_chunk_node(chunk, p);
|
|
/* Racing with audit_tree_freeing_mark()? */
|
|
if (!mark)
|
|
continue;
|
|
fsnotify_get_mark(mark);
|
|
spin_unlock(&hash_lock);
|
|
|
|
untag_chunk(chunk, mark);
|
|
fsnotify_put_mark(mark);
|
|
|
|
spin_lock(&hash_lock);
|
|
}
|
|
spin_unlock(&hash_lock);
|
|
}
|
|
|
|
/*
|
|
* finish killing struct audit_tree
|
|
*/
|
|
static void prune_one(struct audit_tree *victim)
|
|
{
|
|
prune_tree_chunks(victim, false);
|
|
put_tree(victim);
|
|
}
|
|
|
|
/* trim the uncommitted chunks from tree */
|
|
|
|
static void trim_marked(struct audit_tree *tree)
|
|
{
|
|
struct list_head *p, *q;
|
|
spin_lock(&hash_lock);
|
|
if (tree->goner) {
|
|
spin_unlock(&hash_lock);
|
|
return;
|
|
}
|
|
/* reorder */
|
|
for (p = tree->chunks.next; p != &tree->chunks; p = q) {
|
|
struct audit_node *node = list_entry(p, struct audit_node, list);
|
|
q = p->next;
|
|
if (node->index & (1U<<31)) {
|
|
list_del_init(p);
|
|
list_add(p, &tree->chunks);
|
|
}
|
|
}
|
|
spin_unlock(&hash_lock);
|
|
|
|
prune_tree_chunks(tree, true);
|
|
|
|
spin_lock(&hash_lock);
|
|
if (!tree->root && !tree->goner) {
|
|
tree->goner = 1;
|
|
spin_unlock(&hash_lock);
|
|
mutex_lock(&audit_filter_mutex);
|
|
kill_rules(audit_context(), tree);
|
|
list_del_init(&tree->list);
|
|
mutex_unlock(&audit_filter_mutex);
|
|
prune_one(tree);
|
|
} else {
|
|
spin_unlock(&hash_lock);
|
|
}
|
|
}
|
|
|
|
static void audit_schedule_prune(void);
|
|
|
|
/* called with audit_filter_mutex */
|
|
int audit_remove_tree_rule(struct audit_krule *rule)
|
|
{
|
|
struct audit_tree *tree;
|
|
tree = rule->tree;
|
|
if (tree) {
|
|
spin_lock(&hash_lock);
|
|
list_del_init(&rule->rlist);
|
|
if (list_empty(&tree->rules) && !tree->goner) {
|
|
tree->root = NULL;
|
|
list_del_init(&tree->same_root);
|
|
tree->goner = 1;
|
|
list_move(&tree->list, &prune_list);
|
|
rule->tree = NULL;
|
|
spin_unlock(&hash_lock);
|
|
audit_schedule_prune();
|
|
return 1;
|
|
}
|
|
rule->tree = NULL;
|
|
spin_unlock(&hash_lock);
|
|
return 1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int compare_root(struct vfsmount *mnt, void *arg)
|
|
{
|
|
return inode_to_key(d_backing_inode(mnt->mnt_root)) ==
|
|
(unsigned long)arg;
|
|
}
|
|
|
|
void audit_trim_trees(void)
|
|
{
|
|
struct list_head cursor;
|
|
|
|
mutex_lock(&audit_filter_mutex);
|
|
list_add(&cursor, &tree_list);
|
|
while (cursor.next != &tree_list) {
|
|
struct audit_tree *tree;
|
|
struct path path;
|
|
struct vfsmount *root_mnt;
|
|
struct audit_node *node;
|
|
int err;
|
|
|
|
tree = container_of(cursor.next, struct audit_tree, list);
|
|
get_tree(tree);
|
|
list_move(&cursor, &tree->list);
|
|
mutex_unlock(&audit_filter_mutex);
|
|
|
|
err = kern_path(tree->pathname, 0, &path);
|
|
if (err)
|
|
goto skip_it;
|
|
|
|
root_mnt = collect_mounts(&path);
|
|
path_put(&path);
|
|
if (IS_ERR(root_mnt))
|
|
goto skip_it;
|
|
|
|
spin_lock(&hash_lock);
|
|
list_for_each_entry(node, &tree->chunks, list) {
|
|
struct audit_chunk *chunk = find_chunk(node);
|
|
/* this could be NULL if the watch is dying else where... */
|
|
node->index |= 1U<<31;
|
|
if (iterate_mounts(compare_root,
|
|
(void *)(chunk->key),
|
|
root_mnt))
|
|
node->index &= ~(1U<<31);
|
|
}
|
|
spin_unlock(&hash_lock);
|
|
trim_marked(tree);
|
|
drop_collected_mounts(root_mnt);
|
|
skip_it:
|
|
put_tree(tree);
|
|
mutex_lock(&audit_filter_mutex);
|
|
}
|
|
list_del(&cursor);
|
|
mutex_unlock(&audit_filter_mutex);
|
|
}
|
|
|
|
int audit_make_tree(struct audit_krule *rule, char *pathname, u32 op)
|
|
{
|
|
|
|
if (pathname[0] != '/' ||
|
|
(rule->listnr != AUDIT_FILTER_EXIT &&
|
|
rule->listnr != AUDIT_FILTER_URING_EXIT) ||
|
|
op != Audit_equal ||
|
|
rule->inode_f || rule->watch || rule->tree)
|
|
return -EINVAL;
|
|
rule->tree = alloc_tree(pathname);
|
|
if (!rule->tree)
|
|
return -ENOMEM;
|
|
return 0;
|
|
}
|
|
|
|
void audit_put_tree(struct audit_tree *tree)
|
|
{
|
|
put_tree(tree);
|
|
}
|
|
|
|
static int tag_mount(struct vfsmount *mnt, void *arg)
|
|
{
|
|
return tag_chunk(d_backing_inode(mnt->mnt_root), arg);
|
|
}
|
|
|
|
/*
|
|
* That gets run when evict_chunk() ends up needing to kill audit_tree.
|
|
* Runs from a separate thread.
|
|
*/
|
|
static int prune_tree_thread(void *unused)
|
|
{
|
|
for (;;) {
|
|
if (list_empty(&prune_list)) {
|
|
set_current_state(TASK_INTERRUPTIBLE);
|
|
schedule();
|
|
}
|
|
|
|
audit_ctl_lock();
|
|
mutex_lock(&audit_filter_mutex);
|
|
|
|
while (!list_empty(&prune_list)) {
|
|
struct audit_tree *victim;
|
|
|
|
victim = list_entry(prune_list.next,
|
|
struct audit_tree, list);
|
|
list_del_init(&victim->list);
|
|
|
|
mutex_unlock(&audit_filter_mutex);
|
|
|
|
prune_one(victim);
|
|
|
|
mutex_lock(&audit_filter_mutex);
|
|
}
|
|
|
|
mutex_unlock(&audit_filter_mutex);
|
|
audit_ctl_unlock();
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int audit_launch_prune(void)
|
|
{
|
|
if (prune_thread)
|
|
return 0;
|
|
prune_thread = kthread_run(prune_tree_thread, NULL,
|
|
"audit_prune_tree");
|
|
if (IS_ERR(prune_thread)) {
|
|
pr_err("cannot start thread audit_prune_tree");
|
|
prune_thread = NULL;
|
|
return -ENOMEM;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/* called with audit_filter_mutex */
|
|
int audit_add_tree_rule(struct audit_krule *rule)
|
|
{
|
|
struct audit_tree *seed = rule->tree, *tree;
|
|
struct path path;
|
|
struct vfsmount *mnt;
|
|
int err;
|
|
|
|
rule->tree = NULL;
|
|
list_for_each_entry(tree, &tree_list, list) {
|
|
if (!strcmp(seed->pathname, tree->pathname)) {
|
|
put_tree(seed);
|
|
rule->tree = tree;
|
|
list_add(&rule->rlist, &tree->rules);
|
|
return 0;
|
|
}
|
|
}
|
|
tree = seed;
|
|
list_add(&tree->list, &tree_list);
|
|
list_add(&rule->rlist, &tree->rules);
|
|
/* do not set rule->tree yet */
|
|
mutex_unlock(&audit_filter_mutex);
|
|
|
|
if (unlikely(!prune_thread)) {
|
|
err = audit_launch_prune();
|
|
if (err)
|
|
goto Err;
|
|
}
|
|
|
|
err = kern_path(tree->pathname, 0, &path);
|
|
if (err)
|
|
goto Err;
|
|
mnt = collect_mounts(&path);
|
|
path_put(&path);
|
|
if (IS_ERR(mnt)) {
|
|
err = PTR_ERR(mnt);
|
|
goto Err;
|
|
}
|
|
|
|
get_tree(tree);
|
|
err = iterate_mounts(tag_mount, tree, mnt);
|
|
drop_collected_mounts(mnt);
|
|
|
|
if (!err) {
|
|
struct audit_node *node;
|
|
spin_lock(&hash_lock);
|
|
list_for_each_entry(node, &tree->chunks, list)
|
|
node->index &= ~(1U<<31);
|
|
spin_unlock(&hash_lock);
|
|
} else {
|
|
trim_marked(tree);
|
|
goto Err;
|
|
}
|
|
|
|
mutex_lock(&audit_filter_mutex);
|
|
if (list_empty(&rule->rlist)) {
|
|
put_tree(tree);
|
|
return -ENOENT;
|
|
}
|
|
rule->tree = tree;
|
|
put_tree(tree);
|
|
|
|
return 0;
|
|
Err:
|
|
mutex_lock(&audit_filter_mutex);
|
|
list_del_init(&tree->list);
|
|
list_del_init(&tree->rules);
|
|
put_tree(tree);
|
|
return err;
|
|
}
|
|
|
|
int audit_tag_tree(char *old, char *new)
|
|
{
|
|
struct list_head cursor, barrier;
|
|
int failed = 0;
|
|
struct path path1, path2;
|
|
struct vfsmount *tagged;
|
|
int err;
|
|
|
|
err = kern_path(new, 0, &path2);
|
|
if (err)
|
|
return err;
|
|
tagged = collect_mounts(&path2);
|
|
path_put(&path2);
|
|
if (IS_ERR(tagged))
|
|
return PTR_ERR(tagged);
|
|
|
|
err = kern_path(old, 0, &path1);
|
|
if (err) {
|
|
drop_collected_mounts(tagged);
|
|
return err;
|
|
}
|
|
|
|
mutex_lock(&audit_filter_mutex);
|
|
list_add(&barrier, &tree_list);
|
|
list_add(&cursor, &barrier);
|
|
|
|
while (cursor.next != &tree_list) {
|
|
struct audit_tree *tree;
|
|
int good_one = 0;
|
|
|
|
tree = container_of(cursor.next, struct audit_tree, list);
|
|
get_tree(tree);
|
|
list_move(&cursor, &tree->list);
|
|
mutex_unlock(&audit_filter_mutex);
|
|
|
|
err = kern_path(tree->pathname, 0, &path2);
|
|
if (!err) {
|
|
good_one = path_is_under(&path1, &path2);
|
|
path_put(&path2);
|
|
}
|
|
|
|
if (!good_one) {
|
|
put_tree(tree);
|
|
mutex_lock(&audit_filter_mutex);
|
|
continue;
|
|
}
|
|
|
|
failed = iterate_mounts(tag_mount, tree, tagged);
|
|
if (failed) {
|
|
put_tree(tree);
|
|
mutex_lock(&audit_filter_mutex);
|
|
break;
|
|
}
|
|
|
|
mutex_lock(&audit_filter_mutex);
|
|
spin_lock(&hash_lock);
|
|
if (!tree->goner) {
|
|
list_move(&tree->list, &tree_list);
|
|
}
|
|
spin_unlock(&hash_lock);
|
|
put_tree(tree);
|
|
}
|
|
|
|
while (barrier.prev != &tree_list) {
|
|
struct audit_tree *tree;
|
|
|
|
tree = container_of(barrier.prev, struct audit_tree, list);
|
|
get_tree(tree);
|
|
list_move(&tree->list, &barrier);
|
|
mutex_unlock(&audit_filter_mutex);
|
|
|
|
if (!failed) {
|
|
struct audit_node *node;
|
|
spin_lock(&hash_lock);
|
|
list_for_each_entry(node, &tree->chunks, list)
|
|
node->index &= ~(1U<<31);
|
|
spin_unlock(&hash_lock);
|
|
} else {
|
|
trim_marked(tree);
|
|
}
|
|
|
|
put_tree(tree);
|
|
mutex_lock(&audit_filter_mutex);
|
|
}
|
|
list_del(&barrier);
|
|
list_del(&cursor);
|
|
mutex_unlock(&audit_filter_mutex);
|
|
path_put(&path1);
|
|
drop_collected_mounts(tagged);
|
|
return failed;
|
|
}
|
|
|
|
|
|
static void audit_schedule_prune(void)
|
|
{
|
|
wake_up_process(prune_thread);
|
|
}
|
|
|
|
/*
|
|
* ... and that one is done if evict_chunk() decides to delay until the end
|
|
* of syscall. Runs synchronously.
|
|
*/
|
|
void audit_kill_trees(struct audit_context *context)
|
|
{
|
|
struct list_head *list = &context->killed_trees;
|
|
|
|
audit_ctl_lock();
|
|
mutex_lock(&audit_filter_mutex);
|
|
|
|
while (!list_empty(list)) {
|
|
struct audit_tree *victim;
|
|
|
|
victim = list_entry(list->next, struct audit_tree, list);
|
|
kill_rules(context, victim);
|
|
list_del_init(&victim->list);
|
|
|
|
mutex_unlock(&audit_filter_mutex);
|
|
|
|
prune_one(victim);
|
|
|
|
mutex_lock(&audit_filter_mutex);
|
|
}
|
|
|
|
mutex_unlock(&audit_filter_mutex);
|
|
audit_ctl_unlock();
|
|
}
|
|
|
|
/*
|
|
* Here comes the stuff asynchronous to auditctl operations
|
|
*/
|
|
|
|
static void evict_chunk(struct audit_chunk *chunk)
|
|
{
|
|
struct audit_tree *owner;
|
|
struct list_head *postponed = audit_killed_trees();
|
|
int need_prune = 0;
|
|
int n;
|
|
|
|
mutex_lock(&audit_filter_mutex);
|
|
spin_lock(&hash_lock);
|
|
while (!list_empty(&chunk->trees)) {
|
|
owner = list_entry(chunk->trees.next,
|
|
struct audit_tree, same_root);
|
|
owner->goner = 1;
|
|
owner->root = NULL;
|
|
list_del_init(&owner->same_root);
|
|
spin_unlock(&hash_lock);
|
|
if (!postponed) {
|
|
kill_rules(audit_context(), owner);
|
|
list_move(&owner->list, &prune_list);
|
|
need_prune = 1;
|
|
} else {
|
|
list_move(&owner->list, postponed);
|
|
}
|
|
spin_lock(&hash_lock);
|
|
}
|
|
list_del_rcu(&chunk->hash);
|
|
for (n = 0; n < chunk->count; n++)
|
|
list_del_init(&chunk->owners[n].list);
|
|
spin_unlock(&hash_lock);
|
|
mutex_unlock(&audit_filter_mutex);
|
|
if (need_prune)
|
|
audit_schedule_prune();
|
|
}
|
|
|
|
static int audit_tree_handle_event(struct fsnotify_mark *mark, u32 mask,
|
|
struct inode *inode, struct inode *dir,
|
|
const struct qstr *file_name, u32 cookie)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
static void audit_tree_freeing_mark(struct fsnotify_mark *mark,
|
|
struct fsnotify_group *group)
|
|
{
|
|
struct audit_chunk *chunk;
|
|
|
|
fsnotify_group_lock(mark->group);
|
|
spin_lock(&hash_lock);
|
|
chunk = mark_chunk(mark);
|
|
replace_mark_chunk(mark, NULL);
|
|
spin_unlock(&hash_lock);
|
|
fsnotify_group_unlock(mark->group);
|
|
if (chunk) {
|
|
evict_chunk(chunk);
|
|
audit_mark_put_chunk(chunk);
|
|
}
|
|
|
|
/*
|
|
* We are guaranteed to have at least one reference to the mark from
|
|
* either the inode or the caller of fsnotify_destroy_mark().
|
|
*/
|
|
BUG_ON(refcount_read(&mark->refcnt) < 1);
|
|
}
|
|
|
|
static const struct fsnotify_ops audit_tree_ops = {
|
|
.handle_inode_event = audit_tree_handle_event,
|
|
.freeing_mark = audit_tree_freeing_mark,
|
|
.free_mark = audit_tree_destroy_watch,
|
|
};
|
|
|
|
static int __init audit_tree_init(void)
|
|
{
|
|
int i;
|
|
|
|
audit_tree_mark_cachep = KMEM_CACHE(audit_tree_mark, SLAB_PANIC);
|
|
|
|
audit_tree_group = fsnotify_alloc_group(&audit_tree_ops, 0);
|
|
if (IS_ERR(audit_tree_group))
|
|
audit_panic("cannot initialize fsnotify group for rectree watches");
|
|
|
|
for (i = 0; i < HASH_SIZE; i++)
|
|
INIT_LIST_HEAD(&chunk_hash_heads[i]);
|
|
|
|
return 0;
|
|
}
|
|
__initcall(audit_tree_init);
|