// SPDX-License-Identifier: GPL-2.0 #include "audit.h" #include <linux/fsnotify_backend.h> #include <linux/namei.h> #include <linux/mount.h> #include <linux/kthread.h> #include <linux/refcount.h> #include <linux/slab.h> struct audit_tree; struct audit_chunk; struct audit_tree { refcount_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; unsigned long key; struct fsnotify_mark *mark; struct list_head trees; /* with root here */ 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[]; }; struct audit_tree_mark { struct fsnotify_mark mark; struct audit_chunk *chunk; }; 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 through * audit_tree_mark (fsnotify mark). We replace struct chunk on tagging / * untagging, the mark is stable as long as there is chunk attached. The * association between mark and chunk is protected by hash_lock and * audit_tree_group->mark_mutex. Thus as long as we hold * audit_tree_group->mark_mutex and check that the mark is alive by * FSNOTIFY_MARK_FLAG_ATTACHED flag check, we are sure the mark points to * the current chunk. * * 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 .refs. Mark associated with the chunk holds * one chunk reference. This reference is dropped either when a mark is going * to be freed (corresponding inode goes away) or when chunk attached to the * mark gets replaced. This reference must be dropped using * audit_mark_put_chunk() to make sure the reference is dropped only after RCU * grace period as it protects RCU readers of the hash table. * * 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 kmem_cache *audit_tree_mark_cachep __read_mostly; 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) { refcount_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) { refcount_inc(&tree->count); } static inline void put_tree(struct audit_tree *tree) { if (refcount_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); } /* * Drop reference to the chunk that was held by the mark. This is the reference * that gets dropped after we've removed the chunk from the hash table and we * use it to make sure chunk cannot be freed before RCU grace period expires. */ static void audit_mark_put_chunk(struct audit_chunk *chunk) { call_rcu(&chunk->head, __put_chunk); } static inline struct audit_tree_mark *audit_mark(struct fsnotify_mark *mark) { return container_of(mark, struct audit_tree_mark, mark); } static struct audit_chunk *mark_chunk(struct fsnotify_mark *mark) { return audit_mark(mark)->chunk; } static void audit_tree_destroy_watch(struct fsnotify_mark *mark) { kmem_cache_free(audit_tree_mark_cachep, audit_mark(mark)); } static struct fsnotify_mark *alloc_mark(void) { struct audit_tree_mark *amark; amark = kmem_cache_zalloc(audit_tree_mark_cachep, GFP_KERNEL); if (!amark) return NULL; fsnotify_init_mark(&amark->mark, audit_tree_group); amark->mark.mask = FS_IN_IGNORED; return &amark->mark; } 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; } return chunk; } enum {HASH_SIZE = 128}; static struct list_head chunk_hash_heads[HASH_SIZE]; static __cacheline_aligned_in_smp DEFINE_SPINLOCK(hash_lock); /* Function to return search key in our hash from inode. */ static unsigned long inode_to_key(const struct inode *inode) { /* Use address pointed to by connector->obj as the key */ return (unsigned long)&inode->i_fsnotify_marks; } static inline struct list_head *chunk_hash(unsigned long key) { unsigned long n = key / L1_CACHE_BYTES; return chunk_hash_heads + n % HASH_SIZE; } /* hash_lock & mark->group->mark_mutex is held by caller */ static void insert_hash(struct audit_chunk *chunk) { struct list_head *list; /* * Make sure chunk is fully initialized before making it visible in the * hash. Pairs with a data dependency barrier in READ_ONCE() in * audit_tree_lookup(). */ smp_wmb(); WARN_ON_ONCE(!chunk->key); list = chunk_hash(chunk->key); list_add_rcu(&chunk->hash, list); } /* called under rcu_read_lock */ struct audit_chunk *audit_tree_lookup(const struct inode *inode) { unsigned long key = inode_to_key(inode); struct list_head *list = chunk_hash(key); struct audit_chunk *p; list_for_each_entry_rcu(p, list, hash) { /* * We use a data dependency barrier in READ_ONCE() to make sure * the chunk we see is fully initialized. */ if (READ_ONCE(p->key) == key) { atomic_long_inc(&p->refs); return p; } } return NULL; } bool 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 true; return false; } /* 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 replace_mark_chunk(struct fsnotify_mark *mark, struct audit_chunk *chunk) { struct audit_chunk *old; assert_spin_locked(&hash_lock); old = mark_chunk(mark); audit_mark(mark)->chunk = chunk; if (chunk) chunk->mark = mark; if (old) old->mark = NULL; } static void replace_chunk(struct audit_chunk *new, struct audit_chunk *old) { struct audit_tree *owner; int i, j; new->key = old->key; list_splice_init(&old->trees, &new->trees); list_for_each_entry(owner, &new->trees, same_root) owner->root = new; for (i = j = 0; j < old->count; i++, j++) { if (!old->owners[j].owner) { i--; continue; } owner = old->owners[j].owner; new->owners[i].owner = owner; new->owners[i].index = old->owners[j].index - j + i; if (!owner) /* result of earlier fallback */ continue; get_tree(owner); list_replace_init(&old->owners[j].list, &new->owners[i].list); } replace_mark_chunk(old->mark, new); /* * Make sure chunk is fully initialized before making it visible in the * hash. Pairs with a data dependency barrier in READ_ONCE() in * audit_tree_lookup(). */ smp_wmb(); list_replace_rcu(&old->hash, &new->hash); } static void remove_chunk_node(struct audit_chunk *chunk, struct node *p) { struct audit_tree *owner = p->owner; if (owner->root == chunk) { list_del_init(&owner->same_root); owner->root = NULL; } list_del_init(&p->list); p->owner = NULL; put_tree(owner); } static int chunk_count_trees(struct audit_chunk *chunk) { int i; int ret = 0; for (i = 0; i < chunk->count; i++) if (chunk->owners[i].owner) ret++; return ret; } static void untag_chunk(struct audit_chunk *chunk, struct fsnotify_mark *mark) { struct audit_chunk *new; int size; mutex_lock(&audit_tree_group->mark_mutex); /* * mark_mutex stabilizes chunk attached to the mark so we can check * whether it didn't change while we've dropped hash_lock. */ if (!(mark->flags & FSNOTIFY_MARK_FLAG_ATTACHED) || mark_chunk(mark) != chunk) goto out_mutex; size = chunk_count_trees(chunk); if (!size) { spin_lock(&hash_lock); list_del_init(&chunk->trees); list_del_rcu(&chunk->hash); replace_mark_chunk(mark, NULL); spin_unlock(&hash_lock); fsnotify_detach_mark(mark); mutex_unlock(&audit_tree_group->mark_mutex); audit_mark_put_chunk(chunk); fsnotify_free_mark(mark); return; } new = alloc_chunk(size); if (!new) goto out_mutex; spin_lock(&hash_lock); /* * This has to go last when updating chunk as once replace_chunk() is * called, new RCU readers can see the new chunk. */ replace_chunk(new, chunk); spin_unlock(&hash_lock); mutex_unlock(&audit_tree_group->mark_mutex); audit_mark_put_chunk(chunk); return; out_mutex: mutex_unlock(&audit_tree_group->mark_mutex); } /* Call with group->mark_mutex held, releases it */ static int create_chunk(struct inode *inode, struct audit_tree *tree) { struct fsnotify_mark *mark; struct audit_chunk *chunk = alloc_chunk(1); if (!chunk) { mutex_unlock(&audit_tree_group->mark_mutex); return -ENOMEM; } mark = alloc_mark(); if (!mark) { mutex_unlock(&audit_tree_group->mark_mutex); kfree(chunk); return -ENOMEM; } if (fsnotify_add_inode_mark_locked(mark, inode, 0)) { mutex_unlock(&audit_tree_group->mark_mutex); fsnotify_put_mark(mark); kfree(chunk); return -ENOSPC; } spin_lock(&hash_lock); if (tree->goner) { spin_unlock(&hash_lock); fsnotify_detach_mark(mark); mutex_unlock(&audit_tree_group->mark_mutex); fsnotify_free_mark(mark); fsnotify_put_mark(mark); kfree(chunk); return 0; } replace_mark_chunk(mark, chunk); 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); } chunk->key = inode_to_key(inode); /* * Inserting into the hash table has to go last as once we do that RCU * readers can see the chunk. */ insert_hash(chunk); spin_unlock(&hash_lock); mutex_unlock(&audit_tree_group->mark_mutex); /* * Drop our initial reference. When mark we point to is getting freed, * we get notification through ->freeing_mark callback and cleanup * chunk pointing to this mark. */ fsnotify_put_mark(mark); return 0; } /* the first tagged inode becomes root of tree */ static int tag_chunk(struct inode *inode, struct audit_tree *tree) { struct fsnotify_mark *mark; struct audit_chunk *chunk, *old; struct node *p; int n; mutex_lock(&audit_tree_group->mark_mutex); mark = fsnotify_find_mark(&inode->i_fsnotify_marks, audit_tree_group); if (!mark) return create_chunk(inode, tree); /* * Found mark is guaranteed to be attached and mark_mutex protects mark * from getting detached and thus it makes sure there is chunk attached * to the mark. */ /* are we already there? */ spin_lock(&hash_lock); old = mark_chunk(mark); for (n = 0; n < old->count; n++) { if (old->owners[n].owner == tree) { spin_unlock(&hash_lock); mutex_unlock(&audit_tree_group->mark_mutex); fsnotify_put_mark(mark); return 0; } } spin_unlock(&hash_lock); chunk = alloc_chunk(old->count + 1); if (!chunk) { mutex_unlock(&audit_tree_group->mark_mutex); fsnotify_put_mark(mark); return -ENOMEM; } spin_lock(&hash_lock); if (tree->goner) { spin_unlock(&hash_lock); mutex_unlock(&audit_tree_group->mark_mutex); fsnotify_put_mark(mark); kfree(chunk); return 0; } p = &chunk->owners[chunk->count - 1]; p->index = (chunk->count - 1) | (1U<<31); p->owner = tree; get_tree(tree); list_add(&p->list, &tree->chunks); if (!tree->root) { tree->root = chunk; list_add(&tree->same_root, &chunk->trees); } /* * This has to go last when updating chunk as once replace_chunk() is * called, new RCU readers can see the new chunk. */ replace_chunk(chunk, old); spin_unlock(&hash_lock); mutex_unlock(&audit_tree_group->mark_mutex); 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 node *p; struct audit_chunk *chunk; struct fsnotify_mark *mark; p = list_first_entry(&victim->chunks, struct 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); put_tree(victim); } /* * finish killing struct audit_tree */ static void prune_one(struct audit_tree *victim) { prune_tree_chunks(victim, false); } /* 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 node *node = list_entry(p, struct 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 node *node; int err; tree = container_of(cursor.next, struct audit_tree, list); get_tree(tree); list_del(&cursor); list_add(&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 || 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 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_del(&cursor); list_add(&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_del(&tree->list); list_add(&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_del(&tree->list); list_add(&tree->list, &barrier); mutex_unlock(&audit_filter_mutex); if (!failed) { struct 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_group *group, struct inode *to_tell, u32 mask, const void *data, int data_type, const struct qstr *file_name, u32 cookie, struct fsnotify_iter_info *iter_info) { return 0; } static void audit_tree_freeing_mark(struct fsnotify_mark *mark, struct fsnotify_group *group) { struct audit_chunk *chunk; mutex_lock(&mark->group->mark_mutex); spin_lock(&hash_lock); chunk = mark_chunk(mark); replace_mark_chunk(mark, NULL); spin_unlock(&hash_lock); mutex_unlock(&mark->group->mark_mutex); 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_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); 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);