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synced 2024-08-27 11:19:37 +00:00
![Amir Goldstein](/assets/img/avatar_default.png)
The handle_inode_event() interface was added as (quoting comment):
"a simple variant of handle_event() for groups that only have inode
marks and don't have ignore mask".
In other words, all backends except fanotify. The inotify backend
also falls under this category, but because it required extra arguments
it was left out of the initial pass of backends conversion to the
simple interface.
This results in code duplication between the generic helper
fsnotify_handle_event() and the inotify_handle_event() callback
which also happen to be buggy code.
Generalize the handle_inode_event() arguments and add the check for
FS_EXCL_UNLINK flag to the generic helper, so inotify backend could
be converted to use the simple interface.
Link: https://lore.kernel.org/r/20201202120713.702387-2-amir73il@gmail.com
CC: stable@vger.kernel.org
Fixes: b9a1b97725
("fsnotify: create method handle_inode_event() in fsnotify_operations")
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
1089 lines
26 KiB
C
1089 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 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(sizeof(struct audit_tree) + 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 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 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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mutex_lock(&audit_tree_group->mark_mutex);
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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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mutex_unlock(&audit_tree_group->mark_mutex);
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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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mutex_unlock(&audit_tree_group->mark_mutex);
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audit_mark_put_chunk(chunk);
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return;
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out_mutex:
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mutex_unlock(&audit_tree_group->mark_mutex);
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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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mutex_unlock(&audit_tree_group->mark_mutex);
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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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mutex_unlock(&audit_tree_group->mark_mutex);
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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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mutex_unlock(&audit_tree_group->mark_mutex);
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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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mutex_unlock(&audit_tree_group->mark_mutex);
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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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mutex_unlock(&audit_tree_group->mark_mutex);
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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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|
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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 node *p;
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int n;
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|
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mutex_lock(&audit_tree_group->mark_mutex);
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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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/*
|
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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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mutex_unlock(&audit_tree_group->mark_mutex);
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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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|
|
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chunk = alloc_chunk(old->count + 1);
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|
if (!chunk) {
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mutex_unlock(&audit_tree_group->mark_mutex);
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fsnotify_put_mark(mark);
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return -ENOMEM;
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}
|
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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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mutex_unlock(&audit_tree_group->mark_mutex);
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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);
|
|
if (!tree->root) {
|
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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_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;
|
|
|
|
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_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);
|
|
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);
|