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1085 lines
26 KiB
1085 lines
26 KiB
// 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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|
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struct audit_tree; |
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struct audit_chunk; |
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|
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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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|
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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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|
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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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|
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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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/* |
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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/* |
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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/* |
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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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|
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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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|
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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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|
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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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|
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/* tagging and untagging inodes with trees */ |
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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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/* 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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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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* 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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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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spin_lock(&hash_lock); |
|
if (tree->goner) { |
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spin_unlock(&hash_lock); |
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mutex_unlock(&audit_tree_group->mark_mutex); |
|
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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/* |
|
* 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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replace_chunk(chunk, old); |
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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); /* pair to fsnotify_find_mark */ |
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audit_mark_put_chunk(old); |
|
|
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return 0; |
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} |
|
|
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static void audit_tree_log_remove_rule(struct audit_context *context, |
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struct audit_krule *rule) |
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{ |
|
struct audit_buffer *ab; |
|
|
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if (!audit_enabled) |
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return; |
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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); |
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audit_log_key(ab, rule->filterkey); |
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audit_log_format(ab, " list=%d res=1", rule->listnr); |
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audit_log_end(ab); |
|
} |
|
|
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static void kill_rules(struct audit_context *context, struct audit_tree *tree) |
|
{ |
|
struct audit_krule *rule, *next; |
|
struct audit_entry *entry; |
|
|
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list_for_each_entry_safe(rule, next, &tree->rules, rlist) { |
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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); |
|
} |
|
} |
|
} |
|
|
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/* |
|
* 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; |
|
|
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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); |
|
} |
|
|
|
/* |
|
* 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 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_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 || |
|
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_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 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);
|
|
|