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