kernel-ark/kernel/audit_tree.c
Linus Torvalds 5133cd7518 Merge branch 'fsnotify' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs
Pull fsnotify updates from Jan Kara:
 "The branch contains mainly a rework of fsnotify infrastructure fixing
  a shortcoming that we have waited for response to fanotify permission
  events with SRCU read lock held and when the process consuming events
  was slow to respond the kernel has stalled.

  It also contains several cleanups of unnecessary indirections in
  fsnotify framework and a bugfix from Amir fixing leakage of kernel
  internal errno to userspace"

* 'fsnotify' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs: (37 commits)
  fanotify: don't expose EOPENSTALE to userspace
  fsnotify: remove a stray unlock
  fsnotify: Move ->free_mark callback to fsnotify_ops
  fsnotify: Add group pointer in fsnotify_init_mark()
  fsnotify: Drop inode_mark.c
  fsnotify: Remove fsnotify_find_{inode|vfsmount}_mark()
  fsnotify: Remove fsnotify_detach_group_marks()
  fsnotify: Rename fsnotify_clear_marks_by_group_flags()
  fsnotify: Inline fsnotify_clear_{inode|vfsmount}_mark_group()
  fsnotify: Remove fsnotify_recalc_{inode|vfsmount}_mask()
  fsnotify: Remove fsnotify_set_mark_{,ignored_}mask_locked()
  fanotify: Release SRCU lock when waiting for userspace response
  fsnotify: Pass fsnotify_iter_info into handle_event handler
  fsnotify: Provide framework for dropping SRCU lock in ->handle_event
  fsnotify: Remove special handling of mark destruction on group shutdown
  fsnotify: Detach mark from object list when last reference is dropped
  fsnotify: Move queueing of mark for destruction into fsnotify_put_mark()
  inotify: Do not drop mark reference under idr_lock
  fsnotify: Free fsnotify_mark_connector when there is no mark attached
  fsnotify: Lock object list with connector lock
  ...
2017-05-03 11:05:15 -07:00

1033 lines
24 KiB
C

#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;
struct fsnotify_mark mark;
struct list_head trees; /* with root here */
int dead;
int count;
atomic_long_t refs;
struct rcu_head head;
struct node {
struct list_head list;
struct audit_tree *owner;
unsigned index; /* index; upper bit indicates 'will prune' */
} owners[];
};
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.
* We replace struct chunk on tagging/untagging.
* 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 fsnotify_mark + .refs (non-zero refcount
* of watch contributes 1 to .refs).
*
* node.index allows to get from node.list to containing chunk.
* MSB of that sucker is stolen to mark taggings that we might have to
* revert - several operations have very unpleasant cleanup logics and
* that makes a difference. Some.
*/
static struct fsnotify_group *audit_tree_group;
static struct audit_tree *alloc_tree(const char *s)
{
struct audit_tree *tree;
tree = kmalloc(sizeof(struct audit_tree) + strlen(s) + 1, GFP_KERNEL);
if (tree) {
refcount_set(&tree->count, 1);
tree->goner = 0;
INIT_LIST_HEAD(&tree->chunks);
INIT_LIST_HEAD(&tree->rules);
INIT_LIST_HEAD(&tree->list);
INIT_LIST_HEAD(&tree->same_root);
tree->root = NULL;
strcpy(tree->pathname, s);
}
return tree;
}
static inline void get_tree(struct audit_tree *tree)
{
refcount_inc(&tree->count);
}
static inline void put_tree(struct audit_tree *tree)
{
if (refcount_dec_and_test(&tree->count))
kfree_rcu(tree, head);
}
/* to avoid bringing the entire thing in audit.h */
const char *audit_tree_path(struct audit_tree *tree)
{
return tree->pathname;
}
static void free_chunk(struct audit_chunk *chunk)
{
int i;
for (i = 0; i < chunk->count; i++) {
if (chunk->owners[i].owner)
put_tree(chunk->owners[i].owner);
}
kfree(chunk);
}
void audit_put_chunk(struct audit_chunk *chunk)
{
if (atomic_long_dec_and_test(&chunk->refs))
free_chunk(chunk);
}
static void __put_chunk(struct rcu_head *rcu)
{
struct audit_chunk *chunk = container_of(rcu, struct audit_chunk, head);
audit_put_chunk(chunk);
}
static void audit_tree_destroy_watch(struct fsnotify_mark *entry)
{
struct audit_chunk *chunk = container_of(entry, struct audit_chunk, mark);
call_rcu(&chunk->head, __put_chunk);
}
static struct audit_chunk *alloc_chunk(int count)
{
struct audit_chunk *chunk;
size_t size;
int i;
size = offsetof(struct audit_chunk, owners) + count * sizeof(struct node);
chunk = kzalloc(size, GFP_KERNEL);
if (!chunk)
return NULL;
INIT_LIST_HEAD(&chunk->hash);
INIT_LIST_HEAD(&chunk->trees);
chunk->count = count;
atomic_long_set(&chunk->refs, 1);
for (i = 0; i < count; i++) {
INIT_LIST_HEAD(&chunk->owners[i].list);
chunk->owners[i].index = i;
}
fsnotify_init_mark(&chunk->mark, audit_tree_group);
chunk->mark.mask = FS_IN_IGNORED;
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)
{
return (unsigned long)inode;
}
/*
* Function to return search key in our hash from chunk. Key 0 is special and
* should never be present in the hash.
*/
static unsigned long chunk_to_key(struct audit_chunk *chunk)
{
/*
* We have a reference to the mark so it should be attached to a
* connector.
*/
if (WARN_ON_ONCE(!chunk->mark.connector))
return 0;
return (unsigned long)chunk->mark.connector->inode;
}
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 & entry->lock is held by caller */
static void insert_hash(struct audit_chunk *chunk)
{
unsigned long key = chunk_to_key(chunk);
struct list_head *list;
if (!(chunk->mark.flags & FSNOTIFY_MARK_FLAG_ATTACHED))
return;
list = chunk_hash(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) {
if (chunk_to_key(p) == key) {
atomic_long_inc(&p->refs);
return p;
}
}
return NULL;
}
bool audit_tree_match(struct audit_chunk *chunk, struct audit_tree *tree)
{
int n;
for (n = 0; n < chunk->count; n++)
if (chunk->owners[n].owner == tree)
return true;
return false;
}
/* tagging and untagging inodes with trees */
static struct audit_chunk *find_chunk(struct node *p)
{
int index = p->index & ~(1U<<31);
p -= index;
return container_of(p, struct audit_chunk, owners[0]);
}
static void untag_chunk(struct node *p)
{
struct audit_chunk *chunk = find_chunk(p);
struct fsnotify_mark *entry = &chunk->mark;
struct audit_chunk *new = NULL;
struct audit_tree *owner;
int size = chunk->count - 1;
int i, j;
fsnotify_get_mark(entry);
spin_unlock(&hash_lock);
if (size)
new = alloc_chunk(size);
mutex_lock(&entry->group->mark_mutex);
spin_lock(&entry->lock);
/*
* mark_mutex protects mark from getting detached and thus also from
* mark->connector->inode getting NULL.
*/
if (chunk->dead || !(entry->flags & FSNOTIFY_MARK_FLAG_ATTACHED)) {
spin_unlock(&entry->lock);
mutex_unlock(&entry->group->mark_mutex);
if (new)
fsnotify_put_mark(&new->mark);
goto out;
}
owner = p->owner;
if (!size) {
chunk->dead = 1;
spin_lock(&hash_lock);
list_del_init(&chunk->trees);
if (owner->root == chunk)
owner->root = NULL;
list_del_init(&p->list);
list_del_rcu(&chunk->hash);
spin_unlock(&hash_lock);
spin_unlock(&entry->lock);
mutex_unlock(&entry->group->mark_mutex);
fsnotify_destroy_mark(entry, audit_tree_group);
goto out;
}
if (!new)
goto Fallback;
if (fsnotify_add_mark_locked(&new->mark, entry->connector->inode,
NULL, 1)) {
fsnotify_put_mark(&new->mark);
goto Fallback;
}
chunk->dead = 1;
spin_lock(&hash_lock);
list_replace_init(&chunk->trees, &new->trees);
if (owner->root == chunk) {
list_del_init(&owner->same_root);
owner->root = NULL;
}
for (i = j = 0; j <= size; i++, j++) {
struct audit_tree *s;
if (&chunk->owners[j] == p) {
list_del_init(&p->list);
i--;
continue;
}
s = chunk->owners[j].owner;
new->owners[i].owner = s;
new->owners[i].index = chunk->owners[j].index - j + i;
if (!s) /* result of earlier fallback */
continue;
get_tree(s);
list_replace_init(&chunk->owners[j].list, &new->owners[i].list);
}
list_replace_rcu(&chunk->hash, &new->hash);
list_for_each_entry(owner, &new->trees, same_root)
owner->root = new;
spin_unlock(&hash_lock);
spin_unlock(&entry->lock);
mutex_unlock(&entry->group->mark_mutex);
fsnotify_destroy_mark(entry, audit_tree_group);
fsnotify_put_mark(&new->mark); /* drop initial reference */
goto out;
Fallback:
// do the best we can
spin_lock(&hash_lock);
if (owner->root == chunk) {
list_del_init(&owner->same_root);
owner->root = NULL;
}
list_del_init(&p->list);
p->owner = NULL;
put_tree(owner);
spin_unlock(&hash_lock);
spin_unlock(&entry->lock);
mutex_unlock(&entry->group->mark_mutex);
out:
fsnotify_put_mark(entry);
spin_lock(&hash_lock);
}
static int create_chunk(struct inode *inode, struct audit_tree *tree)
{
struct fsnotify_mark *entry;
struct audit_chunk *chunk = alloc_chunk(1);
if (!chunk)
return -ENOMEM;
entry = &chunk->mark;
if (fsnotify_add_mark(entry, inode, NULL, 0)) {
fsnotify_put_mark(entry);
return -ENOSPC;
}
spin_lock(&entry->lock);
spin_lock(&hash_lock);
if (tree->goner) {
spin_unlock(&hash_lock);
chunk->dead = 1;
spin_unlock(&entry->lock);
fsnotify_destroy_mark(entry, audit_tree_group);
fsnotify_put_mark(entry);
return 0;
}
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);
}
insert_hash(chunk);
spin_unlock(&hash_lock);
spin_unlock(&entry->lock);
fsnotify_put_mark(entry); /* drop initial reference */
return 0;
}
/* the first tagged inode becomes root of tree */
static int tag_chunk(struct inode *inode, struct audit_tree *tree)
{
struct fsnotify_mark *old_entry, *chunk_entry;
struct audit_tree *owner;
struct audit_chunk *chunk, *old;
struct node *p;
int n;
old_entry = fsnotify_find_mark(&inode->i_fsnotify_marks,
audit_tree_group);
if (!old_entry)
return create_chunk(inode, tree);
old = container_of(old_entry, struct audit_chunk, mark);
/* are we already there? */
spin_lock(&hash_lock);
for (n = 0; n < old->count; n++) {
if (old->owners[n].owner == tree) {
spin_unlock(&hash_lock);
fsnotify_put_mark(old_entry);
return 0;
}
}
spin_unlock(&hash_lock);
chunk = alloc_chunk(old->count + 1);
if (!chunk) {
fsnotify_put_mark(old_entry);
return -ENOMEM;
}
chunk_entry = &chunk->mark;
mutex_lock(&old_entry->group->mark_mutex);
spin_lock(&old_entry->lock);
/*
* mark_mutex protects mark from getting detached and thus also from
* mark->connector->inode getting NULL.
*/
if (!(old_entry->flags & FSNOTIFY_MARK_FLAG_ATTACHED)) {
/* old_entry is being shot, lets just lie */
spin_unlock(&old_entry->lock);
mutex_unlock(&old_entry->group->mark_mutex);
fsnotify_put_mark(old_entry);
fsnotify_put_mark(&chunk->mark);
return -ENOENT;
}
if (fsnotify_add_mark_locked(chunk_entry,
old_entry->connector->inode, NULL, 1)) {
spin_unlock(&old_entry->lock);
mutex_unlock(&old_entry->group->mark_mutex);
fsnotify_put_mark(chunk_entry);
fsnotify_put_mark(old_entry);
return -ENOSPC;
}
/* even though we hold old_entry->lock, this is safe since chunk_entry->lock could NEVER have been grabbed before */
spin_lock(&chunk_entry->lock);
spin_lock(&hash_lock);
/* we now hold old_entry->lock, chunk_entry->lock, and hash_lock */
if (tree->goner) {
spin_unlock(&hash_lock);
chunk->dead = 1;
spin_unlock(&chunk_entry->lock);
spin_unlock(&old_entry->lock);
mutex_unlock(&old_entry->group->mark_mutex);
fsnotify_destroy_mark(chunk_entry, audit_tree_group);
fsnotify_put_mark(chunk_entry);
fsnotify_put_mark(old_entry);
return 0;
}
list_replace_init(&old->trees, &chunk->trees);
for (n = 0, p = chunk->owners; n < old->count; n++, p++) {
struct audit_tree *s = old->owners[n].owner;
p->owner = s;
p->index = old->owners[n].index;
if (!s) /* result of fallback in untag */
continue;
get_tree(s);
list_replace_init(&old->owners[n].list, &p->list);
}
p->index = (chunk->count - 1) | (1U<<31);
p->owner = tree;
get_tree(tree);
list_add(&p->list, &tree->chunks);
list_replace_rcu(&old->hash, &chunk->hash);
list_for_each_entry(owner, &chunk->trees, same_root)
owner->root = chunk;
old->dead = 1;
if (!tree->root) {
tree->root = chunk;
list_add(&tree->same_root, &chunk->trees);
}
spin_unlock(&hash_lock);
spin_unlock(&chunk_entry->lock);
spin_unlock(&old_entry->lock);
mutex_unlock(&old_entry->group->mark_mutex);
fsnotify_destroy_mark(old_entry, audit_tree_group);
fsnotify_put_mark(chunk_entry); /* drop initial reference */
fsnotify_put_mark(old_entry); /* pair to fsnotify_find mark_entry */
return 0;
}
static void audit_tree_log_remove_rule(struct audit_krule *rule)
{
struct audit_buffer *ab;
ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
if (unlikely(!ab))
return;
audit_log_format(ab, "op=remove_rule");
audit_log_format(ab, " 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_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(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);
}
}
}
/*
* finish killing struct audit_tree
*/
static void prune_one(struct audit_tree *victim)
{
spin_lock(&hash_lock);
while (!list_empty(&victim->chunks)) {
struct node *p;
p = list_entry(victim->chunks.next, struct node, list);
untag_chunk(p);
}
spin_unlock(&hash_lock);
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);
}
}
while (!list_empty(&tree->chunks)) {
struct node *node;
node = list_entry(tree->chunks.next, struct node, list);
/* have we run out of marked? */
if (!(node->index & (1U<<31)))
break;
untag_chunk(node);
}
if (!tree->root && !tree->goner) {
tree->goner = 1;
spin_unlock(&hash_lock);
mutex_lock(&audit_filter_mutex);
kill_rules(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_to_key(chunk),
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();
}
mutex_lock(&audit_cmd_mutex);
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);
mutex_unlock(&audit_cmd_mutex);
}
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 list_head *list)
{
mutex_lock(&audit_cmd_mutex);
mutex_lock(&audit_filter_mutex);
while (!list_empty(list)) {
struct audit_tree *victim;
victim = list_entry(list->next, struct audit_tree, list);
kill_rules(victim);
list_del_init(&victim->list);
mutex_unlock(&audit_filter_mutex);
prune_one(victim);
mutex_lock(&audit_filter_mutex);
}
mutex_unlock(&audit_filter_mutex);
mutex_unlock(&audit_cmd_mutex);
}
/*
* 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;
if (chunk->dead)
return;
chunk->dead = 1;
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(owner);
list_move(&owner->list, &prune_list);
need_prune = 1;
} else {
list_move(&owner->list, postponed);
}
spin_lock(&hash_lock);
}
list_del_rcu(&chunk->hash);
for (n = 0; n < chunk->count; n++)
list_del_init(&chunk->owners[n].list);
spin_unlock(&hash_lock);
mutex_unlock(&audit_filter_mutex);
if (need_prune)
audit_schedule_prune();
}
static int audit_tree_handle_event(struct fsnotify_group *group,
struct inode *to_tell,
struct fsnotify_mark *inode_mark,
struct fsnotify_mark *vfsmount_mark,
u32 mask, const void *data, int data_type,
const unsigned char *file_name, u32 cookie,
struct fsnotify_iter_info *iter_info)
{
return 0;
}
static void audit_tree_freeing_mark(struct fsnotify_mark *entry, struct fsnotify_group *group)
{
struct audit_chunk *chunk = container_of(entry, struct audit_chunk, mark);
evict_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(atomic_read(&entry->refcnt) < 1);
}
static const struct fsnotify_ops audit_tree_ops = {
.handle_event = audit_tree_handle_event,
.freeing_mark = audit_tree_freeing_mark,
.free_mark = audit_tree_destroy_watch,
};
static int __init audit_tree_init(void)
{
int i;
audit_tree_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);