linux/kernel/audit_tree.c
Tejun Heo 5a0e3ad6af include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.

Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-30 22:02:32 +09:00

924 lines
21 KiB
C

#include "audit.h"
#include <linux/inotify.h>
#include <linux/namei.h>
#include <linux/mount.h>
#include <linux/kthread.h>
#include <linux/slab.h>
struct audit_tree;
struct audit_chunk;
struct audit_tree {
atomic_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 inotify_watch watch;
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);
/*
* 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 inotify_watch + .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 inotify_handle *rtree_ih;
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) {
atomic_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)
{
atomic_inc(&tree->count);
}
static void __put_tree(struct rcu_head *rcu)
{
struct audit_tree *tree = container_of(rcu, struct audit_tree, head);
kfree(tree);
}
static inline void put_tree(struct audit_tree *tree)
{
if (atomic_dec_and_test(&tree->count))
call_rcu(&tree->head, __put_tree);
}
/* to avoid bringing the entire thing in audit.h */
const char *audit_tree_path(struct audit_tree *tree)
{
return tree->pathname;
}
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;
}
inotify_init_watch(&chunk->watch);
return chunk;
}
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);
}
enum {HASH_SIZE = 128};
static struct list_head chunk_hash_heads[HASH_SIZE];
static __cacheline_aligned_in_smp DEFINE_SPINLOCK(hash_lock);
static inline struct list_head *chunk_hash(const struct inode *inode)
{
unsigned long n = (unsigned long)inode / L1_CACHE_BYTES;
return chunk_hash_heads + n % HASH_SIZE;
}
/* hash_lock is held by caller */
static void insert_hash(struct audit_chunk *chunk)
{
struct list_head *list = chunk_hash(chunk->watch.inode);
list_add_rcu(&chunk->hash, list);
}
/* called under rcu_read_lock */
struct audit_chunk *audit_tree_lookup(const struct inode *inode)
{
struct list_head *list = chunk_hash(inode);
struct audit_chunk *p;
list_for_each_entry_rcu(p, list, hash) {
if (p->watch.inode == inode) {
atomic_long_inc(&p->refs);
return p;
}
}
return NULL;
}
int 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 1;
return 0;
}
/* 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 audit_chunk *new;
struct audit_tree *owner;
int size = chunk->count - 1;
int i, j;
if (!pin_inotify_watch(&chunk->watch)) {
/*
* Filesystem is shutting down; all watches are getting
* evicted, just take it off the node list for this
* tree and let the eviction logics take care of the
* rest.
*/
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);
return;
}
spin_unlock(&hash_lock);
/*
* pin_inotify_watch() succeeded, so the watch won't go away
* from under us.
*/
mutex_lock(&chunk->watch.inode->inotify_mutex);
if (chunk->dead) {
mutex_unlock(&chunk->watch.inode->inotify_mutex);
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);
inotify_evict_watch(&chunk->watch);
mutex_unlock(&chunk->watch.inode->inotify_mutex);
put_inotify_watch(&chunk->watch);
goto out;
}
new = alloc_chunk(size);
if (!new)
goto Fallback;
if (inotify_clone_watch(&chunk->watch, &new->watch) < 0) {
free_chunk(new);
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);
inotify_evict_watch(&chunk->watch);
mutex_unlock(&chunk->watch.inode->inotify_mutex);
put_inotify_watch(&chunk->watch);
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);
mutex_unlock(&chunk->watch.inode->inotify_mutex);
out:
unpin_inotify_watch(&chunk->watch);
spin_lock(&hash_lock);
}
static int create_chunk(struct inode *inode, struct audit_tree *tree)
{
struct audit_chunk *chunk = alloc_chunk(1);
if (!chunk)
return -ENOMEM;
if (inotify_add_watch(rtree_ih, &chunk->watch, inode, IN_IGNORED | IN_DELETE_SELF) < 0) {
free_chunk(chunk);
return -ENOSPC;
}
mutex_lock(&inode->inotify_mutex);
spin_lock(&hash_lock);
if (tree->goner) {
spin_unlock(&hash_lock);
chunk->dead = 1;
inotify_evict_watch(&chunk->watch);
mutex_unlock(&inode->inotify_mutex);
put_inotify_watch(&chunk->watch);
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);
mutex_unlock(&inode->inotify_mutex);
return 0;
}
/* the first tagged inode becomes root of tree */
static int tag_chunk(struct inode *inode, struct audit_tree *tree)
{
struct inotify_watch *watch;
struct audit_tree *owner;
struct audit_chunk *chunk, *old;
struct node *p;
int n;
if (inotify_find_watch(rtree_ih, inode, &watch) < 0)
return create_chunk(inode, tree);
old = container_of(watch, struct audit_chunk, watch);
/* 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);
put_inotify_watch(&old->watch);
return 0;
}
}
spin_unlock(&hash_lock);
chunk = alloc_chunk(old->count + 1);
if (!chunk) {
put_inotify_watch(&old->watch);
return -ENOMEM;
}
mutex_lock(&inode->inotify_mutex);
if (inotify_clone_watch(&old->watch, &chunk->watch) < 0) {
mutex_unlock(&inode->inotify_mutex);
put_inotify_watch(&old->watch);
free_chunk(chunk);
return -ENOSPC;
}
spin_lock(&hash_lock);
if (tree->goner) {
spin_unlock(&hash_lock);
chunk->dead = 1;
inotify_evict_watch(&chunk->watch);
mutex_unlock(&inode->inotify_mutex);
put_inotify_watch(&old->watch);
put_inotify_watch(&chunk->watch);
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);
inotify_evict_watch(&old->watch);
mutex_unlock(&inode->inotify_mutex);
put_inotify_watch(&old->watch); /* pair to inotify_find_watch */
put_inotify_watch(&old->watch); /* and kill it */
return 0;
}
static void kill_rules(struct audit_tree *tree)
{
struct audit_krule *rule, *next;
struct audit_entry *entry;
struct audit_buffer *ab;
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 */
ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
audit_log_format(ab, "op=");
audit_log_string(ab, "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);
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 mnt->mnt_root->d_inode == 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 (!root_mnt)
goto skip_it;
spin_lock(&hash_lock);
list_for_each_entry(node, &tree->chunks, list) {
struct inode *inode = find_chunk(node)->watch.inode;
node->index |= 1U<<31;
if (iterate_mounts(compare_root, inode, root_mnt))
node->index &= ~(1U<<31);
}
spin_unlock(&hash_lock);
trim_marked(tree);
put_tree(tree);
drop_collected_mounts(root_mnt);
skip_it:
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(mnt->mnt_root->d_inode, arg);
}
/* 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;
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);
err = kern_path(tree->pathname, 0, &path);
if (err)
goto Err;
mnt = collect_mounts(&path);
path_put(&path);
if (!mnt) {
err = -ENOMEM;
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 (!tagged)
return -ENOMEM;
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;
}
/*
* 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)
{
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 void audit_schedule_prune(void)
{
kthread_run(prune_tree_thread, NULL, "audit_prune_tree");
}
/*
* ... 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
*/
/* inode->inotify_mutex is locked */
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);
if (need_prune)
audit_schedule_prune();
mutex_unlock(&audit_filter_mutex);
}
static void handle_event(struct inotify_watch *watch, u32 wd, u32 mask,
u32 cookie, const char *dname, struct inode *inode)
{
struct audit_chunk *chunk = container_of(watch, struct audit_chunk, watch);
if (mask & IN_IGNORED) {
evict_chunk(chunk);
put_inotify_watch(watch);
}
}
static void destroy_watch(struct inotify_watch *watch)
{
struct audit_chunk *chunk = container_of(watch, struct audit_chunk, watch);
call_rcu(&chunk->head, __put_chunk);
}
static const struct inotify_operations rtree_inotify_ops = {
.handle_event = handle_event,
.destroy_watch = destroy_watch,
};
static int __init audit_tree_init(void)
{
int i;
rtree_ih = inotify_init(&rtree_inotify_ops);
if (IS_ERR(rtree_ih))
audit_panic("cannot initialize inotify handle for rectree watches");
for (i = 0; i < HASH_SIZE; i++)
INIT_LIST_HEAD(&chunk_hash_heads[i]);
return 0;
}
__initcall(audit_tree_init);