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authorEric Paris <eparis@redhat.com>2009-12-17 20:12:05 -0500
committerEric Paris <eparis@redhat.com>2010-07-28 09:58:17 -0400
commit28a3a7eb3b1f3e7d834e19f06e794e429058a4dd (patch)
treec025ce90e250786784e18cde38d6c9c89e7b31f9
parent40554c3dae83bd892b7fbfaa2ea9de739cbcf065 (diff)
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audit: reimplement audit_trees using fsnotify rather than inotify
Simply switch audit_trees from using inotify to using fsnotify for it's inode pinning and disappearing act information. Signed-off-by: Eric Paris <eparis@redhat.com>
-rw-r--r--include/linux/fsnotify_backend.h5
-rw-r--r--init/Kconfig2
-rw-r--r--kernel/audit_tree.c234
-rw-r--r--kernel/auditsc.c4
4 files changed, 136 insertions, 109 deletions
diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h
index 1679f250d59..e2528437102 100644
--- a/include/linux/fsnotify_backend.h
+++ b/include/linux/fsnotify_backend.h
@@ -62,8 +62,9 @@
/* listeners that hard code group numbers near the top */
#define DNOTIFY_GROUP_NUM UINT_MAX
-#define AUDIT_WATCH_GROUP_NUM (DNOTIFY_GROUP_NUM-1)
-#define INOTIFY_GROUP_NUM (AUDIT_WATCH_GROUP_NUM-1)
+#define AUDIT_WATCH_GROUP_NUM (DNOTIFY_GROUP_NUM-1)
+#define AUDIT_TREE_GROUP_NUM (AUDIT_WATCH_GROUP_NUM-1)
+#define INOTIFY_GROUP_NUM (AUDIT_TREE_GROUP_NUM-1)
struct fsnotify_group;
struct fsnotify_event;
diff --git a/init/Kconfig b/init/Kconfig
index 5cff9a980c3..84e33c49a0c 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -326,7 +326,7 @@ config AUDITSYSCALL
config AUDIT_TREE
def_bool y
depends on AUDITSYSCALL
- select INOTIFY
+ select FSNOTIFY
menu "RCU Subsystem"
diff --git a/kernel/audit_tree.c b/kernel/audit_tree.c
index 46a57b57a33..a164600dd82 100644
--- a/kernel/audit_tree.c
+++ b/kernel/audit_tree.c
@@ -1,5 +1,5 @@
#include "audit.h"
-#include <linux/inotify.h>
+#include <linux/fsnotify_backend.h>
#include <linux/namei.h>
#include <linux/mount.h>
#include <linux/kthread.h>
@@ -22,7 +22,7 @@ struct audit_tree {
struct audit_chunk {
struct list_head hash;
- struct inotify_watch watch;
+ struct fsnotify_mark_entry mark;
struct list_head trees; /* with root here */
int dead;
int count;
@@ -59,7 +59,7 @@ static LIST_HEAD(prune_list);
* 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
+ * 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.
@@ -68,7 +68,7 @@ static LIST_HEAD(prune_list);
* that makes a difference. Some.
*/
-static struct inotify_handle *rtree_ih;
+static struct fsnotify_group *audit_tree_group;
static struct audit_tree *alloc_tree(const char *s)
{
@@ -111,29 +111,6 @@ 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;
@@ -157,6 +134,35 @@ static void __put_chunk(struct rcu_head *rcu)
audit_put_chunk(chunk);
}
+static void audit_tree_destroy_watch(struct fsnotify_mark_entry *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_destroy_watch);
+ return chunk;
+}
+
enum {HASH_SIZE = 128};
static struct list_head chunk_hash_heads[HASH_SIZE];
static __cacheline_aligned_in_smp DEFINE_SPINLOCK(hash_lock);
@@ -167,10 +173,15 @@ static inline struct list_head *chunk_hash(const struct inode *inode)
return chunk_hash_heads + n % HASH_SIZE;
}
-/* hash_lock is held by caller */
+/* hash_lock & entry->lock is held by caller */
static void insert_hash(struct audit_chunk *chunk)
{
- struct list_head *list = chunk_hash(chunk->watch.inode);
+ struct fsnotify_mark_entry *entry = &chunk->mark;
+ struct list_head *list;
+
+ if (!entry->inode)
+ return;
+ list = chunk_hash(entry->inode);
list_add_rcu(&chunk->hash, list);
}
@@ -181,7 +192,8 @@ struct audit_chunk *audit_tree_lookup(const struct inode *inode)
struct audit_chunk *p;
list_for_each_entry_rcu(p, list, hash) {
- if (p->watch.inode == inode) {
+ /* mark.inode may have gone NULL, but who cares? */
+ if (p->mark.inode == inode) {
atomic_long_inc(&p->refs);
return p;
}
@@ -210,38 +222,19 @@ static struct audit_chunk *find_chunk(struct node *p)
static void untag_chunk(struct node *p)
{
struct audit_chunk *chunk = find_chunk(p);
+ struct fsnotify_mark_entry *entry = &chunk->mark;
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;
- }
+ fsnotify_get_mark(entry);
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);
+ spin_lock(&entry->lock);
+ if (chunk->dead || !entry->inode) {
+ spin_unlock(&entry->lock);
goto out;
}
@@ -256,16 +249,17 @@ static void untag_chunk(struct node *p)
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);
+ spin_unlock(&entry->lock);
+ fsnotify_destroy_mark_by_entry(entry);
+ fsnotify_put_mark(entry);
goto out;
}
new = alloc_chunk(size);
if (!new)
goto Fallback;
- if (inotify_clone_watch(&chunk->watch, &new->watch) < 0) {
+ fsnotify_duplicate_mark(&new->mark, entry);
+ if (fsnotify_add_mark(&new->mark, new->mark.group, new->mark.inode, 1)) {
free_chunk(new);
goto Fallback;
}
@@ -298,9 +292,9 @@ static void untag_chunk(struct node *p)
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);
+ spin_unlock(&entry->lock);
+ fsnotify_destroy_mark_by_entry(entry);
+ fsnotify_put_mark(entry);
goto out;
Fallback:
@@ -314,31 +308,33 @@ Fallback:
p->owner = NULL;
put_tree(owner);
spin_unlock(&hash_lock);
- mutex_unlock(&chunk->watch.inode->inotify_mutex);
+ spin_unlock(&entry->lock);
out:
- unpin_inotify_watch(&chunk->watch);
+ fsnotify_put_mark(entry);
spin_lock(&hash_lock);
}
static int create_chunk(struct inode *inode, struct audit_tree *tree)
{
+ struct fsnotify_mark_entry *entry;
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) {
+ entry = &chunk->mark;
+ if (fsnotify_add_mark(entry, audit_tree_group, inode, 0)) {
free_chunk(chunk);
return -ENOSPC;
}
- mutex_lock(&inode->inotify_mutex);
+ spin_lock(&entry->lock);
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);
+ spin_unlock(&entry->lock);
+ fsnotify_destroy_mark_by_entry(entry);
+ fsnotify_put_mark(entry);
return 0;
}
chunk->owners[0].index = (1U << 31);
@@ -351,30 +347,33 @@ static int create_chunk(struct inode *inode, struct audit_tree *tree)
}
insert_hash(chunk);
spin_unlock(&hash_lock);
- mutex_unlock(&inode->inotify_mutex);
+ spin_unlock(&entry->lock);
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 fsnotify_mark_entry *old_entry, *chunk_entry;
struct audit_tree *owner;
struct audit_chunk *chunk, *old;
struct node *p;
int n;
- if (inotify_find_watch(rtree_ih, inode, &watch) < 0)
+ spin_lock(&inode->i_lock);
+ old_entry = fsnotify_find_mark_entry(audit_tree_group, inode);
+ spin_unlock(&inode->i_lock);
+ if (!old_entry)
return create_chunk(inode, tree);
- old = container_of(watch, struct audit_chunk, watch);
+ 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);
- put_inotify_watch(&old->watch);
+ fsnotify_put_mark(old_entry);
return 0;
}
}
@@ -382,25 +381,44 @@ static int tag_chunk(struct inode *inode, struct audit_tree *tree)
chunk = alloc_chunk(old->count + 1);
if (!chunk) {
- put_inotify_watch(&old->watch);
+ fsnotify_put_mark(old_entry);
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);
+ chunk_entry = &chunk->mark;
+
+ spin_lock(&old_entry->lock);
+ if (!old_entry->inode) {
+ /* old_entry is being shot, lets just lie */
+ spin_unlock(&old_entry->lock);
+ fsnotify_put_mark(old_entry);
free_chunk(chunk);
+ return -ENOENT;
+ }
+
+ fsnotify_duplicate_mark(chunk_entry, old_entry);
+ if (fsnotify_add_mark(chunk_entry, chunk_entry->group, chunk_entry->inode, 1)) {
+ spin_unlock(&old_entry->lock);
+ free_chunk(chunk);
+ 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;
- inotify_evict_watch(&chunk->watch);
- mutex_unlock(&inode->inotify_mutex);
- put_inotify_watch(&old->watch);
- put_inotify_watch(&chunk->watch);
+ spin_unlock(&chunk_entry->lock);
+ spin_unlock(&old_entry->lock);
+
+ fsnotify_destroy_mark_by_entry(chunk_entry);
+
+ fsnotify_put_mark(chunk_entry);
+ fsnotify_put_mark(old_entry);
return 0;
}
list_replace_init(&old->trees, &chunk->trees);
@@ -426,10 +444,11 @@ static int tag_chunk(struct inode *inode, struct audit_tree *tree)
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 */
+ spin_unlock(&chunk_entry->lock);
+ spin_unlock(&old_entry->lock);
+ fsnotify_destroy_mark_by_entry(old_entry);
+ fsnotify_put_mark(old_entry); /* pair to fsnotify_find mark_entry */
+ fsnotify_put_mark(old_entry); /* and kill it */
return 0;
}
@@ -584,7 +603,9 @@ void audit_trim_trees(void)
spin_lock(&hash_lock);
list_for_each_entry(node, &tree->chunks, list) {
- struct inode *inode = find_chunk(node)->watch.inode;
+ struct audit_chunk *chunk = find_chunk(node);
+ /* this could be NULL if the watch is dieing else where... */
+ struct inode *inode = chunk->mark.inode;
node->index |= 1U<<31;
if (iterate_mounts(compare_root, inode, root_mnt))
node->index &= ~(1U<<31);
@@ -846,7 +867,6 @@ void audit_kill_trees(struct list_head *list)
* 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;
@@ -885,35 +905,41 @@ static void evict_chunk(struct audit_chunk *chunk)
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)
+static int audit_tree_handle_event(struct fsnotify_group *group, struct fsnotify_event *event)
{
- struct audit_chunk *chunk = container_of(watch, struct audit_chunk, watch);
+ BUG();
+ return -EOPNOTSUPP;
+}
- if (mask & IN_IGNORED) {
- evict_chunk(chunk);
- put_inotify_watch(watch);
- }
+static void audit_tree_freeing_mark(struct fsnotify_mark_entry *entry, struct fsnotify_group *group)
+{
+ struct audit_chunk *chunk = container_of(entry, struct audit_chunk, mark);
+
+ evict_chunk(chunk);
+ fsnotify_put_mark(entry);
}
-static void destroy_watch(struct inotify_watch *watch)
+static bool audit_tree_send_event(struct fsnotify_group *group, struct inode *inode, __u32 mask)
{
- struct audit_chunk *chunk = container_of(watch, struct audit_chunk, watch);
- call_rcu(&chunk->head, __put_chunk);
+ return 0;
}
-static const struct inotify_operations rtree_inotify_ops = {
- .handle_event = handle_event,
- .destroy_watch = destroy_watch,
+static const struct fsnotify_ops audit_tree_ops = {
+ .handle_event = audit_tree_handle_event,
+ .should_send_event = audit_tree_send_event,
+ .free_group_priv = NULL,
+ .free_event_priv = NULL,
+ .freeing_mark = audit_tree_freeing_mark,
};
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");
+ audit_tree_group = fsnotify_obtain_group(AUDIT_TREE_GROUP_NUM,
+ 0, &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]);
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 240063c370e..786901cd821 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -1725,7 +1725,7 @@ static inline void handle_one(const struct inode *inode)
struct audit_tree_refs *p;
struct audit_chunk *chunk;
int count;
- if (likely(list_empty(&inode->inotify_watches)))
+ if (likely(hlist_empty(&inode->i_fsnotify_mark_entries)))
return;
context = current->audit_context;
p = context->trees;
@@ -1768,7 +1768,7 @@ retry:
seq = read_seqbegin(&rename_lock);
for(;;) {
struct inode *inode = d->d_inode;
- if (inode && unlikely(!list_empty(&inode->inotify_watches))) {
+ if (inode && unlikely(!hlist_empty(&inode->i_fsnotify_mark_entries))) {
struct audit_chunk *chunk;
chunk = audit_tree_lookup(inode);
if (chunk) {