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KEYS: Move the unreferenced key reaper to the keys garbage collector file

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Move the unreferenced key reaper function to the keys garbage collector file
as that's a more appropriate place with the dead key link reaper.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
This commit is contained in:
David Howells 2011-08-22 14:09:11 +01:00 committed by James Morris
parent 012146d072
commit 8bc16deabc
3 changed files with 85 additions and 76 deletions
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87
security/keys/gc.c
View File

@ -10,6 +10,8 @@
*/
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/security.h>
#include <keys/keyring-type.h>
#include "internal.h"
@ -19,12 +21,18 @@
unsigned key_gc_delay = 5 * 60;
/*
* Reaper
* Reaper for unused keys.
*/
static void key_gc_unused_keys(struct work_struct *work);
DECLARE_WORK(key_gc_unused_work, key_gc_unused_keys);
/*
* Reaper for links from keyrings to dead keys.
*/
static void key_gc_timer_func(unsigned long);
static void key_garbage_collector(struct work_struct *);
static void key_gc_dead_links(struct work_struct *);
static DEFINE_TIMER(key_gc_timer, key_gc_timer_func, 0, 0);
static DECLARE_WORK(key_gc_work, key_garbage_collector);
static DECLARE_WORK(key_gc_work, key_gc_dead_links);
static key_serial_t key_gc_cursor; /* the last key the gc considered */
static bool key_gc_again;
static unsigned long key_gc_executing;
@ -108,10 +116,12 @@ static bool key_gc_keyring(struct key *keyring, time_t limit)
}
/*
* Garbage collector for keys. This involves scanning the keyrings for dead,
* expired and revoked keys that have overstayed their welcome
* Garbage collector for links to dead keys.
*
* This involves scanning the keyrings for dead, expired and revoked keys that
* have overstayed their welcome
*/
static void key_garbage_collector(struct work_struct *work)
static void key_gc_dead_links(struct work_struct *work)
{
struct rb_node *rb;
key_serial_t cursor;
@ -220,3 +230,68 @@ static void key_garbage_collector(struct work_struct *work)
}
kleave(" [end]");
}
/*
* Garbage collector for unused keys.
*
* This is done in process context so that we don't have to disable interrupts
* all over the place. key_put() schedules this rather than trying to do the
* cleanup itself, which means key_put() doesn't have to sleep.
*/
static void key_gc_unused_keys(struct work_struct *work)
{
struct rb_node *_n;
struct key *key;
go_again:
/* look for a dead key in the tree */
spin_lock(&key_serial_lock);
for (_n = rb_first(&key_serial_tree); _n; _n = rb_next(_n)) {
key = rb_entry(_n, struct key, serial_node);
if (atomic_read(&key->usage) == 0)
goto found_dead_key;
}
spin_unlock(&key_serial_lock);
return;
found_dead_key:
/* we found a dead key - once we've removed it from the tree, we can
* drop the lock */
rb_erase(&key->serial_node, &key_serial_tree);
spin_unlock(&key_serial_lock);
key_check(key);
security_key_free(key);
/* deal with the user's key tracking and quota */
if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) {
spin_lock(&key->user->lock);
key->user->qnkeys--;
key->user->qnbytes -= key->quotalen;
spin_unlock(&key->user->lock);
}
atomic_dec(&key->user->nkeys);
if (test_bit(KEY_FLAG_INSTANTIATED, &key->flags))
atomic_dec(&key->user->nikeys);
key_user_put(key->user);
/* now throw away the key memory */
if (key->type->destroy)
key->type->destroy(key);
kfree(key->description);
#ifdef KEY_DEBUGGING
key->magic = KEY_DEBUG_MAGIC_X;
#endif
kmem_cache_free(key_jar, key);
/* there may, of course, be more than one key to destroy */
goto go_again;
}

2
security/keys/internal.h
View File

@ -75,6 +75,7 @@ extern unsigned key_quota_maxbytes;
#define KEYQUOTA_LINK_BYTES 4 /* a link in a keyring is worth 4 bytes */
extern struct kmem_cache *key_jar;
extern struct rb_root key_serial_tree;
extern spinlock_t key_serial_lock;
extern struct mutex key_construction_mutex;
@ -146,6 +147,7 @@ extern key_ref_t lookup_user_key(key_serial_t id, unsigned long flags,
extern long join_session_keyring(const char *name);
extern struct work_struct key_gc_unused_work;
extern unsigned key_gc_delay;
extern void keyring_gc(struct key *keyring, time_t limit);
extern void key_schedule_gc(time_t expiry_at);

72
security/keys/key.c
View File

@ -21,7 +21,7 @@
#include <linux/user_namespace.h>
#include "internal.h"
static struct kmem_cache *key_jar;
struct kmem_cache *key_jar;
struct rb_root key_serial_tree; /* tree of keys indexed by serial */
DEFINE_SPINLOCK(key_serial_lock);
@ -36,9 +36,6 @@ unsigned int key_quota_maxbytes = 20000; /* general key space quota */
static LIST_HEAD(key_types_list);
static DECLARE_RWSEM(key_types_sem);
static void key_cleanup(struct work_struct *work);
static DECLARE_WORK(key_cleanup_task, key_cleanup);
/* We serialise key instantiation and link */
DEFINE_MUTEX(key_construction_mutex);
@ -591,71 +588,6 @@ int key_reject_and_link(struct key *key,
}
EXPORT_SYMBOL(key_reject_and_link);
/*
* Garbage collect keys in process context so that we don't have to disable
* interrupts all over the place.
*
* key_put() schedules this rather than trying to do the cleanup itself, which
* means key_put() doesn't have to sleep.
*/
static void key_cleanup(struct work_struct *work)
{
struct rb_node *_n;
struct key *key;
go_again:
/* look for a dead key in the tree */
spin_lock(&key_serial_lock);
for (_n = rb_first(&key_serial_tree); _n; _n = rb_next(_n)) {
key = rb_entry(_n, struct key, serial_node);
if (atomic_read(&key->usage) == 0)
goto found_dead_key;
}
spin_unlock(&key_serial_lock);
return;
found_dead_key:
/* we found a dead key - once we've removed it from the tree, we can
* drop the lock */
rb_erase(&key->serial_node, &key_serial_tree);
spin_unlock(&key_serial_lock);
key_check(key);
security_key_free(key);
/* deal with the user's key tracking and quota */
if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) {
spin_lock(&key->user->lock);
key->user->qnkeys--;
key->user->qnbytes -= key->quotalen;
spin_unlock(&key->user->lock);
}
atomic_dec(&key->user->nkeys);
if (test_bit(KEY_FLAG_INSTANTIATED, &key->flags))
atomic_dec(&key->user->nikeys);
key_user_put(key->user);
/* now throw away the key memory */
if (key->type->destroy)
key->type->destroy(key);
kfree(key->description);
#ifdef KEY_DEBUGGING
key->magic = KEY_DEBUG_MAGIC_X;
#endif
kmem_cache_free(key_jar, key);
/* there may, of course, be more than one key to destroy */
goto go_again;
}
/**
* key_put - Discard a reference to a key.
* @key: The key to discard a reference from.
@ -670,7 +602,7 @@ void key_put(struct key *key)
key_check(key);
if (atomic_dec_and_test(&key->usage))
schedule_work(&key_cleanup_task);
schedule_work(&key_gc_unused_work);
}
}
EXPORT_SYMBOL(key_put);