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Commit ccc3e6d9 authored by David Howells's avatar David Howells
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KEYS: Define a __key_get() wrapper to use rather than atomic_inc() 



Define a __key_get() wrapper to use rather than atomic_inc() on the key usage
count as this makes it easier to hook in refcount error debugging.

Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
parent d0a059ca

Documentation/security/keys.txt

+8 −5
Original line number Diff line number Diff line
@@ -960,14 +960,17 @@ payload contents" for more information. 
    the argument will not be parsed.





(*) Extra references can be made to a key by calling the following function:

(*) Extra references can be made to a key by calling one of the following

    functions:



	struct key *__key_get(struct key *key);

	struct key *key_get(struct key *key);



    These need to be disposed of by calling key_put() when they've been

    finished with. The key pointer passed in will be returned. If the pointer

    is NULL or CONFIG_KEYS is not set then the key will not be dereferenced and

    no increment will take place.

    Keys so references will need to be disposed of by calling key_put() when

    they've been finished with.  The key pointer passed in will be returned.



    In the case of key_get(), if the pointer is NULL or CONFIG_KEYS is not set

    then the key will not be dereferenced and no increment will take place.





(*) A key's serial number can be obtained by calling:

include/linux/key.h

+7 −3
Original line number Diff line number Diff line
@@ -219,13 +219,17 @@ extern void key_revoke(struct key *key); 
extern void key_invalidate(struct key *key);

extern void key_put(struct key *key);



static inline struct key *key_get(struct key *key)

static inline struct key *__key_get(struct key *key)

{

	if (key)

	atomic_inc(&key->usage);

	return key;

}



static inline struct key *key_get(struct key *key)

{

	return key ? __key_get(key) : key;

}



static inline void key_ref_put(key_ref_t key_ref)

{

	key_put(key_ref_to_ptr(key_ref));

security/keys/key.c

+1 −1
Original line number Diff line number Diff line
@@ -644,7 +644,7 @@ struct key *key_lookup(key_serial_t id) 
	/* this races with key_put(), but that doesn't matter since key_put()

	 * doesn't actually change the key

	 */

	atomic_inc(&key->usage);

	__key_get(key);



error:

	spin_unlock(&key_serial_lock);

security/keys/keyring.c

+3 −3
Original line number Diff line number Diff line
@@ -479,7 +479,7 @@ key_ref_t keyring_search_aux(key_ref_t keyring_ref, 


	/* we found a viable match */

found:

	atomic_inc(&key->usage);

	__key_get(key);

	key->last_used_at = ctx->now.tv_sec;

	keyring->last_used_at = ctx->now.tv_sec;

	while (sp > 0)
@@ -573,7 +573,7 @@ key_ref_t __keyring_search_one(key_ref_t keyring_ref, 
	return ERR_PTR(-ENOKEY);



found:

	atomic_inc(&key->usage);

	__key_get(key);

	keyring->last_used_at = key->last_used_at =

		current_kernel_time().tv_sec;

	rcu_read_unlock();
@@ -909,7 +909,7 @@ void __key_link(struct key *keyring, struct key *key, 


	klist = rcu_dereference_locked_keyring(keyring);



	atomic_inc(&key->usage);

	__key_get(key);

	keyring->last_used_at = key->last_used_at =

		current_kernel_time().tv_sec;

security/keys/process_keys.c

+8 −8
Original line number Diff line number Diff line
@@ -235,7 +235,7 @@ int install_session_keyring_to_cred(struct cred *cred, struct key *keyring) 
		if (IS_ERR(keyring))

			return PTR_ERR(keyring);

	} else {

		atomic_inc(&keyring->usage);

		__key_get(keyring);

	}



	/* install the keyring */
@@ -544,7 +544,7 @@ key_ref_t lookup_user_key(key_serial_t id, unsigned long lflags, 
		}



		key = ctx.cred->thread_keyring;

		atomic_inc(&key->usage);

		__key_get(key);

		key_ref = make_key_ref(key, 1);

		break;
@@ -562,7 +562,7 @@ key_ref_t lookup_user_key(key_serial_t id, unsigned long lflags, 
		}



		key = ctx.cred->process_keyring;

		atomic_inc(&key->usage);

		__key_get(key);

		key_ref = make_key_ref(key, 1);

		break;
@@ -593,7 +593,7 @@ key_ref_t lookup_user_key(key_serial_t id, unsigned long lflags, 


		rcu_read_lock();

		key = rcu_dereference(ctx.cred->session_keyring);

		atomic_inc(&key->usage);

		__key_get(key);

		rcu_read_unlock();

		key_ref = make_key_ref(key, 1);

		break;
@@ -606,7 +606,7 @@ key_ref_t lookup_user_key(key_serial_t id, unsigned long lflags, 
		}



		key = ctx.cred->user->uid_keyring;

		atomic_inc(&key->usage);

		__key_get(key);

		key_ref = make_key_ref(key, 1);

		break;
@@ -618,7 +618,7 @@ key_ref_t lookup_user_key(key_serial_t id, unsigned long lflags, 
		}



		key = ctx.cred->user->session_keyring;

		atomic_inc(&key->usage);

		__key_get(key);

		key_ref = make_key_ref(key, 1);

		break;
@@ -632,7 +632,7 @@ key_ref_t lookup_user_key(key_serial_t id, unsigned long lflags, 
		if (!key)

			goto error;



		atomic_inc(&key->usage);

		__key_get(key);

		key_ref = make_key_ref(key, 1);

		break;
@@ -648,7 +648,7 @@ key_ref_t lookup_user_key(key_serial_t id, unsigned long lflags, 
		} else {

			rka = ctx.cred->request_key_auth->payload.data;

			key = rka->dest_keyring;

			atomic_inc(&key->usage);

			__key_get(key);

		}

		up_read(&ctx.cred->request_key_auth->sem);

		if (!key)