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Commit 5801649d authored by Fredrik Tolf's avatar Fredrik Tolf Committed by Linus Torvalds
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[PATCH] keys: let keyctl_chown() change a key's owner 



Let keyctl_chown() change a key's owner, including attempting to transfer the
quota burden to the new user.

Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 31204ed9

security/keys/keyctl.c

+48 −8
Original line number Diff line number Diff line
@@ -673,6 +673,7 @@ long keyctl_read_key(key_serial_t keyid, char __user *buffer, size_t buflen) 
 */

long keyctl_chown_key(key_serial_t id, uid_t uid, gid_t gid)

{

	struct key_user *newowner, *zapowner = NULL;

	struct key *key;

	key_ref_t key_ref;

	long ret;
@@ -696,19 +697,50 @@ long keyctl_chown_key(key_serial_t id, uid_t uid, gid_t gid) 
	if (!capable(CAP_SYS_ADMIN)) {

		/* only the sysadmin can chown a key to some other UID */

		if (uid != (uid_t) -1 && key->uid != uid)

			goto no_access;

			goto error_put;



		/* only the sysadmin can set the key's GID to a group other

		 * than one of those that the current process subscribes to */

		if (gid != (gid_t) -1 && gid != key->gid && !in_group_p(gid))

			goto no_access;

			goto error_put;

	}



	/* change the UID (have to update the quotas) */

	/* change the UID */

	if (uid != (uid_t) -1 && uid != key->uid) {

		/* don't support UID changing yet */

		ret = -EOPNOTSUPP;

		goto no_access;

		ret = -ENOMEM;

		newowner = key_user_lookup(uid);

		if (!newowner)

			goto error_put;



		/* transfer the quota burden to the new user */

		if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) {

			spin_lock(&newowner->lock);

			if (newowner->qnkeys + 1 >= KEYQUOTA_MAX_KEYS ||

			    newowner->qnbytes + key->quotalen >=

			    KEYQUOTA_MAX_BYTES)

				goto quota_overrun;



			newowner->qnkeys++;

			newowner->qnbytes += key->quotalen;

			spin_unlock(&newowner->lock);



			spin_lock(&key->user->lock);

			key->user->qnkeys--;

			key->user->qnbytes -= key->quotalen;

			spin_unlock(&key->user->lock);

		}



		atomic_dec(&key->user->nkeys);

		atomic_inc(&newowner->nkeys);



		if (test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) {

			atomic_dec(&key->user->nikeys);

			atomic_inc(&newowner->nikeys);

		}



		zapowner = key->user;

		key->user = newowner;

		key->uid = uid;

	}



	/* change the GID */
@@ -717,12 +749,20 @@ long keyctl_chown_key(key_serial_t id, uid_t uid, gid_t gid) 


	ret = 0;



 no_access:

error_put:

	up_write(&key->sem);

	key_put(key);

	if (zapowner)

		key_user_put(zapowner);

error:

	return ret;



quota_overrun:

	spin_unlock(&newowner->lock);

	zapowner = newowner;

	ret = -EDQUOT;

	goto error_put;



} /* end keyctl_chown_key() */



/*****************************************************************************/