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Commit 553d603c authored by David Howells's avatar David Howells Committed by James Morris
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KEYS: keyring_serialise_link_sem is only needed for keyring->keyring links 



keyring_serialise_link_sem is only needed for keyring->keyring links as it's
used to prevent cycle detection from being avoided by parallel keyring
additions.

Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Signed-off-by: default avatarJames Morris <jmorris@namei.org>
parent 0ffbe269

security/keys/keyring.c

+9 −7
Original line number Diff line number Diff line
@@ -705,13 +705,14 @@ int __key_link(struct key *keyring, struct key *key) 
	if (keyring->type != &key_type_keyring)

		goto error;



	/* serialise link/link calls to prevent parallel calls causing a

	 * cycle when applied to two keyring in opposite orders */

	/* do some special keyring->keyring link checks */

	if (key->type == &key_type_keyring) {

		/* serialise link/link calls to prevent parallel calls causing

		 * a cycle when applied to two keyring in opposite orders */

		down_write(&keyring_serialise_link_sem);



	/* check that we aren't going to create a cycle adding one keyring to

	 * another */

	if (key->type == &key_type_keyring) {

		/* check that we aren't going to create a cycle adding one

		 * keyring to another */

		ret = keyring_detect_cycle(keyring, key);

		if (ret < 0)

			goto error2;
@@ -814,6 +815,7 @@ int __key_link(struct key *keyring, struct key *key) 
done:

	ret = 0;

error2:

	if (key->type == &key_type_keyring)

		up_write(&keyring_serialise_link_sem);

error:

	return ret;