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Commit 381f20fc authored by Davidlohr Bueso's avatar Davidlohr Bueso Committed by James Morris
Browse files

security: use READ_ONCE instead of deprecated ACCESS_ONCE 

With the new standardized functions, we can replace all ACCESS_ONCE()
calls across relevant security/keyrings/.

ACCESS_ONCE() does not work reliably on non-scalar types. For example
gcc 4.6 and 4.7 might remove the volatile tag for such accesses during
the SRA (scalar replacement of aggregates) step:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58145



Update the new calls regardless of if it is a scalar type, this is
cleaner than having three alternatives.

Signed-off-by: default avatarDavidlohr Bueso <dbueso@suse.de>
Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Signed-off-by: default avatarJames Morris <james.l.morris@oracle.com>
parent 47b2c3ff

security/keys/keyring.c

+6 −6
Original line number Diff line number Diff line
@@ -706,7 +706,7 @@ static bool search_nested_keyrings(struct key *keyring, 
	 * Non-keyrings avoid the leftmost branch of the root entirely (root

	 * slots 1-15).

	 */

	ptr = ACCESS_ONCE(keyring->keys.root);

	ptr = READ_ONCE(keyring->keys.root);

	if (!ptr)

		goto not_this_keyring;
@@ -720,7 +720,7 @@ static bool search_nested_keyrings(struct key *keyring, 
		if ((shortcut->index_key[0] & ASSOC_ARRAY_FAN_MASK) != 0)

			goto not_this_keyring;



		ptr = ACCESS_ONCE(shortcut->next_node);

		ptr = READ_ONCE(shortcut->next_node);

		node = assoc_array_ptr_to_node(ptr);

		goto begin_node;

	}
@@ -740,7 +740,7 @@ static bool search_nested_keyrings(struct key *keyring, 
	if (assoc_array_ptr_is_shortcut(ptr)) {

		shortcut = assoc_array_ptr_to_shortcut(ptr);

		smp_read_barrier_depends();

		ptr = ACCESS_ONCE(shortcut->next_node);

		ptr = READ_ONCE(shortcut->next_node);

		BUG_ON(!assoc_array_ptr_is_node(ptr));

	}

	node = assoc_array_ptr_to_node(ptr);
@@ -752,7 +752,7 @@ static bool search_nested_keyrings(struct key *keyring, 
ascend_to_node:

	/* Go through the slots in a node */

	for (; slot < ASSOC_ARRAY_FAN_OUT; slot++) {

		ptr = ACCESS_ONCE(node->slots[slot]);

		ptr = READ_ONCE(node->slots[slot]);



		if (assoc_array_ptr_is_meta(ptr) && node->back_pointer)

			goto descend_to_node;
@@ -790,13 +790,13 @@ static bool search_nested_keyrings(struct key *keyring, 
	/* We've dealt with all the slots in the current node, so now we need

	 * to ascend to the parent and continue processing there.

	 */

	ptr = ACCESS_ONCE(node->back_pointer);

	ptr = READ_ONCE(node->back_pointer);

	slot = node->parent_slot;



	if (ptr && assoc_array_ptr_is_shortcut(ptr)) {

		shortcut = assoc_array_ptr_to_shortcut(ptr);

		smp_read_barrier_depends();

		ptr = ACCESS_ONCE(shortcut->back_pointer);

		ptr = READ_ONCE(shortcut->back_pointer);

		slot = shortcut->parent_slot;

	}

	if (!ptr)