[64/85] libceph: Fix NULL pointer dereference in auth client code

[Ben Hutchings]

3.2.49-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Tyler Hicks <tyhicks@xxxxxxxxxxxxx>

commit 2cb33cac622afde897aa02d3dcd9fbba8bae839e upstream.

A malicious monitor can craft an auth reply message that could cause a
NULL function pointer dereference in the client's kernel.

To prevent this, the auth_none protocol handler needs an empty
ceph_auth_client_ops->build_request() function.

CVE-2013-1059

Signed-off-by: Tyler Hicks <tyhicks@xxxxxxxxxxxxx>
Reported-by: Chanam Park <chanam.park@xxxxxxxx>
Reviewed-by: Seth Arnold <seth.arnold@xxxxxxxxxxxxx>
Reviewed-by: Sage Weil <sage@xxxxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 net/ceph/auth_none.c | 6 ++++++
 1 file changed, 6 insertions(+)

--- a/net/ceph/auth_none.c
+++ b/net/ceph/auth_none.c
@@ -39,6 +39,11 @@ static int should_authenticate(struct ce
 	return xi->starting;
 }
 
+static int build_request(struct ceph_auth_client *ac, void *buf, void *end)
+{
+	return 0;
+}
+
 /*
  * the generic auth code decode the global_id, and we carry no actual
  * authenticate state, so nothing happens here.
@@ -107,6 +112,7 @@ static const struct ceph_auth_client_ops
 	.destroy = destroy,
 	.is_authenticated = is_authenticated,
 	.should_authenticate = should_authenticate,
+	.build_request = build_request,
 	.handle_reply = handle_reply,
 	.create_authorizer = ceph_auth_none_create_authorizer,
 	.destroy_authorizer = ceph_auth_none_destroy_authorizer,

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