libceph: Fix NULL pointer dereference in auth client code

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@canonical.com>
Reported-by: Chanam Park <chanam.park@hkpco.kr>
Reviewed-by: Seth Arnold <seth.arnold@canonical.com>
Reviewed-by: Sage Weil <sage@inktank.com>
[PG: in v2.6.34, file is fs/ceph and not net/ceph]
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

diff --git a/fs/ceph/auth_none.c b/fs/ceph/auth_none.c
index 8cd9e3af07f7f8df750b2a3ec5ad27a0fbe8ec96..1d1f9b4cbd87c5a5d1279f33e2da6a328848f857 100644 (file)
--- a/fs/ceph/auth_none.c
+++ b/fs/ceph/auth_none.c
@@ -31,6 +31,11 @@ static int is_authenticated(struct ceph_auth_client *ac)
        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.
@@ -97,6 +102,7 @@ static const struct ceph_auth_client_ops ceph_auth_none_ops = {
        .reset = reset,
        .destroy = destroy,
        .is_authenticated = is_authenticated,
+       .build_request = build_request,
        .handle_reply = handle_reply,
        .create_authorizer = ceph_auth_none_create_authorizer,
        .destroy_authorizer = ceph_auth_none_destroy_authorizer,