[v2.6.34-stable 013/213] libceph: Fix NULL pointer dereference in auth client code

[Paul Gortmaker]

From: Tyler Hicks <tyhicks@xxxxxxxxxxxxx>

                   -------------------
    This is a commit scheduled for the next v2.6.34 longterm release.
    http://git.kernel.org/?p=linux/kernel/git/paulg/longterm-queue-2.6.34.git
    If you see a problem with using this for longterm, please comment.
                   -------------------

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>
[PG: in v2.6.34, file is fs/ceph and not net/ceph]
Signed-off-by: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
---
 fs/ceph/auth_none.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/fs/ceph/auth_none.c b/fs/ceph/auth_none.c
index 8cd9e3af07f7..1d1f9b4cbd87 100644
--- 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,
-- 
1.8.5.2

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