From 5199c125d25aeae8615c4fc31652cc0fe624338e Mon Sep 17 00:00:00 2001 From: Raphael Zimmer Date: Wed, 18 Mar 2026 18:09:03 +0100 Subject: libceph: Prevent potential null-ptr-deref in ceph_handle_auth_reply() If a message of type CEPH_MSG_AUTH_REPLY contains a zero value for both protocol and result, this is currently not treated as an error. In case of ac->negotiating == true and ac->protocol > 0, this leads to setting ac->protocol = 0 and ac->ops = NULL. Thereafter, the check for ac->protocol != protocol returns false, and init_protocol() is not called. Subsequently, ac->ops->handle_reply() is called, which leads to a null pointer dereference, because ac->ops is still NULL. This patch changes the check for ac->protocol != protocol to !ac->protocol, as this also includes the case when the protocol was set to zero in the message. This causes the message to be treated as containing a bad auth protocol. Cc: stable@vger.kernel.org Signed-off-by: Raphael Zimmer Reviewed-by: Ilya Dryomov Signed-off-by: Ilya Dryomov --- net/ceph/auth.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/ceph/auth.c b/net/ceph/auth.c index 901b93530b21..3314705e5914 100644 --- a/net/ceph/auth.c +++ b/net/ceph/auth.c @@ -245,7 +245,7 @@ int ceph_handle_auth_reply(struct ceph_auth_client *ac, ac->protocol = 0; ac->ops = NULL; } - if (ac->protocol != protocol) { + if (!ac->protocol) { ret = init_protocol(ac, protocol); if (ret) { pr_err("auth protocol '%s' init failed: %d\n", -- cgit v1.2.3