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From:   Ivan Vecera <ivecera@redhat.com>
To:     netdev@vger.kernel.org
Cc:     Roopa Prabhu <roopa@nvidia.com>,
        Nikolay Aleksandrov <nikolay@nvidia.com>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Horatiu Vultur <horatiu.vultur@microchip.com>,
        Henrik Bjoernlund <henrik.bjoernlund@microchip.com>,
        bridge@lists.linux-foundation.org (moderated list:ETHERNET BRIDGE),
        linux-kernel@vger.kernel.org (open list)
Subject: [PATCH net] net: bridge: fix uninitialized variables when BRIDGE_CFM is disabled
Date:   Wed, 27 Oct 2021 15:49:26 +0200
Message-Id: <20211027134926.1412459-1-ivecera@redhat.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

Function br_get_link_af_size_filtered() calls br_cfm_{,peer}_mep_count()
but does not check their return value. When BRIDGE_CFM is not enabled
these functions return -EOPNOTSUPP but do not modify count parameter.
Calling function then works with uninitialized variables.

Fixes: b6d0425b816e ("bridge: cfm: Netlink Notifications.")
Signed-off-by: Ivan Vecera <ivecera@redhat.com>
---
 net/bridge/br_netlink.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
index 5c6c4305ed23..12d602495ea0 100644
--- a/net/bridge/br_netlink.c
+++ b/net/bridge/br_netlink.c
@@ -126,8 +126,10 @@ static size_t br_get_link_af_size_filtered(const struct net_device *dev,
 		return vinfo_sz;
 
 	/* CFM status info must be added */
-	br_cfm_mep_count(br, &num_cfm_mep_infos);
-	br_cfm_peer_mep_count(br, &num_cfm_peer_mep_infos);
+	if (br_cfm_mep_count(br, &num_cfm_mep_infos) < 0)
+		num_cfm_mep_infos = 0;
+	if (br_cfm_peer_mep_count(br, &num_cfm_peer_mep_infos) < 0)
+		num_cfm_peer_mep_infos = 0;
 
 	vinfo_sz += nla_total_size(0);	/* IFLA_BRIDGE_CFM */
 	/* For each status struct the MEP instance (u32) is added */
-- 
2.32.0