Re: [PATCH net] net: bridge: fix uninitialized variables when BRIDGE_CFM is disabled
From: Nikolay Aleksandrov <hidden>
Date: 2021-10-27 13:54:53
Also in:
bridge, lkml
On 27/10/2021 16:49, Ivan Vecera wrote:
quoted hunk ↗ jump to hunk
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 */
Hi,
Could you please rather update the EOPNOTSUPP helpers to set these infos to 0 before
returning? Someone else might decide to use them and hit the same bug.
E.g.
static inline int br_cfm_mep_count(struct net_bridge *br, u32 *count)
{
*count = 0;
return -EOPNOTSUPP;
}
We already do the same for br_allowed_ingress, nbp_vlan_add() etc.
Thanks,
Nik