[PATCH net] bridge: Netlink interface fix.

From: Henrik Bjoernlund
Date: Wed Oct 07 2020 - 08:09:02 EST


This commit is correcting NETLINK br_fill_ifinfo() to be able to
handle 'filter_mask' with multiple flags asserted.

Fixes: 36a8e8e265420 ("bridge: Extend br_fill_ifinfo to return MPR status")

Signed-off-by: Henrik Bjoernlund <henrik.bjoernlund@xxxxxxxxxxxxx>
Reviewed-by: Horatiu Vultur <horatiu.vultur@xxxxxxxxxxxxx>
Suggested-by: Nikolay Aleksandrov <nikolay@xxxxxxxxxx>
Tested-by: Horatiu Vultur <horatiu.vultur@xxxxxxxxxxxxx>
---
net/bridge/br_netlink.c | 26 +++++++++++---------------
1 file changed, 11 insertions(+), 15 deletions(-)

diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
index 8a71c60fa357..92d64abffa87 100644
--- a/net/bridge/br_netlink.c
+++ b/net/bridge/br_netlink.c
@@ -380,6 +380,7 @@ static int br_fill_ifinfo(struct sk_buff *skb,
u32 filter_mask, const struct net_device *dev)
{
u8 operstate = netif_running(dev) ? dev->operstate : IF_OPER_DOWN;
+ struct nlattr *af = NULL;
struct net_bridge *br;
struct ifinfomsg *hdr;
struct nlmsghdr *nlh;
@@ -423,11 +424,18 @@ static int br_fill_ifinfo(struct sk_buff *skb,
nla_nest_end(skb, nest);
}

+ if (filter_mask & (RTEXT_FILTER_BRVLAN |
+ RTEXT_FILTER_BRVLAN_COMPRESSED |
+ RTEXT_FILTER_MRP)) {
+ af = nla_nest_start_noflag(skb, IFLA_AF_SPEC);
+ if (!af)
+ goto nla_put_failure;
+ }
+
/* Check if the VID information is requested */
if ((filter_mask & RTEXT_FILTER_BRVLAN) ||
(filter_mask & RTEXT_FILTER_BRVLAN_COMPRESSED)) {
struct net_bridge_vlan_group *vg;
- struct nlattr *af;
int err;

/* RCU needed because of the VLAN locking rules (rcu || rtnl) */
@@ -441,11 +449,6 @@ static int br_fill_ifinfo(struct sk_buff *skb,
rcu_read_unlock();
goto done;
}
- af = nla_nest_start_noflag(skb, IFLA_AF_SPEC);
- if (!af) {
- rcu_read_unlock();
- goto nla_put_failure;
- }
if (filter_mask & RTEXT_FILTER_BRVLAN_COMPRESSED)
err = br_fill_ifvlaninfo_compressed(skb, vg);
else
@@ -456,32 +459,25 @@ static int br_fill_ifinfo(struct sk_buff *skb,
rcu_read_unlock();
if (err)
goto nla_put_failure;
-
- nla_nest_end(skb, af);
}

if (filter_mask & RTEXT_FILTER_MRP) {
- struct nlattr *af;
int err;

if (!br_mrp_enabled(br) || port)
goto done;

- af = nla_nest_start_noflag(skb, IFLA_AF_SPEC);
- if (!af)
- goto nla_put_failure;
-
rcu_read_lock();
err = br_mrp_fill_info(skb, br);
rcu_read_unlock();

if (err)
goto nla_put_failure;
-
- nla_nest_end(skb, af);
}

done:
+ if (af)
+ nla_nest_end(skb, af);
nlmsg_end(skb, nlh);
return 0;

--
2.28.0