Commit 8626c56c8279 ("bridge: fix potential use-after-free when hook
returns QUEUE or STOLEN verdict") caused LLDP packets arriving through a
bridge port to be re-injected to the Rx path with skb->dev set to the
bridge device, but this breaks the lldpad daemon.
The lldpad daemon opens a packet socket with protocol set to ETH_P_LLDP
for any valid device on the system, which doesn't not include soft
devices such as bridge and VLAN.
Since packet sockets (ptype_base) are processed in the Rx path after the
Rx handler, LLDP packets with skb->dev set to the bridge device never
reach the lldpad daemon.
Fix this by making the bridge's Rx handler re-inject LLDP packets with
RX_HANDLER_PASS, which effectively restores the behaviour prior to the
mentioned commit.
This means netfilter will never receive LLDP packets coming through a
bridge port, as I don't see a way in which we can have okfn() consume
the packet without breaking existing behaviour. I've already carried out
a similar fix for STP packets in commit 56fae404fb2c ("bridge: Fix
incorrect re-injection of STP packets").
Fixes: 8626c56c8279 ("bridge: fix potential use-after-free when hook returns QUEUE or STOLEN verdict")
Signed-off-by: Ido Schimmel <idosch@xxxxxxxxxxxx>
Reviewed-by: Jiri Pirko <jiri@xxxxxxxxxxxx>
Cc: Florian Westphal <fw@xxxxxxxxx>
Cc: John Fastabend <john.fastabend@xxxxxxxxx>
---
net/bridge/br_input.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/net/bridge/br_input.c b/net/bridge/br_input.c
index 43d2cd8..28d5ec2 100644
--- a/net/bridge/br_input.c
+++ b/net/bridge/br_input.c
@@ -288,6 +288,14 @@ rx_handler_result_t br_handle_frame(struct sk_buff **pskb)
case 0x01: /* IEEE MAC (Pause) */
goto drop;
+ case 0x0E: /* 802.1AB LLDP */
+ fwd_mask |= p->br->group_fwd_mask;
+ if (fwd_mask & (1u << dest[5]))
+ goto forward;
+ *pskb = skb;
+ __br_handle_local_finish(skb);
+ return RX_HANDLER_PASS;
+
default:
/* Allow selective forwarding for most other protocols */
fwd_mask |= p->br->group_fwd_mask;
--
2.8.2
