[PATCH net] bridge: Fix incorrect re-injection of STP packets
From: Ido Schimmel <hidden>
Date: 2016-06-03 09:39:45
Also in:
bridge
Subsystem:
ethernet bridge, networking [general], the rest · Maintainers:
Nikolay Aleksandrov, Ido Schimmel, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
Commit 8626c56c8279 ("bridge: fix potential use-after-free when hook
returns QUEUE or STOLEN verdict") fixed incorrect usage of NF_HOOK's
return value by consuming packets in okfn via br_pass_frame_up().
However, this function re-injects packets to the Rx path with skb->dev
set to the bridge device, which breaks kernel's STP, as all STP packets
appear to originate from the bridge device itself.
Instead, if okfn was called for a packet, make bridge's rx_handler
re-inject it to the Rx path by returning RX_HANDLER_PASS. This is
consistent with previous behavior.
Cc: Florian Westphal <fw@strlen.de>
Fixes: 8626c56c8279 ("bridge: fix potential use-after-free when hook returns QUEUE or STOLEN verdict")
Reviewed-by: Jiri Pirko <redacted>
Signed-off-by: Ido Schimmel <redacted>
---
net/bridge/br_input.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/net/bridge/br_input.c b/net/bridge/br_input.c
index 1607977..c73ed44 100644
--- a/net/bridge/br_input.c
+++ b/net/bridge/br_input.c@@ -223,9 +223,7 @@ static int br_handle_local_finish(struct net *net, struct sock *sk, struct sk_bu if (p->flags & BR_LEARNING && br_should_learn(p, skb, &vid)) br_fdb_update(p->br, p, eth_hdr(skb)->h_source, vid, false); - BR_INPUT_SKB_CB(skb)->brdev = p->br->dev; - br_pass_frame_up(skb); - return 0; + return RX_HANDLER_PASS; } /*
@@ -238,6 +236,7 @@ rx_handler_result_t br_handle_frame(struct sk_buff **pskb) struct sk_buff *skb = *pskb; const unsigned char *dest = eth_hdr(skb)->h_dest; br_should_route_hook_t *rhook; + int err; if (unlikely(skb->pkt_type == PACKET_LOOPBACK)) return RX_HANDLER_PASS;
@@ -287,8 +286,11 @@ rx_handler_result_t br_handle_frame(struct sk_buff **pskb) } /* Deliver packet to local host only */ - NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN, dev_net(skb->dev), - NULL, skb, skb->dev, NULL, br_handle_local_finish); + err = NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN, dev_net(skb->dev), + NULL, skb, skb->dev, NULL, + br_handle_local_finish); + if (err == RX_HANDLER_PASS) + return RX_HANDLER_PASS; return RX_HANDLER_CONSUMED; }
--
2.4.3