* [PATCH 5.10 542/595] bridge: check llc_mac_hdr_init() return value in br_send_bpdu()
[not found] <20260930152347.700140858@linuxfoundation.org>
@ 2026-09-30 15:27 ` Greg Kroah-Hartman
0 siblings, 0 replies; only message in thread
From: Greg Kroah-Hartman @ 2026-09-30 15:27 UTC (permalink / raw)
To: stable
Cc: Greg Kroah-Hartman, patches, Nikolay Aleksandrov, Ido Schimmel,
bridge, Eric Dumazet, Jakub Kicinski, Sasha Levin
5.10-stable review patch. If anyone has any objections, please let me know.
------------------
From: Eric Dumazet <edumazet@google.com>
[ Upstream commit ac704ff08e511c87643799c385f55ecd69b85e03 ]
If llc_mac_hdr_init() fails (for instance if the port device type does
not support LLC or dev_hard_header() fails), br_send_bpdu() should drop
the skb instead of resetting the mac header to the LLC payload and
transmitting a malformed frame.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Closes: https://lore.kernel.org/netdev/179022851638.2160803.1808206741379444999@kernel.org/
Cc: Nikolay Aleksandrov <razor@blackwall.org>
Cc: Ido Schimmel <idosch@nvidia.com>
Cc: bridge@lists.linux.dev
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
Link: https://patch.msgid.link/20260924082951.1599377-3-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/bridge/br_stp_bpdu.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/net/bridge/br_stp_bpdu.c b/net/bridge/br_stp_bpdu.c
index 0e4572f313307..1917d11411d72 100644
--- a/net/bridge/br_stp_bpdu.c
+++ b/net/bridge/br_stp_bpdu.c
@@ -52,7 +52,10 @@ static void br_send_bpdu(struct net_bridge_port *p,
LLC_SAP_BSPAN, LLC_PDU_CMD);
llc_pdu_init_as_ui_cmd(skb);
- llc_mac_hdr_init(skb, p->dev->dev_addr, p->br->group_addr);
+ if (llc_mac_hdr_init(skb, p->dev->dev_addr, p->br->group_addr)) {
+ kfree_skb(skb);
+ return;
+ }
skb_reset_mac_header(skb);
--
2.53.0
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