netdev - [PATCH net-next 01/17] netfilter: flowtable: check for maximum number of encapsulations in bridge vlan

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20251128002345.29378-2-pablo@netfilter.org>
Date: Fri, 28 Nov 2025 00:23:28 +0000
From: Pablo Neira Ayuso <pablo@...filter.org>
To: netfilter-devel@...r.kernel.org
Cc: davem@...emloft.net,
	netdev@...r.kernel.org,
	kuba@...nel.org,
	pabeni@...hat.com,
	edumazet@...gle.com,
	fw@...len.de,
	horms@...nel.org
Subject: [PATCH net-next 01/17] netfilter: flowtable: check for maximum number of encapsulations in bridge vlan

Add a sanity check to skip path discovery if the maximum number of
encapsulation is reached. While at it, check for underflow too.

Fixes: 26267bf9bb57 ("netfilter: flowtable: bridge vlan hardware offload and switchdev")
Signed-off-by: Pablo Neira Ayuso <pablo@...filter.org>
---
 net/netfilter/nft_flow_offload.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/net/netfilter/nft_flow_offload.c b/net/netfilter/nft_flow_offload.c
index 14dd1c0698c3..e95e5f59a3d6 100644
--- a/net/netfilter/nft_flow_offload.c
+++ b/net/netfilter/nft_flow_offload.c
@@ -141,12 +141,19 @@ static void nft_dev_path_info(const struct net_device_path_stack *stack,
 				info->ingress_vlans |= BIT(info->num_encaps - 1);
 				break;
 			case DEV_PATH_BR_VLAN_TAG:
+				if (info->num_encaps >= NF_FLOW_TABLE_ENCAP_MAX) {
+					info->indev = NULL;
+					break;
+				}
 				info->encap[info->num_encaps].id = path->bridge.vlan_id;
 				info->encap[info->num_encaps].proto = path->bridge.vlan_proto;
 				info->num_encaps++;
 				break;
 			case DEV_PATH_BR_VLAN_UNTAG:
-				info->num_encaps--;
+				if (WARN_ON_ONCE(info->num_encaps-- == 0)) {
+					info->indev = NULL;
+					break;
+				}
 				break;
 			case DEV_PATH_BR_VLAN_KEEP:
 				break;
-- 
2.47.3