From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-lr2-f12.google.com (mail-lr2-f12.google.com [74.125.230.76]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 76D67342524 for ; Sat, 19 Sep 2026 13:43:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.125.230.76 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789825434; cv=none; b=PujMyMKNWBcrH6giAzqsTCgcr2XH6tB0SAgGJb+xztTdV1KHLt2k2mShz2nPzs4kYZa6MD0TWfN1ns4i8ujskAADj10lLXotsDv3bkQ3LP6m2+BNPToqXHRTDwqrYKmaD/seAiAE18P7mbtBtUydgC5yXAihc7Axw18SQbPqUVk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789825434; c=relaxed/simple; bh=twYxm8KkBBz5TtdTcshdmfGdvKHWJaaTEKzHj5SSDGo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=HhB4j63w+9Fcgx4lHd4r2crgkcwakVzkvQtYOhX2+sD0gCYCgzomcvUzSGBYvPX+BlYNnw7KNd2Krd38DCuzLhCqhukwtA08ojCb0WRvo1hnU0Fc6vyUy7WOOhiiJKjxwYjEQQ6x08WtUBtYHLOnh7RCb5ioklUhRpUKW+l9+3Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=jvjcVNpG; arc=none smtp.client-ip=74.125.230.76 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="jvjcVNpG" Received: by mail-lr2-f12.google.com with SMTP id 38308e7fff4ca-3a5d4688decso16488381fa.2 for ; Sat, 19 Sep 2026 06:43:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1789825430; x=1790430230; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to:content-type; bh=3+J2l1gP5MhTi9oNQGHstmZ8ANZIuRJDXJgeWc7c7qg=; b=jvjcVNpGBHRtQu0BjhffNo8IA3xBiC85bwcjBjGanpP/5ZkYoSY5wZiRSN5z/enPKN 6N369/dQ8Pl/g4GZvu0qvdZfmO+mN6maFNAavhWdMiOOCJH3+mGWNoiGjNXdpUZ9CaXl aVnzstd27CO/+NewESnEN1EqtMQZRSUJpGwPSRDtzTupCAOb32nwS6LMhJkKOEpu0c9m xBcxUiLgKN9Kj2mMdk2bWIpVgAPjb9E7HHSvSmcmzbkoC03w75vq+B8tOsj3goVYaUEm xh7ZckHtx639rdlRy/M51l85y8uyJ2jz8U6KnVGQ4lUhClfoOdM++PgCmCaA11QbarxH Rllg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1789825430; x=1790430230; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to:content-type; bh=3+J2l1gP5MhTi9oNQGHstmZ8ANZIuRJDXJgeWc7c7qg=; b=O9BM3brP2MJnZ9SfMbgZQ2oRU5pBZJZCK4bi4rQ3DLhd+959DI7oBtCWQDtw7SO01Y qsDZ0RZrdncx0JKR6vt+Q7l8utsP3Vn+B3Xx07MedohgPj0kAQZ0honSW1yNvD7Q8b7t +8OUn+J+EFCpGI9IaoT/D9SewFJ4dq2W2hS1uniPwYfc7oIoXdQImq/QHZZs6kODbJp1 71I27/7jt6jbDwKOV2ZrYpk4kk6xcTT8q0vIsMxMepvIbY3aGlrhovHmH2pJ9GvZhoc0 gPKMJzQD+l03bLB8wPGb7dlFV/1anqDk1PLr8zJTImKA7JvMgYy0fBA61hZvlgaWcJv9 q8Yw== X-Gm-Message-State: AFuF++nwrPIHKXN+v+39OyEJz4EvfxvYAmLDGuy0lwif1YhHW3wWZE7i PouNICeQ7foCZehIjKmRLBP6T1ik+p/j/0Syi9it8Be4SAhJ/H3i67D5ELVTGPOJ X-Gm-Gg: AYBFou18PjX9LGwBgSrV1nPYLdaUlY6PQTR9Xa72EHzWZxdBgSlEoJ6yt/qZnLZ8u4F MWxxMyDC531zf3aw7vmp4umsqJGxaSlI44Q9Mfyznl+931xFikF3R7paX4WRIeXqEsRdOweFAXi 7k4TIMh8gscrEV1pGxSVxray9i+7q0SsfhNqmXn2YDlnuLtz3634EyJUCJ239q+dNTCNPiecBju m67K6tAjM+lE7iJziU4sSYhRprFE6XrmGmooKEts3fTctoow4RWe/8SjGYSUWfL338JK4TojV9u LF1EPwaKj2Umii8676zyXQoYbO2alf4MGAjgdxJXlm1h9C5Qtt5miciENIEh49IL6NGWH6a0VWH XRB5irjM2M0teBAxqOdX69g+rI5D5A9qZKRntG8ck93u3p5pvBV8NeZPJAXnAv1XZkutnJdzYBO QB3a/V76xTHHqE9TBQqeLKbj4nkG+pRAHCLrCoq53wFmoV3xWDoDirGpvVMQY9IGW5sfrfIQStj pcy+NmAg6VCVBxkt/MWbLUyzPhzo47KuLczSTcafExePIkvvDkrea0kM7lLSRx5+WS4 X-Received: by 2002:a2e:a803:0:b0:3a3:361e:6f1a with SMTP id 38308e7fff4ca-3a5fbf5e287mr11840091fa.12.1789825430463; Sat, 19 Sep 2026 06:43:50 -0700 (PDT) Received: from localhost.localdomain (46-138-187-224.dynamic.spd-mgts.ru. [46.138.187.224]) by smtp.gmail.com with ESMTPSA id 38308e7fff4ca-3a60767aa6asm6220941fa.40.2026.09.19.06.43.49 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 19 Sep 2026 06:43:50 -0700 (PDT) From: Artem Lytkin To: netdev@vger.kernel.org Cc: bridge@lists.linux.dev, razor@blackwall.org, idosch@nvidia.com, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, horms@kernel.org, andrew+netdev@lunn.ch, kuniyu@google.com, michael.chan@broadcom.com, pavan.chebbi@broadcom.com, ajit.khaparde@broadcom.com, sriharsha.basavapatna@broadcom.com, anthony.l.nguyen@intel.com, przemyslaw.kitszel@intel.com, intel-wired-lan@lists.osuosl.org, saeedm@nvidia.com, tariqt@nvidia.com, mbloch@nvidia.com, oss-drivers@corigine.com, wintera@linux.ibm.com, aswin@linux.ibm.com, linux-s390@vger.kernel.org Subject: [PATCH net-next v3 2/2] net: bridge: fail link info that does not fit in a netlink attribute Date: Sat, 19 Sep 2026 16:43:33 +0300 Message-ID: <20260919134333.49379-3-iprintercanon@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260919134333.49379-1-iprintercanon@gmail.com> References: <20260919134333.49379-1-iprintercanon@gmail.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit nla_len is a u16, and a port with enough VLANs, tunnels or MST entries makes the IFLA_AF_SPEC nest wrap, so userspace reads garbage. Same for the inner MST and CFM nests. Use nla_nest_end_safe() for all three and return -E2BIG with an extack on overflow. Dumps end with that error, notifications go through rtnl_set_sk_err() so listeners resync. Assisted-by: Claude:claude-opus-5 Signed-off-by: Artem Lytkin --- net/bridge/br_netlink.c | 25 +++++++++++++++++-------- 1 file changed, 17 insertions(+), 8 deletions(-) diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c index 855a46aec3a89..fbd91b86d4268 100644 --- a/net/bridge/br_netlink.c +++ b/net/bridge/br_netlink.c @@ -459,7 +459,7 @@ static int br_fill_ifinfo(struct sk_buff *skb, const struct net_bridge_port *port, u32 pid, u32 seq, int event, unsigned int flags, u32 filter_mask, const struct net_device *dev, - bool getlink) + bool getlink, struct netlink_ext_ack *extack) { u8 operstate = netif_running(dev) ? READ_ONCE(dev->operstate) : IF_OPER_DOWN; @@ -588,7 +588,8 @@ static int br_fill_ifinfo(struct sk_buff *skb, goto nla_put_failure; } - nla_nest_end(skb, cfm_nest); + if (nla_nest_end_safe(skb, cfm_nest) < 0) + goto nla_nest_too_large; } if ((filter_mask & RTEXT_FILTER_MST) && @@ -608,20 +609,27 @@ static int br_fill_ifinfo(struct sk_buff *skb, if (err) goto nla_put_failure; - nla_nest_end(skb, mst_nest); + if (nla_nest_end_safe(skb, mst_nest) < 0) + goto nla_nest_too_large; } done: if (af) { - if (nlmsg_get_pos(skb) - (void *)af > nla_attr_size(0)) - nla_nest_end(skb, af); - else + if (nla_nest_end_safe(skb, af) < 0) + goto nla_nest_too_large; + if (!nla_len(af)) nla_nest_cancel(skb, af); } nlmsg_end(skb, nlh); return 0; +nla_nest_too_large: + NL_SET_ERR_MSG_MOD(extack, + "AF_SPEC info too large, use per-object dumps (e.g. RTM_GETVLAN)"); + nlmsg_cancel(skb, nlh); + return -E2BIG; + nla_put_failure: nlmsg_cancel(skb, nlh); return -EMSGSIZE; @@ -654,7 +662,8 @@ void br_info_notify(int event, const struct net_bridge *br, if (skb == NULL) goto errout; - err = br_fill_ifinfo(skb, port, 0, 0, event, 0, filter, dev, false); + err = br_fill_ifinfo(skb, port, 0, 0, event, 0, filter, dev, false, + NULL); if (err < 0) { /* -EMSGSIZE implies BUG in br_nlmsg_size() */ WARN_ON(err == -EMSGSIZE); @@ -693,7 +702,7 @@ int br_getlink(struct sk_buff *skb, u32 pid, u32 seq, return 0; return br_fill_ifinfo(skb, port, pid, seq, RTM_NEWLINK, nlflags, - filter_mask, dev, true); + filter_mask, dev, true, extack); } static int br_vlan_info(struct net_bridge *br, struct net_bridge_port *p, -- 2.43.0