From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.netfilter.org (mail.netfilter.org [217.70.190.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DC39C37C937; Sat, 16 May 2026 11:56:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.70.190.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778932602; cv=none; b=hc8wSg1J3imYNiN6LJW8Cs9kCyU3iCTTx5FcxNLXDN2WNgCt1QZg+AUzWY9FXtwKTBcbqMkqDjBgJ9NvDKOM9NuGdjcdNpXapuAqayiXxyHZe3wVcl044ckCcDuGDK0j3l6fnkJwf5LiIrK47/SBVF4IxqWF1uvxVFVdAm3zoNw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778932602; c=relaxed/simple; bh=AkBosYE6dkFdWGwYlkNYL64YRPEyHCeZSUrdrVMZyR8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=P2ZNpjaJcuTQdFHfGnuXyIeJ4IFn9T+enbLidRQWm4tcAoT/nDx4sisq8scbpNiIqMH6SCIK6l3z6bYaX8L1WRjkiI5yYJ4r5+bH/KoDX6smDcWeBuFam6kUGgnKH/fU/O/woAl3TNnUkekEYYhU2reIFP83XIF74aFfAPZMEuA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=netfilter.org; spf=pass smtp.mailfrom=netfilter.org; dkim=pass (2048-bit key) header.d=netfilter.org header.i=@netfilter.org header.b=HflGJOj8; arc=none smtp.client-ip=217.70.190.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=netfilter.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=netfilter.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=netfilter.org header.i=@netfilter.org header.b="HflGJOj8" Received: from localhost.localdomain (mail-agni [217.70.190.124]) by mail.netfilter.org (Postfix) with ESMTPSA id BE092601A9; Sat, 16 May 2026 13:56:36 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=netfilter.org; s=2025; t=1778932597; bh=0GmtqaXtt+ZaSlWG1mBiVsaFE9cLgk2OKCrSYbK+tnc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=HflGJOj8vN7D4GLhuMBrQry+1dbB5l7p+30VuqGIh2Iv/SpKGMHq0P+KNX6Q2wm2k IPfFYHkCYfvwQ1LZzo4Zh167AYVbQIkg6LveFyO+Jnwz64rHhedH2nmIxRnPO/z8tp nz8/xGvxqVvREaWMPNPs754XknqOpaWibNFY9J7duIbWkkVpTrDoO3OH/yodfZ8W6Z pS3gAzaGRe2nWaGUOkhFmLplsoIhbJUfjv1QM1C6i1Q5tWH4Rd/l1ZTsa+4QsniSSs 2WYTJtfW8u/nEDQptlh7UlbeKB0XDRdcRA5f47XfgdsaVFrzMkiG3tY+Ws28FHtRux MtwWVop0K5D5A== From: Pablo Neira Ayuso To: netfilter-devel@vger.kernel.org Cc: davem@davemloft.net, netdev@vger.kernel.org, kuba@kernel.org, pabeni@redhat.com, edumazet@google.com, fw@strlen.de, horms@kernel.org Subject: [PATCH net 04/12] netfilter: nft_inner: Fix IPv6 inner_thoff desync Date: Sat, 16 May 2026 13:56:19 +0200 Message-ID: <20260516115627.967773-5-pablo@netfilter.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260516115627.967773-1-pablo@netfilter.org> References: <20260516115627.967773-1-pablo@netfilter.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Yizhou Zhao In nft_inner_parse_l2l3(), when processing inner IPv6 packets, ipv6_find_hdr() correctly computes the transport header offset traversing all extension headers, but the result is immediately overwritten with nhoff + sizeof(_ip6h) (40 bytes), which only accounts for the IPv6 base header. This creates a desync between inner_thoff (wrong — points to extension header start) and l4proto (correct — e.g., IPPROTO_TCP), enabling transport header forgery and potential firewall bypass. This issue affects stable versions from Linux 6.2. For comparison, the normal (non-inner) IPv6 path correctly preserves ipv6_find_hdr()'s result. Removing the incorrect overwrite ensures that ipv6_find_hdr()'s calculated transport header offset is preserved, thereby fixing the desynchronization. Fixes: 3a07327d10a0 ("netfilter: nft_inner: support for inner tunnel header matching") Cc: stable@vger.kernel.org Reported-by: Yizhou Zhao Reported-by: Yuxiang Yang Reported-by: Xuewei Feng Reported-by: Qi Li Reported-by: Ke Xu Assisted-by: GLM:5.1 Z.ai Signed-off-by: Yizhou Zhao Reviewed-by: Fernando Fernandez Mancera Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nft_inner.c | 1 - 1 file changed, 1 deletion(-) diff --git a/net/netfilter/nft_inner.c b/net/netfilter/nft_inner.c index 03ffb1159fc1..859aa38e333b 100644 --- a/net/netfilter/nft_inner.c +++ b/net/netfilter/nft_inner.c @@ -163,7 +163,6 @@ static int nft_inner_parse_l2l3(const struct nft_inner *priv, return -1; if (fragoff == 0) { - thoff = nhoff + sizeof(_ip6h); ctx->flags |= NFT_PAYLOAD_CTX_INNER_TH; ctx->inner_thoff = thoff; ctx->l4proto = l4proto; -- 2.47.3