From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-lj1-f180.google.com (mail-lj1-f180.google.com [209.85.208.180]) (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 B976713AC1 for ; Fri, 29 Aug 2025 06:50:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.208.180 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756450256; cv=none; b=O5aChsXMB8zRke5GsTTw+8GBsdAwyQnGyApIIHSFMmDU+2uZ6RUJhQSBurM1ee/rkv/Kl+YwKLWIKxlsAvJgMmysZZUg2esx+ZHLCfxOiZrKwhafHXCQ+rUirgOh8wsBLXvevedGmr/zgSZCyeOsWMX0JOYrewh5BSmlLOfRURo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756450256; c=relaxed/simple; bh=lohsmysJSeD1DzUAZ+GjNFAhL2lFYLR2NrOdCdIGwTM=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=Ll7GxnV0oMmJRYyCqWVt7OAhQvyStUZBPtv6H7chP+uX+gAESqdBvzWoiQUZFjsJiOmq44Ge9KKxx5QIAQxyiyXHzSbkSs+13eXrqTUOnIic/wOiHdxOhxUWy7WAr+WOZ3fTtHKitkQ3tCe9U2Llxr/iJyty95+HPNGmJ/JLl/s= 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=gGNGBl7k; arc=none smtp.client-ip=209.85.208.180 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="gGNGBl7k" Received: by mail-lj1-f180.google.com with SMTP id 38308e7fff4ca-33685e3b16aso13261751fa.3 for ; Thu, 28 Aug 2025 23:50:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1756450252; x=1757055052; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=Q4bv9XpJPRyW4PIPg5BanTpAyhiBzzJ4kfKB2EmS6yA=; b=gGNGBl7k+V7jVxitG0yZzQ43ps02cuecrqtB02SwHtti3rRkGXbWSYavdMvU9WPEv0 9uMS4XGrvwlwRoxCv7N/5BdqW0lh8W4uon0BFjujj/8jWY1UaYKETZdA+oZpTDqtjpWw rvQ27nDvXhk/zqkzXk7SPVzH1ipfe8BHaLD8dzAtE+yREEQgJVZrDXadnmuyPVsyGZ7M 89JvQXzIknkZOG9iHPp7gI1jFEaZH5WywA+aCcYo78pMIPU/T8f548yrYV9nDFz2kulB za/VCzePmFjCubc9ZphyVDiPTwsy4eyWsE+QDDdbVKJ2CnTd9Bq8sXSjzK+xfLSW5mEC 6Igg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1756450252; x=1757055052; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=Q4bv9XpJPRyW4PIPg5BanTpAyhiBzzJ4kfKB2EmS6yA=; b=gv1REnxg05gts70tCaMZ1OyWJWtoDQHzTZ+O5lbapPt4S/EXroyOteXeeyhndUX6JP 0rgDeRnllFdRMivf2W87Dy44LMu3Zz5UdWUcf3Dmg4l6cTdnRLF3jrK27dHeS10GjFC0 AVoPX9QCrq24BNj4Hd+f/2bqoHrHzIwBZ10+EwG2Ucr0k6T+61FfGZLhY6Ndp0BCYNxC +dnw6BGUOXLL2Qwnk2lh/VZm+Lvwd/WjHKKxYLi/3rJkO1J26HQWlXtxU+KhZeZU/WR6 gaAUyDedB3mUwmMO1CFqe8ohg0xOjAr+6GdlbJdd9pIw4sa6xTRomiIpKj58Zo9rhPSZ ydhQ== X-Gm-Message-State: AOJu0YzpYe5dYQjY9dT/wuIhossAg1ZCYnwKfiqRfgNozNRimnA69Ig5 bMXCURa8AKaOLaU/nV8pbMUtS+5NxslCSCSXUF/AD0MQ8xaS7Z+Ci3UqHzg5zXC/+bc= X-Gm-Gg: ASbGncvuMy9dyrqoD+CaSadbsLGFTMrRvUT7hFm2NuS9KkkEOppyUCu5Jm5dBdK0YSI NbPaa5+1FrKzT67nCaHjcJBBHW+CWF1S/AP2jy/ZXsR80TmdI2SLVGEXWUoaZum74JuLmMc98YQ BtA6u+50wxMUWJM5UHDXcU+Sii2mXCYc03U70GymuGPALT4BsoGRng1NgamWv/BpP1lKbgBqva6 lN1IhTkDtmsWuzfqSIN2eJ6Nf/3Z8gX1HuJe0XRMGsjOnVrdRGL4ZE55tljdFn/XYbA/Lk3EvvZ vb1X+ZkGbUZiSIz1Bcoub6bEbXfAcmkqZo7NV9H72rV6rfepgit7YDh69147Y1gNAHn6YZAonh6 8HoxrVOFfezkv/K4tGzkm73P6yIOBdZJAXK4gmDwc3KNRp2aUZs0ADwWAEq2Y25uLMmPYUVlyM6 nnraGVKxRoOW5oing/Da910Vo2kmAWc8WtGn8SlDw= X-Google-Smtp-Source: AGHT+IEitkqBBUlO9gDjRL4vH70BRNxeEkp9jhhWrBW9XMaio50YmhL/AmhtB7Z4ZYw3Ck1PjltuHg== X-Received: by 2002:a05:651c:20ce:10b0:335:40e6:d066 with SMTP id 38308e7fff4ca-33650feeb2cmr51370131fa.45.1756450252353; Thu, 28 Aug 2025 23:50:52 -0700 (PDT) Received: from localhost.localdomain ([2001:464e:6820:0:4bef:9480:233:512]) by smtp.gmail.com with ESMTPSA id 2adb3069b0e04-55f6770d931sm390085e87.39.2025.08.28.23.50.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 28 Aug 2025 23:50:51 -0700 (PDT) From: Nikolaos Gkarlis To: netfilter-devel@vger.kernel.org Cc: pablo@netfilter.org, fw@strlen.de, Nikolaos Gkarlis Subject: [PATCH] netfilter: nft_ct: reject ambiguous conntrack expressions in inet tables Date: Fri, 29 Aug 2025 08:50:11 +0200 Message-Id: <20250829065011.12936-1-nickgarlis@gmail.com> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: netfilter-devel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit The kernel accepts netlink messages using the legacy NFT_CT_SRC, NFT_CT_DST keys in inet tables, creating ambiguous conntrack expressions that cannot be properly evaluated during packet processing. When NFPROTO_INET is used with NFT_CT_SRC, NFT_CT_DST the register size calculation defaults to IPv6 (16 bytes) regardless of the actual packet family. This causes two issues: 1. For IPv4 packets, only 4 bytes contain valid address data while 12 bytes contain uninitialized memory during comparison. 2. nft userspace cannot properly display these rules ([invalid type]). The bug is not reproducible through standard nft commands, which properly use NFT_CT_SRC_IP(6), NFT_CT_DST_IP(6) keys instead. Fix by rejecting such expressions with EAFNOSUPPORT when used in inet tables. Signed-off-by: Nikolaos Gkarlis --- As an example, packets from 192.0.2.1 (0xc0000201) would also match rules filtering on c000:201:: (0xc0000201000000000000000000000000), which is likely unintended. To my knowledge, the keys NFT_CT_SRC and NFT_CT_DST were never officially used by nft userspace, so I assume rejecting them should be safe. I have tested this change and it appears to work as expected. net/netfilter/nft_ct.c | 1 - 1 file changed, 1 deletion(-) diff --git a/net/netfilter/nft_ct.c b/net/netfilter/nft_ct.c index d526e69a2..23ce90975 100644 --- a/net/netfilter/nft_ct.c +++ b/net/netfilter/nft_ct.c @@ -439,7 +439,6 @@ static int nft_ct_get_init(const struct nft_ctx *ctx, src.u3.ip); break; case NFPROTO_IPV6: - case NFPROTO_INET: len = sizeof_field(struct nf_conntrack_tuple, src.u3.ip6); break; -- 2.34.1