From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ej1-f44.google.com (mail-ej1-f44.google.com [209.85.218.44]) (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 EFAC722F74A for ; Sun, 9 Nov 2025 19:24:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.218.44 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762716285; cv=none; b=SXXIqE6b6yNfmUucqd48nkZvk0PWJEMixIwtJ4W9nWw+W0w/gDMyQJjVck7TfSThgVnA2RRZnsueFEl4IGBObbBKyhkbFKPQKYC9yINyheZ+V4Mlp/fNKJbUP+PCyTopQMOWUpfHRC6xfqp5GuKBdIc8bRdQMpFSWFzLmNurbW4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762716285; c=relaxed/simple; bh=fdY4s91tI+lPau1JubbQ0x8fEYiPT2Mrr0LtPH6xCk0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=iNJTqYzrlrDWqbM9UQ9MXhQWFWEY5hZXpvRzSrtBRy00s6okQau5Vx+P5DxW9wb1psiP6P0A+IJopy6dRppUkgBgoXi/wVeQVzMM+rx2E6rAgn7jcrn5PHU+GluqnHj1qsLmvfJ7YztY2nnUDT6Dpwgs1kd6/ARoIPKvWGjIm5s= 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=EmB2l+B6; arc=none smtp.client-ip=209.85.218.44 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="EmB2l+B6" Received: by mail-ej1-f44.google.com with SMTP id a640c23a62f3a-b7155207964so401228366b.2 for ; Sun, 09 Nov 2025 11:24:43 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1762716282; x=1763321082; 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; bh=/+3n/wt4G7GIqXmLm7jMx2L0Drt9lvIRoMC4cC/d+Ac=; b=EmB2l+B6gizAHsZ+0x5DOo1VURQjq4FqFDRQAQQvD73AygzFPREL0ckIcCBdw5w6Jk YoBu58htsURqGLty+mAizzNY/3IvusoU0DqmNwT6xIW8xpanKD/I3z1nT/kXpZdS+mRG viXqFUape+RjkomJ0hKFLN3Fa3M9w+Hvc/0m/ZaMIca/PEFd8DfvX8DHjWtV6KldKmuR Vjjoqbfsix+FdrD/PDCRkx0SPnPYK88ygww61RWCOScP5tje3yil0Lnwfi2eIaQgDzX5 1sIcZZiFJLrdzjJ+OMq3d6WCKdh25hwHYjxUCCiEcxBhGBFM4SHJ0kCJJvY7h/5O6/iW fTng== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1762716282; x=1763321082; 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; bh=/+3n/wt4G7GIqXmLm7jMx2L0Drt9lvIRoMC4cC/d+Ac=; b=N0YxKAkEjPgjDdWCR3jeAlysPuAtwnJb7iG/Em3oyQSJIsFk7PaOZHpyQl9O6AGuYJ E21dCQks3JkZF2Vugt1QucwpTMNp4K+AY13PYt88ue9B/FEiUi4qrkGR1OrZsHatOcla 5/kR2qNfaV4ZoavWWwgU1u/jmNGWzRgTWCpSiP1Jk1nsX57jKJgbRUMZAuzc2uwj/ha5 k80sa1A9jxYR2I89PXUDLne1ftqPOYBrpbEJdmQT5rsj1ikgZxuDIB73Ij1N+Q3P4x6d HMEcgfG9A0vgk7DN+IP7jfOLyAM4xPqeQudqQG7Umeqz/fjU9cnTFA3jYhNtnShA5T4F Gd0w== X-Forwarded-Encrypted: i=1; AJvYcCVMAw1E+jU5stX/HohwpvtWgTXllcAVcP6Ch9W1Fh9VFooWUwjxu4FHoXEh7JV3fA6ahbvCqtY=@vger.kernel.org X-Gm-Message-State: AOJu0Yz2MOg0faHVMvIFSpG7yrYTUVuwgZCgMmFapD2fxyauHu9bz/uR Hr7+KDPAxsmcbnhEB5SRQ6QCpTuFEAhL2So9r0S/aSz/RLCqbCkwdMh6 X-Gm-Gg: ASbGncseErIXiKXMI1fpEm3k9/kHYSrsCxuLEkc7T+fmw+hTBVO2c7dVWKJg99TaQH8 1W4w9VQIzguzbGI7ZVBvPCiiEPyGdSJI+7QKKSOKLkiuiExhUBmpbO+QFjZv4szMpcMUVvJ11TB YAp8lSpqi6G6O3eJcLOHGPEw3tKyyRNo00fgg0mrJ7gylvaCC8FFiY2QgoesGsMVANRtuD2lfpL FyDA34VM5TKMFIvN88MGrcYdlcsOmZDHru6F6IFynSbgkWgdz3IF+tHVZRaZRW2k1I5pVq0oBIc Y4sfop70UWzvDF44COU0aPadwKkHJ6LUbCdMoqxLhsmzjQ6cPNqsYVCD3C76KFyeylpkMJ4O0bg 0Xf2HVIlkD8T5KI2KEAGD45DA9+0G6ruQPkpjLExbYPYg2ePIZ7K7qA8BQOiHtdzZoQ2qsQ5U3f 0zFa41PUmmHzyHEywkX1H8K7SZRu0imLqvMNOzAWIVnlzXb59rD0eyNmFmSh/iQomtE3ST7aOyJ oRbD9xp4JTexUHqLulp X-Google-Smtp-Source: AGHT+IGz2KRI1O39uoZsEqlvnLp53H/kYakBnxCti71eJRyaYaJ3y+qwmBNp1s7c1ixCSsXVxeHDAA== X-Received: by 2002:a17:906:ef02:b0:b72:b97b:b6fc with SMTP id a640c23a62f3a-b72e03ef38emr633081066b.30.1762716282139; Sun, 09 Nov 2025 11:24:42 -0800 (PST) Received: from eric (2001-1c00-020d-1300-1b1c-4449-176a-89ea.cable.dynamic.v6.ziggo.nl. [2001:1c00:20d:1300:1b1c:4449:176a:89ea]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-b72bf97e447sm919652466b.42.2025.11.09.11.24.41 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 09 Nov 2025 11:24:41 -0800 (PST) From: Eric Woudstra To: Pablo Neira Ayuso , Jozsef Kadlecsik , Florian Westphal , Phil Sutter , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Nikolay Aleksandrov , Ido Schimmel Cc: netfilter-devel@vger.kernel.org, netdev@vger.kernel.org, bridge@lists.linux.dev, Eric Woudstra Subject: [PATCH v17 nf-next 1/4] netfilter: utils: nf_checksum(_partial) correct data!=networkheader Date: Sun, 9 Nov 2025 20:24:24 +0100 Message-ID: <20251109192427.617142-2-ericwouds@gmail.com> X-Mailer: git-send-email 2.50.0 In-Reply-To: <20251109192427.617142-1-ericwouds@gmail.com> References: <20251109192427.617142-1-ericwouds@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 In the conntrack hook it may not always be the case that: skb_network_header(skb) == skb->data, i.e. skb_network_offset(skb) is zero. This is problematic when L4 function nf_conntrack_handle_packet() is accessing L3 data. This function uses thoff and ip_hdr() to finds it's data. But it also calculates the checksum. nf_checksum() and nf_checksum_partial() both use lower skb-checksum functions that are based on using skb->data. Adjust for skb_network_offset(skb), so that the checksum is calculated correctly. Signed-off-by: Eric Woudstra --- net/netfilter/utils.c | 28 ++++++++++++++++++++++------ 1 file changed, 22 insertions(+), 6 deletions(-) diff --git a/net/netfilter/utils.c b/net/netfilter/utils.c index 008419db815a..7b33fe63c5fa 100644 --- a/net/netfilter/utils.c +++ b/net/netfilter/utils.c @@ -124,16 +124,25 @@ __sum16 nf_checksum(struct sk_buff *skb, unsigned int hook, unsigned int dataoff, u8 protocol, unsigned short family) { + unsigned int nhpull = skb_network_offset(skb); __sum16 csum = 0; + if (WARN_ON(!skb_pointer_if_linear(skb, nhpull, 0))) + return 0; + + /* pull/push because the lower csum functions assume that + * skb_network_offset(skb) is zero. + */ + __skb_pull(skb, nhpull); switch (family) { case AF_INET: - csum = nf_ip_checksum(skb, hook, dataoff, protocol); + csum = nf_ip_checksum(skb, hook, dataoff - nhpull, protocol); break; case AF_INET6: - csum = nf_ip6_checksum(skb, hook, dataoff, protocol); + csum = nf_ip6_checksum(skb, hook, dataoff - nhpull, protocol); break; } + __skb_push(skb, nhpull); return csum; } @@ -143,18 +152,25 @@ __sum16 nf_checksum_partial(struct sk_buff *skb, unsigned int hook, unsigned int dataoff, unsigned int len, u8 protocol, unsigned short family) { + unsigned int nhpull = skb_network_offset(skb); __sum16 csum = 0; + if (WARN_ON(!skb_pointer_if_linear(skb, nhpull, 0))) + return 0; + + /* See nf_checksum() */ + __skb_pull(skb, nhpull); switch (family) { case AF_INET: - csum = nf_ip_checksum_partial(skb, hook, dataoff, len, - protocol); + csum = nf_ip_checksum_partial(skb, hook, dataoff - nhpull, + len, protocol); break; case AF_INET6: - csum = nf_ip6_checksum_partial(skb, hook, dataoff, len, - protocol); + csum = nf_ip6_checksum_partial(skb, hook, dataoff - nhpull, + len, protocol); break; } + __skb_push(skb, nhpull); return csum; } -- 2.50.0