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 4C12C2EA749; Sun, 7 Jun 2026 09:50:05 +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=1780825806; cv=none; b=IfvZ86wuKOFdO2qd9byaI/hR3nUngeVXU5hPwJAnwjIV5pEdnnBBQIBlt/BO3+I8PJnT5W5w2bmnco/LQcYGT5TzFkvYK0hzijqQEPeMzRiKgLS/W+ByRFfcwD99wRE+Yzg8f0jvonM/+FtmJeXBf46FIqPMEjzPKsO1NTWmbNQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780825806; c=relaxed/simple; bh=7BmVU4tkNybgTi7CezIgNFD+tIc9a04Bw3NSwlWmOEs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Sw2cR+JJIurE0MwsJu6RZOHSG0W+RZaAOla6r8qNsmxsFC+nChwcQ6NPQ6joqV5Zjj5njwSviQyCuBlXSY/dJdv0ICGTd0b9yKv7qiQKW3CK9t9nXm1zfygEw1NAt76Km0fwRyBeXL9dEjPGoQn4jEUiu/LK66SxXlrGT/KsPxs= 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=uYduBuZF; 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="uYduBuZF" Received: from localhost.localdomain (mail-agni [217.70.190.124]) by mail.netfilter.org (Postfix) with ESMTPSA id 1CB326019C; Sun, 7 Jun 2026 11:50:03 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=netfilter.org; s=2025; t=1780825803; bh=lH/8Y4s/HAN0AI55N4GmKCh8A5UwLJBN8qLlXk0B/E4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=uYduBuZFWVAg0XIH/Cyhh7GOUgoMKji9CxSN0U3p0kfmpwDYTuvX3GCftNk8VoMae Cb8yD0lJJxIt+S/X3Vu8FuOn9vGPCKZ1ONjGWqXehZk/ZvrIgAYiBlLA+jFlOSEqYR iApE4ZKi764EZOa1z115q8pYMTCJLKrJgOpzoxGfx9hDfOGfz+PMDXOOn9UHnM/9aJ khozBBGbA7l9dxeK+az3ZhsuOB6KUoVo7xNN+Adc1slZufU6Blg5IHOvdO9WAaE5Yy cOpS2bnw3jM1vriw9V3UObmVVc81RdchcXuvBKHvE4wiEd7nVbrRF1jiBvQcAW7FO1 PqJD88ipXfBFw== 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-next 02/15] netfilter: nfnetlink_osf: fix mss parsing on big-endian architectures Date: Sun, 7 Jun 2026 11:49:41 +0200 Message-ID: <20260607094954.48892-3-pablo@netfilter.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260607094954.48892-1-pablo@netfilter.org> References: <20260607094954.48892-1-pablo@netfilter.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Fernando Fernandez Mancera The MSS calculation in nf_osf_match_one() manually shifts bytes to construct a 16-bit value before passing it to ntohs(). This works on little-endian hosts but it does not work on big-endian as the bytes are being always shifted and set in the same way for all architectures. Use get_unaligned_be16() to fix this on big-endian systems. It also simplifies the code. Fixes: 11eeef41d5f6 ("netfilter: passive OS fingerprint xtables match") Signed-off-by: Fernando Fernandez Mancera Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nfnetlink_osf.c | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) diff --git a/net/netfilter/nfnetlink_osf.c b/net/netfilter/nfnetlink_osf.c index acb753ec5697..92002079f8ea 100644 --- a/net/netfilter/nfnetlink_osf.c +++ b/net/netfilter/nfnetlink_osf.c @@ -95,11 +95,7 @@ static bool nf_osf_match_one(const struct sk_buff *skb, switch (*optp) { case OSFOPT_MSS: - mss = optp[3]; - mss <<= 8; - mss |= optp[2]; - - mss = ntohs((__force __be16)mss); + mss = get_unaligned_be16(&optp[2]); break; case OSFOPT_TS: break; -- 2.47.3