From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from abb.hmeau.com (abb.hmeau.com [180.181.231.80]) (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 5EC1C3CFF5C; Fri, 15 May 2026 04:22:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=180.181.231.80 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778818979; cv=none; b=i6su0jkKzusOa+oCxIuu0AMqqgtg4BQQSiLno4qTWCIr+oCZ4hxjMz6vI7UYqVqaUABEenDvf/aLkNEXjUBCoEFuIIYEdzobL9KwQ/2xbtkO3L/PLDN5Kyoaos7O7nzrKJ0WNcvSzfVkt9w7ca5ln92QBOVtffnH43iuUaK93gc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778818979; c=relaxed/simple; bh=wRKIbuEXjpxqTkUyNSVCBtUJJm+xY2T42hd7lP5qJe8=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=S0TDPmqbeXwB2aIYYRgB44AWtsma6dTvWU3hy4YDnon4cpXq7qzFkiQIVBWwtMIm8GOOjNLf5wtPqWVDYXlPW6CtgqCIx+OQ4tCcpXjsECCT3QMaR9w7zSiDDDrKy2hdX6hSm9GoyKW0z9RftevGzJ8IX9jALOzrQmqj6KbfSko= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=gondor.apana.org.au; spf=pass smtp.mailfrom=gondor.apana.org.au; dkim=pass (2048-bit key) header.d=gondor.apana.org.au header.i=@gondor.apana.org.au header.b=A2EdxkRY; arc=none smtp.client-ip=180.181.231.80 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=gondor.apana.org.au Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gondor.apana.org.au Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gondor.apana.org.au header.i=@gondor.apana.org.au header.b="A2EdxkRY" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=gondor.apana.org.au; s=h01; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:cc:to:subject:message-id:date: from:content-type:reply-to; bh=6nH6bJWAeGtbmVExN7pnUKMyzJoqiIby5o4vaYMfyoo=; b=A2EdxkRYiz9xEqdMomkWf5eJR6kHHn6L7NZUzB43FcPG9jSK4VbmFCUvTRhiST/E5PC6SFd0aI2 kIkGNlHHYXV/FeCUzg0bpsfGore6Pt40K37IBd3+MrvaNidnXnrkPjquUBS3aHaRJ+/IZL2QuB1Cu 2LuR9+W8jyNu8slE94E5HEeiZftGfQQvw8f3cGuSzas3tGaLfeUqk1xsFLj3lRLtabIe8uNA3W6fR v2VETrcwFILuXt83w5LUJR0mdQxsz2MLkZRNtoCZChYF8Or9HQNrd+xkQ/EFGe2aAAi0hJwILb6ZD 9hV4Ch66iYsRkhy0D67WW8k+K14/trmJ9tVw==; Received: from loth.rohan.me.apana.org.au ([192.168.167.2]) by formenos.hmeau.com with smtp (Exim 4.96 #2 (Debian)) id 1wNk4O-00EIph-1E; Fri, 15 May 2026 12:22:41 +0800 Received: by loth.rohan.me.apana.org.au (sSMTP sendmail emulation); Fri, 15 May 2026 12:22:40 +0800 Date: Fri, 15 May 2026 12:22:40 +0800 From: Herbert Xu To: Pablo Neira Ayuso Cc: Michael Bommarito , Steffen Klassert , Eric Dumazet , netdev@vger.kernel.org, "David S . Miller" , Jakub Kicinski , Paolo Abeni , Kuniyuki Iwashima , Maciej Zenczykowski , Kees Cook , Jeff Layton , "Gustavo A . R . Silva" , Florian Westphal , netfilter-devel@vger.kernel.org, coreteam@netfilter.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH net 0/2] ipv4: harden against ihl < 5 IP_HDRINCL packets Message-ID: References: Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Wed, May 13, 2026 at 12:34:50AM +0200, Pablo Neira Ayuso wrote: > > There are possibly more ways to mangle ihl in the kernel in 2026, not > only NFQUEUE and nft_payload. If a packet will be processed further by our stack, we should not allow it to be modified in such a way that it becomes a threat to our network stack's consistency. This is especially the case in containers where unprivileged users may be able to create these mangling rules. So any time after a packet has been mangled by nftables where it may result in a bogus packet, it needs to be checked for consistency before it is reinjected into our IP stack. Thanks, -- Email: Herbert Xu Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt