From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from outbound.ci.icloud.com (ci-2005i-snip4-1.eps.apple.com [57.103.89.212]) (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 5D8AF4C77B5 for ; Wed, 22 Jul 2026 10:24:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=57.103.89.212 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784715896; cv=none; b=sc+tSxQrIJXz3HVkSXz4n7gpYwO/prJtamcUA94uLV8Sv0EGUGRjwgHcehWwCpf1g2Inr8GSXij5nkiXYiJ+2bhWmtni1kDnZetFwTcqI2jlZ9tpOMb6Y/WD0BBymAqPWmlQuriE6g1hKiGJiHg6Y8AtoKhuYHSatewO2w4isZg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784715896; c=relaxed/simple; bh=v+ib2dRWpZc6cejiBpvWLhHBsW9p7G2032Ilkk/3G9o=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=RnHBoliAZiKhrxPA/o/LKggzcHyeoPG45/cgkffOiXAkVUU1/f8ABwHGDH+4VuvhNbg2Xdo8NJyp7lJDEau2xhRJZ97eeWSBjIbU/x6MDFMebgUMBWUXlMWpMGids7FqA/iMANjpARO/tWETlJNDfxbmCZ122q0l4FwwXKKwqyg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=thehaxbys.co.uk; spf=pass smtp.mailfrom=thehaxbys.co.uk; dkim=pass (2048-bit key) header.d=thehaxbys.co.uk header.i=@thehaxbys.co.uk header.b=x3wX2Eht; arc=none smtp.client-ip=57.103.89.212 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=thehaxbys.co.uk Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=thehaxbys.co.uk Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=thehaxbys.co.uk header.i=@thehaxbys.co.uk header.b="x3wX2Eht" Received: from outbound.ci.icloud.com (unknown [127.0.0.2]) by p00-icloudmta-asmtp-us-central-1k-60-percent-8 (Postfix) with ESMTPS id 6C4981800133; Wed, 22 Jul 2026 10:24:50 +0000 (UTC) X-ICL-RepId: 019f895b-4e37-750a-92c3-01f450a07315 X-ICL-Out-Info: HUtFAUMHWwJACUgBTUQeDx5WFlZNRAJCTQtJBEMGXgdeAFYCWgBLVxQEElAFdx9aFVEZSw9OGBwTVlZGBhcNVk1NEFYFVhNQCUpWUAIZHllQSxsOWRcDVxxWRVwYQwldBVccHQ5eRVsTVRdGCRkIXR0ZCEcfCjADQg5WA0MHRQAtGRxXUEMDVxhYAFEUREVRHxcNWE1aAlZNBUoDXwFbBUILSQNfA18DXgFPBV8aWh8aWhBzGV8OWhFBGkoeGQhdXkwTDU1DEkIVBBtGHkMEXy9dF14MXgU= Dkim-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=thehaxbys.co.uk; s=sig1; t=1784715892; x=1787307892; bh=Ym4CnQ83I9M1zT+uXLcZh8HICnLIvGZK5ngCQ19Iwi8=; h=From:To:Subject:Date:Message-ID:MIME-Version:x-icloud-hme; b=x3wX2EhtiKLDlhFNBgx7a3f3yJW+IOLZRvmbSlAnLaThGmBLxarcw2pcMIGXBSjo+0dbdrFG4/nbsNVPF5ISEmg27/dQBK8U3m7BKkDw2XFCsBLbd+BRIcNerLwg693zbJWVICmxMinvuaWyHZep/pY4L3zX4a7KDF3ebXnaT4jqeZoU71cXIqdZ1rxSKK0EdBkMetqkJRpNSr1AEfxpaAmc5Kdst2t8Y2Pk/8LMW7ggrr8lJ+iEX1V8WrmbzLp1E2tMyM5ZtUnnqGZAGD0GYGKKZY+cZrC0DCE+AxIQg246DMVeizG2ryC1E1Ku/eMUYMbXw7U8uKFCxP3wkO0eow== mail-alias-created-date: 1318449231000 Received: from localhost (unknown [17.57.156.36]) by p00-icloudmta-asmtp-us-central-1k-60-percent-8 (Postfix) with ESMTPSA id E25AD18004B6; Wed, 22 Jul 2026 10:24:47 +0000 (UTC) From: jch@thehaxbys.co.uk To: dsahern@kernel.org, idosch@nvidia.com Cc: netdev@vger.kernel.org, John Haxby Subject: [PATCH 0/1] net/ipv4: discard icmp timestamp requests Date: Wed, 22 Jul 2026 11:24:40 +0100 Message-ID: <20260722102441.8762-1-jch@thehaxbys.co.uk> X-Mailer: git-send-email 2.55.0 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Proofpoint-GUID: gkqW7uSvMpnXJC1_0RvsFHjKDoUEIkDS X-Proofpoint-ORIG-GUID: gkqW7uSvMpnXJC1_0RvsFHjKDoUEIkDS X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNzIyMDEwMCBTYWx0ZWRfX32alqj0hjoaR LyU+Da+SzOhtD/WYi73WXl4yQo5duB+Z3fO9F+1v604PHf2Jv+R8DdPdVLe6fplKYsuR4lCg9HU f5Ihl7SAyzstj/xvubPlDs9e1mEyVnWXSuYK9WxWFfnUGq0K3f1Xz9bpPSFWLw4D/aeQJ4PN1cV QvmRh3Vj6GJ0M6IdZ4cuqBcpZu+JlqFOgkm0ePM23+lq7ALKbyr1cBHRUgMG0jp/EN5A7JSaFM/ jtNJd5Sn32xWMcomykpG3Nz9VSU3mGQwYROr8qIMXAo4FPZyGYZXVPqXiQDtjmNbkbZwz9wyYDB zgg+ONPLF1b4a4gBVkC If you google "CVE-1999-0524 fix" you'll see quite a few comments along the lines "this recently showed up in vulnerability scans, this is how I fixed it". It shows up because in late 2022, the CVSS score for that CVE changed from 0.0 to 2.1. There are actually two part to this: one relates to disclosing address information (which is long gone from linux) and the other relates to disclosing timestamp information. This is regarded a a vulnerability because it allows you see the host's count of the number of milliseconds since midnight. Indeed, according to RFC 0792, and back in 1981 it had a potential use for time synchronisation across hosts. That early use-case has long since been supplanted by NTP so you know how many milliseconds there are since midnight: it's the same as on your host, your smartwatch, your phone and practically any other computer you care to mention. It's not as though the ICMP timestamp is an actual vulnerability, it's just a pain in the neck because world+dog wants to know how to configure iptables or nft to just discard this, so let's help everyone out by discarding it in the kernel. jch John Haxby (1): net/ipv4: discard icmp timestamp requests net/ipv4/icmp.c | 42 +----------------------------------------- 1 file changed, 1 insertion(+), 41 deletions(-) -- 2.55.0