From 070f9e651d187f1db4741fa9e1ff37f7972f9252 Mon Sep 17 00:00:00 2001 From: Daniel Kahn Gillmor Date: Fri, 9 Mar 2012 12:16:18 +1900 Subject: [PATCH] Re: a DoS vulnerability associated with conflated Message-IDs? --- ea/c6fb5e81e79d67c640831090b4fd96e16356f7 | 77 +++++++++++++++++++++++ 1 file changed, 77 insertions(+) create mode 100644 ea/c6fb5e81e79d67c640831090b4fd96e16356f7 diff --git a/ea/c6fb5e81e79d67c640831090b4fd96e16356f7 b/ea/c6fb5e81e79d67c640831090b4fd96e16356f7 new file mode 100644 index 000000000..b7ce344c8 --- /dev/null +++ b/ea/c6fb5e81e79d67c640831090b4fd96e16356f7 @@ -0,0 +1,77 @@ +Return-Path: +X-Original-To: notmuch@notmuchmail.org +Delivered-To: notmuch@notmuchmail.org +Received: from localhost (localhost [127.0.0.1]) + by olra.theworths.org (Postfix) with ESMTP id 5C9B8431FB6 + for ; Thu, 8 Mar 2012 09:16:22 -0800 (PST) +X-Virus-Scanned: Debian amavisd-new at olra.theworths.org +X-Spam-Flag: NO +X-Spam-Score: 0 +X-Spam-Level: +X-Spam-Status: No, score=0 tagged_above=-999 required=5 tests=[none] + autolearn=disabled +Received: from olra.theworths.org ([127.0.0.1]) + by localhost (olra.theworths.org [127.0.0.1]) (amavisd-new, port 10024) + with ESMTP id l68mOR6wLNd6 for ; + Thu, 8 Mar 2012 09:16:21 -0800 (PST) +Received: from che.mayfirst.org (che.mayfirst.org [209.234.253.108]) + by olra.theworths.org (Postfix) with ESMTP id CAD03431FAE + for ; Thu, 8 Mar 2012 09:16:21 -0800 (PST) +Received: from [192.168.13.75] (lair.fifthhorseman.net [108.58.6.98]) + by che.mayfirst.org (Postfix) with ESMTPSA id F005BF970; + Thu, 8 Mar 2012 12:16:17 -0500 (EST) +Message-ID: <4F58E962.1050403@fifthhorseman.net> +Date: Thu, 08 Mar 2012 12:16:18 -0500 +From: Daniel Kahn Gillmor +User-Agent: Mozilla/5.0 (X11; Linux i686; rv:9.0) Gecko/20120125 Icedove/9.0.1 +MIME-Version: 1.0 +To: James Vasile +Subject: Re: a DoS vulnerability associated with conflated Message-IDs? +References: <87k42vrqve.fsf@pip.fifthhorseman.net> + <87ipif2fdn.fsf@wyzanski.jamesvasile.com> +In-Reply-To: <87ipif2fdn.fsf@wyzanski.jamesvasile.com> +Content-Type: text/plain; charset=UTF-8; format=flowed +Content-Transfer-Encoding: 7bit +Cc: notmuch mailing list +X-BeenThere: notmuch@notmuchmail.org +X-Mailman-Version: 2.1.13 +Precedence: list +Reply-To: notmuch +List-Id: "Use and development of the notmuch mail system." + +List-Unsubscribe: , + +List-Archive: +List-Post: +List-Help: +List-Subscribe: , + +X-List-Received-Date: Thu, 08 Mar 2012 17:16:22 -0000 + +On 03/08/2012 12:04 PM, James Vasile wrote: +> On Thu, 08 Mar 2012 11:37:09 -0500, Daniel Kahn Gillmor wrote: +>> Any ideas on how to approach this? +> +> Treat messages with the same ID but different hashes as different? + +Given that a message hash would include all headers, including Received: +and other MTA-added stuff, i think that would remove all relevance of +the Message-ID field. in particular, it seems like we would just be +identifying messages by their digest. + +If you're willing to ignore the headers and just look at a digest of the +body, that still doesn't provide any help for the common (legitimate) +case of a message jointly-delivered to a mailing list and to a specific +(already-subscribed) user. + +That user will get two copies of the message, and since most mailing +lists modify the body of the message (usually by adding a footer section +with mailing list info) their bodies will also have different digests. + +So i don't see how to make this suggestion work without giving up on +Message-IDs as the identifier entirely (and therefore accepting many +more spurious duplicates than users currently need to tolerate). + +Any other suggestions or ideas? + + --dkg -- 2.26.2