From owner-freebsd-hackers@FreeBSD.ORG Tue Apr 8 10:59:36 2014 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id DCF13712 for ; Tue, 8 Apr 2014 10:59:36 +0000 (UTC) Received: from nm9-vm2.bullet.mail.ir2.yahoo.com (nm9-vm2.bullet.mail.ir2.yahoo.com [212.82.96.145]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 1855C125A for ; Tue, 8 Apr 2014 10:59:35 +0000 (UTC) Received: from [212.82.98.127] by nm9.bullet.mail.ir2.yahoo.com with NNFMP; 08 Apr 2014 10:59:33 -0000 Received: from [46.228.39.92] by tm20.bullet.mail.ir2.yahoo.com with NNFMP; 08 Apr 2014 10:59:33 -0000 Received: from [127.0.0.1] by smtp129.mail.ir2.yahoo.com with NNFMP; 08 Apr 2014 10:59:33 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yahoo.es; s=s1024; t=1396954773; bh=q7vPSnM7OlmMtt1DofpxeZqB0T2gexKos59oSM20KXQ=; h=X-Yahoo-Newman-Id:X-Yahoo-Newman-Property:X-YMail-OSG:X-Yahoo-SMTP:X-Rocket-Received:Date:From:To:Subject:Message-Id:In-Reply-To:References:X-Mailer:Disposition-Notification-To:Mime-Version:Content-Type:Content-Transfer-Encoding; b=WnDjbakqaTbEDIkBw2ejy6gmvCVQKKL7yNBPpSFo+zLsHM/n+U+XJ+p1+U2ZUrQqYCx0sFzswd79kYTVTD0gb/BcsAkCLWVAwRAYvznVWVdWOpdlp06Cb8ukJdsv7bMY5PxP7kecCXl5MFgXAgxuQ4jPljYL9u+vnAAfg45/l2U= X-Yahoo-Newman-Id: 795383.83109.bm@smtp129.mail.ir2.yahoo.com X-Yahoo-Newman-Property: ymail-3 X-YMail-OSG: LmGDN5QVM1kpMFUmS67ky3e8zQQhVlAiPHytrWi8YVK6vqu cIBB0ghVOge6x_dzvPd5xnY9tADVLqbmhv.Y5cjHS7G6pkcEmc9WMjqqIa_J BDYycqWVW8Fwe9uLnQtBYJOPBk7aDGUPqUkBXpFV4t4dybZNQNCzYfaxt1Cn BvGO1jvkzz6EcjWT02xie574rJRMQeLuCFtw4rY8cLIcGALxeWunKgpBjKD. QVJYH39RWYJNX57rY1yZtJf99xhvlMEglpLT1F3NwrhK4aUpzbIK9S2XaaqH ZuNg3v.ovmry.OGry2.5hbPKJVm7fQSwTT99bLxxzI.xuTTl4umYCB6noAww SJNNQfTLl5m7fafmAvEW3M2Veb4nSMi8VlYSyp2CGsjb50GRs_mIVbUZnr4N zAxPIlFVRTx0YW7grFKLxJgbon5U84DDUd9NzR3PRD1X9vzdluZdSW.y1XT9 r.eWe_qmJLr6.7oGerd6YZv5NKAo9TKgnooqhQCwJHD6tnI3STIQZsoMe X-Yahoo-SMTP: mX392iiswBAeJNdO_s.EW62LZDJR X-Rocket-Received: from camibar.emorras.eu (emorrasg@85.219.45.142 with plain [63.250.193.228]) by smtp129.mail.ir2.yahoo.com with SMTP; 08 Apr 2014 10:59:33 +0000 UTC Date: Tue, 8 Apr 2014 13:02:06 +0200 From: Eduardo Morras To: freebsd-hackers@freebsd.org Subject: Re: pipe() resource exhaustion Message-Id: <20140408130206.e75f3bf6c6df28b6e4839e70@yahoo.es> In-Reply-To: References: X-Mailer: Sylpheed 3.3.1 (GTK+ 2.24.22; amd64-portbld-freebsd9.2) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.17 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 08 Apr 2014 10:59:36 -0000 On Mon, 7 Apr 2014 07:25:22 -0500 Mark Felder wrote: > On 2014-04-07 06:02, Ivan Voras wrote: > > Hello, > > > > Last time I mentioned this it didn't get any attention, so I'll try > > again. By accident (via a buggy synergy server process) I found > > that a simple userland process can exhaust kernel pipe memory > > (kern.ipc.pipekva > > sysctl) which as a consequence has that new processes which use pipe > > cannot be started, which includes "su", by which an administrator > > could kill such a process. > > > > That's a pretty painful local denial of service :( Yes it is. Perhaps there should be 8% fd reserved for root, su and setuid family syscalls like in filesystem space or postgresql reserved connections for db admin. --- --- Eduardo Morras