From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Philipp Stephani Newsgroups: gmane.emacs.devel Subject: Re: Preview: portable dumper Date: Tue, 29 Nov 2016 22:22:44 +0000 Message-ID: References: <047a67ec-9e29-7e4e-0fb0-24c3e59b5886@dancol.org> <9b6a0571-b2ae-a5dd-a643-3595e8f71cd6@cs.ucla.edu> NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: multipart/alternative; boundary=001a1148d9fea523730542780779 X-Trace: blaine.gmane.org 1480458285 756 195.159.176.226 (29 Nov 2016 22:24:45 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Tue, 29 Nov 2016 22:24:45 +0000 (UTC) Cc: emacs-devel@gnu.org To: Paul Eggert , Daniel Colascione Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Tue Nov 29 23:24:41 2016 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1cBqpM-00072L-HD for ged-emacs-devel@m.gmane.org; Tue, 29 Nov 2016 23:24:40 +0100 Original-Received: from localhost ([::1]:39508 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cBqpJ-0007l5-R5 for ged-emacs-devel@m.gmane.org; Tue, 29 Nov 2016 17:24:37 -0500 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:35041) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cBqok-0007kn-8h for emacs-devel@gnu.org; Tue, 29 Nov 2016 17:24:03 -0500 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cBqof-0005yT-G2 for emacs-devel@gnu.org; Tue, 29 Nov 2016 17:24:02 -0500 Original-Received: from mail-wm0-f51.google.com ([74.125.82.51]:35414) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1cBqof-0005yK-83 for emacs-devel@gnu.org; Tue, 29 Nov 2016 17:23:57 -0500 Original-Received: by mail-wm0-f51.google.com with SMTP id a197so251594916wmd.0 for ; Tue, 29 Nov 2016 14:23:56 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=ujg5LbPmTzfZudR4zrc+bX6uo3VxRYMY/8eKnbDJHnU=; b=O/5YV2JD1lq6cXm4WuV8DuP+dfPwSFcmJH7cJNC7r0pLObl8YkSH4Gpy5uVQsjLY5m xwr9hMjmdkqxABZ7KhDCPtC1AtyCpe7rbvzw/ffu8uwLLD/7FygG3cvjzmH3p2K4gaN7 SaRyabhk0ydKztsXcWwCUvm1pFmG8+fBWwdX8xlMcUTMfr6o1DUyVwMBf1+xFRB+UvsY bgRMjyfMEAmRsQg+a+qDq6+LSDfQw9h4sN0S9jyo4p+gOPENCaEhz4fo9a6M9CIjKeWa 8Zoi1qlbxRXdBK/0nSv6xRTvXrexl3oKbP2e4Qlt35NNBuWTULOvwe0GwXFjdISLY0gW UffQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=ujg5LbPmTzfZudR4zrc+bX6uo3VxRYMY/8eKnbDJHnU=; b=h763kLP5ZEzblfsyyZ7Xh2cLPGvnnHGrDRVwa+jXvlEODwDaQnO8NmDT0xuoAZ8A9a hMJsQni6iIduyn7WPaW1u9PJj5jI8LNWmdO6rIE3mkSZROEYS4e94Ash0WX6N6Z/4scQ mU5D/v1N5uGh/FLLtuHKp/cNGslrdjU1sSmclb6IFtrAKDL9aiNJz2vxQmmi3579VEJg F4AUTLLJwVwL4AyVn4P/7dHgH0DRFq0FqGJA7aDzJ6npWGzOdY7JsaqCUWHWEy7ieBtt EVajmFGwf/v4ZiEwBECTXHUc/cjNlEQ9wtEKw8VUtSR64GcBXDfc+9Jn50XEY5owCZ31 V3mw== X-Gm-Message-State: AKaTC02hOWSD0I60CFvtGQJoMmvuDwVvCqrVVj9dL4JuCbvDfnuXJtXDQLxQ1epjAq5CzYs5B/FE4wdNiVbEkQ== X-Received: by 10.28.195.9 with SMTP id t9mr24401071wmf.92.1480458175322; Tue, 29 Nov 2016 14:22:55 -0800 (PST) In-Reply-To: <9b6a0571-b2ae-a5dd-a643-3595e8f71cd6@cs.ucla.edu> X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 74.125.82.51 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Original-Sender: "Emacs-devel" Xref: news.gmane.org gmane.emacs.devel:209777 Archived-At: --001a1148d9fea523730542780779 Content-Type: text/plain; charset=UTF-8 Paul Eggert schrieb am Di., 29. Nov. 2016 um 22:35 Uhr: > On 11/29/2016 01:19 PM, Daniel Colascione wrote: > > Even*with* a PIC Emacs (which I hope is the default, because ASLR > > greatly improves security), we can get these savings if > > mmap(BASE_ADDRESS_STORED_IN_DUMP, ...) succeeds and we can map the dump > > where we want. If we can't map the dump where we want, we'll just > > relocate it. > > Although your other advantages sound good, this one sounds worrisome. If > Emacs maps the dump to the same place every time, we are giving up ASLR > for the dump itself Is that actually the case? Looking at the code, I see nothing that would prevent dumping with ASLR enabled. --001a1148d9fea523730542780779 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable


Paul E= ggert <eggert@cs.ucla.edu> = schrieb am Di., 29. Nov. 2016 um 22:35=C2=A0Uhr:
On 11/29/2016 01:19 PM, Daniel Colascione wrote:
> Even*with*=C2=A0 a PIC Emacs (which I hope is the default, because ASL= R
> greatly improves security), we can get these savings if
> mmap(BASE_ADDRESS_STORED_IN_DUMP, ...) succeeds and we can map the dum= p
> where we want.=C2=A0 If we can't map the dump where we want, we= 9;ll just
> relocate it.

Although your other advantages sound good, this one sounds worrisome. If Emacs maps the dump to the same place every time, we are giving up ASLR
for the dump itself

Is that actually the ca= se? Looking at the code, I see nothing that would prevent dumping with ASLR= enabled.=C2=A0
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