From owner-svn-src-all@freebsd.org  Mon Jun 10 14:19:59 2019
Return-Path: <owner-svn-src-all@freebsd.org>
Delivered-To: svn-src-all@mailman.ysv.freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1])
 by mailman.ysv.freebsd.org (Postfix) with ESMTP id 49B0E15C0776;
 Mon, 10 Jun 2019 14:19:59 +0000 (UTC)
 (envelope-from unkadoug@gmail.com)
Received: from mail-oi1-x242.google.com (mail-oi1-x242.google.com
 [IPv6:2607:f8b0:4864:20::242])
 (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits)
 server-signature RSA-PSS (4096 bits)
 client-signature RSA-PSS (2048 bits) client-digest SHA256)
 (Client CN "smtp.gmail.com", Issuer "GTS CA 1O1" (verified OK))
 by mx1.freebsd.org (Postfix) with ESMTPS id D808A754E4;
 Mon, 10 Jun 2019 14:19:58 +0000 (UTC)
 (envelope-from unkadoug@gmail.com)
Received: by mail-oi1-x242.google.com with SMTP id e189so6332250oib.11;
 Mon, 10 Jun 2019 07:19:58 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025;
 h=from:subject:to:cc:references:message-id:date:user-agent
 :mime-version:in-reply-to:content-transfer-encoding:content-language;
 bh=7KCGBB0pnkjWRrWFLi5sXN/Z/zEoLBQ5v+E0bTvu05o=;
 b=bxj+FflYCcVus0PTNDuP658OGW4F1ww2vOYhsWzBrZBITlihypyD4hdWw1MvUakapU
 6BLTGI3LtEXA4bJNoMi44q22NHz+gqWVW6sY+aMDzsCPk32GF430ZW4O3MoiDugmbijY
 22/tateN6m0P2uLSWsYYWrfBkPtMNMCv/jSaH4d7ABsx4hKgpdoPUEvsPrwR3Ai9jJVx
 1IzgcHJwaiyo2gyyTgzi+BHrgBe/fKqNn7R59k/30jgWJNLRrFEyBpBgNWMWHV/znFYc
 zQ3AV8h/RsUAhOqETXF5b9pMcJc14+kDsCmiGufz/ubrgbmiwUft7VnKL/6e6NXQujCX
 huGQ==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
 d=1e100.net; s=20161025;
 h=x-gm-message-state:from:subject:to:cc:references:message-id:date
 :user-agent:mime-version:in-reply-to:content-transfer-encoding
 :content-language;
 bh=7KCGBB0pnkjWRrWFLi5sXN/Z/zEoLBQ5v+E0bTvu05o=;
 b=Fogg+EYM80OgsyB+3+VKzzEdZ6B0DqyLVYL51qGSxi5BKL3Pby89kpYDePBmtjhmLx
 eO/tcU7O+iq5cIyeWGlVLH+jqAnYZfUnyfq2WNdCHP581QKjyA9dUqNBtNy8pnaUGAwM
 BLGH4ASaKvejWVLg2Sqkrf8Xm5el3DW4eQMSLij0U9k3oUeeuSiI4KjjpnQM6lzU9/iZ
 TFfdwQO3h/DiJJEzIHNTbX83m0I6Av5yVKpHczIfG82wPkauS8hZuijcyj3rBKKhY5Cw
 7pKGfnZsRu37lYBGg8o92RdtLXsoSOZaxJFSfJ1N1mN0qJXECn6cnsIIbC9CsUddIxg6
 aZqw==
X-Gm-Message-State: APjAAAUZAYdneOYlWhzLjp4ngUQbI2V4KoL51ToBPRdYhtiINpRkdwpC
 xmf7V5ym/RGb8gQrJ0S31j80n8bz4Ks=
X-Google-Smtp-Source: APXvYqyHuZJvPPkevy2szU9Xo9vDDy3DDzSxzesCeNtCbXhnRSF2/OQhW88lc/9CnnXKmslSFe8gKw==
X-Received: by 2002:aca:ab57:: with SMTP id u84mr12441025oie.61.1560176397654; 
 Mon, 10 Jun 2019 07:19:57 -0700 (PDT)
Received: from 108-254-203-202.lightspeed.hstntx.sbcglobal.net
 (108-254-203-202.lightspeed.hstntx.sbcglobal.net. [108.254.203.202])
 by smtp.gmail.com with ESMTPSA id w17sm1351453oia.24.2019.06.10.07.19.56
 (version=TLS1_3 cipher=AEAD-AES128-GCM-SHA256 bits=128/128);
 Mon, 10 Jun 2019 07:19:57 -0700 (PDT)
From: Doug Moore <unkadoug@gmail.com>
X-Google-Original-From: Doug Moore <dougm@freebsd.org>
Subject: Re: svn commit: r348843 - head/sys/vm
To: Shawn Webb <shawn.webb@hardenedbsd.org>
Cc: src-committers@freebsd.org, svn-src-all@freebsd.org,
 svn-src-head@freebsd.org, pho@freebsd.org
References: <201906100307.x5A37BFt099669@repo.freebsd.org>
 <20190610130034.k2nzitvaxvpj5lzx@mutt-hbsd>
Message-ID: <c084ec12-5f44-c3e1-bad0-2c702a3032f9@freebsd.org>
Date: Mon, 10 Jun 2019 09:19:55 -0500
User-Agent: Mozilla/5.0 (X11; FreeBSD i386; rv:60.0) Gecko/20100101
 Thunderbird/60.2.1
MIME-Version: 1.0
In-Reply-To: <20190610130034.k2nzitvaxvpj5lzx@mutt-hbsd>
Content-Type: text/plain; charset=windows-1252
Content-Transfer-Encoding: 8bit
Content-Language: en-US
X-Rspamd-Queue-Id: D808A754E4
X-Spamd-Bar: ------
Authentication-Results: mx1.freebsd.org
X-Spamd-Result: default: False [-6.96 / 15.00];
 NEURAL_HAM_MEDIUM(-1.00)[-1.000,0];
 NEURAL_HAM_SHORT(-0.96)[-0.963,0];
 NEURAL_HAM_LONG(-1.00)[-1.000,0]; REPLY(-4.00)[]
X-BeenThere: svn-src-all@freebsd.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: "SVN commit messages for the entire src tree \(except for &quot;
 user&quot; and &quot; projects&quot; \)" <svn-src-all.freebsd.org>
List-Unsubscribe: <https://lists.freebsd.org/mailman/options/svn-src-all>,
 <mailto:svn-src-all-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/svn-src-all/>
List-Post: <mailto:svn-src-all@freebsd.org>
List-Help: <mailto:svn-src-all-request@freebsd.org?subject=help>
List-Subscribe: <https://lists.freebsd.org/mailman/listinfo/svn-src-all>,
 <mailto:svn-src-all-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Mon, 10 Jun 2019 14:19:59 -0000

This comment appears in vm_mmap.c:

     * Mapping of length 0 is only allowed for old binaries.

and my intent was to say, to whoever wrote that comment, that I was not
disallowing the mapping of length zero with this change.  I was only
intending to affect a case in which the length was transformed to zero,
and which was the problem that Peter Holm reported.

Doug Moore

On 6/10/19 8:00 AM, Shawn Webb wrote:
> On Mon, Jun 10, 2019 at 03:07:11AM +0000, Doug Moore wrote:
>> Author: dougm
>> Date: Mon Jun 10 03:07:10 2019
>> New Revision: 348843
>> URL: https://svnweb.freebsd.org/changeset/base/348843
>>
>> Log:
>>   There are times when a len==0 parameter to mmap is okay. But on a
>>   32-bit machine, a len parameter just a few bytes short of 4G, rounded
>>   up to a page boundary and hitting zero then, is not okay. Return
>>   failure in that case.
>>   
>>   Reported by: pho
>>   Reviewed by: alc, kib (mentor)
>>   Tested by: pho
>>   Differential Revision: https://reviews.freebsd.org/D20580
>>
>> Modified:
>>   head/sys/vm/vm_mmap.c
>>
>> Modified: head/sys/vm/vm_mmap.c
>> ==============================================================================
>> --- head/sys/vm/vm_mmap.c	Sun Jun  9 22:55:21 2019	(r348842)
>> +++ head/sys/vm/vm_mmap.c	Mon Jun 10 03:07:10 2019	(r348843)
>> @@ -257,7 +257,10 @@ kern_mmap(struct thread *td, uintptr_t addr0, size_t s
>>  
>>  	/* Adjust size for rounding (on both ends). */
>>  	size += pageoff;			/* low end... */
>> -	size = (vm_size_t) round_page(size);	/* hi end */
>> +	/* Check for rounding up to zero. */
>> +	if (round_page(size) < size)
>> +		return (EINVAL);
> The mmap(2) manpage says that len==0 results in EINVAL, so the manpage
> needs updating.
>
> I'm curious what "there are times" refers to. Can you or the original
> reporter elaborate those cases?
>
> Thanks a lot!
>