Re: kern/49692: impossibly large mmap does not fail

[Justin Cormack <justin%specialbusservice.com@localhost>]

The following reply was made to PR kern/49692; it has been noted by GNATS.

From: Justin Cormack <justin%specialbusservice.com@localhost>
To: gnats-bugs%netbsd.org@localhost
Cc: kern-bug-people%netbsd.org@localhost, gnats-admin%netbsd.org@localhost, netbsd-bugs%netbsd.org@localhost
Subject: Re: kern/49692: impossibly large mmap does not fail
Date: Sun, 1 Mar 2015 10:03:22 +0000

 On 1 March 2015 at 06:40, David Holland <dholland-bugs%netbsd.org@localhost> wrote:
 > The following reply was made to PR kern/49692; it has been noted by GNATS.
 >
 > From: David Holland <dholland-bugs%netbsd.org@localhost>
 > To: gnats-bugs%NetBSD.org@localhost
 > Cc:
 > Subject: Re: kern/49692: impossibly large mmap does not fail
 > Date: Sun, 1 Mar 2015 06:35:08 +0000
 >
 >  On Tue, Feb 24, 2015 at 07:05:00PM +0000, Justin Cormack wrote:
 >   >  On 24 February 2015 at 18:53, Martin Husemann <martin%duskware.de@localhost> wrote:
 >   >  > Note that -1 is not a multiple of the machines PAGE_SIZE, so it gets
 >   >  > rounded up to the next full page.
 >   >
 >   >  Ah yes, -8192 say is ok and gives ENOMEM. But it is size_t so it is
 >   >  unsigned, so with *size_t)-1 that is an unsigned overflow to 0 that is
 >   >  taking place, which is undefined behaviour.
 >
 >  Eh wut? No it isn't. It's signed overflow that's undefined.
 
 Indeed. So it seems harmless, if unexpected, so I guess we can close it.
 
 Justin