linux-ext4 - Re: [PATCH 10/13] mm: Wire up MAP

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20170822093625.GD4909@quack2.suse.cz>
Date:   Tue, 22 Aug 2017 11:36:25 +0200
From:   Jan Kara <jack@...e.cz>
To:     Ross Zwisler <ross.zwisler@...ux.intel.com>
Cc:     Jan Kara <jack@...e.cz>, linux-fsdevel@...r.kernel.org,
        linux-nvdimm@...ts.01.org, Andy Lutomirski <luto@...nel.org>,
        linux-ext4@...r.kernel.org, linux-xfs@...r.kernel.org,
        Christoph Hellwig <hch@...radead.org>,
        Dan Williams <dan.j.williams@...el.com>,
        Boaz Harrosh <boazh@...app.com>
Subject: Re: [PATCH 10/13] mm: Wire up MAP_SYNC

On Mon 21-08-17 15:37:04, Ross Zwisler wrote:
> > diff --git a/mm/mmap.c b/mm/mmap.c
> > index f19efcf75418..18453c04b09f 100644
> > --- a/mm/mmap.c
> > +++ b/mm/mmap.c
> > @@ -1423,12 +1423,17 @@ unsigned long do_mmap(struct file *file, unsigned long addr,
> >  				return -ENODEV;
> >  			if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP))
> >  				return -EINVAL;
> > +			if (!(vm_flags & VM_SHARED) && (vm_flags & VM_SYNC))
> > +				return -EINVAL;
> 
> I know this will be reworked with Dan's new mmap() interface, but I was
> curious what the !(vm_flags & VM_SHARED) check here was for.  We're in a
> MAP_PRIVATE case, so is it ever possible for VM_SHARED to be set in vm_flags?
> I tried to make this happen with some various test scenarios, but wasn't able.

I was also caught by this :). Check how MAP_SHARED case above falls through
to the MAP_PRIVATE case...

								Honza
-- 
Jan Kara <jack@...e.com>
SUSE Labs, CR