linux-kernel - RE: [RFC PATCH 0/5] madvise MADV

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 for Android: free password hash cracker in your pocket

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

Date:   Sat, 14 Aug 2021 20:07:42 +0000
From:   David Laight <David.Laight@...LAB.COM>
To:     'Khalid Aziz' <khalid.aziz@...cle.com>,
        "Longpeng (Mike, Cloud Infrastructure Service Product Dept.)" 
        <longpeng2@...wei.com>, Matthew Wilcox <willy@...radead.org>
CC:     Steven Sistare <steven.sistare@...cle.com>,
        Anthony Yznaga <anthony.yznaga@...cle.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-mm@...ck.org" <linux-mm@...ck.org>,
        "Gonglei (Arei)" <arei.gonglei@...wei.com>
Subject: RE: [RFC PATCH 0/5] madvise MADV_DOEXEC

...
> > > > Let me describe my use case more clearly (just ignore if you're not
> > > > interested in it):
> > > >
> > > > 1. Prog A mmap() 4GB memory (anon or file-mapping), suppose the
> > > > allocated VA range is [0x40000000,0x140000000)
> > > >
> > > > 2. Prog A specifies [0x48000000,0x50000000) and
> > > > [0x80000000,0x100000000) will be shared by its child.
> > > >
> > > > 3. Prog A fork() Prog B and then Prog B exec() a new ELF binary.
> > > >
> > > > 4. Prog B notice the shared ranges (e.g. by input parameters or
> > > > ...)
> > > > and remap them to a continuous VA range.

Remapping to contiguous VA is going to be difficult in the
general case for (IIRC) VIVT caches.
The required cache coherence may only be attainable by
using uncached mappings.

	David

-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)