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  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]
Date:   Wed, 22 May 2019 11:24:02 +0800
From:   Dave Young <dyoung@...hat.com>
To:     Baoquan He <bhe@...hat.com>
Cc:     linux-kernel@...r.kernel.org, tglx@...utronix.de, mingo@...nel.org,
        bp@...en8.de, hpa@...or.com, kirill.shutemov@...ux.intel.com,
        x86@...nel.org
Subject: Re: [PATCH v4 2/3] x86/kexec/64: Error out if try to jump to old
 4-level kernel from 5-level kernel

On 05/22/19 at 11:20am, Dave Young wrote:
> On 05/09/19 at 09:36am, Baoquan He wrote:
> > If the running kernel has 5-level paging activated, the 5-level paging
> > mode is preserved across kexec. If the kexec'ed kernel does not contain
> > support for handling active 5-level paging mode in the decompressor, the
> > decompressor will crash with #GP.
> > 
> > Prevent this situation at load time. If 5-level paging is active, check the
> > xloadflags whether the kexec kernel can handle 5-level paging at least in
> > the decompressor. If not, reject the load attempt and print out error
> > message.
> > 
> > Signed-off-by: Baoquan He <bhe@...hat.com>
> > Acked-by: Kirill A. Shutemov <kirill.shutemov@...ux.intel.com>
> > ---
> >  arch/x86/kernel/kexec-bzimage64.c | 5 +++++
> 
> How about the userspace kexec-tools?  It needs a similar detection, but
> I'm not sure how to detect paging mode, maybe some sysfs entry or
> vmcoreinfo in /proc/vmcore

meant /proc/kcore ...

Thanks
Dave

Powered by blists - more mailing lists