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  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:   Sun, 20 Sep 2020 15:55:47 +0200
From:   Arnd Bergmann <>
To:     Al Viro <>
Cc:     Christoph Hellwig <>,
        Andrew Morton <>,
        Jens Axboe <>,
        David Howells <>,
        Linux ARM <>,
        "the arch/x86 maintainers" <>,
        "" <>,
        "open list:BROADCOM NVRAM DRIVER" <>,
        Parisc List <>,
        linuxppc-dev <>,
        linux-s390 <>,
        sparclinux <>,
        linux-block <>,
        linux-scsi <>,
        Linux FS-devel Mailing List <>,
        linux-aio <>,,
        linux-arch <>,
        Linux-MM <>,
        Networking <>,,
        LSM List <>
Subject: Re: [PATCH 1/9] kernel: add a PF_FORCE_COMPAT flag

On Sun, Sep 20, 2020 at 12:09 AM Al Viro <> wrote:
> On Fri, Sep 18, 2020 at 05:16:15PM +0200, Christoph Hellwig wrote:
> > On Fri, Sep 18, 2020 at 02:58:22PM +0100, Al Viro wrote:
> > > Said that, why not provide a variant that would take an explicit
> > > "is it compat" argument and use it there?  And have the normal
> > > one pass in_compat_syscall() to that...
> >
> > That would help to not introduce a regression with this series yes.
> > But it wouldn't fix existing bugs when io_uring is used to access
> > read or write methods that use in_compat_syscall().  One example that
> > I recently ran into is drivers/scsi/sg.c.
> So screw such read/write methods - don't use them with io_uring.
> That, BTW, is one of the reasons I'm sceptical about burying the
> decisions deep into the callchain - we don't _want_ different
> data layouts on read/write depending upon the 32bit vs. 64bit
> caller, let alone the pointer-chasing garbage that is /dev/sg.

Would it be too late to limit what kind of file descriptors we allow
io_uring to read/write on?

If io_uring can get changed to return -EINVAL on trying to
read/write something other than S_IFREG file descriptors,
that particular problem space gets a lot simpler, but this
is of course only possible if nobody actually relies on it yet.


Powered by blists - more mailing lists