Re: Fixing DRM after phk's drive-by axeing

From: Jeremy Messenger (mezz7_at_cox.net)
Date: 03/29/05

  • Next message: John Baldwin: "Re: Fixing DRM after phk's drive-by axeing" 
    Date: Mon, 28 Mar 2005 16:39:55 -0600
To: "John Baldwin" <jhb@freebsd.org>

    On Mon, 28 Mar 2005 17:34:45 -0500, John Baldwin <jhb@FreeBSD.org> wrote:

    > I have a commit-ready version of the vm_mmap() changes I made to get drm
    > to
    > work happily with the newer, cleaner cdev stuff that phk has been
    > working on.
    > Basically, I've changed vm_mmap() so that it can accept either a vnode
    > or a
    > cdev as its handle argument rather than just vnodes. For the cdev case,
    > it
    > calls a vm_mmap_cdev() function that is a cut down version of
    > vm_mmap_vnode(). One thing to note is that this case loses the MAC
    > check for
    > this type of mmap() (currently only done from DRM) since MAC only checks
    > mmaps for vnodes. If cdev were to grow a label, then a mmap check for
    > the
    > cdev could be added I suppose, though the case of a mmap'ing a vnode that
    > maps to a cdev would have to be adjusted to make that extra call as well.
    >
    > The first cut at the patch added a new MAP_CDEV flag to vm_mmap() that
    > specified that the handle argument was a cdev rather than a vnode.
    > However,
    > this method requires that any kernel code that calls vm_mmap() passing in
    > flags from userland has to verify that MAP_CDEV isn't passed in from
    > userland
    > to avoid potential DOSs from random user processes that result in kernel
    > panics. Thus, I decided to change vm_mmap() to instead take a objtype_t
    > parameter that specifies what type of object the handle argument is.
    > Thus,
    > for MAP_ANON, the code passes in OBJT_DEFAULT, for vnodes OBJT_VNODE,
    > and for
    > cdevs (in drm) OBJT_DEVICE. I've stuck the patch at
    > http://www.FreeBSD.org/~jhb/patches/mmap_cdev3.patch and am using it
    > locally

    You had it typo for ',' instead '.'.. mmap_cdev3,patch

    http://people.freebsd.org/~jhb/patches/mmap_cdev3,patch

    Cheers,
    Mezz

    > to get X working on my laptop. Any objections or bikeshed^Wsuggestions
    > for a
    > different interface? 

    -- 
mezz7@cox.net  -  mezz@FreeBSD.org
FreeBSD GNOME Team
http://www.FreeBSD.org/gnome/  -  gnome@FreeBSD.org
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  • Next message: John Baldwin: "Re: Fixing DRM after phk's drive-by axeing"