Re: mmap breakage?

From: Alexander Kabaev (ak03_at_gte.com)
Date: 04/05/04

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    Date: Mon, 5 Apr 2004 00:56:18 -0400
To: Alan Cox <alc@cs.rice.edu>

    On Sun, Apr 04, 2004 at 11:20:10PM -0500, Alan Cox wrote:
    > On Mon, Apr 05, 2004 at 12:11:47AM -0400, Alexander Kabaev wrote:
    > > On Sun, Apr 04, 2004 at 03:12:51PM -0500, Alan Cox wrote:
    > > > Alfred,
    > > >
    > > > Please try the attached patch. This problems appears to be a
    > > > consequence of vm/vm_mmap.c revision 1.180, where as part of a much
    > > > needed code reorganization for locking the check for the /dev/zero
    > > > special case got placed after the permissions check for the general
    > > > case. This patch simply delays the permissions check for devices
    > > > until you have the necessary lock to also check for /dev/zero.
    > > >
    > > > Since kan@ authored the reorganization, I'm cc:'ing him on this
    > > > message for purposes of obtaining a review. (At least one comment
    > > > should be updated to reflect my code changes.)
    > > >
    > > > Regards,
    > > > Alan
    > > >
    > > >
    > > Alan, Alfred,
    > >
    > > I had the following patch which is currently pending a review by
    > > Peter Wemm. I meant to commit it on Friday, but ran out of time:
    > >
    > >
    > > http://perforce.freebsd.org/chv.cgi?CH=50213
    > >
    >
    > I believe that there is a problem with this patch. Specifically, if
    > maxprot is set to VM_PROT_ALL for devices in mmap(), then the security
    > check in vm_mmap_vnode() has no effect. Please take a look at the
    > entirety of the changes that I propose to mmap().
    >
    > Regards,
    > Alan
    There is a problem indeed. I committed your (correct!) patch instead.
    Thanks! 

    -- 
Alexander Kabaev
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