[FFmpeg-cvslog] r29509 - trunk/libswscale/swscale.c

Reimar Döffinger Reimar.Doeffinger
Fri Aug 14 13:49:27 CEST 2009

On Fri, Aug 14, 2009 at 08:31:43AM -0300, Ramiro Polla wrote:
> On Fri, Aug 14, 2009 at 8:18 AM, Reimar
> D?ffinger<Reimar.Doeffinger at gmx.de> wrote:
> > It is what it says. What you read into it is "If an implementation
> > cannot support the _exact_ combination" - which I admit is _one_
> > reasonable way to read it, but not in the context...
> > E.g. by supporting READ+WRITE+EXEC at once an architecture also
> > supports READ or READ+WRITE or READ+EXEC etc., it just does not
> > deny _all_ other types of access.
> > Whereas an architecture where e.g. all code is in ROM indeed really
> > and in no way can support anything with WRITE+EXEC.
> Hmm, I just remembered this code is strictly x86+mmx2. It has worked
> up to now. We could remove READ and wait for a possible regression, or
> leave it the way we know it works. I prefer just leaving it as is.

Uh, what "has worked up to now" is READ+WRITE+EXEC.
Now it is READ+WRITE which is supported by x86 but until NX was
introduced (and then only when PAE is used) it is always
So if any implementor went with M?ns interpretation the current code
couldn't work on any system that doesn't support NX+PAE.
Now I admit that removing read in difference to EXEC does probably
not provide any relevant security advantage though, I still consider
it more correct anyway.

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