[Ffmpeg-cvslog] CVS: ffmpeg/libavformat rtp.c,1.24,1.25
Sat Apr 1 10:49:34 CEST 2006
2006/4/1, Rich Felker <dalias at aerifal.cx>:
> On Sat, Apr 01, 2006 at 12:34:51AM +0100, M?ns Rullg?rd wrote:
> > Luca Barbato <lu_zero at gentoo.org> writes:
> > > Richard Felker CVS wrote:
> > >> Update of /cvsroot/ffmpeg/ffmpeg/libavformat
> > >> In directory mail:/var2/tmp/cvs-serv5251
> > >> Modified Files:
> > >> rtp.c Log Message:
> > >> fix constraint violation: libavformat is not allowed to modify state of caller, including rng state
> > >> Index: rtp.c
> > >> ===================================================================
> > >> RCS file: /cvsroot/ffmpeg/ffmpeg/libavformat/rtp.c,v
> > >> retrieving revision 1.24
> > >> retrieving revision 1.25
> > >> diff -u -d -r1.24 -r1.25
> > >> --- rtp.c 1 Mar 2006 22:45:27 -0000 1.24
> > >> +++ rtp.c 30 Mar 2006 16:44:32 -0000 1.25
> > >> @@ -532,9 +532,9 @@
> > >> payload_type = RTP_PT_PRIVATE; /* private payload type */
> > >> s->payload_type = payload_type;
> > >> - s->base_timestamp = random();
> > >> + s->base_timestamp = 0; /* FIXME: was random(), what should this be? */
> > >
> > > random (check the rfc)
> > >
> > >> s->timestamp = s->base_timestamp;
> > >> - s->ssrc = random();
> > >> + s->ssrc = 0; /* FIXME: was random(), what should this be? */
> > >
> > > any value would fit, random warmly suggested
> > What sort of sick spec mandates random values? It's not like we're
> > generating encryption keys here.
> 0 is a random number, and so is any arbitrarily long string of zeros.
> It may be low probability, but if the protocol can't handle it then
> the protocol is broken.
> If someone wants to implement their own PRNG with internal (constant!)
> seed or seed provided by the called, be my guest. However, keep in
> mind the following are all illegal:
> - corrupting the calling program's state (the caller may be using
> random and the internal state it keeps and expect deterministic
> results given the same seed!)
> - use of non-reentrant library functions, since lavf muxers/demuxers
> may be used in multithreaded programs (random is non-reentrant).
> - anything that leaks information, especially the time() function.
Hum... how this patch changes anything?
The caller state is still changed. So it doesn't do whay is says it does.
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