[ovs-dev] [PATCH] ofp-util: Make decoding switch features harder to misuse (and fix leak).

[Ben Pfaff]

On Wed, Jan 20, 2016 at 09:47:32PM -0800, Andy Zhou wrote:
> On Wed, Jan 20, 2016 at 4:33 PM, Ben Pfaff <blp at ovn.org> wrote:
> 
> > Until now, ofputil_decode_switch_features() has put the ports from the
> > switch features message into a separate ofpbuf supplied as an argument.
> > The natural desire for a caller is to just reuse an ofpbuf that it already
> > has, and that's what one of the callers did.  This however has the
> > nonobvious effect of leaking the memory that the ofpbuf previously owned,
> > since it gets replaced by an OFPBUF_CONST-type ofpbuf.
> >
> > This commit avoids the problem by changing the interface to pull the
> > header from an ofpbuf that the caller already has.
> >
> > This fixes a leak in testcase 909 "ofproto-dpif - patch ports".
> >
> > Found by valgrind.
> >
> > Reported-by: William Tu <u9012063 at gmail.com>
> > Reported-at: http://openvswitch.org/pipermail/dev/2016-January/064771.html
> > Signed-off-by: Ben Pfaff <blp at ovn.org>
> >
> >
> Nice!
> 
> Acked-by: Andy Zhou <azhou at ovn.org>

Thanks, I applied this to master.  I didn't backport it because the only
real bug it fixes is a memory leak in ovs-ofctl, which I don't think
matters.