[ovs-dev] [PATCH] ofp-util: Fix buffer overrread in ofputil_pull_queue_get_config_reply10().

Ben Pfaff blp at ovn.org
Thu May 25 21:28:09 UTC 2017


On Sat, May 20, 2017 at 08:59:39PM -0700, Greg Rose wrote:
> On Sat, 2017-05-20 at 16:41 -0700, Ben Pfaff wrote:
> > msg->size isn't the relevant measurement here because we're only supposed
> > to read 'len' bytes.  Reading more than that causes 'len' to underflow to a
> > large number at the end of the loop.
> > 
> > Reported-by: Bhargava Shastry <bshastry at sec.t-labs.tu-berlin.de>
> > Signed-off-by: Ben Pfaff <blp at ovn.org>
> > ---
> >  lib/ofp-util.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/lib/ofp-util.c b/lib/ofp-util.c
> > index bdf89b6c3017..f05ca398c13e 100644
> > --- a/lib/ofp-util.c
> > +++ b/lib/ofp-util.c
> > @@ -2610,7 +2610,7 @@ ofputil_pull_queue_get_config_reply10(struct ofpbuf *msg,
> >  
> >          hdr = ofpbuf_at_assert(msg, 0, sizeof *hdr);
> >          prop_len = ntohs(hdr->len);
> > -        if (prop_len < sizeof *hdr || prop_len > msg->size || prop_len % 8) {
> > +        if (prop_len < sizeof *hdr || prop_len > len || prop_len % 8) {
> >              return OFPERR_OFPBRC_BAD_LEN;
> >          }
> >  
> 
> Yikes.  Good catch.
> 
> Acked-by: Greg Rose <gvrose8192 at gmail.com>

Thanks!  I applied this to master, branch-2.7, branch-2.6, and branch-2.5.


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