On 01/06/2020 15:58, Ido Schimmel wrote: > From: Ido Schimmel <idosch@xxxxxxxxxxxx> > > When neighbor suppression is enabled the bridge device might reply to > Neighbor Solicitation (NS) messages on behalf of remote hosts. > > In case the NS message includes the "Source link-layer address" option > [1], the bridge device will use the specified address as the link-layer > destination address in its reply. > > To avoid an infinite loop, break out of the options parsing loop when > encountering an option with length zero and disregard the NS message. > > This is consistent with the IPv6 ndisc code and RFC 4886 which states > that "Nodes MUST silently discard an ND packet that contains an option > with length zero" [2]. > > [1] https://tools.ietf.org/html/rfc4861#section-4.3 > [2] https://tools.ietf.org/html/rfc4861#section-4.6 > > Fixes: ed842faeb2bd ("bridge: suppress nd pkts on BR_NEIGH_SUPPRESS ports") > Signed-off-by: Ido Schimmel <idosch@xxxxxxxxxxxx> > Reported-by: Alla Segal <allas@xxxxxxxxxxxx> > Tested-by: Alla Segal <allas@xxxxxxxxxxxx> > --- > net/bridge/br_arp_nd_proxy.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/net/bridge/br_arp_nd_proxy.c b/net/bridge/br_arp_nd_proxy.c > index 37908561a64b..b18cdf03edb3 100644 > --- a/net/bridge/br_arp_nd_proxy.c > +++ b/net/bridge/br_arp_nd_proxy.c > @@ -276,6 +276,10 @@ static void br_nd_send(struct net_bridge *br, struct net_bridge_port *p, > ns_olen = request->len - (skb_network_offset(request) + > sizeof(struct ipv6hdr)) - sizeof(*ns); > for (i = 0; i < ns_olen - 1; i += (ns->opt[i + 1] << 3)) { > + if (!ns->opt[i + 1]) { > + kfree_skb(reply); > + return; > + } > if (ns->opt[i] == ND_OPT_SOURCE_LL_ADDR) { > daddr = ns->opt + i + sizeof(struct nd_opt_hdr); > break; > Good catch! Acked-by: Nikolay Aleksandrov <nikolay@xxxxxxxxxxxxxxxxxxx>
