On 01/06/2020 15:58, Ido Schimmel wrote: > From: Ido Schimmel <idosch@xxxxxxxxxxxx> > > When proxy mode is enabled the vxlan 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 vxlan 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: 4b29dba9c085 ("vxlan: fix nonfunctional neigh_reduce()") > Signed-off-by: Ido Schimmel <idosch@xxxxxxxxxxxx> > --- > drivers/net/vxlan.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c > index a5b415fed11e..779e56c43d27 100644 > --- a/drivers/net/vxlan.c > +++ b/drivers/net/vxlan.c > @@ -1924,6 +1924,10 @@ static struct sk_buff *vxlan_na_create(struct sk_buff *request, > 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 NULL; > + } > if (ns->opt[i] == ND_OPT_SOURCE_LL_ADDR) { > daddr = ns->opt + i + sizeof(struct nd_opt_hdr); > break; > Acked-by: Nikolay Aleksandrov <nikolay@xxxxxxxxxxxxxxxxxxx>