From: Ido Schimmel Date: Mon, 1 Jun 2020 12:58:55 +0000 (+0300) Subject: vxlan: Avoid infinite loop when suppressing NS messages with invalid options X-Git-Tag: v5.10.7~2469^2~34^2 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=8066e6b449e050675df48e7c4b16c29f00507ff0;p=platform%2Fkernel%2Flinux-rpi.git vxlan: Avoid infinite loop when suppressing NS messages with invalid options 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 Acked-by: Nikolay Aleksandrov Signed-off-by: David S. Miller --- diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c index 39bc10a..d5906b4 100644 --- a/drivers/net/vxlan.c +++ b/drivers/net/vxlan.c @@ -2092,6 +2092,10 @@ 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;