Commit 85083796 authored Mar 26, 2026 by Yang Yang Committed by Jakub Kicinski Mar 27, 2026

bridge: br_nd_send: validate ND option lengths



br_nd_send() walks ND options according to option-provided lengths.
A malformed option can make the parser advance beyond the computed
option span or use a too-short source LLADDR option payload.

Validate option lengths against the remaining NS option area before
advancing, and only read source LLADDR when the option is large enough
for an Ethernet address.

Fixes: ed842fae ("bridge: suppress nd pkts on BR_NEIGH_SUPPRESS ports")
Cc: stable@vger.kernel.org
Reported-by: Yifan Wu <yifanwucs@gmail.com>
Reported-by: Juefei Pu <tomapufckgml@gmail.com>
Tested-by: Ao Zhou <n05ec@lzu.edu.cn>
Co-developed-by: Yuan Tan <tanyuan98@outlook.com>
Signed-off-by: Yuan Tan <tanyuan98@outlook.com>
Suggested-by: Xin Liu <bird@lzu.edu.cn>
Signed-off-by: Yang Yang <n05ec@lzu.edu.cn>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
Link: https://patch.msgid.link/20260326034441.2037420-3-n05ec@lzu.edu.cn


Signed-off-by: Jakub Kicinski <kuba@kernel.org>

parent a01aee7c

net/bridge/br_arp_nd_proxy.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -288,11 +288,13 @@ 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]) {
		if (!ns->opt[i + 1] \|\| i + (ns->opt[i + 1] << 3) > ns_olen) {
		kfree_skb(reply);
		return;
		}
		if (ns->opt[i] == ND_OPT_SOURCE_LL_ADDR) {
		if ((ns->opt[i + 1] << 3) >=
		sizeof(struct nd_opt_hdr) + ETH_ALEN)
		daddr = ns->opt + i + sizeof(struct nd_opt_hdr);
		break;
		}