From b69c4236255bd8de16cd876e58c6f0867d1d78b1 Mon Sep 17 00:00:00 2001 From: Yang Yang Date: Thu, 26 Mar 2026 03:44:41 +0000 Subject: vxlan: validate ND option lengths in vxlan_na_create commit afa9a05e6c4971bd5586f1b304e14d61fb3d9385 upstream. vxlan_na_create() 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: 4b29dba9c085 ("vxlan: fix nonfunctional neigh_reduce()") Cc: stable@vger.kernel.org Reported-by: Yifan Wu Reported-by: Juefei Pu Tested-by: Ao Zhou Co-developed-by: Yuan Tan Signed-off-by: Yuan Tan Suggested-by: Xin Liu Signed-off-by: Yang Yang Reviewed-by: Ido Schimmel Acked-by: Nikolay Aleksandrov Link: https://patch.msgid.link/20260326034441.2037420-4-n05ec@lzu.edu.cn Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- drivers/net/vxlan/vxlan_core.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/net/vxlan/vxlan_core.c b/drivers/net/vxlan/vxlan_core.c index 2a140be86baf..d2d0e0bd4371 100644 --- a/drivers/net/vxlan/vxlan_core.c +++ b/drivers/net/vxlan/vxlan_core.c @@ -1965,12 +1965,14 @@ 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]) { + if (!ns->opt[i + 1] || i + (ns->opt[i + 1] << 3) > ns_olen) { kfree_skb(reply); return NULL; } if (ns->opt[i] == ND_OPT_SOURCE_LL_ADDR) { - daddr = ns->opt + i + sizeof(struct nd_opt_hdr); + if ((ns->opt[i + 1] << 3) >= + sizeof(struct nd_opt_hdr) + ETH_ALEN) + daddr = ns->opt + i + sizeof(struct nd_opt_hdr); break; } } -- cgit v1.2.3