The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 1ff15a710a862db1101b97810af14aedc835a86a Mon Sep 17 00:00:00 2001 From: David Ahern dsahern@kernel.org Date: Thu, 30 Dec 2021 17:36:34 -0700 Subject: [PATCH] ipv6: Check attribute length for RTA_GATEWAY when deleting multipath route

Make sure RTA_GATEWAY for IPv6 multipath route has enough bytes to hold an IPv6 address.

Fixes: 6b9ea5a64ed5 ("ipv6: fix multipath route replace error recovery") Signed-off-by: David Ahern dsahern@kernel.org Cc: Roopa Prabhu roopa@nvidia.com Signed-off-by: David S. Miller davem@davemloft.net

diff --git a/net/ipv6/route.c b/net/ipv6/route.c index d16599c225b8..b311c0bc9983 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -5453,7 +5453,11 @@ static int ip6_route_multipath_del(struct fib6_config *cfg,

nla = nla_find(attrs, attrlen, RTA_GATEWAY); if (nla) { - nla_memcpy(&r_cfg.fc_gateway, nla, 16); + err = fib6_gw_from_attr(&r_cfg.fc_gateway, nla, + extack); + if (err) + return err; + r_cfg.fc_flags |= RTF_GATEWAY; } }