Commit 4619bcf9 authored by David Ahern's avatar David Ahern Committed by David S. Miller
Browse files

ipv6: Check attribute length for RTA_GATEWAY in multipath route 



Commit referenced in the Fixes tag used nla_memcpy for RTA_GATEWAY as
does the current nla_get_in6_addr. nla_memcpy protects against accessing
memory greater than what is in the attribute, but there is no check
requiring the attribute to have an IPv6 address. Add it.

Fixes: 51ebd318 ("ipv6: add support of equal cost multipath (ECMP)")
Signed-off-by: default avatarDavid Ahern <dsahern@kernel.org>
Cc: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 664b9c4b

net/ipv6/route.c

+20 −1
Original line number Diff line number Diff line
@@ -5224,6 +5224,19 @@ static bool ip6_route_mpath_should_notify(const struct fib6_info *rt) 
	return should_notify;

}



static int fib6_gw_from_attr(struct in6_addr *gw, struct nlattr *nla,

			     struct netlink_ext_ack *extack)

{

	if (nla_len(nla) < sizeof(*gw)) {

		NL_SET_ERR_MSG(extack, "Invalid IPv6 address in RTA_GATEWAY");

		return -EINVAL;

	}



	*gw = nla_get_in6_addr(nla);



	return 0;

}



static int ip6_route_multipath_add(struct fib6_config *cfg,

				   struct netlink_ext_ack *extack)

{
@@ -5264,7 +5277,13 @@ static int ip6_route_multipath_add(struct fib6_config *cfg, 


			nla = nla_find(attrs, attrlen, RTA_GATEWAY);

			if (nla) {

				r_cfg.fc_gateway = nla_get_in6_addr(nla);

				int ret;



				ret = fib6_gw_from_attr(&r_cfg.fc_gateway, nla,

							extack);

				if (ret)

					return ret;



				r_cfg.fc_flags |= RTF_GATEWAY;

			}

			r_cfg.fc_encap = nla_find(attrs, attrlen, RTA_ENCAP);