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: 51ebd31815 ("ipv6: add support of equal cost multipath (ECMP)")
Signed-off-by: David Ahern <dsahern@kernel.org>
Cc: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David Ahern 2021-12-30 17:36:33 -07:00 committed by David S. Miller
parent 664b9c4b73
commit 4619bcf913

View file

@ -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);