ipv6: Set errno after ip_fib_metrics_init() in ip6_route_info_create().

While creating a new IPv6, we could get a weird -ENOMEM when
RTA_NH_ID is set and either of the conditions below is true:

  1) CONFIG_IPV6_SUBTREES is enabled and rtm_src_len is specified
  2) nexthop_get() fails

e.g.)

  # strace ip -6 route add fe80::dead:beef:dead:beef nhid 1 from ::
  recvmsg(3, {msg_iov=[{iov_base=[...[
    {error=-ENOMEM, msg=[... [...]]},
    [{nla_len=49, nla_type=NLMSGERR_ATTR_MSG}, "Nexthops can not be used with so"...]
  ]], iov_len=32768}], msg_iovlen=1, msg_controllen=0, msg_flags=0}, 0) = 148

Let's set err explicitly after ip_fib_metrics_init() in
ip6_route_info_create().

Fixes: f88d8ea67fbd ("ipv6: Plumb support for nexthop object in a fib6_info")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://patch.msgid.link/20250312013854.61125-1-kuniyu@amazon.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index bc6bcf5d7133e9b1566ad8b471d781fc10b4f4c7..15ce21afc8c62819693f3f2c57f3066cca92e543 100644 (file)
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -3803,10 +3803,12 @@ static struct fib6_info *ip6_route_info_create(struct fib6_config *cfg,
        if (nh) {
                if (rt->fib6_src.plen) {
                        NL_SET_ERR_MSG(extack, "Nexthops can not be used with source routing");
+                       err = -EINVAL;
                        goto out_free;
                }
                if (!nexthop_get(nh)) {
                        NL_SET_ERR_MSG(extack, "Nexthop has been deleted");
+                       err = -ENOENT;
                        goto out_free;
                }
                rt->nh = nh;