[PATCH 5.4 057/154] ipv6: Set errno after ip_fib_metrics_init() in ip6_route_info_create().

Greg Kroah-Hartman
2025-04-08T12:04:50Z

From: Kuniyuki Iwashima <kuniyu@amazon.com>

[ Upstream commit 9a81fc3480bf5dbe2bf80e278c440770f6ba2692 ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/ipv6/route.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index d037979f6579f..b321cec711270 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -3729,10 +3729,12 @@ 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;
--
2.39.5