From: Kuniyuki Iwashima <kuniyu@amazon.com>
Date: Wed, 19 Mar 2025 23:06:49 +0000 (-0700)
Subject: nexthop: Check NLM_F_REPLACE and NHA_ID in rtm_new_nexthop().
X-Git-Tag: v6.15-rc1~160^2~26^2~3
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=53b18aa998b733d91ee4be45619d8e9738aac67c;p=thirdparty%2Fkernel%2Flinux.git

nexthop: Check NLM_F_REPLACE and NHA_ID in rtm_new_nexthop().

nexthop_add() checks if NLM_F_REPLACE is specified without
non-zero NHA_ID, which does not require RTNL.

Let's move the check to rtm_new_nexthop().

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://patch.msgid.link/20250319230743.65267-5-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---

diff --git a/net/ipv4/nexthop.c b/net/ipv4/nexthop.c
index 426cdf301c6fa..fb129c8300406 100644
--- a/net/ipv4/nexthop.c
+++ b/net/ipv4/nexthop.c
@@ -2928,11 +2928,6 @@ static struct nexthop *nexthop_add(struct net *net, struct nh_config *cfg,
 	struct nexthop *nh;
 	int err;
 
-	if (cfg->nlflags & NLM_F_REPLACE && !cfg->nh_id) {
-		NL_SET_ERR_MSG(extack, "Replace requires nexthop id");
-		return ERR_PTR(-EINVAL);
-	}
-
 	if (!cfg->nh_id) {
 		cfg->nh_id = nh_find_unused_id(net);
 		if (!cfg->nh_id) {
@@ -3247,6 +3242,12 @@ static int rtm_new_nexthop(struct sk_buff *skb, struct nlmsghdr *nlh,
 	if (err)
 		goto out;
 
+	if (cfg.nlflags & NLM_F_REPLACE && !cfg.nh_id) {
+		NL_SET_ERR_MSG(extack, "Replace requires nexthop id");
+		err = -EINVAL;
+		goto out;
+	}
+
 	err = rtm_to_nh_config_rtnl(net, tb, &cfg, extack);
 	if (err)
 		goto out;