Merge tag 'nf-25-05-08' of git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf

Pablo Neira Ayuso says:

====================
Netfilter/IPVS fixes for net

The following patchset contain Netfilter/IPVS fixes for net:

1) Fix KMSAN uninit-value in do_output_route4, reported by syzbot.
   Patch from Julian Anastasov.

2) ipset hashtable set type breaks up the hashtable into regions of
   2^10 buckets. Fix the macro that determines the hashtable lock
   region to protect concurrent updates. From Jozsef Kadlecsik.

* tag 'nf-25-05-08' of git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf:
  netfilter: ipset: fix region locking in hash types
  ipvs: fix uninit-value for saddr in do_output_route4
====================

Link: https://patch.msgid.link/20250507221952.86505-1-pablo@netfilter.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: kuba-moo

net/netfilter/ipset/ip_set_hash_gen.h

@@ -64,7 +64,7 @@ struct hbucket {
 #define ahash_sizeof_regions(htable_bits)		\
 	(ahash_numof_locks(htable_bits) * sizeof(struct ip_set_region))
 #define ahash_region(n, htable_bits)		\
-	((n) % ahash_numof_locks(htable_bits))
+	((n) / jhash_size(HTABLE_REGION_BITS))
 #define ahash_bucket_start(h,  htable_bits)	\
 	((htable_bits) < HTABLE_REGION_BITS ? 0	\
 		: (h) * jhash_size(HTABLE_REGION_BITS))

net/netfilter/ipvs/ip_vs_xmit.c

@@ -119,13 +119,12 @@ __mtu_check_toobig_v6(const struct sk_buff *skb, u32 mtu)
 	return false;
 }
 
-/* Get route to daddr, update *saddr, optionally bind route to saddr */
+/* Get route to daddr, optionally bind route to saddr */
 static struct rtable *do_output_route4(struct net *net, __be32 daddr,
-				       int rt_mode, __be32 *saddr)
+				       int rt_mode, __be32 *ret_saddr)
 {
 	struct flowi4 fl4;
 	struct rtable *rt;
-	bool loop = false;
 
 	memset(&fl4, 0, sizeof(fl4));
 	fl4.daddr = daddr;
@@ -135,23 +134,17 @@ static struct rtable *do_output_route4(struct net *net, __be32 daddr,
 retry:
 	rt = ip_route_output_key(net, &fl4);
 	if (IS_ERR(rt)) {
-		/* Invalid saddr ? */
-		if (PTR_ERR(rt) == -EINVAL && *saddr &&
-		    rt_mode & IP_VS_RT_MODE_CONNECT && !loop) {
-			*saddr = 0;
-			flowi4_update_output(&fl4, 0, daddr, 0);
-			goto retry;
-		}
 		IP_VS_DBG_RL("ip_route_output error, dest: %pI4\n", &daddr);
 		return NULL;
-	} else if (!*saddr && rt_mode & IP_VS_RT_MODE_CONNECT && fl4.saddr) {
+	}
+	if (rt_mode & IP_VS_RT_MODE_CONNECT && fl4.saddr) {
 		ip_rt_put(rt);
-		*saddr = fl4.saddr;
 		flowi4_update_output(&fl4, 0, daddr, fl4.saddr);
-		loop = true;
+		rt_mode = 0;
 		goto retry;
 	}
-	*saddr = fl4.saddr;
+	if (ret_saddr)
+		*ret_saddr = fl4.saddr;
 	return rt;
 }
 
@@ -344,19 +337,15 @@ __ip_vs_get_out_rt(struct netns_ipvs *ipvs, int skb_af, struct sk_buff *skb,
 		if (ret_saddr)
 			*ret_saddr = dest_dst->dst_saddr.ip;
 	} else {
-		__be32 saddr = htonl(INADDR_ANY);
-
 		noref = 0;
 
 		/* For such unconfigured boxes avoid many route lookups
 		 * for performance reasons because we do not remember saddr
 		 */
 		rt_mode &= ~IP_VS_RT_MODE_CONNECT;
-		rt = do_output_route4(net, daddr, rt_mode, &saddr);
+		rt = do_output_route4(net, daddr, rt_mode, ret_saddr);
 		if (!rt)
 			goto err_unreach;
-		if (ret_saddr)
-			*ret_saddr = saddr;
 	}
 
 	local = (rt->rt_flags & RTCF_LOCAL) ? 1 : 0;