From: Pablo Neira Ayuso <pablo@netfilter.org>
Date: Tue, 30 Mar 2021 16:24:11 +0200
Subject: netfilter: flowtable: fix NAT IPv6 offload mangling
Patch-mainline: v5.12-rc8
Git-commit: 0e07e25b481aa021e4b48085ecb8a049e9614510
References: bsc#1176447

Fix out-of-bound access in the address array.

Fixes: 5c27d8d76ce8 ("netfilter: nf_flow_table_offload: add IPv6 support")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 net/netfilter/nf_flow_table_offload.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

--- a/net/netfilter/nf_flow_table_offload.c
+++ b/net/netfilter/nf_flow_table_offload.c
@@ -305,12 +305,12 @@ static void flow_offload_ipv6_mangle(str
 				     const __be32 *addr, const __be32 *mask)
 {
 	struct flow_action_entry *entry;
-	int i;
+	int i, j;
 
-	for (i = 0; i < sizeof(struct in6_addr) / sizeof(u32); i += sizeof(u32)) {
+	for (i = 0, j = 0; i < sizeof(struct in6_addr) / sizeof(u32); i += sizeof(u32), j++) {
 		entry = flow_action_entry_next(flow_rule);
 		flow_offload_mangle(entry, FLOW_ACT_MANGLE_HDR_TYPE_IP6,
-				    offset + i, &addr[i], mask);
+				    offset + i, &addr[j], mask);
 	}
 }