From 7e867f5d66510cb70bfae7be2d4ec28351934f66 Mon Sep 17 00:00:00 2001
From: Ian Pilcher <arequipeno@gmail.com>
Date: Tue, 18 Oct 2022 11:45:28 -0500
Subject: libnftnl: Fix res_id byte order

The res_id member of struct nfgenmsg is supposed to be in network
byte order (big endian).  Call htons() in __nftnl_nlmsg_build_hdr()
to ensure that this is true on little endian systems.

There is a kernel workaround that was introduced in 4.3 to address
this issue:

 commit a9de9777d613500b089a7416f936bf3ae5f070d2
 Author: Pablo Neira Ayuso <pablo@netfilter.org>
 Date:   Fri Aug 28 21:01:43 2015 +0200

    netfilter: nfnetlink: work around wrong endianess in res_id field

And current oldest stable kernel branch in 4.9, merge this to fix
the incorrect endianness from userspace.

Signed-off-by: Ian Pilcher <arequipeno@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 src/common.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

(limited to 'src')

diff --git a/src/common.c b/src/common.c
index 2d83c12..08572c3 100644
--- a/src/common.c
+++ b/src/common.c
@@ -10,6 +10,7 @@
 #include <stdlib.h>
 #include <sys/socket.h>
 #include <time.h>
+#include <arpa/inet.h>
 #include <linux/netlink.h>
 #include <linux/netfilter/nfnetlink.h>
 #include <linux/netfilter/nf_tables.h>
@@ -37,7 +38,7 @@ static struct nlmsghdr *__nftnl_nlmsg_build_hdr(char *buf, uint16_t type,
 	nfh = mnl_nlmsg_put_extra_header(nlh, sizeof(struct nfgenmsg));
 	nfh->nfgen_family = family;
 	nfh->version = NFNETLINK_V0;
-	nfh->res_id = res_id;
+	nfh->res_id = htons(res_id);
 
 	return nlh;
 }
-- 
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