From: David Ahern <dsahern@gmail.com>
Date: Sat, 27 May 2017 16:19:28 -0600
Subject: [PATCH] net: add extack arg to lwtunnel build state
Patch-mainline: v4.13-rc1
Git-commit: 9ae287274817c032a4428fde84d1ab26d6b96761 (partial)
References: bsc#1152107 CVE-2019-16746

Pass extack arg down to lwtunnel_build_state and the build_state callbacks.
Add messages for failures in lwtunnel_build_state, and add the extarg to
nla_parse where possible in the build_state callbacks.

Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Cho, Yu-Chen <acho@suse.com>
---
 include/linux/netlink.h |   11 +++++++++++
 1 file changed, 11 insertions(+)

--- a/include/linux/netlink.h
+++ b/include/linux/netlink.h
@@ -102,6 +102,17 @@ struct netlink_ext_ack {
 		(extack)->bad_attr = (attr);		\
 } while (0)
 
+#define NL_SET_ERR_MSG_ATTR(extack, attr, msg) do {	\
+	static const char __msg[] = (msg);		\
+	struct netlink_ext_ack *__extack = (extack);	\
+							\
+	if (__extack) {					\
+		__extack->_msg = __msg;			\
+		__extack->bad_attr = (attr);		\
+	}						\
+} while (0)
+
+
 extern void netlink_kernel_release(struct sock *sk);
 extern int __netlink_change_ngroups(struct sock *sk, unsigned int groups);
 extern int netlink_change_ngroups(struct sock *sk, unsigned int groups);