[PATCH] net: tipc: fix a missing check of nla_nest_start

[Kangjie Lu]

nla_nest_start could fail and requires a check. The fix returns
-EMSGSIZE if it fails.

Signed-off-by: Kangjie Lu <kjlu@xxxxxxx>
---
 net/tipc/group.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/tipc/group.c b/net/tipc/group.c
index 06fee142f09f..63f39201e41e 100644
--- a/net/tipc/group.c
+++ b/net/tipc/group.c
@@ -919,6 +919,9 @@ int tipc_group_fill_sock_diag(struct tipc_group *grp, struct sk_buff *skb)
 {
 	struct nlattr *group = nla_nest_start(skb, TIPC_NLA_SOCK_GROUP);
 
+	if (!group)
+		return -EMSGSIZE;
+
 	if (nla_put_u32(skb, TIPC_NLA_SOCK_GROUP_ID,
 			grp->type) ||
 	    nla_put_u32(skb, TIPC_NLA_SOCK_GROUP_INSTANCE,
-- 
2.17.1