[PATCH net] inet_diag: Fix error path to cancel the meseage in inet_req_diag_fill()

[Wang Hai]

nlmsg_cancel() needs to be called in the error path of
inet_req_diag_fill to cancel the message.

Fixes: d545caca827b ("net: inet: diag: expose the socket mark to privileged 
processes.")
Reported-by: Hulk Robot <hul...@huawei.com>
Signed-off-by: Wang Hai <wangha...@huawei.com>
---
 net/ipv4/inet_diag.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/ipv4/inet_diag.c b/net/ipv4/inet_diag.c
index 366a4507b5a3..93474b1bea4e 100644
--- a/net/ipv4/inet_diag.c
+++ b/net/ipv4/inet_diag.c
@@ -479,8 +479,10 @@ static int inet_req_diag_fill(struct sock *sk, struct 
sk_buff *skb,
        r->idiag_inode  = 0;
 
        if (net_admin && nla_put_u32(skb, INET_DIAG_MARK,
-                                    inet_rsk(reqsk)->ir_mark))
+                                    inet_rsk(reqsk)->ir_mark)) {
+               nlmsg_cancel(skb, nlh);
                return -EMSGSIZE;
+       }
 
        nlmsg_end(skb, nlh);
        return 0;
-- 
2.17.1