Re: [PATCH net] dccp: fix a memleak that dccp_ipv6 doesn't put reqsk properly

[David Miller <davem@davemloft.net>]

From: Xin Long <lucien.xin@gmail.com>
Date: Wed, 26 Jul 2017 14:19:09 +0800

> In dccp_v6_conn_request, after reqsk gets alloced and hashed into
> ehash table, reqsk's refcnt is set 3. one is for req->rsk_timer,
> one is for hlist, and the other one is for current using.
> 
> The problem is when dccp_v6_conn_request returns and finishes using
> reqsk, it doesn't put reqsk. This will cause reqsk refcnt leaks and
> reqsk obj never gets freed.
> 
> Jianlin found this issue when running dccp_memleak.c in a loop, the
> system memory would run out.
> 
> dccp_memleak.c:
>   int s1 = socket(PF_INET6, 6, IPPROTO_IP);
>   bind(s1, &sa1, 0x20);
>   listen(s1, 0x9);
>   int s2 = socket(PF_INET6, 6, IPPROTO_IP);
>   connect(s2, &sa1, 0x20);
>   close(s1);
>   close(s2);
> 
> This patch is to put the reqsk before dccp_v6_conn_request returns,
> just as what tcp_conn_request does.
> 
> Reported-by: Jianlin Shi <jishi@redhat.com>
> Signed-off-by: Xin Long <lucien.xin@gmail.com>

Applied and queued up for -stable.