Re: [PATCH net] udp: must lock the socket in udp_disconnect()

[David Miller <davem@davemloft.net>]

From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Thu, 20 Oct 2016 09:39:40 -0700

> From: Eric Dumazet <edumazet@google.com>
> 
> Baozeng Ding reported KASAN traces showing uses after free in
> udp_lib_get_port() and other related UDP functions.
> 
> A CONFIG_DEBUG_PAGEALLOC=y kernel would eventually crash.
> 
> I could write a reproducer with two threads doing :
> 
> static int sock_fd;
> static void *thr1(void *arg)
> {
> 	for (;;) {
> 		connect(sock_fd, (const struct sockaddr *)arg,
> 			sizeof(struct sockaddr_in));
> 	}
> }
> 
> static void *thr2(void *arg)
> {
> 	struct sockaddr_in unspec;
> 
> 	for (;;) {
> 		memset(&unspec, 0, sizeof(unspec));
> 	        connect(sock_fd, (const struct sockaddr *)&unspec,
> 			sizeof(unspec));
>         }
> }
> 
> Problem is that udp_disconnect() could run without holding socket lock,
> and this was causing list corruptions.
> 
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> Reported-by: Baozeng Ding <sploving1@gmail.com>

Applied, sounds like I should queue this up for -stable too right?