SCTP: Check to make sure file is valid before setting timeout

In-kernel sockets created with sock_create_kern don't usually
have a file and file descriptor allocated to them.  As a result,
when SCTP tries to check the non-blocking flag, we Oops when
dereferencing a NULL file pointer.

Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 9 insertions, 1 deletions

diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 1e788279bb22..b1917f68723c 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -980,6 +980,7 @@ static int __sctp_connect(struct sock* sk,
         union sctp_addr *sa_addr;
         void *addr_buf;
         unsigned short port;
+        unsigned int f_flags = 0;
 
         sp = sctp_sk(sk);
         ep = sp->ep;
@@ -1106,7 +1107,14 @@ static int __sctp_connect(struct sock* sk,
         af->to_sk_daddr(&to, sk);
         sk->sk_err = 0;
 
-        timeo = sock_sndtimeo(sk, sk->sk_socket->file->f_flags & O_NONBLOCK);
+        /* in-kernel sockets don't generally have a file allocated to them
+         * if all they do is call sock_create_kern().
+         */
+        if (sk->sk_socket->file)
+                f_flags = sk->sk_socket->file->f_flags;
+
+        timeo = sock_sndtimeo(sk, f_flags & O_NONBLOCK);
+
         err = sctp_wait_for_connect(asoc, &timeo);
 
         /* Don't free association on exit. */