From mboxrd@z Thu Jan  1 00:00:00 1970
From: Dan Carpenter <dan.carpenter@oracle.com>
Subject: [PATCH net] sctp: Fix a big endian bug in sctp_for_each_transport()
Date: Sat, 23 Sep 2017 13:25:37 +0300
Message-ID: <20170923102537.wra55nqyqsfoduxo@mwanda>
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Cc: Neil Horman <nhorman@tuxdriver.com>,
        "David S. Miller" <davem@davemloft.net>,
        linux-sctp@vger.kernel.org, netdev@vger.kernel.org,
        kernel-janitors@vger.kernel.org
To: Vlad Yasevich <vyasevich@gmail.com>,
        Xin Long <lucien.xin@gmail.com>
Return-path: <kernel-janitors-owner@vger.kernel.org>
Content-Disposition: inline
Sender: kernel-janitors-owner@vger.kernel.org
List-Id: netdev.vger.kernel.org

Fundamentally, the "pos" pointer points to "cb->args[2]" which is a long.
In the current code, we only use the high 32 bits and cast it as an
int.  That works on little endian systems but will fail on big endian
systems.

Fixes: d25adbeb0cdb ("sctp: fix an use-after-free issue in sctp_sock_dump")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>

diff --git a/include/net/sctp/sctp.h b/include/net/sctp/sctp.h
index d7d8cba01469..7d87439f299a 100644
--- a/include/net/sctp/sctp.h
+++ b/include/net/sctp/sctp.h
@@ -121,14 +121,14 @@ void sctp_transport_walk_stop(struct rhashtable_iter *iter);
 struct sctp_transport *sctp_transport_get_next(struct net *net,
 			struct rhashtable_iter *iter);
 struct sctp_transport *sctp_transport_get_idx(struct net *net,
-			struct rhashtable_iter *iter, int pos);
+			struct rhashtable_iter *iter, long pos);
 int sctp_transport_lookup_process(int (*cb)(struct sctp_transport *, void *),
 				  struct net *net,
 				  const union sctp_addr *laddr,
 				  const union sctp_addr *paddr, void *p);
 int sctp_for_each_transport(int (*cb)(struct sctp_transport *, void *),
 			    int (*cb_done)(struct sctp_transport *, void *),
-			    struct net *net, int *pos, void *p);
+			    struct net *net, long *pos, void *p);
 int sctp_for_each_endpoint(int (*cb)(struct sctp_endpoint *, void *), void *p);
 int sctp_get_sctp_info(struct sock *sk, struct sctp_association *asoc,
 		       struct sctp_info *info);
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index d4730ada7f32..0222743b3aa8 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -4603,7 +4603,7 @@ struct sctp_transport *sctp_transport_get_next(struct net *net,
 
 struct sctp_transport *sctp_transport_get_idx(struct net *net,
 					      struct rhashtable_iter *iter,
-					      int pos)
+					      long pos)
 {
 	void *obj = SEQ_START_TOKEN;
 
@@ -4659,7 +4659,7 @@ EXPORT_SYMBOL_GPL(sctp_transport_lookup_process);
 
 int sctp_for_each_transport(int (*cb)(struct sctp_transport *, void *),
 			    int (*cb_done)(struct sctp_transport *, void *),
-			    struct net *net, int *pos, void *p) {
+			    struct net *net, long *pos, void *p) {
 	struct rhashtable_iter hti;
 	struct sctp_transport *tsp;
 	int ret;
diff --git a/net/sctp/sctp_diag.c b/net/sctp/sctp_diag.c
index 22ed01a76b19..e9d5405aa6ac 100644
--- a/net/sctp/sctp_diag.c
+++ b/net/sctp/sctp_diag.c
@@ -493,7 +493,7 @@ static void sctp_diag_dump(struct sk_buff *skb, struct netlink_callback *cb,
 		goto done;
 
 	sctp_for_each_transport(sctp_sock_filter, sctp_sock_dump,
-				net, (int *)&cb->args[2], &commp);
+				net, &cb->args[2], &commp);
 
 done:
 	cb->args[1] = cb->args[4];