Subject: [PATCH 4.14 46/71] af_unix: add compat_ioctl support

From: Greg Kroah-Hartman <[email-masked]>
Date: Fri, 17 Jan 2020 00:18:44 +0100

From: Arnd Bergmann <[email-masked]>

commit 5f6beb9e0f633f3cc845cdd67973c506372931b4 upstream.

The af_unix protocol family has a custom ioctl command (inexplicibly
based on SIOCPROTOPRIVATE), but never had a compat_ioctl handler for
32-bit applications.

Since all commands are compatible here, add a trivial wrapper that
performs the compat_ptr() conversion for SIOCOUTQ/SIOCINQ.  SIOCUNIXFILE
does not use the argument, but it doesn't hurt to also use compat_ptr()
here.

Fixes: ba94f3088b79 ("unix: add ioctl to open a unix socket file with O_PATH")
Cc: [email-masked]
Cc: "David S. Miller" <[email-masked]>
Cc: Eric Dumazet <[email-masked]>
Signed-off-by: Arnd Bergmann <[email-masked]>
Signed-off-by: Greg Kroah-Hartman <[email-masked]>

---
 net/unix/af_unix.c |   19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -644,6 +644,9 @@ static unsigned int unix_poll(struct fil
 static unsigned int unix_dgram_poll(struct file *, struct socket *,
 				    poll_table *);
 static int unix_ioctl(struct socket *, unsigned int, unsigned long);
+#ifdef CONFIG_COMPAT
+static int unix_compat_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg);
+#endif
 static int unix_shutdown(struct socket *, int);
 static int unix_stream_sendmsg(struct socket *, struct msghdr *, size_t);
 static int unix_stream_recvmsg(struct socket *, struct msghdr *, size_t, int);
@@ -685,6 +688,9 @@ static const struct proto_ops unix_strea
 	.getname =	unix_getname,
 	.poll =		unix_poll,
 	.ioctl =	unix_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl =	unix_compat_ioctl,
+#endif
 	.listen =	unix_listen,
 	.shutdown =	unix_shutdown,
 	.setsockopt =	sock_no_setsockopt,
@@ -708,6 +714,9 @@ static const struct proto_ops unix_dgram
 	.getname =	unix_getname,
 	.poll =		unix_dgram_poll,
 	.ioctl =	unix_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl =	unix_compat_ioctl,
+#endif
 	.listen =	sock_no_listen,
 	.shutdown =	unix_shutdown,
 	.setsockopt =	sock_no_setsockopt,
@@ -730,6 +739,9 @@ static const struct proto_ops unix_seqpa
 	.getname =	unix_getname,
 	.poll =		unix_dgram_poll,
 	.ioctl =	unix_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl =	unix_compat_ioctl,
+#endif
 	.listen =	unix_listen,
 	.shutdown =	unix_shutdown,
 	.setsockopt =	sock_no_setsockopt,
@@ -2650,6 +2662,13 @@ static int unix_ioctl(struct socket *soc
 	return err;
 }
 
+#ifdef CONFIG_COMPAT
+static int unix_compat_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
+{
+	return unix_ioctl(sock, cmd, (unsigned long)compat_ptr(arg));
+}
+#endif
+
 static unsigned int unix_poll(struct file *file, struct socket *sock, poll_table *wait)
 {
 	struct sock *sk = sock->sk;