[PATCH 4.14 021/211] pty: fix compat ioctls

[Greg Kroah-Hartman]

From: Al Viro <viro@xxxxxxxxxxxxxxxxxx>

[ Upstream commit 50f45326afab723df529eca54095e2feac24da2d ]

pointer-taking ones need compat_ptr(); int-taking one doesn't.

Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/tty/pty.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/pty.c b/drivers/tty/pty.c
index 9e26c530d2ddb..b3208b1b1028d 100644
--- a/drivers/tty/pty.c
+++ b/drivers/tty/pty.c
@@ -28,6 +28,7 @@
 #include <linux/mount.h>
 #include <linux/file.h>
 #include <linux/ioctl.h>
+#include <linux/compat.h>
 
 #undef TTY_DEBUG_HANGUP
 #ifdef TTY_DEBUG_HANGUP
@@ -488,6 +489,7 @@ static int pty_bsd_ioctl(struct tty_struct *tty,
 	return -ENOIOCTLCMD;
 }
 
+#ifdef CONFIG_COMPAT
 static long pty_bsd_compat_ioctl(struct tty_struct *tty,
 				 unsigned int cmd, unsigned long arg)
 {
@@ -495,8 +497,11 @@ static long pty_bsd_compat_ioctl(struct tty_struct *tty,
 	 * PTY ioctls don't require any special translation between 32-bit and
 	 * 64-bit userspace, they are already compatible.
 	 */
-	return pty_bsd_ioctl(tty, cmd, arg);
+	return pty_bsd_ioctl(tty, cmd, (unsigned long)compat_ptr(arg));
 }
+#else
+#define pty_bsd_compat_ioctl NULL
+#endif
 
 static int legacy_count = CONFIG_LEGACY_PTY_COUNT;
 /*
@@ -676,6 +681,7 @@ static int pty_unix98_ioctl(struct tty_struct *tty,
 	return -ENOIOCTLCMD;
 }
 
+#ifdef CONFIG_COMPAT
 static long pty_unix98_compat_ioctl(struct tty_struct *tty,
 				 unsigned int cmd, unsigned long arg)
 {
@@ -683,8 +689,12 @@ static long pty_unix98_compat_ioctl(struct tty_struct *tty,
 	 * PTY ioctls don't require any special translation between 32-bit and
 	 * 64-bit userspace, they are already compatible.
 	 */
-	return pty_unix98_ioctl(tty, cmd, arg);
+	return pty_unix98_ioctl(tty, cmd,
+		cmd == TIOCSIG ? arg : (unsigned long)compat_ptr(arg));
 }
+#else
+#define pty_unix98_compat_ioctl NULL
+#endif
 
 /**
  *	ptm_unix98_lookup	-	find a pty master
-- 
2.20.1