[PATCH AUTOSEL 4.19 008/237] pty: fix compat ioctls

Sasha Levin
2019-11-16T16:28:28Z

From: Al Viro <viro@zeniv.linux.org.uk>

[ Upstream commit 50f45326afab723df529eca54095e2feac24da2d ]

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

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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 678406e0948b2..00099a8439d21 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