patch "tty: fix compat TIOCGSERIAL leaking uninitialized memory" added to tty-linus

This is a note to let you know that I've just added the patch titled

tty: fix compat TIOCGSERIAL leaking uninitialized memory

to my tty git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git
in the tty-linus branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the next -rc kernel release.

If you have any questions about this process, please let me know.

From 17329563a97df3ba474eca5037c1336e46e14ff8 Mon Sep 17 00:00:00 2001
From: Eric Biggers <[email protected]>
Date: Mon, 24 Feb 2020 10:20:43 -0800
Subject: tty: fix compat TIOCGSERIAL leaking uninitialized memory

Commit 77654350306a ("take compat TIOC[SG]SERIAL treatment into tty_compat_ioctl()") changed the compat version of TIOCGSERIAL to start copying a whole 'serial_struct32' to userspace rather than individual fields, but failed to initialize all padding and fields -- namely the hole after the 'iomem_reg_shift' field, and the 'reserved' field.

Fix this by initializing the struct to zero.

[v2: use sizeof, and convert the adjacent line for consistency.]

---
 drivers/tty/tty_io.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

index 1fcf7ad83dfa..db4a13bc855e 100644
@@ -2730,7 +2730,9 @@ static int compat_tty_tiocgserial(struct tty_struct *tty,
 	struct serial_struct32 v32;
 	struct serial_struct v;
 	int err;
-	memset(&v, 0, sizeof(struct serial_struct));
+
+	memset(&v, 0, sizeof(v));
+	memset(&v32, 0, sizeof(v32));
 
 	if (!tty->ops->set_serial)
 		return -ENOTTY;

2.25.1