blob: a6e1a3a9338052f751e6c0c1f0cb764240de1e4b [file] [log] [blame]
From f5fa846bb8484be917546617778c3b8772233092 Mon Sep 17 00:00:00 2001
From: Eric Biggers <>
Date: Mon, 24 Feb 2020 10:20:43 -0800
Subject: [PATCH] tty: fix compat TIOCGSERIAL leaking uninitialized memory
commit 17329563a97df3ba474eca5037c1336e46e14ff8 upstream.
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.]
Fixes: 77654350306a ("take compat TIOC[SG]SERIAL treatment into tty_compat_ioctl()")
Cc: <> # v4.20+
Signed-off-by: Eric Biggers <>
Acked-by: Jiri Slaby <>
Signed-off-by: Greg Kroah-Hartman <>
Signed-off-by: Paul Gortmaker <>
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 033ac7e6a70d..ca439e220f7e 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -2729,7 +2729,9 @@ 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;