Messages in this thread Patch in this message | | | From | Eric Biggers <> | Subject | [PATCH v2 1/2] tty: fix compat TIOCGSERIAL leaking uninitialized memory | Date | Mon, 24 Feb 2020 10:20:43 -0800 |
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From: Eric Biggers <ebiggers@google.com>
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.]
Reported-by: syzbot+8da9175e28eadcb203ce@syzkaller.appspotmail.com Fixes: 77654350306a ("take compat TIOC[SG]SERIAL treatment into tty_compat_ioctl()") Cc: <stable@vger.kernel.org> # v4.20+ Signed-off-by: Eric Biggers <ebiggers@google.com> --- drivers/tty/tty_io.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c index 1fcf7ad83dfa0a..db4a13bc855ed6 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -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; -- 2.25.0.265.gbab2e86ba0-goog
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