Use tty kref to release the fake tty in usb_console_setup to avoid use
after free if the underlying serial driver has acquired a reference.
Fixes: 4a90f09b20f4 ("tty: usb-serial krefs")
Cc: stable <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
---
drivers/usb/serial/console.c | 13 ++++++++++---
1 file changed, 10 insertions(+), 3 deletions(-)
diff --git a/drivers/usb/serial/console.c b/drivers/usb/serial/console.c
index e56f394b58d8..4fbf7fe64860 100644
--- a/drivers/usb/serial/console.c
+++ b/drivers/usb/serial/console.c
@@ -47,6 +47,13 @@ static struct console usbcons;
*/
+static void usb_console_release_fake_tty(struct kref *kref)
+{
+ struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
+
+ kfree(tty);
+}
+
/*
* The parsing of the command line works exactly like the
* serial.c code, except that the specifier is "ttyUSB" instead
@@ -137,7 +144,6 @@ static int usb_console_setup(struct console *co, char *options)
goto reset_open_count;
}
kref_init(&tty->kref);
- tty_port_tty_set(&port->port, tty);
tty->driver = usb_serial_tty_driver;
tty->index = co->index;
init_ldsem(&tty->ldisc_sem);
@@ -145,6 +151,7 @@ static int usb_console_setup(struct console *co, char *options)
retval = -ENOMEM;
goto free_tty;
}
+ tty_port_tty_set(&port->port, tty);
}
/* only call the device specific open if this
@@ -162,7 +169,7 @@ static int usb_console_setup(struct console *co, char *options)
serial->type->set_termios(tty, port, &dummy);
tty_port_tty_set(&port->port, NULL);
- kfree(tty);
+ kref_put(&tty->kref, usb_console_release_fake_tty);
}
set_bit(ASYNCB_INITIALIZED, &port->port.flags);
}
@@ -179,7 +186,7 @@ static int usb_console_setup(struct console *co, char *options)
fail:
tty_port_tty_set(&port->port, NULL);
free_tty:
- kfree(tty);
+ kref_put(&tty->kref, usb_console_release_fake_tty);
reset_open_count:
port->port.count = 0;
usb_autopm_put_interface(serial->interface);
--
2.0.5
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